From 92405f32bb0cf4acd0d860b354fca411281f62ee Mon Sep 17 00:00:00 2001
From: blam <ben@blam.sh>
Date: Wed, 24 Nov 2021 13:55:28 +0100
Subject: [PATCH 1/3] bug: should check the children of the first parse, not
 the root.

Signed-off-by: blam <ben@blam.sh>
---
 ...WorkflowRunner.test.ts => NunjucksWorkflowRunner.test.ts} | 0
 .../src/scaffolder/tasks/NunjucksWorkflowRunner.ts           | 5 +++--
 2 files changed, 3 insertions(+), 2 deletions(-)
 rename plugins/scaffolder-backend/src/scaffolder/tasks/{DefaultWorkflowRunner.test.ts => NunjucksWorkflowRunner.test.ts} (100%)

diff --git a/plugins/scaffolder-backend/src/scaffolder/tasks/DefaultWorkflowRunner.test.ts b/plugins/scaffolder-backend/src/scaffolder/tasks/NunjucksWorkflowRunner.test.ts
similarity index 100%
rename from plugins/scaffolder-backend/src/scaffolder/tasks/DefaultWorkflowRunner.test.ts
rename to plugins/scaffolder-backend/src/scaffolder/tasks/NunjucksWorkflowRunner.test.ts
diff --git a/plugins/scaffolder-backend/src/scaffolder/tasks/NunjucksWorkflowRunner.ts b/plugins/scaffolder-backend/src/scaffolder/tasks/NunjucksWorkflowRunner.ts
index c66d967103..1139ce41c5 100644
--- a/plugins/scaffolder-backend/src/scaffolder/tasks/NunjucksWorkflowRunner.ts
+++ b/plugins/scaffolder-backend/src/scaffolder/tasks/NunjucksWorkflowRunner.ts
@@ -114,9 +114,10 @@ export class NunjucksWorkflowRunner implements WorkflowRunner {
   private isSingleTemplateString(input: string) {
     const { parser, nodes } = require('nunjucks');
     const parsed = parser.parse(input, {}, this.nunjucksOptions);
+
     return (
       parsed.children.length === 1 &&
-      !(parsed.children[0] instanceof nodes.TemplateData)
+      !(parsed.children[0]?.children?.[0] instanceof nodes.TemplateData)
     );
   }
 
@@ -147,7 +148,7 @@ export class NunjucksWorkflowRunner implements WorkflowRunner {
               return JSON.parse(templated);
             }
           } catch (ex) {
-            this.options.logger.error(
+            console.error(
               `Failed to parse template string: ${value} with error ${ex.message}`,
             );
           }

From 5fd0e077bc3e38cf98dfb172690b4fcdbab4a1d1 Mon Sep 17 00:00:00 2001
From: blam <ben@blam.sh>
Date: Wed, 24 Nov 2021 14:01:26 +0100
Subject: [PATCH 2/3] chore: adding test for this bug

Signed-off-by: blam <ben@blam.sh>
---
 .../tasks/NunjucksWorkflowRunner.test.ts      | 25 +++++++++++++++++++
 .../tasks/NunjucksWorkflowRunner.ts           |  2 +-
 2 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/plugins/scaffolder-backend/src/scaffolder/tasks/NunjucksWorkflowRunner.test.ts b/plugins/scaffolder-backend/src/scaffolder/tasks/NunjucksWorkflowRunner.test.ts
index 1f7877791c..b2e2e85a6c 100644
--- a/plugins/scaffolder-backend/src/scaffolder/tasks/NunjucksWorkflowRunner.test.ts
+++ b/plugins/scaffolder-backend/src/scaffolder/tasks/NunjucksWorkflowRunner.test.ts
@@ -270,6 +270,31 @@ describe('DefaultWorkflowRunner', () => {
       );
     });
 
+    it('should not try and parse something that is not parsable', async () => {
+      jest.spyOn(logger, 'error');
+      const task = createMockTaskWithSpec({
+        apiVersion: 'scaffolder.backstage.io/v1beta3',
+        steps: [
+          {
+            id: 'test',
+            name: 'name',
+            action: 'jest-mock-action',
+            input: {
+              foo: 'bob',
+            },
+          },
+        ],
+        output: {},
+        parameters: {
+          input: 'BACKSTAGE',
+        },
+      });
+
+      await runner.execute(task);
+
+      expect(logger.error).not.toHaveBeenCalled();
+    });
+
     it('should keep the original types for the input and not parse things that arent meant to be parsed', async () => {
       const task = createMockTaskWithSpec({
         apiVersion: 'scaffolder.backstage.io/v1beta3',
diff --git a/plugins/scaffolder-backend/src/scaffolder/tasks/NunjucksWorkflowRunner.ts b/plugins/scaffolder-backend/src/scaffolder/tasks/NunjucksWorkflowRunner.ts
index 1139ce41c5..5b42eef459 100644
--- a/plugins/scaffolder-backend/src/scaffolder/tasks/NunjucksWorkflowRunner.ts
+++ b/plugins/scaffolder-backend/src/scaffolder/tasks/NunjucksWorkflowRunner.ts
@@ -148,7 +148,7 @@ export class NunjucksWorkflowRunner implements WorkflowRunner {
               return JSON.parse(templated);
             }
           } catch (ex) {
-            console.error(
+            this.options.logger.error(
               `Failed to parse template string: ${value} with error ${ex.message}`,
             );
           }

From e634a47ce50236b65a73140f0c4b0c7fbd559c1f Mon Sep 17 00:00:00 2001
From: blam <ben@blam.sh>
Date: Wed, 24 Nov 2021 14:03:22 +0100
Subject: [PATCH 3/3] chore: added changeset

Signed-off-by: blam <ben@blam.sh>
---
 .changeset/shiny-insects-remember.md | 5 +++++
 1 file changed, 5 insertions(+)
 create mode 100644 .changeset/shiny-insects-remember.md

diff --git a/.changeset/shiny-insects-remember.md b/.changeset/shiny-insects-remember.md
new file mode 100644
index 0000000000..a26882b65d
--- /dev/null
+++ b/.changeset/shiny-insects-remember.md
@@ -0,0 +1,5 @@
+---
+'@backstage/plugin-scaffolder-backend': patch
+---
+
+Fix bug where there was error log lines written when failing to `JSON.parse` things that were not `JSON` values.