From 3b6a7c9e8bef7ee4fc219a10c5a5cec6f13b3e5a Mon Sep 17 00:00:00 2001
From: Pankaj Patil <patilpankaj212@gmail.com>
Date: Mon, 19 Apr 2021 09:17:06 +0530
Subject: [PATCH] fix recursive variable reference resolution

---
 .../terraform/commons/variable-references.go      |  4 ++--
 pkg/iac-providers/terraform/v14/load-dir_test.go  |  7 +++++++
 .../terraform/v14/testdata/recursive-loop/bug.tf  |  9 +++++++++
 .../v14/testdata/recursive-loop/dummy/main.tf     | 12 ++++++++++++
 .../v14/testdata/tfjson/recursive-loop.json       | 15 +++++++++++++++
 5 files changed, 45 insertions(+), 2 deletions(-)
 create mode 100644 pkg/iac-providers/terraform/v14/testdata/recursive-loop/bug.tf
 create mode 100644 pkg/iac-providers/terraform/v14/testdata/recursive-loop/dummy/main.tf
 create mode 100644 pkg/iac-providers/terraform/v14/testdata/tfjson/recursive-loop.json

diff --git a/pkg/iac-providers/terraform/commons/variable-references.go b/pkg/iac-providers/terraform/commons/variable-references.go
index 56443bc9d..c77023631 100644
--- a/pkg/iac-providers/terraform/commons/variable-references.go
+++ b/pkg/iac-providers/terraform/commons/variable-references.go
@@ -148,9 +148,9 @@ func (r *RefResolver) ResolveVarRefFromParentModuleCall(varRef string) interface
 	if reflect.TypeOf(val).Kind() == reflect.String {
 		valStr := val.(string)
 		resolvedVal := strings.Replace(varRef, varExpr, valStr, 1)
-		if varRef == resolvedVal {
+		if strings.Contains(valStr, varExpr) {
 			zap.S().Debugf("resolved str variable ref refers to self: '%v'", varRef)
-			return varRef
+			return resolvedVal
 		}
 		zap.S().Debugf("resolved str variable ref: '%v', value: '%v'", varRef, string(resolvedVal))
 		return r.ResolveStrRef(resolvedVal)
diff --git a/pkg/iac-providers/terraform/v14/load-dir_test.go b/pkg/iac-providers/terraform/v14/load-dir_test.go
index 2121d1b38..5b9b81eec 100644
--- a/pkg/iac-providers/terraform/v14/load-dir_test.go
+++ b/pkg/iac-providers/terraform/v14/load-dir_test.go
@@ -119,6 +119,13 @@ func TestLoadIacDir(t *testing.T) {
 			tfv14:       TfV14{},
 			wantErr:     nil,
 		},
+		{
+			name:        "recursive loop while resolving variables",
+			tfConfigDir: filepath.Join(testDataDir, "recursive-loop"),
+			tfJSONFile:  filepath.Join(tfJSONDir, "recursive-loop.json"),
+			tfv14:       TfV14{},
+			wantErr:     nil,
+		},
 	}
 
 	for _, tt := range table2 {
diff --git a/pkg/iac-providers/terraform/v14/testdata/recursive-loop/bug.tf b/pkg/iac-providers/terraform/v14/testdata/recursive-loop/bug.tf
new file mode 100644
index 000000000..249b94510
--- /dev/null
+++ b/pkg/iac-providers/terraform/v14/testdata/recursive-loop/bug.tf
@@ -0,0 +1,9 @@
+variable "filename" {
+  type = string
+}
+
+module "dummy" {
+  source = "./dummy"
+
+  filename = "${path.module}/${var.filename}"
+}
\ No newline at end of file
diff --git a/pkg/iac-providers/terraform/v14/testdata/recursive-loop/dummy/main.tf b/pkg/iac-providers/terraform/v14/testdata/recursive-loop/dummy/main.tf
new file mode 100644
index 000000000..4e4bc2d72
--- /dev/null
+++ b/pkg/iac-providers/terraform/v14/testdata/recursive-loop/dummy/main.tf
@@ -0,0 +1,12 @@
+variable "filename" {
+  type = string
+}
+
+resource "null_resource" "example" {
+  container_definitions = templatefile(
+    var.filename,
+    {
+      foo = "bar"
+    }
+  )
+}
\ No newline at end of file
diff --git a/pkg/iac-providers/terraform/v14/testdata/tfjson/recursive-loop.json b/pkg/iac-providers/terraform/v14/testdata/tfjson/recursive-loop.json
new file mode 100644
index 000000000..0917e30d2
--- /dev/null
+++ b/pkg/iac-providers/terraform/v14/testdata/tfjson/recursive-loop.json
@@ -0,0 +1,15 @@
+{
+    "null_resource": [
+      {
+        "id": "null_resource.example",
+        "name": "example",
+        "source": "dummy/main.tf",
+        "line": 5,
+        "type": "null_resource",
+        "config": {
+          "container_definitions": "${templatefile(\n    ${path.module}/${var.filename},\n    {\n      foo = \"bar\"\n    }\n  )}"
+        },
+        "skip_rules": null
+      }
+    ]
+  }
\ No newline at end of file