Cut 0.3.0

[contrasam]

Release prep for 0.3.0. Everything from #7 through #14 is on main; this bumps the version, rewrites the changelog, and raises the mutation ratchet.

Changes

File	What
pom.xml	0.2.0 → 0.3.0; mutation ratchet 75 → 76
CHANGELOG.md	[Unreleased] rewritten as [0.3.0] — 2026-07-26
README.md	Maven/Gradle install snippets and the mvn package output name

The changelog is rewritten, not renamed

[Unreleased] had accumulated per-PR entries and was missing work that landed without touching it — the subscription delivery rewrite (#10), the close() contract (#11), and most of the fixes that came out of review on #13.

That mattered enough to redo rather than tidy. A release note that omitted ordered delivery and a now-blocking close() would have been misleading about behaviour a caller can observe. Both are in Changed — breaking now, alongside the localId rename and the conditional-append signature.

It's ordered by what someone upgrading needs first: breaking, then added, then fixed. Several of the fixes were silent failures — data lost or duplicated with no error — so each entry says what was wrong, not just what changed. Someone deciding whether they were affected needs the symptom:

Entries appended during a subscriber's backlog delivery were silently dropped. The backlog read had already happened and the live path skipped not-yet-ready subscribers, so the entry arrived by neither route — no error, no retry, nothing logged.

Two known limitations are carried into the release rather than dropped at the door: the multi-tag version (needs a record layout change and a log migration) and the batching adapter's unbounded buffer under sustained write failure.

Mutation ratchet 75 → 76

Measured on main after #13: 422/553, test strength 82%. Raising it when the number rises is the point of a ratchet — leaving it at 75 would quietly bank the improvement as slack. Verified passing at 76.

212 tests, 0 failures.

Publishing — needs a tag after merge

JitPack builds from tags, and the existing convention is a bare version tag (0.2.0, no v prefix). So once this merges:

git tag 0.3.0 <merge-commit>
git push origin 0.3.0

I can push that tag once the merge lands — it has to point at the merge commit, so it can't be created ahead of time. Consumers then get com.github.CajunSystems:gumbo:0.3.0.

What this unblocks

Catalyst's D4 — the bug that started the whole report. Its GumboEventLog passes a per-execution cursor into a seqnum-keyed read, which double-counts through the snapshot warm path (43 steps vs 51). The fix is readFromVersion, shipped here but unusable until Catalyst can depend on a released Gumbo.

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Generated by Claude Code

[greptile-apps]

Greptile Summary

Release preparation for Gumbo 0.3.0:

• Updates the project version and installation/build examples from 0.2.0 to 0.3.0.
• Rewrites the changelog to document the release’s breaking changes, additions, fixes, and known limitations.
• Raises the PIT mutation threshold to 76 and corrects the documented mutation-count floor.

Confidence Score: 5/5

The PR appears safe to merge.

No blocking failure remains.

Important Files Changed

Filename	Overview
pom.xml	Bumps the release version and mutation threshold while correcting the previously reported headroom calculation.
CHANGELOG.md	Replaces the accumulated unreleased notes with structured release notes for version 0.3.0.
README.md	Updates Maven, Gradle, and packaged JAR examples to reference version 0.3.0.

_{Reviews (2): Last reviewed commit: "Recompute the mutation headroom against ..." | Re-trigger Greptile}