From ee52f2664739e9077acbcdaeb3a4cc4c993ea70c Mon Sep 17 00:00:00 2001
From: James Bardin <j.bardin@gmail.com>
Date: Mon, 7 Dec 2020 14:01:44 -0500
Subject: [PATCH] ignore_changes can ignore unknowns too

The logic for handling unknown equality was incorrect, and would miss
changes where the configuration is still not known during plan.
---
 terraform/eval_diff.go      |  2 +-
 terraform/eval_diff_test.go | 72 +++++++++++++++++++++++++++++++++++++
 2 files changed, 73 insertions(+), 1 deletion(-)

diff --git a/terraform/eval_diff.go b/terraform/eval_diff.go
index bf2c86b31..5124b6cd1 100644
--- a/terraform/eval_diff.go
+++ b/terraform/eval_diff.go
@@ -673,7 +673,7 @@ func processIgnoreChangesIndividual(prior, config cty.Value, ignoreChanges []hcl
 		// won't cause any changes in the transformation, but allows us to skip
 		// breaking up the maps and checking for key existence here too.
 		eq := p.Equals(c)
-		if eq.IsKnown() && eq.False() {
+		if !eq.IsKnown() || eq.False() {
 			// there a change to ignore at this path, store the prior value
 			ignoredValues = append(ignoredValues, ignoreChange{icPath, p, key})
 		}
diff --git a/terraform/eval_diff_test.go b/terraform/eval_diff_test.go
index 491b18c72..30d819aad 100644
--- a/terraform/eval_diff_test.go
+++ b/terraform/eval_diff_test.go
@@ -92,6 +92,30 @@ func TestProcessIgnoreChangesIndividual(t *testing.T) {
 				"b": cty.StringVal("new b value"),
 			}),
 		},
+		"map": {
+			cty.ObjectVal(map[string]cty.Value{
+				"a": cty.MapVal(map[string]cty.Value{
+					"a0": cty.StringVal("a0 value"),
+					"a1": cty.StringVal("a1 value"),
+				}),
+				"b": cty.StringVal("b value"),
+			}),
+			cty.ObjectVal(map[string]cty.Value{
+				"a": cty.MapVal(map[string]cty.Value{
+					"a0": cty.StringVal("new a0 value"),
+					"a1": cty.UnknownVal(cty.String),
+				}),
+				"b": cty.StringVal("b value"),
+			}),
+			[]string{`a`},
+			cty.ObjectVal(map[string]cty.Value{
+				"a": cty.MapVal(map[string]cty.Value{
+					"a0": cty.StringVal("a0 value"),
+					"a1": cty.StringVal("a1 value"),
+				}),
+				"b": cty.StringVal("b value"),
+			}),
+		},
 		"map_index": {
 			cty.ObjectVal(map[string]cty.Value{
 				"a": cty.MapVal(map[string]cty.Value{
@@ -136,6 +160,30 @@ func TestProcessIgnoreChangesIndividual(t *testing.T) {
 				"b": cty.StringVal("b value"),
 			}),
 		},
+		"map_index_unknown_value": {
+			cty.ObjectVal(map[string]cty.Value{
+				"a": cty.MapVal(map[string]cty.Value{
+					"a0": cty.StringVal("a0 value"),
+					"a1": cty.StringVal("a1 value"),
+				}),
+				"b": cty.StringVal("b value"),
+			}),
+			cty.ObjectVal(map[string]cty.Value{
+				"a": cty.MapVal(map[string]cty.Value{
+					"a0": cty.StringVal("a0 value"),
+					"a1": cty.UnknownVal(cty.String),
+				}),
+				"b": cty.StringVal("b value"),
+			}),
+			[]string{`a["a1"]`},
+			cty.ObjectVal(map[string]cty.Value{
+				"a": cty.MapVal(map[string]cty.Value{
+					"a0": cty.StringVal("a0 value"),
+					"a1": cty.StringVal("a1 value"),
+				}),
+				"b": cty.StringVal("b value"),
+			}),
+		},
 		"map_index_multiple_keys": {
 			cty.ObjectVal(map[string]cty.Value{
 				"a": cty.MapVal(map[string]cty.Value{
@@ -297,6 +345,30 @@ func TestProcessIgnoreChangesIndividual(t *testing.T) {
 				"b": cty.StringVal("new b value"),
 			}),
 		},
+		"unknown_object_attribute": {
+			cty.ObjectVal(map[string]cty.Value{
+				"a": cty.ObjectVal(map[string]cty.Value{
+					"foo": cty.StringVal("a.foo value"),
+					"bar": cty.StringVal("a.bar value"),
+				}),
+				"b": cty.StringVal("b value"),
+			}),
+			cty.ObjectVal(map[string]cty.Value{
+				"a": cty.ObjectVal(map[string]cty.Value{
+					"foo": cty.StringVal("new a.foo value"),
+					"bar": cty.UnknownVal(cty.String),
+				}),
+				"b": cty.StringVal("new b value"),
+			}),
+			[]string{"a.bar"},
+			cty.ObjectVal(map[string]cty.Value{
+				"a": cty.ObjectVal(map[string]cty.Value{
+					"foo": cty.StringVal("new a.foo value"),
+					"bar": cty.StringVal("a.bar value"),
+				}),
+				"b": cty.StringVal("new b value"),
+			}),
+		},
 	}
 
 	for name, test := range tests {