Adds prompt for missing static variables (#2047)

Signed-off-by: Andrew Hayes <andrew.hayes@harness.io>

internal/command/init_test.go

@@ -2930,6 +2930,8 @@ func TestInit_moduleSource(t *testing.T) {
 
 		ui := cli.NewMockUi()
 		view, _ := testView(t)
+		closeInput := testInteractiveInput(t, []string{"./mod"})
+		defer closeInput()
 		c := &InitCommand{
 			Meta: Meta{
 				Ui:   ui,
@@ -2937,13 +2939,54 @@ func TestInit_moduleSource(t *testing.T) {
 			},
 		}
 
-		if code := c.Run(nil); code != 1 {
-			t.Fatalf("got exit status %d; want 1\nstderr:\n%s\n\nstdout:\n%s", code, ui.ErrorWriter.String(), ui.OutputWriter.String())
+		if code := c.Run(nil); code != 0 {
+			t.Fatalf("got exit status %d; want 0\nstderr:\n%s\n\nstdout:\n%s", code, ui.ErrorWriter.String(), ui.OutputWriter.String())
+		}
+	})
+
+	t.Run("missing-twice", func(t *testing.T) {
+		td := t.TempDir()
+		testCopyDir(t, testFixturePath("init-module-variable-source-multiple"), td)
+		defer testChdir(t, td)()
+
+		ui := cli.NewMockUi()
+		view, _ := testView(t)
+		closeInput := testInteractiveInput(t, []string{"./mod"})
+		defer closeInput()
+		c := &InitCommand{
+			Meta: Meta{
+				Ui:   ui,
+				View: view,
+			},
 		}
 
-		errStr := ui.ErrorWriter.String()
-		if !strings.Contains(errStr, `Variable not provided`) {
-			t.Fatalf("output should point to unmet version constraint, but is:\n\n%s", errStr)
+		if code := c.Run(nil); code != 0 {
+			t.Fatalf("got exit status %d; want 0\nstderr:\n%s\n\nstdout:\n%s", code, ui.ErrorWriter.String(), ui.OutputWriter.String())
+		}
+	})
+
+	t.Run("no-input", func(t *testing.T) {
+		td := t.TempDir()
+		testCopyDir(t, testFixturePath("init-module-variable-source"), td)
+		defer testChdir(t, td)()
+
+		ui := cli.NewMockUi()
+		view, _ := testView(t)
+		closeInput := testInteractiveInput(t, []string{})
+		defer closeInput()
+		c := &InitCommand{
+			Meta: Meta{
+				Ui:   ui,
+				View: view,
+			},
+		}
+
+		args := []string{
+			"-input=false",
+		}
+
+		if code := c.Run(args); code != 1 {
+			t.Fatalf("got exit status %d; want 1\nstderr:\n%s\n\nstdout:\n%s", code, ui.ErrorWriter.String(), ui.OutputWriter.String())
 		}
 	})
 

internal/command/meta_config.go

@@ -8,6 +8,7 @@ package command
 import (
 	"context"
 	"fmt"
+	"log"
 	"os"
 	"path/filepath"
 	"sort"
@@ -129,19 +130,27 @@ func (m *Meta) rootModuleCall(rootDir string) (configs.StaticModuleCall, tfdiags
 		name := variable.Name
 		v, ok := variables[name]
 		if !ok {
-			// For now, we are simply failing when the user omits a required variable. This is due to complex interactions between variables in different code paths (apply existing plan for example)
-			// Ideally, we should be able to use something like backend_local.go:interactiveCollectVariables() in the future to allow users to provide values if input is enabled
-			// This is probably blocked by command package refactoring
 			if variable.Required() {
-				// Not specified on CLI or in var files, without a valid default.
+				// User prompts are best efforts, so we accept the input here
+				// and rely on downstream checks to validate it
+				rawVal, err := m.getInput(context.Background(), variable)
+				if err != nil {
 					return cty.NilVal, hcl.Diagnostics{&hcl.Diagnostic{
 						Severity: hcl.DiagError,
-					Summary:  "Variable not provided via -var, tfvars files, or env",
+						Summary:  fmt.Sprintf("Failed to request input from user for variable var.%s", variable.Name),
 						Subject:  variable.DeclRange.Ptr(),
 					}}
 				}
+				v = unparsedVariableValueString{
+					str:        rawVal,
+					name:       name,
+					sourceType: tofu.ValueFromInput,
+				}
+				m.updateInputVariableCache(name, v)
+			} else {
 				return variable.Default, nil
 			}
+		}
 
 		parsed, parsedDiags := v.ParseVariableValue(variable.ParsingMode)
 		return parsed.Value, parsedDiags.ToHCL()
@@ -150,6 +159,24 @@ func (m *Meta) rootModuleCall(rootDir string) (configs.StaticModuleCall, tfdiags
 	return call, diags
 }
 
+func (m *Meta) getInput(ctx context.Context, variable *configs.Variable) (string, error) {
+	if !m.Input() {
+		return "", fmt.Errorf("input is disabled")
+	}
+	uiInput := m.UIInput()
+	rawValue, err := uiInput.Input(ctx, &tofu.InputOpts{
+		Id:          fmt.Sprintf("var.%s", variable.Name),
+		Query:       fmt.Sprintf("var.%s", variable.Name),
+		Description: variable.Description,
+		Secret:      variable.Sensitive,
+	})
+	if err != nil {
+		log.Printf("[TRACE] Meta.getInput Failed to prompt for %s: %s", variable.Name, err)
+		return "", err
+	}
+	return rawValue, nil
+}
+
 // loadSingleModuleWithTests matches loadSingleModule except it also loads any
 // tests for the target module.
 func (m *Meta) loadSingleModuleWithTests(dir string, testDir string) (*configs.Module, tfdiags.Diagnostics) {

internal/command/meta_vars.go

@@ -132,6 +132,10 @@ func (m *Meta) collectVariableValues() (map[string]backend.UnparsedVariableValue
 	return ret, diags
 }
 
+func (m *Meta) updateInputVariableCache(key string, value backend.UnparsedVariableValue) {
+	m.inputVariableCache[key] = value
+}
+
 func (m *Meta) addVarsFromDir(currDir string, ret map[string]backend.UnparsedVariableValue) tfdiags.Diagnostics {
 	var diags tfdiags.Diagnostics
 

internal/command/plan_test.go

@@ -918,6 +918,41 @@ func TestPlan_providerArgumentUnset(t *testing.T) {
 	}
 }
 
+// based on the TestPlan_varsUnset test
+// this is to check if we use the static variable in a resource
+// does Plan ask for input
+func TestPlan_resource_variable_inputs(t *testing.T) {
+	td := t.TempDir()
+	testCopyDir(t, testFixturePath("plan-vars-unset"), td)
+	defer testChdir(t, td)()
+
+	// The plan command will prompt for interactive input of var.src.
+	// We'll answer "mod" to that prompt, which should then allow this
+	// configuration to apply even though var.src doesn't have a
+	// default value and there are no -var arguments on our command line.
+
+	// This will (helpfully) panic if more than one variable is requested during plan:
+	// https://github.com/hashicorp/terraform/issues/26027
+	inputClose := testInteractiveInput(t, []string{"./mod"})
+	defer inputClose()
+
+	p := planVarsFixtureProvider()
+	view, done := testView(t)
+	c := &PlanCommand{
+		Meta: Meta{
+			testingOverrides: metaOverridesForProvider(p),
+			View:             view,
+		},
+	}
+
+	args := []string{}
+	code := c.Run(args)
+	output := done(t)
+	if code != 0 {
+		t.Fatalf("bad: %d\n\n%s", code, output.Stderr())
+	}
+}
+
 // Test that tofu properly merges provider configuration that's split
 // between config files and interactive input variables.
 // https://github.com/hashicorp/terraform/issues/28956

internal/command/testdata/init-module-variable-source-multiple/main.tf

@@ -0,0 +1,11 @@
+variable "src" {
+	type = string
+}
+
+module "mod" {
+	source = var.src
+}
+
+module "mod2" {
+	source = var.src
+}

internal/command/testdata/plan-vars-unset/.terraform/modules/modules.json

@@ -0,0 +1,14 @@
+{
+    "Modules": [
+        {
+            "Key": "",
+            "Source": "",
+            "Dir": "."
+        },
+        {
+            "Key": "mod",
+            "Source": "./mod",
+            "Dir": "mod"
+        }
+    ]
+}

internal/command/testdata/plan-vars-unset/main.tf

@@ -0,0 +1,11 @@
+variable "src" {
+	type = string
+}
+
+module "mod" {
+	source = "${var.src}"
+}
+
+resource "test_instance" "src" {
+    value = "${var.src}"
+}

internal/command/testdata/plan-vars-unset/mod/mod.tf

@@ -0,0 +1,3 @@
+output "stuff" {
+  value = "things"
+}