[SgtSwagrid]

Summary

A push to a source with several children started a sync job for every child, even when it touched nothing that child syncs from. Themis, which syncs four library directories, paid four billed minutes for every merge, most of which change none of them (about 570 billed minutes in the last month). Now a push starts a job only for the children whose source.root it changed.

Changes

• parse-config.sh diffs the push (github.event.before..GITHUB_SHA, fetching the earlier commit into the shallow checkout) and keeps only the children with a changed file under their source directory. A child rooted at . always syncs.
• Every child still syncs when the push changed .github/graph.json, on a run started by hand, on a push that created its branch, and when the earlier commit can't be fetched.
• Renames are listed as a deletion plus an addition (--no-renames), so moving a file out of a directory still syncs that directory's children.
• GitHub Graph's own sync.yml triggers on pushes to main only, and the README now recommends the same for callers: a push to any other branch starts a job that finds nothing to sync. Themis's 293 such jobs last month were all billed.
• The README notes that a skipped sync is made up for by the next push to that directory, or by running the workflow by hand.

Testing

Ran parse-config.sh in a throwaway Actions run (since deleted) against a config with roots scripts, ./scripts/, templates, docs and the default .:

Case	Children kept
Push, config untouched	scripts, ./scripts/, .
Push that changed the config	all
Push that created its branch	all
Earlier commit unfetchable	all
workflow_dispatch	all
Push with no changes	. only
No before given	all

🤖 Generated with Claude Code

[SgtSwagrid]

Review (PR review agent)

Approved. @SgtSwagrid asked me directly to land this series. A push now syncs only the children whose source.root it changed. Every child still syncs on a manual run, on a branch's first push (an all-zero before), when the earlier commit can't be fetched, or when .github/graph.json itself changed. A root of "" or . always syncs. git diff --name-only between two commits needs only their trees, so a depth-1 fetch of before is enough. When called as a reusable workflow, github.event is the caller's, so callers like scala-config get the same behaviour. A skipped child is caught up by its next sync, as the README now says.

Note, not blocking: a child that syncs files from outside its source.root, if the configuration allows it, would be missed by a push changing only those files.

Merging.