slim builds for postgres versions just latest extension

[samrose]

a build of postgres with just the latest extension version and postgres itself

Summary by CodeRabbit

• New Features

  • Slim PostgreSQL package variants for smaller container images.
  • Optional "latest-only" build mode for many PostgreSQL extensions to produce single-version builds.

• Chores

  • Updated PostgreSQL version identifiers to include slim build metadata.

[coderabbitai]

📝 Walkthrough

Walkthrough

This change set adds a new boolean input latestOnly ? false across many Nix extension derivations and the postgres packaging code, and wires it through build logic to allow building only the latest PostgreSQL/extension versions (versionsToUse, versionsBuilt, numberOfVersionsBuilt). Packages, postBuild checks, and passthru metadata (versions, numberOfVersions, version, latestOnly) are adjusted to reflect latest-only mode. postgres packaging gains slim variants (latestOnly=true) with minimal locales and systemd disabled. ansible/vars.yml updates three Postgres release strings by appending "-slim-1".

Estimated code review effort

🎯 4 (Complex) | ⏱️ ~45 minutes

Possibly related PRs

• fix: set restart limits to 0 to prevent being marked as failed #1952: Modifies the same ansible/vars.yml postgres_release entries for postgres15, postgres17, and orioledb-17.
• Update nixpkgs #1714: Updates ansible/vars.yml postgres_release version entries for PostgreSQL versions.

Suggested labels

nix, extensions, infrastructure

Suggested reviewers

• LGUG2Z
• hunleyd

🚥 Pre-merge checks | ✅ 1 | ❌ 2

❌ Failed checks (1 warning, 1 inconclusive)

Check name	Status	Explanation	Resolution
Description check	⚠️ Warning	The pull request description is minimal and vague, providing only a single sentence that lacks specific details about what changes are made or how they work.	Expand the description to follow the template structure: explain what changes are made, why they're needed, how the latestOnly flag works, and provide examples of the new slim build outputs.
Title check	❓ Inconclusive	The title 'slim builds for postgres versions just latest extension' is somewhat vague and grammatically awkward, using non-standard phrasing that doesn't clearly convey the core change.	Revise to a clearer title such as 'Add slim PostgreSQL builds with only latest extension versions' or 'Introduce latestOnly flag for minimal PostgreSQL extension builds'.

✅ Passed checks (1 passed)

Check name	Status	Explanation
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.

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✨ Finishing touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment
• Commit unit tests in branch slim-build

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[coderabbitai]

Actionable comments posted: 0

Caution

Some comments are outside the diff and can’t be posted inline due to platform limitations.

⚠️ Outside diff range comments (2)

nix/ext/plpgsql-check.nix (1)

128-136: ⚠️ Potential issue | 🟡 Minor

Inconsistent use of versions vs versionsBuilt for upgrade scripts.

The loop on line 131 uses versions (all supported versions) instead of versionsBuilt. When latestOnly=true, this creates empty upgrade scripts for version transitions that aren't included in the slim build.

For consistency with the rest of the latestOnly logic, consider using versionsBuilt:

🔧 Proposed fix

     # Create empty upgrade files between consecutive versions
     # plpgsql_check ships without upgrade scripts - extensions are backward-compatible
     previous_version=""
-    for ver in ${lib.concatStringsSep " " versions}; do
+    for ver in ${lib.concatStringsSep " " versionsBuilt}; do
       if [[ -n "$previous_version" ]]; then
         touch $out/share/postgresql/extension/${pname}--''${previous_version}--''${ver}.sql
       fi
       previous_version=$ver
     done

nix/ext/wal2json.nix (1)

89-94: ⚠️ Potential issue | 🔴 Critical

Use versionsBuilt instead of versions for upgrade script files to match built versions.

The loop at line 89 creates upgrade path files using versions (all supported versions), but only the versions in versionsBuilt are actually compiled. In latestOnly mode, this creates upgrade files for versions that were never built. For example, if only v1.1 is built, the loop still creates --1.0--1.1.sql even though v1.0 was never compiled. Change the loop to iterate over versionsBuilt:

Suggested change

-    for ver in ${lib.concatStringsSep " " versions}; do
+    for ver in ${lib.concatStringsSep " " versionsBuilt}; do

This same bug exists in nix/ext/plpgsql-check.nix at line 131.

🧹 Nitpick comments (1)

nix/ext/index_advisor.nix (1)

78-79: Consider propagating latestOnly to hypopg dependency.

The hypopg dependency is instantiated without passing latestOnly. When building index_advisor with latestOnly=true, hypopg will still build all its versions. For a truly slim build, consider:

-  paths = packages ++ [ (callPackage ./hypopg.nix { inherit postgresql; }) ];
+  paths = packages ++ [ (callPackage ./hypopg.nix { inherit postgresql latestOnly; }) ];

If hypopg should always include all versions regardless of index_advisor's setting, this can be left as-is.

[samrose]

We won't need this one after all closing