From bf2d095d861f748920a56b2302a185e52ae6d1b1 Mon Sep 17 00:00:00 2001
From: James Bardin <j.bardin@gmail.com>
Date: Fri, 7 Apr 2023 13:08:33 -0400
Subject: [PATCH] cty: Path.Apply should not panic with marked collections

The return value of `HasIndex` can contain marks, so `IndexStep.Apply`
must strip those marks before checking `True`.
---
 cty/path.go      |  4 ++-
 cty/path_test.go | 64 ++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 67 insertions(+), 1 deletion(-)

diff --git a/cty/path.go b/cty/path.go
index 636e68c6..4995a8c7 100644
--- a/cty/path.go
+++ b/cty/path.go
@@ -225,7 +225,9 @@ func (s IndexStep) Apply(val Value) (Value, error) {
 		return NilVal, errors.New("key value not number or string")
 	}
 
-	has := val.HasIndex(s.Key)
+	// This value needs to be stripped of marks to check True(), but Index will
+	// apply the correct marks for the result.
+	has, _ := val.HasIndex(s.Key).Unmark()
 	if !has.IsKnown() {
 		return UnknownVal(val.Type().ElementType()), nil
 	}
diff --git a/cty/path_test.go b/cty/path_test.go
index 84d0fe2b..93eaafc3 100644
--- a/cty/path_test.go
+++ b/cty/path_test.go
@@ -96,6 +96,70 @@ func TestPathApply(t *testing.T) {
 			cty.NilVal,
 			`at step 0: cannot access attributes on a null value`,
 		},
+		{
+			cty.ListVal([]cty.Value{
+				cty.ListVal([]cty.Value{cty.StringVal("hello")}).Mark(2),
+			}).Mark(1),
+			(cty.Path)(nil).Index(cty.NumberIntVal(0)).Index(cty.NumberIntVal(0)),
+			cty.StringVal("hello").Mark(1).Mark(2),
+			``,
+		},
+		{
+			cty.TupleVal([]cty.Value{
+				cty.ListVal([]cty.Value{cty.StringVal("hello")}).Mark(2),
+			}).Mark(1),
+			(cty.Path)(nil).Index(cty.NumberIntVal(0)).Index(cty.NumberIntVal(0)),
+			cty.StringVal("hello").Mark(1).Mark(2),
+			``,
+		},
+		{
+			cty.MapVal(map[string]cty.Value{
+				"hello": cty.StringVal("there"),
+			}).Mark(1),
+			(cty.Path)(nil).Index(cty.StringVal("hello")),
+			cty.StringVal("there").Mark(1),
+			``,
+		},
+		{
+			cty.ObjectVal(map[string]cty.Value{
+				"hello": cty.StringVal("there"),
+			}).Mark(1),
+			cty.GetAttrPath("hello"),
+			cty.StringVal("there").Mark(1),
+			``,
+		},
+		{
+			cty.ListVal([]cty.Value{
+				cty.StringVal("hello").Mark(1),
+			}),
+			(cty.Path)(nil).Index(cty.NumberIntVal(0)),
+			cty.StringVal("hello").Mark(1),
+			``,
+		},
+		{
+			cty.TupleVal([]cty.Value{
+				cty.StringVal("hello").Mark(1),
+			}),
+			(cty.Path)(nil).Index(cty.NumberIntVal(0)),
+			cty.StringVal("hello").Mark(1),
+			``,
+		},
+		{
+			cty.MapVal(map[string]cty.Value{
+				"hello": cty.StringVal("there").Mark(1),
+			}),
+			(cty.Path)(nil).Index(cty.StringVal("hello")),
+			cty.StringVal("there").Mark(1),
+			``,
+		},
+		{
+			cty.ObjectVal(map[string]cty.Value{
+				"hello": cty.StringVal("there").Mark(1),
+			}),
+			cty.GetAttrPath("hello"),
+			cty.StringVal("there").Mark(1),
+			``,
+		},
 	}
 
 	for _, test := range tests {