fix: implement cursor-based pagination for ListRepositories endpoint

[MayankSharmaCSE]

Summary

The ListRepositories gRPC endpoint was returning all registered repositories in a single unbounded response, with no pagination support. A TODO comment in the code explicitly acknowledged this: "TODO: Implement cursor-based pagination using entity IDs. For now, return all results without pagination."

This caused memory exhaustion and timeouts on projects with large numbers of repositories. The fix implements cursor-based pagination using entity IDs as cursors. The handler now accepts optional limit (default 100, max 1000) and cursor parameters in the request, and returns a cursor field in the response. When the cursor is non-empty, clients can use it to fetch the next page.

Files changed:

• internal/repositories/service.go - Added ListRepositoriesPaginated method to interface and implementation
• internal/controlplane/handlers_repositories.go - Updated handler to use paginated method
• internal/repositories/mock/service.go - Mock regenerated via go generate
• internal/repositories/mock/fixtures/service.go - Added paginated mock fixtures
• internal/controlplane/handlers_repositories_test.go - Updated tests for new pagination behavior

Dependencies: None - uses existing ListEntitiesAfterID DB query that already supports cursor-based pagination.

Fixes #6340

Testing

• Unit tests pass:

go test ./internal/controlplane/... -run "TestServer_ListRepositories" -v
go test ./internal/repositories/...

• All controlplane tests pass: go test ./internal/controlplane/...
• Build succeeds: go build ./...
• Manual testing:
• First page: minder repo list --limit 10
• Next page: minder repo list --limit 10 --cursor <cursor_from_previous_response>

[Copilot]

Pull request overview

Implements cursor-based pagination for the ListRepositories controlplane endpoint to avoid unbounded responses when projects contain large numbers of registered repositories.

Changes:

• Added a new ListRepositoriesPaginated method to the repositories service interface + implementation.
• Updated the ListRepositories gRPC handler to accept limit and cursor and return a response cursor.
• Regenerated/extended repository service mocks and updated handler tests to use the new method.

Reviewed changes

Copilot reviewed 5 out of 5 changed files in this pull request and generated 7 comments.

Show a summary per file

File	Description
internal/repositories/service.go	Adds paginated listing method and pagination logic in repository service.
internal/controlplane/handlers_repositories.go	Switches handler to parse cursor/limit and call paginated service; returns response cursor.
internal/repositories/mock/service.go	Regenerated mock to include ListRepositoriesPaginated.
internal/repositories/mock/fixtures/service.go	Adds fixtures for the new paginated mock method.
internal/controlplane/handlers_repositories_test.go	Updates ListRepositories handler tests to use the new paginated mock fixture.

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[Copilot]

The cursor branch calls ListEntitiesAfterID with only entity_type + id + limit. That query is not scoped to provider_id/project_id, so this endpoint can return repositories from other projects/providers once a non-empty cursor is used (and potentially leak data). Add a scoped pagination query (entity_type + provider_id + project_id + id > cursor ORDER BY id LIMIT ...) and use it here.

[Copilot]

When cursor == uuid.Nil this calls GetEntitiesByType, which has no LIMIT and (in SQL) no ORDER BY. That means the first page still loads all repositories into memory (defeating the pagination goal) and the resulting nextCursor based on the last element is not stable (can skip/duplicate results). Use a DB-level ordered + limited query for the first page too.

[evankanderson]

I think this is the critical comment -- you should set a database limit to avoid doing a lot of extra backend work. Given the cursor-based query, you should be able to fetch using the natural order of the table (ORDER BY id) and then a WHERE clause on id > cursor.

[Copilot]

Rollback is gated on outErr, but outErr is only set around the initial query. If an error occurs later (e.g., in the properties loop), outErr can be nil and the deferred rollback won't run, leaving the transaction open. Use a named return error (like ListRepositories) or defer an unconditional rollback (ignoring ErrTxDone after Commit).

[Copilot]

This method clamps limit to 1000, but the protobuf contract for ListRepositoriesRequest.limit is validated to lte: 100 via protovalidate. Consider aligning the server-side clamp/docs with the API contract (or update the proto + any clients in the same PR).

Suggested change

	if limit > 1000 {
	limit = 1000
	if limit > 100 {
	limit = 100

[Copilot]

ListRepositoriesRequest.cursor is protovalidate-constrained to the pattern ^[[:word:]=]*$, which is not a UUID shape (notably excludes '-'). Parsing the cursor strictly as uuid.UUID can reject otherwise-valid client cursors, and will also fail round-tripping if the server returns a hyphenated UUID. Consider using an opaque cursor encoding that matches the proto constraints (e.g., base64 or hex).

[evankanderson]

You may need to update the annotations in minder.proto, or consider blinding the cursor (e.g. base64 the contents) to make it less of an explicit contract.

[Copilot]

resp.Cursor is set using nextCursor.String(), which produces a hyphenated UUID. Because request validation restricts cursor to ^[[:word:]=]*$, clients may not be able to send this cursor back on the next request. Return an encoding that matches the proto constraints (e.g., UUID hex without hyphens or base64).

Suggested change

	resp.Cursor = nextCursor.String()
	resp.Cursor = strings.ReplaceAll(nextCursor.String(), "-", "")

[Copilot]

This fixture always returns uuid.Nil as nextCursor, so tests can’t cover the new behavior of returning a non-empty cursor and fetching subsequent pages. Consider accepting nextCursor as an argument and adding a test that asserts ListRepositoriesResponse.Cursor is set.

[coveralls]

coverage: 59.204% (-0.1%) from 59.327% — MayankSharmaCSE:fix/list-repositories-pagination into mindersec:main

[MayankSharmaCSE]

@evankanderson Thanks for the review! Both comments are valid and we'll address them:

1. Database limit: You're right that fetching all entities and then truncating in memory defeats pagination. We'll add a new ListEntitiesByTypePaginated query that
   applies LIMIT at the database level for the first page.
2. Cursor blinding: The hyphenated UUIDs don't match the proto pattern ^[[:word:]=]*$. We'll encode the cursor as base64 to make it compliant and less of an
   explicit contract.

We also identified a related issue we'll fix:

• Data scoping: ListEntitiesAfterID needs to be scoped by provider_id/project_id to prevent cross-project data access.

We'll proceed with implementing these fixes. Let us know if you have any concerns!