Merge pull request #26187 from hashicorp/alisdair/concise-diff

command: Add experimental concise diff renderer

backend/local/backend_plan_test.go

@@ -289,12 +289,9 @@ Terraform will perform the following actions:
 
   # test_instance.foo is tainted, so must be replaced
 -/+ resource "test_instance" "foo" {
-        ami = "bar"
+        # (1 unchanged attribute hidden)
 
-        network_interface {
+        # (1 unchanged block hidden)
-            description  = "Main network interface"
-            device_index = 0
-        }
     }
 
 Plan: 1 to add, 0 to change, 1 to destroy.`
@@ -468,12 +465,9 @@ Terraform will perform the following actions:
 
   # test_instance.foo is tainted, so must be replaced
 +/- resource "test_instance" "foo" {
-        ami = "bar"
+        # (1 unchanged attribute hidden)
 
-        network_interface {
+        # (1 unchanged block hidden)
-            description  = "Main network interface"
-            device_index = 0
-        }
     }
 
 Plan: 1 to add, 0 to change, 1 to destroy.`

command/format/diff.go

@@ -14,6 +14,7 @@ import (
 
 	"github.com/hashicorp/terraform/addrs"
 	"github.com/hashicorp/terraform/configs/configschema"
+	"github.com/hashicorp/terraform/helper/experiment"
 	"github.com/hashicorp/terraform/plans"
 	"github.com/hashicorp/terraform/plans/objchange"
 	"github.com/hashicorp/terraform/states"
@@ -98,6 +99,7 @@ func ResourceChange(
 		color:           color,
 		action:          change.Action,
 		requiredReplace: change.RequiredReplace,
+		concise:         experiment.Enabled(experiment.X_concise_diff),
 	}
 
 	// Most commonly-used resources have nested blocks that result in us
@@ -123,10 +125,10 @@ func ResourceChange(
 	changeV.Change.Before = objchange.NormalizeObjectFromLegacySDK(changeV.Change.Before, schema)
 	changeV.Change.After = objchange.NormalizeObjectFromLegacySDK(changeV.Change.After, schema)
 
-	bodyWritten := p.writeBlockBodyDiff(schema, changeV.Before, changeV.After, 6, path)
+	result := p.writeBlockBodyDiff(schema, changeV.Before, changeV.After, 6, path)
-	if bodyWritten {
+	if result.bodyWritten {
-		buf.WriteString("\n")
+		p.buf.WriteString("\n")
-		buf.WriteString(strings.Repeat(" ", 4))
+		p.buf.WriteString(strings.Repeat(" ", 4))
 	}
 	buf.WriteString("}\n")
 
@@ -144,9 +146,10 @@ func OutputChanges(
 ) string {
 	var buf bytes.Buffer
 	p := blockBodyDiffPrinter{
-		buf:    &buf,
+		buf:     &buf,
-		color:  color,
+		color:   color,
-		action: plans.Update, // not actually used in this case, because we're not printing a containing block
+		action:  plans.Update, // not actually used in this case, because we're not printing a containing block
+		concise: experiment.Enabled(experiment.X_concise_diff),
 	}
 
 	// We're going to reuse the codepath we used for printing resource block
@@ -189,16 +192,24 @@ type blockBodyDiffPrinter struct {
 	color           *colorstring.Colorize
 	action          plans.Action
 	requiredReplace cty.PathSet
+	concise         bool
+}
+
+type blockBodyDiffResult struct {
+	bodyWritten       bool
+	skippedAttributes int
+	skippedBlocks     int
 }
 
 const forcesNewResourceCaption = " [red]# forces replacement[reset]"
 
 // writeBlockBodyDiff writes attribute or block differences
 // and returns true if any differences were found and written
-func (p *blockBodyDiffPrinter) writeBlockBodyDiff(schema *configschema.Block, old, new cty.Value, indent int, path cty.Path) bool {
+func (p *blockBodyDiffPrinter) writeBlockBodyDiff(schema *configschema.Block, old, new cty.Value, indent int, path cty.Path) blockBodyDiffResult {
 	path = ctyEnsurePathCapacity(path, 1)
 
-	bodyWritten := false
+	result := blockBodyDiffResult{}
+
 	blankBeforeBlocks := false
 	{
 		attrNames := make([]string, 0, len(schema.Attributes))
@@ -229,8 +240,21 @@ func (p *blockBodyDiffPrinter) writeBlockBodyDiff(schema *configschema.Block, ol
 			oldVal := ctyGetAttrMaybeNull(old, name)
 			newVal := ctyGetAttrMaybeNull(new, name)
 
-			bodyWritten = true
+			result.bodyWritten = true
-			p.writeAttrDiff(name, attrS, oldVal, newVal, attrNameLen, indent, path)
+			skipped := p.writeAttrDiff(name, attrS, oldVal, newVal, attrNameLen, indent, path)
+			if skipped {
+				result.skippedAttributes++
+			}
+		}
+
+		if result.skippedAttributes > 0 {
+			noun := "attributes"
+			if result.skippedAttributes == 1 {
+				noun = "attribute"
+			}
+			p.buf.WriteString("\n")
+			p.buf.WriteString(strings.Repeat(" ", indent+2))
+			p.buf.WriteString(p.color.Color(fmt.Sprintf("[dark_gray]# (%d unchanged %s hidden)[reset]", result.skippedAttributes, noun)))
 		}
 	}
 
@@ -246,21 +270,31 @@ func (p *blockBodyDiffPrinter) writeBlockBodyDiff(schema *configschema.Block, ol
 			oldVal := ctyGetAttrMaybeNull(old, name)
 			newVal := ctyGetAttrMaybeNull(new, name)
 
-			bodyWritten = true
+			result.bodyWritten = true
-			p.writeNestedBlockDiffs(name, blockS, oldVal, newVal, blankBeforeBlocks, indent, path)
+			skippedBlocks := p.writeNestedBlockDiffs(name, blockS, oldVal, newVal, blankBeforeBlocks, indent, path)
+			if skippedBlocks > 0 {
+				result.skippedBlocks += skippedBlocks
+			}
 
 			// Always include a blank for any subsequent block types.
 			blankBeforeBlocks = true
 		}
+		if result.skippedBlocks > 0 {
+			noun := "blocks"
+			if result.skippedBlocks == 1 {
+				noun = "block"
+			}
+			p.buf.WriteString("\n")
+			p.buf.WriteString(strings.Repeat(" ", indent+2))
+			p.buf.WriteString(p.color.Color(fmt.Sprintf("[dark_gray]# (%d unchanged %s hidden)[reset]", result.skippedBlocks, noun)))
+		}
 	}
 
-	return bodyWritten
+	return result
 }
 
-func (p *blockBodyDiffPrinter) writeAttrDiff(name string, attrS *configschema.Attribute, old, new cty.Value, nameLen, indent int, path cty.Path) {
+func (p *blockBodyDiffPrinter) writeAttrDiff(name string, attrS *configschema.Attribute, old, new cty.Value, nameLen, indent int, path cty.Path) bool {
 	path = append(path, cty.GetAttrStep{Name: name})
-	p.buf.WriteString("\n")
-	p.buf.WriteString(strings.Repeat(" ", indent))
 	showJustNew := false
 	var action plans.Action
 	switch {
@@ -276,6 +310,12 @@ func (p *blockBodyDiffPrinter) writeAttrDiff(name string, attrS *configschema.At
 		action = plans.Update
 	}
 
+	if action == plans.NoOp && p.concise && !identifyingAttribute(name, attrS) {
+		return true
+	}
+
+	p.buf.WriteString("\n")
+	p.buf.WriteString(strings.Repeat(" ", indent))
 	p.writeActionSymbol(action)
 
 	p.buf.WriteString(p.color.Color("[bold]"))
@@ -300,13 +340,16 @@ func (p *blockBodyDiffPrinter) writeAttrDiff(name string, attrS *configschema.At
 			p.writeValueDiff(old, new, indent+2, path)
 		}
 	}
+
+	return false
 }
 
-func (p *blockBodyDiffPrinter) writeNestedBlockDiffs(name string, blockS *configschema.NestedBlock, old, new cty.Value, blankBefore bool, indent int, path cty.Path) {
+func (p *blockBodyDiffPrinter) writeNestedBlockDiffs(name string, blockS *configschema.NestedBlock, old, new cty.Value, blankBefore bool, indent int, path cty.Path) int {
+	skippedBlocks := 0
 	path = append(path, cty.GetAttrStep{Name: name})
 	if old.IsNull() && new.IsNull() {
 		// Nothing to do if both old and new is null
-		return
+		return skippedBlocks
 	}
 
 	// Where old/new are collections representing a nesting mode other than
@@ -335,7 +378,10 @@ func (p *blockBodyDiffPrinter) writeNestedBlockDiffs(name string, blockS *config
 		if blankBefore {
 			p.buf.WriteRune('\n')
 		}
-		p.writeNestedBlockDiff(name, nil, &blockS.Block, action, old, new, indent, path)
+		skipped := p.writeNestedBlockDiff(name, nil, &blockS.Block, action, old, new, indent, path)
+		if skipped {
+			return 1
+		}
 	case configschema.NestingList:
 		// For the sake of handling nested blocks, we'll treat a null list
 		// the same as an empty list since the config language doesn't
@@ -377,19 +423,28 @@ func (p *blockBodyDiffPrinter) writeNestedBlockDiffs(name string, blockS *config
 			if oldItem.RawEquals(newItem) {
 				action = plans.NoOp
 			}
-			p.writeNestedBlockDiff(name, nil, &blockS.Block, action, oldItem, newItem, indent, path)
+			skipped := p.writeNestedBlockDiff(name, nil, &blockS.Block, action, oldItem, newItem, indent, path)
+			if skipped {
+				skippedBlocks++
+			}
 		}
 		for i := commonLen; i < len(oldItems); i++ {
 			path := append(path, cty.IndexStep{Key: cty.NumberIntVal(int64(i))})
 			oldItem := oldItems[i]
 			newItem := cty.NullVal(oldItem.Type())
-			p.writeNestedBlockDiff(name, nil, &blockS.Block, plans.Delete, oldItem, newItem, indent, path)
+			skipped := p.writeNestedBlockDiff(name, nil, &blockS.Block, plans.Delete, oldItem, newItem, indent, path)
+			if skipped {
+				skippedBlocks++
+			}
 		}
 		for i := commonLen; i < len(newItems); i++ {
 			path := append(path, cty.IndexStep{Key: cty.NumberIntVal(int64(i))})
 			newItem := newItems[i]
 			oldItem := cty.NullVal(newItem.Type())
-			p.writeNestedBlockDiff(name, nil, &blockS.Block, plans.Create, oldItem, newItem, indent, path)
+			skipped := p.writeNestedBlockDiff(name, nil, &blockS.Block, plans.Create, oldItem, newItem, indent, path)
+			if skipped {
+				skippedBlocks++
+			}
 		}
 	case configschema.NestingSet:
 		// For the sake of handling nested blocks, we'll treat a null set
@@ -403,7 +458,7 @@ func (p *blockBodyDiffPrinter) writeNestedBlockDiffs(name string, blockS *config
 
 		if (len(oldItems) + len(newItems)) == 0 {
 			// Nothing to do if both sets are empty
-			return
+			return 0
 		}
 
 		allItems := make([]cty.Value, 0, len(oldItems)+len(newItems))
@@ -437,7 +492,10 @@ func (p *blockBodyDiffPrinter) writeNestedBlockDiffs(name string, blockS *config
 				newValue = val
 			}
 			path := append(path, cty.IndexStep{Key: val})
-			p.writeNestedBlockDiff(name, nil, &blockS.Block, action, oldValue, newValue, indent, path)
+			skipped := p.writeNestedBlockDiff(name, nil, &blockS.Block, action, oldValue, newValue, indent, path)
+			if skipped {
+				skippedBlocks++
+			}
 		}
 
 	case configschema.NestingMap:
@@ -451,7 +509,7 @@ func (p *blockBodyDiffPrinter) writeNestedBlockDiffs(name string, blockS *config
 		newItems := new.AsValueMap()
 		if (len(oldItems) + len(newItems)) == 0 {
 			// Nothing to do if both maps are empty
-			return
+			return 0
 		}
 
 		allKeys := make(map[string]bool)
@@ -489,12 +547,20 @@ func (p *blockBodyDiffPrinter) writeNestedBlockDiffs(name string, blockS *config
 			}
 
 			path := append(path, cty.IndexStep{Key: cty.StringVal(k)})
-			p.writeNestedBlockDiff(name, &k, &blockS.Block, action, oldValue, newValue, indent, path)
+			skipped := p.writeNestedBlockDiff(name, &k, &blockS.Block, action, oldValue, newValue, indent, path)
+			if skipped {
+				skippedBlocks++
+			}
 		}
 	}
+	return skippedBlocks
 }
 
-func (p *blockBodyDiffPrinter) writeNestedBlockDiff(name string, label *string, blockS *configschema.Block, action plans.Action, old, new cty.Value, indent int, path cty.Path) {
+func (p *blockBodyDiffPrinter) writeNestedBlockDiff(name string, label *string, blockS *configschema.Block, action plans.Action, old, new cty.Value, indent int, path cty.Path) bool {
+	if action == plans.NoOp && p.concise {
+		return true
+	}
+
 	p.buf.WriteString("\n")
 	p.buf.WriteString(strings.Repeat(" ", indent))
 	p.writeActionSymbol(action)
@@ -509,12 +575,14 @@ func (p *blockBodyDiffPrinter) writeNestedBlockDiff(name string, label *string,
 		p.buf.WriteString(p.color.Color(forcesNewResourceCaption))
 	}
 
-	bodyWritten := p.writeBlockBodyDiff(blockS, old, new, indent+4, path)
+	result := p.writeBlockBodyDiff(blockS, old, new, indent+4, path)
-	if bodyWritten {
+	if result.bodyWritten {
 		p.buf.WriteString("\n")
 		p.buf.WriteString(strings.Repeat(" ", indent+2))
 	}
 	p.buf.WriteString("}")
+
+	return false
 }
 
 func (p *blockBodyDiffPrinter) writeValue(val cty.Value, action plans.Action, indent int) {
@@ -819,11 +887,10 @@ func (p *blockBodyDiffPrinter) writeValueDiff(old, new cty.Value, indent int, pa
 				removed = cty.SetValEmpty(ty.ElementType())
 			}
 
+			suppressedElements := 0
 			for it := all.ElementIterator(); it.Next(); {
 				_, val := it.Element()
 
-				p.buf.WriteString(strings.Repeat(" ", indent+2))
-
 				var action plans.Action
 				switch {
 				case !val.IsKnown():
@@ -836,11 +903,28 @@ func (p *blockBodyDiffPrinter) writeValueDiff(old, new cty.Value, indent int, pa
 					action = plans.NoOp
 				}
 
+				if action == plans.NoOp && p.concise {
+					suppressedElements++
+					continue
+				}
+
+				p.buf.WriteString(strings.Repeat(" ", indent+2))
 				p.writeActionSymbol(action)
 				p.writeValue(val, action, indent+4)
 				p.buf.WriteString(",\n")
 			}
 
+			if suppressedElements > 0 {
+				p.writeActionSymbol(plans.NoOp)
+				p.buf.WriteString(strings.Repeat(" ", indent+2))
+				noun := "elements"
+				if suppressedElements == 1 {
+					noun = "element"
+				}
+				p.buf.WriteString(p.color.Color(fmt.Sprintf("[dark_gray]# (%d unchanged %s hidden)[reset]", suppressedElements, noun)))
+				p.buf.WriteString("\n")
+			}
+
 			p.buf.WriteString(strings.Repeat(" ", indent))
 			p.buf.WriteString("]")
 			return
@@ -852,7 +936,74 @@ func (p *blockBodyDiffPrinter) writeValueDiff(old, new cty.Value, indent int, pa
 			p.buf.WriteString("\n")
 
 			elemDiffs := ctySequenceDiff(old.AsValueSlice(), new.AsValueSlice())
-			for _, elemDiff := range elemDiffs {
+
+			// Maintain a stack of suppressed lines in the diff for later
+			// display or elision
+			var suppressedElements []*plans.Change
+			var changeShown bool
+
+			for i := 0; i < len(elemDiffs); i++ {
+				// In concise mode, push any no-op diff elements onto the stack
+				if p.concise {
+					for i < len(elemDiffs) && elemDiffs[i].Action == plans.NoOp {
+						suppressedElements = append(suppressedElements, elemDiffs[i])
+						i++
+					}
+				}
+
+				// If we have some suppressed elements on the stack…
+				if len(suppressedElements) > 0 {
+					// If we've just rendered a change, display the first
+					// element in the stack as context
+					if changeShown {
+						elemDiff := suppressedElements[0]
+						p.buf.WriteString(strings.Repeat(" ", indent+4))
+						p.writeValue(elemDiff.After, elemDiff.Action, indent+4)
+						p.buf.WriteString(",\n")
+						suppressedElements = suppressedElements[1:]
+					}
+
+					hidden := len(suppressedElements)
+
+					// If we're not yet at the end of the list, capture the
+					// last element on the stack as context for the upcoming
+					// change to be rendered
+					var nextContextDiff *plans.Change
+					if hidden > 0 && i < len(elemDiffs) {
+						hidden--
+						nextContextDiff = suppressedElements[hidden]
+						suppressedElements = suppressedElements[:hidden]
+					}
+
+					// If there are still hidden elements, show an elision
+					// statement counting them
+					if hidden > 0 {
+						p.writeActionSymbol(plans.NoOp)
+						p.buf.WriteString(strings.Repeat(" ", indent+2))
+						noun := "elements"
+						if hidden == 1 {
+							noun = "element"
+						}
+						p.buf.WriteString(p.color.Color(fmt.Sprintf("[dark_gray]# (%d unchanged %s hidden)[reset]", hidden, noun)))
+						p.buf.WriteString("\n")
+					}
+
+					// Display the next context diff if it was captured above
+					if nextContextDiff != nil {
+						p.buf.WriteString(strings.Repeat(" ", indent+4))
+						p.writeValue(nextContextDiff.After, nextContextDiff.Action, indent+4)
+						p.buf.WriteString(",\n")
+					}
+
+					// Suppressed elements have now been handled so clear them again
+					suppressedElements = nil
+				}
+
+				if i >= len(elemDiffs) {
+					break
+				}
+
+				elemDiff := elemDiffs[i]
 				p.buf.WriteString(strings.Repeat(" ", indent+2))
 				p.writeActionSymbol(elemDiff.Action)
 				switch elemDiff.Action {
@@ -869,10 +1020,12 @@ func (p *blockBodyDiffPrinter) writeValueDiff(old, new cty.Value, indent int, pa
 				}
 
 				p.buf.WriteString(",\n")
+				changeShown = true
 			}
 
 			p.buf.WriteString(strings.Repeat(" ", indent))
 			p.buf.WriteString("]")
+
 			return
 
 		case ty.IsMapType():
@@ -903,6 +1056,7 @@ func (p *blockBodyDiffPrinter) writeValueDiff(old, new cty.Value, indent int, pa
 
 			sort.Strings(allKeys)
 
+			suppressedElements := 0
 			lastK := ""
 			for i, k := range allKeys {
 				if i > 0 && lastK == k {
@@ -910,7 +1064,6 @@ func (p *blockBodyDiffPrinter) writeValueDiff(old, new cty.Value, indent int, pa
 				}
 				lastK = k
 
-				p.buf.WriteString(strings.Repeat(" ", indent+2))
 				kV := cty.StringVal(k)
 				var action plans.Action
 				if old.HasIndex(kV).False() {
@@ -923,8 +1076,14 @@ func (p *blockBodyDiffPrinter) writeValueDiff(old, new cty.Value, indent int, pa
 					action = plans.Update
 				}
 
+				if action == plans.NoOp && p.concise {
+					suppressedElements++
+					continue
+				}
+
 				path := append(path, cty.IndexStep{Key: kV})
 
+				p.buf.WriteString(strings.Repeat(" ", indent+2))
 				p.writeActionSymbol(action)
 				p.writeValue(kV, action, indent+4)
 				p.buf.WriteString(strings.Repeat(" ", keyLen-len(k)))
@@ -946,8 +1105,20 @@ func (p *blockBodyDiffPrinter) writeValueDiff(old, new cty.Value, indent int, pa
 				p.buf.WriteByte('\n')
 			}
 
+			if suppressedElements > 0 {
+				p.writeActionSymbol(plans.NoOp)
+				p.buf.WriteString(strings.Repeat(" ", indent+2))
+				noun := "elements"
+				if suppressedElements == 1 {
+					noun = "element"
+				}
+				p.buf.WriteString(p.color.Color(fmt.Sprintf("[dark_gray]# (%d unchanged %s hidden)[reset]", suppressedElements, noun)))
+				p.buf.WriteString("\n")
+			}
+
 			p.buf.WriteString(strings.Repeat(" ", indent))
 			p.buf.WriteString("}")
+
 			return
 		case ty.IsObjectType():
 			p.buf.WriteString("{")
@@ -976,6 +1147,7 @@ func (p *blockBodyDiffPrinter) writeValueDiff(old, new cty.Value, indent int, pa
 
 			sort.Strings(allKeys)
 
+			suppressedElements := 0
 			lastK := ""
 			for i, k := range allKeys {
 				if i > 0 && lastK == k {
@@ -983,7 +1155,6 @@ func (p *blockBodyDiffPrinter) writeValueDiff(old, new cty.Value, indent int, pa
 				}
 				lastK = k
 
-				p.buf.WriteString(strings.Repeat(" ", indent+2))
 				kV := k
 				var action plans.Action
 				if !old.Type().HasAttribute(kV) {
@@ -996,8 +1167,14 @@ func (p *blockBodyDiffPrinter) writeValueDiff(old, new cty.Value, indent int, pa
 					action = plans.Update
 				}
 
+				if action == plans.NoOp && p.concise {
+					suppressedElements++
+					continue
+				}
+
 				path := append(path, cty.GetAttrStep{Name: kV})
 
+				p.buf.WriteString(strings.Repeat(" ", indent+2))
 				p.writeActionSymbol(action)
 				p.buf.WriteString(k)
 				p.buf.WriteString(strings.Repeat(" ", keyLen-len(k)))
@@ -1020,6 +1197,17 @@ func (p *blockBodyDiffPrinter) writeValueDiff(old, new cty.Value, indent int, pa
 				p.buf.WriteString("\n")
 			}
 
+			if suppressedElements > 0 {
+				p.writeActionSymbol(plans.NoOp)
+				p.buf.WriteString(strings.Repeat(" ", indent+2))
+				noun := "elements"
+				if suppressedElements == 1 {
+					noun = "element"
+				}
+				p.buf.WriteString(p.color.Color(fmt.Sprintf("[dark_gray]# (%d unchanged %s hidden)[reset]", suppressedElements, noun)))
+				p.buf.WriteString("\n")
+			}
+
 			p.buf.WriteString(strings.Repeat(" ", indent))
 			p.buf.WriteString("}")
 
@@ -1266,3 +1454,11 @@ func DiffActionSymbol(action plans.Action) string {
 		return "  ?"
 	}
 }
+
+// Extremely coarse heuristic for determining whether or not a given attribute
+// name is important for identifying a resource. In the future, this may be
+// replaced by a flag in the schema, but for now this is likely to be good
+// enough.
+func identifyingAttribute(name string, attrSchema *configschema.Attribute) bool {
+	return name == "id" || name == "tags" || name == "name"
+}

command/format/diff_test.go

@@ -4,8 +4,10 @@ import (
 	"fmt"
 	"testing"
 
+	"github.com/google/go-cmp/cmp"
 	"github.com/hashicorp/terraform/addrs"
 	"github.com/hashicorp/terraform/configs/configschema"
+	"github.com/hashicorp/terraform/helper/experiment"
 	"github.com/hashicorp/terraform/plans"
 	"github.com/mitchellh/colorstring"
 	"github.com/zclconf/go-cty/cty"
@@ -204,12 +206,19 @@ func TestResourceChange_primitiveTypes(t *testing.T) {
 			Before: cty.ObjectVal(map[string]cty.Value{
 				"id": cty.StringVal("i-02ae66f368e8518a9"),
 				"more_lines": cty.StringVal(`original
+long
+multi-line
+string
+field
 `),
 			}),
 			After: cty.ObjectVal(map[string]cty.Value{
 				"id": cty.UnknownVal(cty.String),
 				"more_lines": cty.StringVal(`original
-new line
+extremely long
+multi-line
+string
+field
 `),
 			}),
 			Schema: &configschema.Block{
@@ -225,7 +234,11 @@ new line
       ~ id         = "i-02ae66f368e8518a9" -> (known after apply)
       ~ more_lines = <<~EOT
             original
-          + new line
+          - long
+          + extremely long
+            multi-line
+            string
+            field
         EOT
     }
 `,
@@ -344,6 +357,13 @@ new line
 			RequiredReplace: cty.NewPathSet(),
 			Tainted:         false,
 			ExpectedOutput: `  # test_instance.example will be updated in-place
+  ~ resource "test_instance" "example" {
+      ~ id       = "blah" -> (known after apply)
+      ~ str      = "before" -> "after"
+        # (1 unchanged attribute hidden)
+    }
+`,
+			VerboseOutput: `  # test_instance.example will be updated in-place
   ~ resource "test_instance" "example" {
       ~ id       = "blah" -> (known after apply)
         password = (sensitive value)
@@ -435,6 +455,65 @@ new line
       + forced = "example" # forces replacement
         name   = "name"
     }
+`,
+		},
+		"show all identifying attributes even if unchanged": {
+			Action: plans.Update,
+			Mode:   addrs.ManagedResourceMode,
+			Before: cty.ObjectVal(map[string]cty.Value{
+				"id":   cty.StringVal("i-02ae66f368e8518a9"),
+				"ami":  cty.StringVal("ami-BEFORE"),
+				"bar":  cty.StringVal("bar"),
+				"foo":  cty.StringVal("foo"),
+				"name": cty.StringVal("alice"),
+				"tags": cty.MapVal(map[string]cty.Value{
+					"name": cty.StringVal("bob"),
+				}),
+			}),
+			After: cty.ObjectVal(map[string]cty.Value{
+				"id":   cty.StringVal("i-02ae66f368e8518a9"),
+				"ami":  cty.StringVal("ami-AFTER"),
+				"bar":  cty.StringVal("bar"),
+				"foo":  cty.StringVal("foo"),
+				"name": cty.StringVal("alice"),
+				"tags": cty.MapVal(map[string]cty.Value{
+					"name": cty.StringVal("bob"),
+				}),
+			}),
+			Schema: &configschema.Block{
+				Attributes: map[string]*configschema.Attribute{
+					"id":   {Type: cty.String, Optional: true, Computed: true},
+					"ami":  {Type: cty.String, Optional: true},
+					"bar":  {Type: cty.String, Optional: true},
+					"foo":  {Type: cty.String, Optional: true},
+					"name": {Type: cty.String, Optional: true},
+					"tags": {Type: cty.Map(cty.String), Optional: true},
+				},
+			},
+			RequiredReplace: cty.NewPathSet(),
+			Tainted:         false,
+			ExpectedOutput: `  # test_instance.example will be updated in-place
+  ~ resource "test_instance" "example" {
+      ~ ami  = "ami-BEFORE" -> "ami-AFTER"
+        id   = "i-02ae66f368e8518a9"
+        name = "alice"
+        tags = {
+            "name" = "bob"
+        }
+        # (2 unchanged attributes hidden)
+    }
+`,
+			VerboseOutput: `  # test_instance.example will be updated in-place
+  ~ resource "test_instance" "example" {
+      ~ ami  = "ami-BEFORE" -> "ami-AFTER"
+        bar  = "bar"
+        foo  = "foo"
+        id   = "i-02ae66f368e8518a9"
+        name = "alice"
+        tags = {
+            "name" = "bob"
+        }
+    }
 `,
 		},
 	}
@@ -489,7 +568,7 @@ func TestResourceChange_JSON(t *testing.T) {
 			Mode:   addrs.ManagedResourceMode,
 			Before: cty.ObjectVal(map[string]cty.Value{
 				"id":         cty.StringVal("i-02ae66f368e8518a9"),
-				"json_field": cty.StringVal(`{"aaa": "value"}`),
+				"json_field": cty.StringVal(`{"aaa": "value","ccc": 5}`),
 			}),
 			After: cty.ObjectVal(map[string]cty.Value{
 				"id":         cty.UnknownVal(cty.String),
@@ -504,12 +583,26 @@ func TestResourceChange_JSON(t *testing.T) {
 			RequiredReplace: cty.NewPathSet(),
 			Tainted:         false,
 			ExpectedOutput: `  # test_instance.example will be updated in-place
+  ~ resource "test_instance" "example" {
+      ~ id         = "i-02ae66f368e8518a9" -> (known after apply)
+      ~ json_field = jsonencode(
+          ~ {
+              + bbb = "new_value"
+              - ccc = 5 -> null
+                # (1 unchanged element hidden)
+            }
+        )
+    }
+`,
+
+			VerboseOutput: `  # test_instance.example will be updated in-place
   ~ resource "test_instance" "example" {
       ~ id         = "i-02ae66f368e8518a9" -> (known after apply)
       ~ json_field = jsonencode(
           ~ {
                 aaa = "value"
               + bbb = "new_value"
+              - ccc = 5 -> null
             }
         )
     }
@@ -637,6 +730,17 @@ func TestResourceChange_JSON(t *testing.T) {
 			}),
 			Tainted: false,
 			ExpectedOutput: `  # test_instance.example must be replaced
+-/+ resource "test_instance" "example" {
+      ~ id         = "i-02ae66f368e8518a9" -> (known after apply)
+      ~ json_field = jsonencode(
+          ~ {
+              + bbb = "new_value"
+                # (1 unchanged element hidden)
+            } # forces replacement
+        )
+    }
+`,
+			VerboseOutput: `  # test_instance.example must be replaced
 -/+ resource "test_instance" "example" {
       ~ id         = "i-02ae66f368e8518a9" -> (known after apply)
       ~ json_field = jsonencode(
@@ -757,6 +861,18 @@ func TestResourceChange_JSON(t *testing.T) {
 			RequiredReplace: cty.NewPathSet(),
 			Tainted:         false,
 			ExpectedOutput: `  # test_instance.example will be updated in-place
+  ~ resource "test_instance" "example" {
+      ~ id         = "i-02ae66f368e8518a9" -> (known after apply)
+      ~ json_field = jsonencode(
+          ~ [
+                # (1 unchanged element hidden)
+                "second",
+              - "third",
+            ]
+        )
+    }
+`,
+			VerboseOutput: `  # test_instance.example will be updated in-place
   ~ resource "test_instance" "example" {
       ~ id         = "i-02ae66f368e8518a9" -> (known after apply)
       ~ json_field = jsonencode(
@@ -789,6 +905,19 @@ func TestResourceChange_JSON(t *testing.T) {
 			RequiredReplace: cty.NewPathSet(),
 			Tainted:         false,
 			ExpectedOutput: `  # test_instance.example will be updated in-place
+  ~ resource "test_instance" "example" {
+      ~ id         = "i-02ae66f368e8518a9" -> (known after apply)
+      ~ json_field = jsonencode(
+          ~ [
+                # (1 unchanged element hidden)
+                "second",
+              + "third",
+            ]
+        )
+    }
+`,
+
+			VerboseOutput: `  # test_instance.example will be updated in-place
   ~ resource "test_instance" "example" {
       ~ id         = "i-02ae66f368e8518a9" -> (known after apply)
       ~ json_field = jsonencode(
@@ -825,8 +954,8 @@ func TestResourceChange_JSON(t *testing.T) {
       ~ id         = "i-02ae66f368e8518a9" -> (known after apply)
       ~ json_field = jsonencode(
           ~ {
-                first  = "111"
               + second = "222"
+                # (1 unchanged element hidden)
             }
         )
     }
@@ -1087,6 +1216,15 @@ func TestResourceChange_primitiveList(t *testing.T) {
 			RequiredReplace: cty.NewPathSet(),
 			Tainted:         false,
 			ExpectedOutput: `  # test_instance.example will be updated in-place
+  ~ resource "test_instance" "example" {
+      ~ id         = "i-02ae66f368e8518a9" -> (known after apply)
+      + list_field = [
+          + "new-element",
+        ]
+        # (1 unchanged attribute hidden)
+    }
+`,
+			VerboseOutput: `  # test_instance.example will be updated in-place
   ~ resource "test_instance" "example" {
         ami        = "ami-STATIC"
       ~ id         = "i-02ae66f368e8518a9" -> (known after apply)
@@ -1121,6 +1259,15 @@ func TestResourceChange_primitiveList(t *testing.T) {
 			RequiredReplace: cty.NewPathSet(),
 			Tainted:         false,
 			ExpectedOutput: `  # test_instance.example will be updated in-place
+  ~ resource "test_instance" "example" {
+      ~ id         = "i-02ae66f368e8518a9" -> (known after apply)
+      ~ list_field = [
+          + "new-element",
+        ]
+        # (1 unchanged attribute hidden)
+    }
+`,
+			VerboseOutput: `  # test_instance.example will be updated in-place
   ~ resource "test_instance" "example" {
         ami        = "ami-STATIC"
       ~ id         = "i-02ae66f368e8518a9" -> (known after apply)
@@ -1138,7 +1285,10 @@ func TestResourceChange_primitiveList(t *testing.T) {
 				"ami": cty.StringVal("ami-STATIC"),
 				"list_field": cty.ListVal([]cty.Value{
 					cty.StringVal("aaaa"),
-					cty.StringVal("cccc"),
+					cty.StringVal("bbbb"),
+					cty.StringVal("dddd"),
+					cty.StringVal("eeee"),
+					cty.StringVal("ffff"),
 				}),
 			}),
 			After: cty.ObjectVal(map[string]cty.Value{
@@ -1148,6 +1298,9 @@ func TestResourceChange_primitiveList(t *testing.T) {
 					cty.StringVal("aaaa"),
 					cty.StringVal("bbbb"),
 					cty.StringVal("cccc"),
+					cty.StringVal("dddd"),
+					cty.StringVal("eeee"),
+					cty.StringVal("ffff"),
 				}),
 			}),
 			Schema: &configschema.Block{
@@ -1160,13 +1313,29 @@ func TestResourceChange_primitiveList(t *testing.T) {
 			RequiredReplace: cty.NewPathSet(),
 			Tainted:         false,
 			ExpectedOutput: `  # test_instance.example will be updated in-place
+  ~ resource "test_instance" "example" {
+      ~ id         = "i-02ae66f368e8518a9" -> (known after apply)
+      ~ list_field = [
+            # (1 unchanged element hidden)
+            "bbbb",
+          + "cccc",
+            "dddd",
+            # (2 unchanged elements hidden)
+        ]
+        # (1 unchanged attribute hidden)
+    }
+`,
+			VerboseOutput: `  # test_instance.example will be updated in-place
   ~ resource "test_instance" "example" {
         ami        = "ami-STATIC"
       ~ id         = "i-02ae66f368e8518a9" -> (known after apply)
       ~ list_field = [
             "aaaa",
-          + "bbbb",
+            "bbbb",
-            "cccc",
+          + "cccc",
+            "dddd",
+            "eeee",
+            "ffff",
         ]
     }
 `,
@@ -1203,6 +1372,17 @@ func TestResourceChange_primitiveList(t *testing.T) {
 			}),
 			Tainted: false,
 			ExpectedOutput: `  # test_instance.example must be replaced
+-/+ resource "test_instance" "example" {
+      ~ id         = "i-02ae66f368e8518a9" -> (known after apply)
+      ~ list_field = [ # forces replacement
+            "aaaa",
+          + "bbbb",
+            "cccc",
+        ]
+        # (1 unchanged attribute hidden)
+    }
+`,
+			VerboseOutput: `  # test_instance.example must be replaced
 -/+ resource "test_instance" "example" {
         ami        = "ami-STATIC"
       ~ id         = "i-02ae66f368e8518a9" -> (known after apply)
@@ -1224,6 +1404,8 @@ func TestResourceChange_primitiveList(t *testing.T) {
 					cty.StringVal("aaaa"),
 					cty.StringVal("bbbb"),
 					cty.StringVal("cccc"),
+					cty.StringVal("dddd"),
+					cty.StringVal("eeee"),
 				}),
 			}),
 			After: cty.ObjectVal(map[string]cty.Value{
@@ -1231,6 +1413,8 @@ func TestResourceChange_primitiveList(t *testing.T) {
 				"ami": cty.StringVal("ami-STATIC"),
 				"list_field": cty.ListVal([]cty.Value{
 					cty.StringVal("bbbb"),
+					cty.StringVal("dddd"),
+					cty.StringVal("eeee"),
 				}),
 			}),
 			Schema: &configschema.Block{
@@ -1243,6 +1427,19 @@ func TestResourceChange_primitiveList(t *testing.T) {
 			RequiredReplace: cty.NewPathSet(),
 			Tainted:         false,
 			ExpectedOutput: `  # test_instance.example will be updated in-place
+  ~ resource "test_instance" "example" {
+      ~ id         = "i-02ae66f368e8518a9" -> (known after apply)
+      ~ list_field = [
+          - "aaaa",
+            "bbbb",
+          - "cccc",
+            "dddd",
+            # (1 unchanged element hidden)
+        ]
+        # (1 unchanged attribute hidden)
+    }
+`,
+			VerboseOutput: `  # test_instance.example will be updated in-place
   ~ resource "test_instance" "example" {
         ami        = "ami-STATIC"
       ~ id         = "i-02ae66f368e8518a9" -> (known after apply)
@@ -1250,6 +1447,8 @@ func TestResourceChange_primitiveList(t *testing.T) {
           - "aaaa",
             "bbbb",
           - "cccc",
+            "dddd",
+            "eeee",
         ]
     }
 `,
@@ -1307,6 +1506,17 @@ func TestResourceChange_primitiveList(t *testing.T) {
 			RequiredReplace: cty.NewPathSet(),
 			Tainted:         false,
 			ExpectedOutput: `  # test_instance.example will be updated in-place
+  ~ resource "test_instance" "example" {
+      ~ id         = "i-02ae66f368e8518a9" -> (known after apply)
+      ~ list_field = [
+          - "aaaa",
+          - "bbbb",
+          - "cccc",
+        ]
+        # (1 unchanged attribute hidden)
+    }
+`,
+			VerboseOutput: `  # test_instance.example will be updated in-place
   ~ resource "test_instance" "example" {
         ami        = "ami-STATIC"
       ~ id         = "i-02ae66f368e8518a9" -> (known after apply)
@@ -1341,6 +1551,13 @@ func TestResourceChange_primitiveList(t *testing.T) {
 			RequiredReplace: cty.NewPathSet(),
 			Tainted:         false,
 			ExpectedOutput: `  # test_instance.example will be updated in-place
+  ~ resource "test_instance" "example" {
+      ~ id         = "i-02ae66f368e8518a9" -> (known after apply)
+      + list_field = []
+        # (1 unchanged attribute hidden)
+    }
+`,
+			VerboseOutput: `  # test_instance.example will be updated in-place
   ~ resource "test_instance" "example" {
         ami        = "ami-STATIC"
       ~ id         = "i-02ae66f368e8518a9" -> (known after apply)
@@ -1379,6 +1596,18 @@ func TestResourceChange_primitiveList(t *testing.T) {
 			RequiredReplace: cty.NewPathSet(),
 			Tainted:         false,
 			ExpectedOutput: `  # test_instance.example will be updated in-place
+  ~ resource "test_instance" "example" {
+      ~ id         = "i-02ae66f368e8518a9" -> (known after apply)
+      ~ list_field = [
+            "aaaa",
+          - "bbbb",
+          + (known after apply),
+            "cccc",
+        ]
+        # (1 unchanged attribute hidden)
+    }
+`,
+			VerboseOutput: `  # test_instance.example will be updated in-place
   ~ resource "test_instance" "example" {
         ami        = "ami-STATIC"
       ~ id         = "i-02ae66f368e8518a9" -> (known after apply)
@@ -1401,6 +1630,8 @@ func TestResourceChange_primitiveList(t *testing.T) {
 					cty.StringVal("aaaa"),
 					cty.StringVal("bbbb"),
 					cty.StringVal("cccc"),
+					cty.StringVal("dddd"),
+					cty.StringVal("eeee"),
 				}),
 			}),
 			After: cty.ObjectVal(map[string]cty.Value{
@@ -1411,6 +1642,8 @@ func TestResourceChange_primitiveList(t *testing.T) {
 					cty.UnknownVal(cty.String),
 					cty.UnknownVal(cty.String),
 					cty.StringVal("cccc"),
+					cty.StringVal("dddd"),
+					cty.StringVal("eeee"),
 				}),
 			}),
 			Schema: &configschema.Block{
@@ -1423,6 +1656,20 @@ func TestResourceChange_primitiveList(t *testing.T) {
 			RequiredReplace: cty.NewPathSet(),
 			Tainted:         false,
 			ExpectedOutput: `  # test_instance.example will be updated in-place
+  ~ resource "test_instance" "example" {
+      ~ id         = "i-02ae66f368e8518a9" -> (known after apply)
+      ~ list_field = [
+            "aaaa",
+          - "bbbb",
+          + (known after apply),
+          + (known after apply),
+            "cccc",
+            # (2 unchanged elements hidden)
+        ]
+        # (1 unchanged attribute hidden)
+    }
+`,
+			VerboseOutput: `  # test_instance.example will be updated in-place
   ~ resource "test_instance" "example" {
         ami        = "ami-STATIC"
       ~ id         = "i-02ae66f368e8518a9" -> (known after apply)
@@ -1432,6 +1679,72 @@ func TestResourceChange_primitiveList(t *testing.T) {
           + (known after apply),
           + (known after apply),
             "cccc",
+            "dddd",
+            "eeee",
+        ]
+    }
+`,
+		},
+	}
+	runTestCases(t, testCases)
+}
+
+func TestResourceChange_primitiveTuple(t *testing.T) {
+	testCases := map[string]testCase{
+		"in-place update": {
+			Action: plans.Update,
+			Mode:   addrs.ManagedResourceMode,
+			Before: cty.ObjectVal(map[string]cty.Value{
+				"id": cty.StringVal("i-02ae66f368e8518a9"),
+				"tuple_field": cty.TupleVal([]cty.Value{
+					cty.StringVal("aaaa"),
+					cty.StringVal("bbbb"),
+					cty.StringVal("dddd"),
+					cty.StringVal("eeee"),
+					cty.StringVal("ffff"),
+				}),
+			}),
+			After: cty.ObjectVal(map[string]cty.Value{
+				"id": cty.StringVal("i-02ae66f368e8518a9"),
+				"tuple_field": cty.TupleVal([]cty.Value{
+					cty.StringVal("aaaa"),
+					cty.StringVal("bbbb"),
+					cty.StringVal("cccc"),
+					cty.StringVal("eeee"),
+					cty.StringVal("ffff"),
+				}),
+			}),
+			Schema: &configschema.Block{
+				Attributes: map[string]*configschema.Attribute{
+					"id":          {Type: cty.String, Required: true},
+					"tuple_field": {Type: cty.Tuple([]cty.Type{cty.String, cty.String, cty.String, cty.String, cty.String}), Optional: true},
+				},
+			},
+			RequiredReplace: cty.NewPathSet(),
+			Tainted:         false,
+			ExpectedOutput: `  # test_instance.example will be updated in-place
+  ~ resource "test_instance" "example" {
+        id          = "i-02ae66f368e8518a9"
+      ~ tuple_field = [
+            # (1 unchanged element hidden)
+            "bbbb",
+          - "dddd",
+          + "cccc",
+            "eeee",
+            # (1 unchanged element hidden)
+        ]
+    }
+`,
+			VerboseOutput: `  # test_instance.example will be updated in-place
+  ~ resource "test_instance" "example" {
+        id          = "i-02ae66f368e8518a9"
+      ~ tuple_field = [
+            "aaaa",
+            "bbbb",
+          - "dddd",
+          + "cccc",
+            "eeee",
+            "ffff",
         ]
     }
 `,
@@ -1467,6 +1780,15 @@ func TestResourceChange_primitiveSet(t *testing.T) {
 			RequiredReplace: cty.NewPathSet(),
 			Tainted:         false,
 			ExpectedOutput: `  # test_instance.example will be updated in-place
+  ~ resource "test_instance" "example" {
+      ~ id        = "i-02ae66f368e8518a9" -> (known after apply)
+      + set_field = [
+          + "new-element",
+        ]
+        # (1 unchanged attribute hidden)
+    }
+`,
+			VerboseOutput: `  # test_instance.example will be updated in-place
   ~ resource "test_instance" "example" {
         ami       = "ami-STATIC"
       ~ id        = "i-02ae66f368e8518a9" -> (known after apply)
@@ -1501,6 +1823,15 @@ func TestResourceChange_primitiveSet(t *testing.T) {
 			RequiredReplace: cty.NewPathSet(),
 			Tainted:         false,
 			ExpectedOutput: `  # test_instance.example will be updated in-place
+  ~ resource "test_instance" "example" {
+      ~ id        = "i-02ae66f368e8518a9" -> (known after apply)
+      ~ set_field = [
+          + "new-element",
+        ]
+        # (1 unchanged attribute hidden)
+    }
+`,
+			VerboseOutput: `  # test_instance.example will be updated in-place
   ~ resource "test_instance" "example" {
         ami       = "ami-STATIC"
       ~ id        = "i-02ae66f368e8518a9" -> (known after apply)
@@ -1540,6 +1871,16 @@ func TestResourceChange_primitiveSet(t *testing.T) {
 			RequiredReplace: cty.NewPathSet(),
 			Tainted:         false,
 			ExpectedOutput: `  # test_instance.example will be updated in-place
+  ~ resource "test_instance" "example" {
+      ~ id        = "i-02ae66f368e8518a9" -> (known after apply)
+      ~ set_field = [
+          + "bbbb",
+            # (2 unchanged elements hidden)
+        ]
+        # (1 unchanged attribute hidden)
+    }
+`,
+			VerboseOutput: `  # test_instance.example will be updated in-place
   ~ resource "test_instance" "example" {
         ami       = "ami-STATIC"
       ~ id        = "i-02ae66f368e8518a9" -> (known after apply)
@@ -1583,6 +1924,16 @@ func TestResourceChange_primitiveSet(t *testing.T) {
 			}),
 			Tainted: false,
 			ExpectedOutput: `  # test_instance.example must be replaced
+-/+ resource "test_instance" "example" {
+      ~ id        = "i-02ae66f368e8518a9" -> (known after apply)
+      ~ set_field = [ # forces replacement
+          + "bbbb",
+            # (2 unchanged elements hidden)
+        ]
+        # (1 unchanged attribute hidden)
+    }
+`,
+			VerboseOutput: `  # test_instance.example must be replaced
 -/+ resource "test_instance" "example" {
         ami       = "ami-STATIC"
       ~ id        = "i-02ae66f368e8518a9" -> (known after apply)
@@ -1623,6 +1974,17 @@ func TestResourceChange_primitiveSet(t *testing.T) {
 			RequiredReplace: cty.NewPathSet(),
 			Tainted:         false,
 			ExpectedOutput: `  # test_instance.example will be updated in-place
+  ~ resource "test_instance" "example" {
+      ~ id        = "i-02ae66f368e8518a9" -> (known after apply)
+      ~ set_field = [
+          - "aaaa",
+          - "cccc",
+            # (1 unchanged element hidden)
+        ]
+        # (1 unchanged attribute hidden)
+    }
+`,
+			VerboseOutput: `  # test_instance.example will be updated in-place
   ~ resource "test_instance" "example" {
         ami       = "ami-STATIC"
       ~ id        = "i-02ae66f368e8518a9" -> (known after apply)
@@ -1685,6 +2047,16 @@ func TestResourceChange_primitiveSet(t *testing.T) {
 			},
 			RequiredReplace: cty.NewPathSet(),
 			ExpectedOutput: `  # test_instance.example will be updated in-place
+  ~ resource "test_instance" "example" {
+      ~ id        = "i-02ae66f368e8518a9" -> (known after apply)
+      ~ set_field = [
+          - "aaaa",
+          - "bbbb",
+        ]
+        # (1 unchanged attribute hidden)
+    }
+`,
+			VerboseOutput: `  # test_instance.example will be updated in-place
   ~ resource "test_instance" "example" {
         ami       = "ami-STATIC"
       ~ id        = "i-02ae66f368e8518a9" -> (known after apply)
@@ -1718,6 +2090,13 @@ func TestResourceChange_primitiveSet(t *testing.T) {
 			RequiredReplace: cty.NewPathSet(),
 			Tainted:         false,
 			ExpectedOutput: `  # test_instance.example will be updated in-place
+  ~ resource "test_instance" "example" {
+      ~ id        = "i-02ae66f368e8518a9" -> (known after apply)
+      + set_field = []
+        # (1 unchanged attribute hidden)
+    }
+`,
+			VerboseOutput: `  # test_instance.example will be updated in-place
   ~ resource "test_instance" "example" {
         ami       = "ami-STATIC"
       ~ id        = "i-02ae66f368e8518a9" -> (known after apply)
@@ -1751,6 +2130,16 @@ func TestResourceChange_primitiveSet(t *testing.T) {
 			RequiredReplace: cty.NewPathSet(),
 			Tainted:         false,
 			ExpectedOutput: `  # test_instance.example will be updated in-place
+  ~ resource "test_instance" "example" {
+      ~ id        = "i-02ae66f368e8518a9" -> (known after apply)
+      ~ set_field = [
+          - "aaaa",
+          - "bbbb",
+        ] -> (known after apply)
+        # (1 unchanged attribute hidden)
+    }
+`,
+			VerboseOutput: `  # test_instance.example will be updated in-place
   ~ resource "test_instance" "example" {
         ami       = "ami-STATIC"
       ~ id        = "i-02ae66f368e8518a9" -> (known after apply)
@@ -1790,6 +2179,17 @@ func TestResourceChange_primitiveSet(t *testing.T) {
 			RequiredReplace: cty.NewPathSet(),
 			Tainted:         false,
 			ExpectedOutput: `  # test_instance.example will be updated in-place
+  ~ resource "test_instance" "example" {
+      ~ id        = "i-02ae66f368e8518a9" -> (known after apply)
+      ~ set_field = [
+          - "bbbb",
+          ~ (known after apply),
+            # (1 unchanged element hidden)
+        ]
+        # (1 unchanged attribute hidden)
+    }
+`,
+			VerboseOutput: `  # test_instance.example will be updated in-place
   ~ resource "test_instance" "example" {
         ami       = "ami-STATIC"
       ~ id        = "i-02ae66f368e8518a9" -> (known after apply)
@@ -1832,6 +2232,15 @@ func TestResourceChange_map(t *testing.T) {
 			RequiredReplace: cty.NewPathSet(),
 			Tainted:         false,
 			ExpectedOutput: `  # test_instance.example will be updated in-place
+  ~ resource "test_instance" "example" {
+      ~ id        = "i-02ae66f368e8518a9" -> (known after apply)
+      + map_field = {
+          + "new-key" = "new-element"
+        }
+        # (1 unchanged attribute hidden)
+    }
+`,
+			VerboseOutput: `  # test_instance.example will be updated in-place
   ~ resource "test_instance" "example" {
         ami       = "ami-STATIC"
       ~ id        = "i-02ae66f368e8518a9" -> (known after apply)
@@ -1866,6 +2275,15 @@ func TestResourceChange_map(t *testing.T) {
 			RequiredReplace: cty.NewPathSet(),
 			Tainted:         false,
 			ExpectedOutput: `  # test_instance.example will be updated in-place
+  ~ resource "test_instance" "example" {
+      ~ id        = "i-02ae66f368e8518a9" -> (known after apply)
+      ~ map_field = {
+          + "new-key" = "new-element"
+        }
+        # (1 unchanged attribute hidden)
+    }
+`,
+			VerboseOutput: `  # test_instance.example will be updated in-place
   ~ resource "test_instance" "example" {
         ami       = "ami-STATIC"
       ~ id        = "i-02ae66f368e8518a9" -> (known after apply)
@@ -1905,6 +2323,16 @@ func TestResourceChange_map(t *testing.T) {
 			RequiredReplace: cty.NewPathSet(),
 			Tainted:         false,
 			ExpectedOutput: `  # test_instance.example will be updated in-place
+  ~ resource "test_instance" "example" {
+      ~ id        = "i-02ae66f368e8518a9" -> (known after apply)
+      ~ map_field = {
+          + "b" = "bbbb"
+            # (2 unchanged elements hidden)
+        }
+        # (1 unchanged attribute hidden)
+    }
+`,
+			VerboseOutput: `  # test_instance.example will be updated in-place
   ~ resource "test_instance" "example" {
         ami       = "ami-STATIC"
       ~ id        = "i-02ae66f368e8518a9" -> (known after apply)
@@ -1948,6 +2376,16 @@ func TestResourceChange_map(t *testing.T) {
 			}),
 			Tainted: false,
 			ExpectedOutput: `  # test_instance.example must be replaced
+-/+ resource "test_instance" "example" {
+      ~ id        = "i-02ae66f368e8518a9" -> (known after apply)
+      ~ map_field = { # forces replacement
+          + "b" = "bbbb"
+            # (2 unchanged elements hidden)
+        }
+        # (1 unchanged attribute hidden)
+    }
+`,
+			VerboseOutput: `  # test_instance.example must be replaced
 -/+ resource "test_instance" "example" {
         ami       = "ami-STATIC"
       ~ id        = "i-02ae66f368e8518a9" -> (known after apply)
@@ -1988,6 +2426,17 @@ func TestResourceChange_map(t *testing.T) {
 			RequiredReplace: cty.NewPathSet(),
 			Tainted:         false,
 			ExpectedOutput: `  # test_instance.example will be updated in-place
+  ~ resource "test_instance" "example" {
+      ~ id        = "i-02ae66f368e8518a9" -> (known after apply)
+      ~ map_field = {
+          - "a" = "aaaa" -> null
+          - "c" = "cccc" -> null
+            # (1 unchanged element hidden)
+        }
+        # (1 unchanged attribute hidden)
+    }
+`,
+			VerboseOutput: `  # test_instance.example will be updated in-place
   ~ resource "test_instance" "example" {
         ami       = "ami-STATIC"
       ~ id        = "i-02ae66f368e8518a9" -> (known after apply)
@@ -2056,6 +2505,16 @@ func TestResourceChange_map(t *testing.T) {
 			RequiredReplace: cty.NewPathSet(),
 			Tainted:         false,
 			ExpectedOutput: `  # test_instance.example will be updated in-place
+  ~ resource "test_instance" "example" {
+      ~ id        = "i-02ae66f368e8518a9" -> (known after apply)
+      ~ map_field = {
+          ~ "b" = "bbbb" -> (known after apply)
+            # (2 unchanged elements hidden)
+        }
+        # (1 unchanged attribute hidden)
+    }
+`,
+			VerboseOutput: `  # test_instance.example will be updated in-place
   ~ resource "test_instance" "example" {
         ami       = "ami-STATIC"
       ~ id        = "i-02ae66f368e8518a9" -> (known after apply)
@@ -2121,6 +2580,14 @@ func TestResourceChange_nestedList(t *testing.T) {
       ~ ami = "ami-BEFORE" -> "ami-AFTER"
         id  = "i-02ae66f368e8518a9"
 
+        # (1 unchanged block hidden)
+    }
+`,
+			VerboseOutput: `  # test_instance.example will be updated in-place
+  ~ resource "test_instance" "example" {
+      ~ ami = "ami-BEFORE" -> "ami-AFTER"
+        id  = "i-02ae66f368e8518a9"
+
         root_block_device {
             volume_type = "gp2"
         }
@@ -2284,6 +2751,17 @@ func TestResourceChange_nestedList(t *testing.T) {
       ~ ami = "ami-BEFORE" -> "ami-AFTER"
         id  = "i-02ae66f368e8518a9"
 
+      ~ root_block_device {
+          + new_field   = "new_value"
+            # (1 unchanged attribute hidden)
+        }
+    }
+`,
+			VerboseOutput: `  # test_instance.example will be updated in-place
+  ~ resource "test_instance" "example" {
+      ~ ami = "ami-BEFORE" -> "ami-AFTER"
+        id  = "i-02ae66f368e8518a9"
+
       ~ root_block_device {
           + new_field   = "new_value"
             volume_type = "gp2"
@@ -2861,6 +3339,17 @@ func TestResourceChange_nestedMap(t *testing.T) {
       ~ ami = "ami-BEFORE" -> "ami-AFTER"
         id  = "i-02ae66f368e8518a9"
 
+      ~ root_block_device "a" {
+          + new_field   = "new_value"
+            # (1 unchanged attribute hidden)
+        }
+    }
+`,
+			VerboseOutput: `  # test_instance.example will be updated in-place
+  ~ resource "test_instance" "example" {
+      ~ ami = "ami-BEFORE" -> "ami-AFTER"
+        id  = "i-02ae66f368e8518a9"
+
       ~ root_block_device "a" {
           + new_field   = "new_value"
             volume_type = "gp2"
@@ -2927,6 +3416,18 @@ func TestResourceChange_nestedMap(t *testing.T) {
       ~ ami = "ami-BEFORE" -> "ami-AFTER"
         id  = "i-02ae66f368e8518a9"
 
+      + root_block_device "b" {
+          + new_field   = "new_value"
+          + volume_type = "gp2"
+        }
+        # (1 unchanged block hidden)
+    }
+`,
+			VerboseOutput: `  # test_instance.example will be updated in-place
+  ~ resource "test_instance" "example" {
+      ~ ami = "ami-BEFORE" -> "ami-AFTER"
+        id  = "i-02ae66f368e8518a9"
+
         root_block_device "a" {
             volume_type = "gp2"
         }
@@ -2994,6 +3495,17 @@ func TestResourceChange_nestedMap(t *testing.T) {
       ~ ami = "ami-BEFORE" -> "ami-AFTER"
         id  = "i-02ae66f368e8518a9"
 
+      ~ root_block_device "a" { # forces replacement
+          ~ volume_type = "gp2" -> "different"
+        }
+        # (1 unchanged block hidden)
+    }
+`,
+			VerboseOutput: `  # test_instance.example must be replaced
+-/+ resource "test_instance" "example" {
+      ~ ami = "ami-BEFORE" -> "ami-AFTER"
+        id  = "i-02ae66f368e8518a9"
+
       ~ root_block_device "a" { # forces replacement
           ~ volume_type = "gp2" -> "different"
         }
@@ -3119,6 +3631,10 @@ type testCase struct {
 	RequiredReplace cty.PathSet
 	Tainted         bool
 	ExpectedOutput  string
+
+	// This field and all associated values can be removed if the concise diff
+	// experiment succeeds.
+	VerboseOutput string
 }
 
 func runTestCases(t *testing.T, testCases map[string]testCase) {
@@ -3170,9 +3686,24 @@ func runTestCases(t *testing.T, testCases map[string]testCase) {
 				RequiredReplace: tc.RequiredReplace,
 			}
 
+			experiment.SetEnabled(experiment.X_concise_diff, true)
 			output := ResourceChange(change, tc.Tainted, tc.Schema, color)
 			if output != tc.ExpectedOutput {
-				t.Fatalf("Unexpected diff.\ngot:\n%s\nwant:\n%s\n", output, tc.ExpectedOutput)
+				t.Errorf("Unexpected diff.\ngot:\n%s\nwant:\n%s\n", output, tc.ExpectedOutput)
+				t.Errorf("%s", cmp.Diff(output, tc.ExpectedOutput))
+			}
+
+			// Temporary coverage for verbose diff behaviour. All lines below
+			// in this function can be removed if the concise diff experiment
+			// succeeds.
+			if tc.VerboseOutput == "" {
+				return
+			}
+			experiment.SetEnabled(experiment.X_concise_diff, false)
+			output = ResourceChange(change, tc.Tainted, tc.Schema, color)
+			if output != tc.VerboseOutput {
+				t.Errorf("Unexpected diff.\ngot:\n%s\nwant:\n%s\n", output, tc.VerboseOutput)
+				t.Errorf("%s", cmp.Diff(output, tc.VerboseOutput))
 			}
 		})
 	}
@@ -3243,11 +3774,11 @@ func TestOutputChanges(t *testing.T) {
 			},
 			`
   ~ foo = [
-        "alpha",
+        # (1 unchanged element hidden)
         "beta",
       + "gamma",
         "delta",
-        "epsilon",
+        # (1 unchanged element hidden)
     ]`,
 		},
 		"multiple outputs changed, one sensitive": {
@@ -3280,6 +3811,7 @@ func TestOutputChanges(t *testing.T) {
 
 	for name, tc := range testCases {
 		t.Run(name, func(t *testing.T) {
+			experiment.SetEnabled(experiment.X_concise_diff, true)
 			output := OutputChanges(tc.changes, color)
 			if output != tc.output {
 				t.Errorf("Unexpected diff.\ngot:\n%s\nwant:\n%s\n", output, tc.output)

command/format/state.go

@@ -198,8 +198,8 @@ func formatStateModule(p blockBodyDiffPrinter, m *states.Module, schemas *terraf
 				}
 
 				path := make(cty.Path, 0, 3)
-				bodyWritten := p.writeBlockBodyDiff(schema, val.Value, val.Value, 2, path)
+				result := p.writeBlockBodyDiff(schema, val.Value, val.Value, 2, path)
-				if bodyWritten {
+				if result.bodyWritten {
 					p.buf.WriteString("\n")
 				}
 

helper/experiment/experiment.go

@@ -53,6 +53,9 @@ var (
 	// Shadow graph. This is already on by default. Disabling it will be
 	// allowed for awhile in order for it to not block operations.
 	X_shadow = newBasicID("shadow", "SHADOW", false)
+
+	// Concise plan diff output
+	X_concise_diff = newBasicID("concise_diff", "CONCISE_DIFF", true)
 )
 
 // Global variables this package uses because we are a package
@@ -73,6 +76,7 @@ func init() {
 	// The list of all experiments, update this when an experiment is added.
 	All = []ID{
 		X_shadow,
+		X_concise_diff,
 		x_force,
 	}