Allow specifying the branching point even for trunk parents #621

draftcode · 2025-10-30T06:04:09Z

This relax the semantics of the branch metadata. In the branch metadata,
we track trunk: bool and head: string, but only one of them could be
specified in the current semantics. This update allows them to specify
both. That is, even if the parent branch is a trunk branch, a branch
metadata can specify the branching point. Accordingly, we update the
internal name of that branching point as BranchingPointCommitHash.

Newly added av branch --remote motivates this change. In that command,
we might see a partially merged stack. In that case, we will have a case
where a topic branch would have a trunk branch as a parent (because its
original parent has been merged), but at the same time, such topic
branches would need to have an explicit branching point in order to
avoid already merged commits to be considered as a part of that topic
branch.

Behavior updates would be necessary in the sequencer, but we will do
that in the following PRs.

aviator-app · 2025-10-30T06:04:13Z

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aviator-app · 2025-10-30T06:04:15Z

✅ FlexReview Status

Common Owner: aviator-co/engineering (expert-load-balance assignment)
Owner and Assignment:

✅ aviator-co/engineering (expert-load-balance assignment)
- Slack: #av-slack-testing
- Assigned: simsinght, tulioz
Owned Files
- 🔒 e2e_tests/restack_test.go
- 🔒 e2e_tests/sync_test.go
- 🔒 cmd/av/adopt.go
- 🔒 cmd/av/branch.go
- 🔒 cmd/av/branchmeta.go
- 🔒 cmd/av/diff.go
- 🔒 internal/actions/get_remote_stacked_pr.go
- 🔒 internal/actions/pr.go
- 🔒 internal/meta/branchstate.go
- 🔒 internal/reorder/plan.go
- 🔒 internal/reorder/plan_test.go
- 🔒 internal/reorder/stackbranch.go
- 🔒 internal/sequencer/sequencer.go
- 🔒 internal/gh/ghui/push.go

Review SLO: 7 business hours if PR size is <= 200 LOC for the first response.

gemini-code-assist · 2025-10-30T06:04:30Z

Summary of Changes

Hello @draftcode, I'm Gemini Code Assist¹! I'm currently reviewing this pull request and will post my feedback shortly. In the meantime, here's a summary to help you and other reviewers quickly get up to speed!

This pull request introduces a significant refinement to how branch metadata is managed, specifically by allowing the explicit tracking of a BranchingPointCommitHash even when a branch's parent is identified as a trunk branch. This change is crucial for accurately representing complex branching scenarios, such as those encountered with partially merged stacks, where a topic branch might derive from a trunk but still needs a fixed reference point to distinguish its own commits. By renaming the Head field to BranchingPointCommitHash and updating its usage across the codebase, the PR enhances the precision and flexibility of branch tracking within the system.

Highlights

Enhanced Branch Metadata Semantics: The BranchState metadata now allows specifying both Trunk status and an explicit BranchingPointCommitHash simultaneously, relaxing previous constraints and enabling more flexible branch tracking.
Renamed Head to BranchingPointCommitHash: The Head field in meta.BranchState has been renamed to BranchingPointCommitHash for improved clarity regarding its purpose, though the underlying JSON field name remains head for backward compatibility.
Support for Partially Merged Stacks: This change addresses scenarios where a topic branch might have a trunk parent but still requires an explicit branching point to correctly identify its unique commits, as demonstrated by the av branch --remote command.
Widespread Codebase Updates: Numerous files across cmd/av, e2e_tests, internal/actions, internal/gh/ghui, internal/meta, internal/reorder, and internal/sequencer have been updated to reflect the new BranchingPointCommitHash field.

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Code Review

This pull request primarily refactors the codebase by renaming the Head field in BranchState to BranchingPointCommitHash for better clarity, and updates all its usages accordingly. This is a welcome change for maintainability. The PR also aims to relax the branch metadata semantics to allow specifying a branching point even for trunk parents, which is a useful enhancement for handling partially merged stacks, especially for the av adopt --remote flow. I have one point of feedback regarding the implementation of this new semantic, which I've detailed in a specific comment.

internal/actions/get_remote_stacked_pr.go

This relax the semantics of the branch metadata. In the branch metadata, we track `trunk: bool` and `head: string`, but only one of them could be specified in the current semantics. This update allows them to specify both. That is, even if the parent branch is a trunk branch, a branch metadata can specify the branching point. Accordingly, we update the internal name of that branching point as BranchingPointCommitHash. Newly added av branch --remote motivates this change. In that command, we might see a partially merged stack. In that case, we will have a case where a topic branch would have a trunk branch as a parent (because its original parent has been merged), but at the same time, such topic branches would need to have an explicit branching point in order to avoid already merged commits to be considered as a part of that topic branch. Behavior updates would be necessary in the sequencer, but we will do that in the following PRs.

draftcode requested a review from a team as a code owner October 30, 2025 06:04

aviator-app bot requested a review from simsinght October 30, 2025 06:04

gemini-code-assist bot reviewed Oct 30, 2025

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internal/actions/get_remote_stacked_pr.go Show resolved Hide resolved

draftcode force-pushed the update_metadata_semantics branch from 047eb15 to 55a6700 Compare October 30, 2025 07:34

tulioz approved these changes Oct 30, 2025

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aviator-app bot closed this in e3a2206 Oct 31, 2025

aviator-app bot added the merged-by-mq label Oct 31, 2025

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Allow specifying the branching point even for trunk parents #621

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