From d15355c9b8f22d29324ae20be52dd69334572a41 Mon Sep 17 00:00:00 2001
From: Peter Macdonald <peterm4c@pm.me>
Date: Wed, 16 Apr 2025 12:58:02 +0200
Subject: [PATCH] feat: Update gitlab repo push error handling slightly when
 the commit action is not create

Signed-off-by: Peter Macdonald <peterm4c@pm.me>
---
 .changeset/bumpy-showers-design.md            |  5 ++
 .../src/actions/gitlabRepoPush.test.ts        | 71 +++++++++++++++++++
 .../src/actions/gitlabRepoPush.ts             |  7 ++
 3 files changed, 83 insertions(+)
 create mode 100644 .changeset/bumpy-showers-design.md

diff --git a/.changeset/bumpy-showers-design.md b/.changeset/bumpy-showers-design.md
new file mode 100644
index 0000000000..2db5006944
--- /dev/null
+++ b/.changeset/bumpy-showers-design.md
@@ -0,0 +1,5 @@
+---
+'@backstage/plugin-scaffolder-backend-module-gitlab': patch
+---
+
+If the commit action is not `create` log a more appropriate error message to the end user advising that the files they're trying to modify might not exist
diff --git a/plugins/scaffolder-backend-module-gitlab/src/actions/gitlabRepoPush.test.ts b/plugins/scaffolder-backend-module-gitlab/src/actions/gitlabRepoPush.test.ts
index 65cf2244d4..5644e0b952 100644
--- a/plugins/scaffolder-backend-module-gitlab/src/actions/gitlabRepoPush.test.ts
+++ b/plugins/scaffolder-backend-module-gitlab/src/actions/gitlabRepoPush.test.ts
@@ -376,4 +376,75 @@ describe('createGitLabCommit', () => {
       );
     });
   });
+
+  describe('error handling', () => {
+    it('throws appropriate error for create action when commit fails', async () => {
+      const input = {
+        repoUrl: 'gitlab.com?repo=repo&owner=owner',
+        commitMessage: 'Create my new commit',
+        branchName: 'some-branch',
+        commitAction: 'create',
+      };
+      mockDir.setContent({
+        [workspacePath]: {
+          'foo.txt': 'Hello there!',
+        },
+      });
+
+      const ctx = createMockActionContext({ input, workspacePath });
+      mockGitlabClient.Commits.create.mockRejectedValue(
+        new Error('Commit failed'),
+      );
+
+      await expect(instance.handler(ctx)).rejects.toThrow(
+        'Committing the changes to some-branch failed. Please check that none of the files created by the template already exists. Error: Commit failed',
+      );
+    });
+
+    it('throws appropriate error for update action when commit fails', async () => {
+      const input = {
+        repoUrl: 'gitlab.com?repo=repo&owner=owner',
+        commitMessage: 'Update my commit',
+        branchName: 'some-branch',
+        commitAction: 'update',
+      };
+      mockDir.setContent({
+        [workspacePath]: {
+          'foo.txt': 'Hello there!',
+        },
+      });
+
+      const ctx = createMockActionContext({ input, workspacePath });
+      mockGitlabClient.Commits.create.mockRejectedValue(
+        new Error('Commit failed'),
+      );
+
+      await expect(instance.handler(ctx)).rejects.toThrow(
+        "Modifying the files in some-branch failed. Please verify that all files you're trying to modify exist in the repository. Error: Commit failed",
+      );
+    });
+
+    it('throws appropriate error for delete action when commit fails', async () => {
+      const input = {
+        repoUrl: 'gitlab.com?repo=repo&owner=owner',
+        commitMessage: 'Delete my commit',
+        branchName: 'some-branch',
+        commitAction: 'delete',
+      };
+      mockDir.setContent({
+        [workspacePath]: {
+          'foo.txt': 'Hello there!',
+        },
+      });
+
+      const ctx = createMockActionContext({ input, workspacePath });
+      mockGitlabClient.Commits.create.mockRejectedValue(
+        new Error('Commit failed'),
+      );
+
+      await expect(instance.handler(ctx)).rejects.toThrow(
+        "Modifying the files in some-branch failed. Please verify that all files you're trying to modify exist in the repository. Error: Commit failed",
+      );
+    });
+  });
 });
diff --git a/plugins/scaffolder-backend-module-gitlab/src/actions/gitlabRepoPush.ts b/plugins/scaffolder-backend-module-gitlab/src/actions/gitlabRepoPush.ts
index 666e236cda..8b6f5cca50 100644
--- a/plugins/scaffolder-backend-module-gitlab/src/actions/gitlabRepoPush.ts
+++ b/plugins/scaffolder-backend-module-gitlab/src/actions/gitlabRepoPush.ts
@@ -203,6 +203,13 @@ export const createGitlabRepoPushAction = (options: {
         ctx.output('projectPath', repoID);
         ctx.output('commitHash', commitId);
       } catch (e) {
+        if (commitAction !== 'create') {
+          throw new InputError(
+            `Modifying the files in ${branchName} failed. Please verify that all files you're trying to modify exist in the repository. ${getErrorMessage(
+              e,
+            )}`,
+          );
+        }
         throw new InputError(
           `Committing the changes to ${branchName} failed. Please check that none of the files created by the template already exists. ${getErrorMessage(
             e,