fix: isolate concurrent builds via build_id namespace on git resources#2
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fix: isolate concurrent builds via build_id namespace on git resources#2
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When two build() calls run simultaneously on the same repository, they
collide on shared git resources: the integration branch (feature/<slug>)
and issue branches/worktrees (issue/<NN>-<name>). The workspace setup
agent even deletes existing branches when they conflict, silently
destroying the other build's in-progress work.
Fix: generate a short build_id (8 hex chars) at the start of build() and
thread it through the entire pipeline so all per-build git resources are
uniquely namespaced:
- Integration branch: feature/<build_id>-<goal-slug>
- Issue branches: issue/<build_id>-<NN>-<name>
- Worktree dirs: .worktrees/issue-<build_id>-<NN>-<name>/
The cleanup path derivation (branch.replace("/", "-")) continues to map
correctly to worktree directories because setup and cleanup use the same
naming convention.
All new parameters default to "" for backward compatibility — builds
that call execute() directly without a build_id fall back to the
existing naming convention with no regressions.
Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
Two bugs in the original implementation: 1. Per-level cleanup (dag_executor.py ~1154) derived branch names as `issue/<NN>-<name>` without build_id, so it tried to delete branches that didn't exist (build_id-namespaced builds create `issue/<bid>-<NN>-<name>`). Prefer `branch_name` already injected by _setup_worktrees; fall back to build_id-prefixed derivation otherwise. 2. Final cleanup sweep (dag_executor.py ~1333) had the same bug when constructing the list from dag_state.all_issues. Also tighten the workspace SETUP_SYSTEM_PROMPT to explicitly document both the plain and Build-ID-prefixed command formats and instruct the agent to always follow the task's specified format. Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>
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Summary
build()calls on the same repository collide on shared git resources (integration branch, issue branches, worktree dirs), with the second build silently destroying the first's in-progress workbuild_id(8 hex chars) at the start ofbuild()and thread it through the pipeline so all per-build git resources are uniquely namespaced""— fully backward compatibleWhat Was Broken
When two builds run simultaneously on the same repo, they share:
feature/<goal-slug>: second build fails or hijacks the first's branchissue/<NN>-<name>: workspace setup agent explicitly deletes existing branches before recreating, silently destroying the other build's committed work.worktrees/issue-<NN>-<name>/: same filesystem collisionChanges Made
All git resources are now namespaced by
build_id:feature/<build_id>-<goal-slug>issue/<build_id>-<NN>-<name>.worktrees/issue-<build_id>-<NN>-<name>/The cleanup path derivation (
branch.replace("/", "-")) continues to map correctly to worktree directories since setup and cleanup use the same convention.Files changed:
swe_af/app.py— generatebuild_id, pass torun_git_initandexecute()swe_af/execution/dag_executor.py— threadbuild_idthroughrun_dag(),_init_dag_state(),_setup_worktrees()swe_af/execution/schemas.py— addbuild_idfield toDAGStateswe_af/prompts/git_init.py— instruct agent to usefeature/<build_id>-<goal-slug>swe_af/prompts/workspace.py— instruct agent to useissue/<build_id>-<NN>-<name>branch/dir namesswe_af/reasoners/execution_agents.py— passbuild_idtogit_init_task_promptandworkspace_setup_task_promptTest Plan
issue/abc12345-01-namevsissue/def67890-01-name)execute()called directly withoutbuild_idfalls back to old naming🤖 Generated with Claude Code