[philrz]

This is the v0.4.0 changelog, ready for approval so we can tag the release. Please give Highlights a final look, along with anything in your area of the code that looks wrong or is missing.

How it was made

I drafted this with help from Claude. Claude went through all 592 PRs merged since we tagged v0.3.0, classified each one, and wrote the first draft of the bullets. I then reviewed and edited it over several rounds. Wherever practical, Claude tested a claim by running the same command with v0.3.0 and current main builds, rather than going only by the PR descriptions.

The "rules" for what goes in and how it's worded build on the conventions of our earlier hand-written changelogs, adjusted to match what similar projects do now, and we hope to reuse them for future releases. If you have high-level critiques (e.g., grouping, or what's in vs. out), it's easy to adjust the rules and generate an alternate draft, so all feedback is welcome.

About 323 PRs are cited in the draft. The rest were left out because they're internal (refactoring, tests, CI), docs-only, reverted, or aimed at developers, such as super dev commands and Go API changes. I've got detail on that "triage" exercise if anyone wants to see it.

Conventions

• The sections follow Keep a Changelog, plus a Highlights section at the top and a separate Performance section.
• BREAKING CHANGES covers v0.3.0 files, databases, commands, flags, and query syntax that now fail or were renamed. That includes the blend/fuse swap, where an old query still runs but does something different. Other changes in query results, like collect() now keeping nulls, are under Changed.
• Follow-up fixes to features that are new in this release are cited on that feature's bullet rather than listed under Fixed.
• Links to doc pages are limited to a few function pages that we checked against current behavior, since many other doc pages haven't been updated for this release yet.

Style

The changelog has an improved style with reference PR links (definitions at the end of each section), version heading links, and periods at the end of each bullet. The older entries were reformatted to match this updated style, with their wording unchanged.

Status

• This now covers every PR through bump versions for malibu release #7573, the last change before the release, and the release date is filled in.
• The [0.4.0] heading link will be added in a follow-up PR after tagging, since its target (compare/v0.3.0...v0.4.0) doesn't exist until the tag does.