Strip foreign-architecture code from the macOS bundle (#10063)

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Summary

The macOS app is built for a single architecture (matching the build machine, via ${ARCH}), but relocatable-python pulls the python.org universal2 installer, so the entire Python.framework ships both arm64 and x86_64 slices. PostgreSQL-sourced dylibs (libpq, libssl, ...) may be universal too. The foreign slice is dead weight that bloats the bundle and DMG.

Fixes #10063.

Changes

• New _strip_architecture() in pkg/mac/build-functions.sh, called from build.sh after _complete_bundle and before code-signing (lipo invalidates signatures, so the existing _codesign_* passes re-sign the thinned binaries — no extra re-sign needed).
• Removes the universal2 stragglers: the python*-intel64 launcher and the stray config-*-darwin/python.o build object.
• lipo -thins every fat Mach-O in the bundle to the build arch, preserving file modes (the +x bit the signing pass relies on) and warning rather than failing on any binary that lacks the target slice.
• Already single-arch inputs (Electron and its helpers, downloaded per-arch) are skipped.
• Changelog entry under Housekeeping in release_notes_9_16.rst.

Notes

lipo can only keep a slice that already exists — this strips the build machine's foreign slice from an otherwise-correct build; it does not let an arm64 build produce an x86_64 bundle or vice versa.

Summary by CodeRabbit

• Housekeeping
  • Optimized macOS builds to exclude unused architecture slices from the bundled Python framework, reducing bundle size for single-architecture builds.
  • Resulting app bundles are smaller, which can reduce download size and disk usage.
  • No changes to functionality or user-facing behavior; installs, signing, and notarization remain unaffected.

[coderabbitai]

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ℹ️ Recent review info

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📥 Commits

Reviewing files that changed from the base of the PR and between 45abd1e and a5f1763.

📒 Files selected for processing (1)

• docs/en_US/release_notes_9_16.rst

✅ Files skipped from review due to trivial changes (1)

• docs/en_US/release_notes_9_16.rst

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Walkthrough

This PR adds _strip_architecture() to thin universal/fat Mach-O binaries in the macOS app bundle to the build-machine architecture, removes Python framework universal2 stragglers, calls it during the build before SBOM generation, and documents the change in the release notes.

Changes

macOS architecture stripping

Layer / File(s)	Summary
Strip architecture function pkg/mac/build-functions.sh	_strip_architecture() thins universal/fat Mach-O binaries in the bundle to the build-machine target architecture. It removes Python framework universal2 artifacts, iterates through regular files to detect fat binaries via lipo -archs, and replaces them with single-arch versions using lipo -thin while preserving permissions. Non-applicable or failed operations emit warnings and continue.
Build integration and release notes pkg/mac/build.sh, docs/en_US/release_notes_9_16.rst	_strip_architecture is called after _complete_bundle and before _generate_sbom to establish build step ordering. Release notes document the housekeeping improvement for Issue #10063 stating that foreign-architecture slices are stripped from the macOS bundle so single-arch builds no longer ship unused universal2 Python framework code.

Estimated code review effort

🎯 3 (Moderate) | ⏱️ ~20 minutes

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 0.00% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely summarizes the main change: stripping foreign-architecture code from the macOS bundle, directly matching the primary objective and the linked issue #10063.
Linked Issues check	✅ Passed	The PR implements all coding requirements from issue #10063: it strips foreign-architecture slices using lipo -thin on all universal Mach-O binaries, removes architecture-specific stragglers (bin/python3.x-intel64 and python.o), preserves single-arch artifacts, handles missing target slices gracefully, and performs thinning before code-signing.
Out of Scope Changes check	✅ Passed	All changes are directly scoped to the objectives: _strip_architecture() function for thinning binaries, build step ordering adjustments, and a Housekeeping changelog entry. No unrelated modifications detected.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

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[Copilot]

Pull request overview

Reduces the size of the macOS pgAdmin4 app bundle by stripping unused (foreign) CPU architecture slices from universal/fat Mach-O binaries (notably the universal2 Python.framework pulled in via relocatable-python) before code-signing.

Changes:

• Adds _strip_architecture() to thin fat Mach-O files in the bundle to the build machine’s target architecture and remove universal2 installer stragglers.
• Wires the new strip step into the macOS build pipeline before SBOM generation and code-signing.
• Documents the change in the v9.16 release notes (Housekeeping).

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 3 comments.

File	Description
pkg/mac/build.sh	Invokes _strip_architecture after bundle completion and before SBOM/signing.
pkg/mac/build-functions.sh	Implements architecture stripping/thinning and removes universal2 Python installer leftovers.
docs/en_US/release_notes_9_16.rst	Adds a release note entry for Issue #10063 under Housekeeping.

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