fix(backend): match GitLab topics case-insensitively (#1393)

* Match GitLab topic filters case-insensitively

Normalize GitLab project topics before include/exclude matching so mixed-case GitLab topics obey the lowercased filter patterns.\n\nConstraint: GitLab connection configs already normalize configured topic filters to lowercase.\nRejected: Preserve project-side case sensitivity | it makes mixed-case GitLab topics fail otherwise matching filters.\nConfidence: high\nScope-risk: narrow\nDirective: Keep GitLab topic include and exclude matching symmetric.\nTested: node .yarn/releases/yarn-4.7.0.cjs workspace @sourcebot/backend test src/gitlab.test.ts; node .yarn/releases/yarn-4.7.0.cjs workspace @sourcebot/backend build\nNot-tested: Live GitLab API sync against mixed-case project topics

* Record GitLab topic matching fix

Document the GitLab topic case-insensitive matching fix in the Unreleased changelog after the PR number was assigned.\n\nConstraint: Sourcebot requires every PR to include a changelog entry with the PR link.\nConfidence: high\nScope-risk: narrow\nDirective: Keep changelog entries as follow-up commits once PR numbers exist.\nTested: not run; changelog-only change\nNot-tested: Runtime behavior

* Cover GitLab topic glob case folding

Add a regression for mixed-case GitLab project topics matching lowercase include-topic glob filters.\n\nConstraint: CodeRabbit requested explicit glob coverage for the new case-insensitive topic matching behavior.\nConfidence: high\nScope-risk: narrow\nDirective: Keep topic filter behavior covered for exact and glob patterns.\nTested: node .yarn/releases/yarn-4.7.0.cjs workspace @sourcebot/backend test src/gitlab.test.ts; node .yarn/releases/yarn-4.7.0.cjs workspace @sourcebot/backend build\nNot-tested: Live GitLab API sync against mixed-case project topics

* Update CHANGELOG.md

---------

Co-authored-by: Brendan Kellam <brendan@sourcebot.dev>

Author: DivyamTalwar

CHANGELOG.md

@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Fixed
 - Upgraded `brace-expansion` to `^1.1.17`/`^2.1.3`/`^5.0.8`. [#1527](https://github.com/sourcebot-dev/sourcebot/pull/1527)
 - Upgraded `tar` to `^7.5.22`. [#1472](https://github.com/sourcebot-dev/sourcebot/pull/1472)
+- Fixed GitLab topic filters being incorrectly case-sensitive. [#1393](https://github.com/sourcebot-dev/sourcebot/pull/1393)
 
 ## [5.1.5] - 2026-07-31
 

packages/backend/src/gitlab.test.ts

@@ -117,6 +117,18 @@ test('shouldExcludeProject returns false when include.topics matches via glob pa
     })).toBe(false);
 });
 
+test('shouldExcludeProject matches include.topics glob patterns case-insensitively.', () => {
+    const project = {
+        path_with_namespace: 'test/project',
+        topics: ['Core-API'],
+    } as unknown as ProjectSchema;
+
+    expect(shouldExcludeProject({
+        project,
+        include: { topics: ['core-*'] },
+    })).toBe(false);
+});
+
 test('shouldExcludeProject returns true when exclude.topics matches a project topic.', () => {
     const project = {
         path_with_namespace: 'test/project',
@@ -141,16 +153,26 @@ test('shouldExcludeProject returns false when exclude.topics does not match any
     })).toBe(false);
 });
 
-test('shouldExcludeProject include.topics matching is case-sensitive on the project side.', () => {
+test('shouldExcludeProject matches include.topics case-insensitively.', () => {
     const project = {
         path_with_namespace: 'test/project',
         topics: ['Backend'],
     } as unknown as ProjectSchema;
 
-    // The function lowercases config topics but not project topics,
-    // so 'Backend' does not match the lowercased pattern 'backend'.
     expect(shouldExcludeProject({
         project,
         include: { topics: ['backend'] },
+    })).toBe(false);
+});
+
+test('shouldExcludeProject matches exclude.topics case-insensitively.', () => {
+    const project = {
+        path_with_namespace: 'test/project',
+        topics: ['Deprecated'],
+    } as unknown as ProjectSchema;
+
+    expect(shouldExcludeProject({
+        project,
+        exclude: { topics: ['deprecated'] },
     })).toBe(true);
 });

packages/backend/src/gitlab.ts

@@ -249,7 +249,7 @@ export const shouldExcludeProject = ({
 
         if (include?.topics) {
             const configTopics = include.topics.map(topic => topic.toLowerCase());
-            const projectTopics = project.topics ?? [];
+            const projectTopics = (project.topics ?? []).map(topic => topic.toLowerCase());
 
             const matchingTopics = projectTopics.filter((topic) => micromatch.isMatch(topic, configTopics));
             if (matchingTopics.length === 0) {
@@ -260,7 +260,7 @@ export const shouldExcludeProject = ({
 
         if (exclude?.topics) {
             const configTopics = exclude.topics.map(topic => topic.toLowerCase());
-            const projectTopics = project.topics ?? [];
+            const projectTopics = (project.topics ?? []).map(topic => topic.toLowerCase());
 
             const matchingTopics = projectTopics.filter((topic) => micromatch.isMatch(topic, configTopics));
             if (matchingTopics.length > 0) {
@@ -333,4 +333,4 @@ export const getOAuthScopesForAuthenticatedUser = async (api: InstanceType<typeo
         logger.error('Failed to fetch OAuth scopes for authenticated user.', error);
         throw error;
     }
-}
+}