From c05baec7fdcd599bc72d7d8023cbbbede8634d9c Mon Sep 17 00:00:00 2001
From: Alan Crosswell <alan@columbia.edu>
Date: Sat, 23 Jan 2021 14:12:18 -0500
Subject: [PATCH] Fix gitlab prepare fails with a 404.

A GitLab URL not ending in .git requires a redirect which isomorphic-git doesn't follow, resulting in a 404.
This incorporates @ruloweb's fix in #4134.
---
 .changeset/breezy-meals-lie.md                                | 2 ++
 .../src/scaffolder/stages/prepare/gitlab.test.ts              | 4 ++--
 .../src/scaffolder/stages/prepare/gitlab.ts                   | 1 +
 3 files changed, 5 insertions(+), 2 deletions(-)

diff --git a/.changeset/breezy-meals-lie.md b/.changeset/breezy-meals-lie.md
index cbdd876614..4ca4f1ac35 100644
--- a/.changeset/breezy-meals-lie.md
+++ b/.changeset/breezy-meals-lie.md
@@ -16,3 +16,5 @@ catalog:
     - type: url
       target: https://github.com/backstage/backstage/blob/other/plugins/scaffolder-backend/sample-templates/docs-template/template.yaml
 ```
+
+This also fixes a 404 in the prepare stage for GitLab URLs.
diff --git a/plugins/scaffolder-backend/src/scaffolder/stages/prepare/gitlab.test.ts b/plugins/scaffolder-backend/src/scaffolder/stages/prepare/gitlab.test.ts
index 8ea1d77859..0b77fd813b 100644
--- a/plugins/scaffolder-backend/src/scaffolder/stages/prepare/gitlab.test.ts
+++ b/plugins/scaffolder-backend/src/scaffolder/stages/prepare/gitlab.test.ts
@@ -87,7 +87,7 @@ describe('GitLabPreparer', () => {
     await preparer.prepare(mockEntity, { logger: getVoidLogger() });
 
     expect(mockGitClient.clone).toHaveBeenCalledWith({
-      url: 'https://gitlab.com/benjdlambert/backstage-graphql-template',
+      url: 'https://gitlab.com/benjdlambert/backstage-graphql-template.git',
       dir: expect.any(String),
       ref: expect.any(String),
     });
@@ -112,7 +112,7 @@ describe('GitLabPreparer', () => {
     await preparer.prepare(mockEntity, { logger: getVoidLogger() });
 
     expect(mockGitClient.clone).toHaveBeenCalledWith({
-      url: 'https://gitlab.com/benjdlambert/backstage-graphql-template',
+      url: 'https://gitlab.com/benjdlambert/backstage-graphql-template.git',
       dir: expect.any(String),
       ref: expect.any(String),
     });
diff --git a/plugins/scaffolder-backend/src/scaffolder/stages/prepare/gitlab.ts b/plugins/scaffolder-backend/src/scaffolder/stages/prepare/gitlab.ts
index 0ce5466915..4368c1c242 100644
--- a/plugins/scaffolder-backend/src/scaffolder/stages/prepare/gitlab.ts
+++ b/plugins/scaffolder-backend/src/scaffolder/stages/prepare/gitlab.ts
@@ -41,6 +41,7 @@ export class GitlabPreparer implements PreparerBase {
     const templateId = template.metadata.name;
 
     const parsedGitLocation = parseGitUrl(location);
+    parsedGitLocation.git_suffix = true;
     const repositoryCheckoutUrl = parsedGitLocation.toString('https');
     const ref = parsedGitLocation.ref;
     const tempDir = await fs.promises.mkdtemp(