From df626e898c7d52d70fbaa6d4209a05f36dcdad13 Mon Sep 17 00:00:00 2001
From: Alisdair McDiarmid <alisdair@users.noreply.github.com>
Date: Thu, 10 Dec 2020 11:20:57 -0500
Subject: [PATCH] lang/funcs: Fix alltrue/anytrue with unknowns

The alltrue/anytrue functions did not correctly handle unknown values.
This commit changes these functions so that the result is unknown if:

- The list argument is unknown
- For alltrue: any elements are unknown
- For anytrue: any elements are unknown and no known elements are true

The last change is a little subtle, so there are test cases to cover it
specifically. Examples:

- anytrue(unknown) -> unknown
- anytrue(false, unknown) -> unknown
- anytrue(false, unknown, true) -> true
---
 lang/funcs/collection.go      | 11 ++++++++
 lang/funcs/collection_test.go | 48 +++++++++++++++++++++++++++++++++--
 2 files changed, 57 insertions(+), 2 deletions(-)

diff --git a/lang/funcs/collection.go b/lang/funcs/collection.go
index 6b8d1e6bbe..4324e589db 100644
--- a/lang/funcs/collection.go
+++ b/lang/funcs/collection.go
@@ -70,6 +70,9 @@ var AllTrueFunc = function.New(&function.Spec{
 		result := cty.True
 		for it := args[0].ElementIterator(); it.Next(); {
 			_, v := it.Element()
+			if !v.IsKnown() {
+				return cty.UnknownVal(cty.Bool), nil
+			}
 			if v.IsNull() {
 				return cty.False, nil
 			}
@@ -94,8 +97,13 @@ var AnyTrueFunc = function.New(&function.Spec{
 	Type: function.StaticReturnType(cty.Bool),
 	Impl: func(args []cty.Value, retType cty.Type) (ret cty.Value, err error) {
 		result := cty.False
+		var hasUnknown bool
 		for it := args[0].ElementIterator(); it.Next(); {
 			_, v := it.Element()
+			if !v.IsKnown() {
+				hasUnknown = true
+				continue
+			}
 			if v.IsNull() {
 				continue
 			}
@@ -104,6 +112,9 @@ var AnyTrueFunc = function.New(&function.Spec{
 				return cty.True, nil
 			}
 		}
+		if hasUnknown {
+			return cty.UnknownVal(cty.Bool), nil
+		}
 		return result, nil
 	},
 })
diff --git a/lang/funcs/collection_test.go b/lang/funcs/collection_test.go
index 89cb2a15f7..457ef7f735 100644
--- a/lang/funcs/collection_test.go
+++ b/lang/funcs/collection_test.go
@@ -169,10 +169,28 @@ func TestAllTrue(t *testing.T) {
 			cty.False,
 			false,
 		},
+		{
+			cty.ListVal([]cty.Value{cty.True, cty.NullVal(cty.Bool)}),
+			cty.False,
+			false,
+		},
 		{
 			cty.ListVal([]cty.Value{cty.UnknownVal(cty.Bool)}),
 			cty.UnknownVal(cty.Bool),
-			true,
+			false,
+		},
+		{
+			cty.ListVal([]cty.Value{
+				cty.UnknownVal(cty.Bool),
+				cty.UnknownVal(cty.Bool),
+			}),
+			cty.UnknownVal(cty.Bool),
+			false,
+		},
+		{
+			cty.UnknownVal(cty.List(cty.Bool)),
+			cty.UnknownVal(cty.Bool),
+			false,
 		},
 		{
 			cty.NullVal(cty.List(cty.Bool)),
@@ -232,10 +250,36 @@ func TestAnyTrue(t *testing.T) {
 			cty.True,
 			false,
 		},
+		{
+			cty.ListVal([]cty.Value{cty.NullVal(cty.Bool), cty.True}),
+			cty.True,
+			false,
+		},
 		{
 			cty.ListVal([]cty.Value{cty.UnknownVal(cty.Bool)}),
 			cty.UnknownVal(cty.Bool),
-			true,
+			false,
+		},
+		{
+			cty.ListVal([]cty.Value{
+				cty.UnknownVal(cty.Bool),
+				cty.False,
+			}),
+			cty.UnknownVal(cty.Bool),
+			false,
+		},
+		{
+			cty.ListVal([]cty.Value{
+				cty.UnknownVal(cty.Bool),
+				cty.True,
+			}),
+			cty.True,
+			false,
+		},
+		{
+			cty.UnknownVal(cty.List(cty.Bool)),
+			cty.UnknownVal(cty.Bool),
+			false,
 		},
 		{
 			cty.NullVal(cty.List(cty.Bool)),