kandev/docs/plans/fork-pr-base-resolution/task-01-pr-base-identity.md

id, title, status, wave, depends_on, plan, requirements, acceptance_criteria, system_design

id	title	status	wave	depends_on	plan	requirements	acceptance_criteria	system_design
01-pr-base-identity	Preserve qualified PR base identity	done	1		plan.md	REQ-WORKSPACES-WORKTREE-BASE-REFRESH-001	AC-WORKSPACES-WORKTREE-BASE-REFRESH-001.11 AC-WORKSPACES-WORKTREE-BASE-REFRESH-001.15 AC-WORKSPACES-WORKTREE-BASE-REFRESH-001.16 AC-WORKSPACES-WORKTREE-BASE-REFRESH-001.17 AC-WORKSPACES-WORKTREE-BASE-REFRESH-001.19	../../specs/workspaces/system-design/worktree-base-refresh.md

Task 01: Preserve qualified PR base identity

Summary

Preserve provider repository, branch, and base OID through the PR base resolver. Resolve the namespace from the exact attachment instead of assuming origin.

In scope

• Introduce a typed resolver result that reuses validated ComparisonTarget identity and carries a transient optional observed OID.
• Retain base.sha / baseRefOid across REST and GraphQL conversion. Keep gh pr view/list --json within the supported CLI field set; read the base OID through gh api REST because baseRefOid is not a supported CLI field.
• Validate namespace, number, head repository, and checkout branch together. Use existing exact task-PR associations for legacy attachments. For a contribution attached to the PR base, validate the head against its source repository and the target against the attachment.
• Preserve validated stored targets on provider outage. Reject known cross- repository inputs that lack a valid target. Preserve same-repository fallback.
• Add the failing executor regression before changing the resolver contract.

Out of scope

Git materialization, recovery mutation, database migrations, and public UI.

Acceptance

• TestResolveTaskRepoInfo_PRBaseUsesTargetRepository queries upstream, even when the fork has an unrelated PR with the same number.
• Provider conversion tests retain target branch/OID and reject incomplete or mismatched identity. Same-repository and non-PR tests still pass.
• A legacy attachment with no stored comparison_target rejects a same-number, same-branch PR from another head repository.
• gh pr view/list --json requests contain no unsupported baseRefOid field; GetPR reads the base SHA through gh api without losing the PR on a non-cancellation OID-read error.
• A live retarget changes only the intended launch target. An ambiguous or historical association cannot change another attachment.

Verification

(cd apps/backend && go test ./internal/github ./internal/backendapp ./internal/orchestrator/executor -run 'Test(PRBase|ResolveTaskRepoInfo|GithubPRBase)' -count=1)
(cd apps/backend && go test ./internal/github ./internal/orchestrator/executor -count=1)
git diff --check

Use the named prefixes for new tests so the focused command executes them. Record the expected red regression before the implementation and green results.

Files likely touched

• apps/backend/internal/github/models.go
• apps/backend/internal/github/pat_client.go
• apps/backend/internal/github/gh_client.go
• apps/backend/internal/github/graphql.go
• apps/backend/internal/github/pr_base_identity_test.go (new)
• apps/backend/internal/backendapp/orchestrator.go
• apps/backend/internal/backendapp/pr_base_resolver_test.go (new)
• apps/backend/internal/orchestrator/executor/executor.go
• apps/backend/internal/orchestrator/executor/executor_resume.go
• apps/backend/internal/orchestrator/executor/executor_pr_base_resolver_test.go
• apps/backend/internal/task/models/pr_base.go (new transient contract)

Dependencies

None. Read the current task-PR matching and comparison reconciliation helpers.

Risks

A bare PR number can identify an unrelated fork PR. Query success is not proof of ownership. Custom REST decoding must preserve the new SHA field.

Parallelism

sequential

Inputs

• Worktree base refresh design: Identity and provider lookup.
• github/service_comparison_target.go and task/models/comparison_target.go.
• Existing executor PR-base tests and the plan's temporary reproduction.

Results

• The initial fork/upstream regression failed as expected: the resolver queried fork-owner/widgets instead of upstream/widgets for PR #42.
• The permanent tests cover upstream lookup, live retargeting, rejection of a colliding PR with a different head repository, exact TaskPR selection, and REST/GraphQL base OID conversion. GH CLI command-contract tests verify its supported pr view/list --json fields and REST base SHA/ref/repository read.
• go test ./internal/github ./internal/backendapp ./internal/orchestrator/executor -run 'Test(PRBase|ResolveTaskRepoInfo|GithubPRBase)' -count=1: passed.
• go test ./internal/github ./internal/backendapp ./internal/orchestrator/executor -count=1: passed.
• git diff --check: passed.
• Review correction: the GH CLI does not support baseRefOid in its JSON field list. GetPR reads base SHA, ref, and repository identity through gh api; PR view/list keep the existing supported fields, and a REST read failure does not discard otherwise usable PR details. Command-contract tests cover these paths.
• Review correction: live legacy PR data must match both the attached head repository and checkout branch. Contribution bindings use the validated source repository for that head check and the attachment for the target.
• Review correction: GitHub repository records store ProviderHost as an HTTPS URL. Identity normalization accepts that canonical form without accepting custom ports, paths, or lookalike domains; regression tests cover both the supported host and rejected variants.