fix(build): externalize @galacean peers in miniprogram build instead of bundling

[cptbtptpbcptdtptp]

Fixes #349.

Problem

@galacean/engine-toolkit-xr@1.6.0 ships a ~2.5 MB dist/miniprogram.js (vs ~80 KB) because @galacean/engine-xr and its @galacean/engine-math dependency are bundled inline instead of kept external.

Two defects in the miniprogram build config:

1. rollup.config.mjs — the external list only contained the <pkg>/dist/miniprogram variants, so any peer import that wasn't redirected there fell through to bundling.
2. rollup.miniprogram.plugin.mjs — the redirect regex hard-coded mismatched quotes ("@galacean/engine" double, '@galacean/engine-xr' single). The transpiled source uses double quotes, so the @galacean/engine-xr import was never redirected → bundled → dragged @galacean/engine-math in with it.

Note: @galacean/engine-xr ships no /dist/miniprogram build (only dist/main.js/dist/module.js), so it must be externalized at its bare name — only @galacean/engine actually has a miniprogram build to redirect to.

Change

• external now lists each peer/dep at both its package name and /dist/miniprogram, so a peer that isn't redirected stays external instead of being bundled.
• The redirect now targets only @galacean/engine and is quote-agnostic (matches single or double quotes, anchored by a back-reference so @galacean/engine can't partially match @galacean/engine-xr).

Result: @galacean/engine → require('@galacean/engine/dist/miniprogram'), @galacean/engine-xr → require('@galacean/engine-xr') (a path that exists), neither bundled.

Verification

A full native pnpm build wasn't run here, so the fix was verified with a focused harness using the real rollup + rollup-plugin-modify and the exact external lists, stubbing the engine packages so only the external-vs-bundled decision is exercised:

OLD (buggy)   | engine -> /dist/miniprogram: true | engine-xr external(bare): false | engine-xr BUNDLED: true
NEW (fixed)   | engine -> /dist/miniprogram: true | engine-xr external(bare): true  | engine-xr BUNDLED: false

i.e. the original config bundles @galacean/engine-xr; the patched config externalizes it to require('@galacean/engine-xr'), while @galacean/engine stays redirected to its miniprogram build. A native build + a CI dist/miniprogram.js size guard would be a good follow-up to lock this in.

🤖 Generated with Claude Code

Summary by CodeRabbit

• Bug Fixes

  • Fixed module redirection logic to prevent incorrect package path resolution in miniprogram builds

• Chores

  • Optimized miniprogram build configuration for improved dependency externalization handling

[coderabbitai]

Walkthrough

Two bugs in the miniprogram Rollup build are fixed. The rollup.miniprogram.plugin.mjs plugin's module-redirect regex is replaced with a quote-aware, back-referenced pattern that targets only @galacean/engine. The rollup.config.mjs external list is changed to emit both the bare package name and the /dist/miniprogram path for each dependency.

Changes

Miniprogram bundle externalization fix

Layer / File(s)	Summary
Plugin redirect regex: target only @galacean/engine rollup.miniprogram.plugin.mjs	Introduces redirectModules constant and a dynamically generated alternation pattern. The modify plugin's find regex now uses a capture group for quote style with a back-reference, preventing partial matches against @galacean/engine-xr. The replace appends /dist/miniprogram while preserving the original quote character.
Config: externalize deps at both bare name and /dist/miniprogram rollup.config.mjs	Switches the miniprogram build's external list from .map to .flatMap, so each dependency/peer dependency is externalized as both name and ${name}/dist/miniprogram. Inline comments document which packages have a dedicated miniprogram build versus which are external at their bare name only.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~10 minutes

Poem

🐰 A sneaky regex once matched the wrong hare,
Bundling up engine-xr beyond its fair share.
Now quotes are back-referenced, names are precise,
And flatMap externalizes everything twice.
The miniprogram dist? A svelte 80 KB—
No more 2.5 MB ruining the day! 🎉

🚥 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 accurately describes the main fix: externalizing @galacean peer dependencies in the miniprogram build instead of bundling them, which directly addresses the ~2.5 MB bundle size issue.
Linked Issues check	✅ Passed	The PR successfully implements all requirements from issue #349: externalizes peers at both package name and /dist/miniprogram path, fixes the quote-agnostic redirect for @galacean/engine only, and prevents @galacean/engine-xr from being bundled.
Out of Scope Changes check	✅ Passed	All changes are directly scoped to the two configuration files identified in issue #349 as root causes; no unrelated modifications or scope creep is present.

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✨ Finishing Touches

📝 Generate docstrings

• Create stacked PR
• Commit on current branch

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/miniprogram-externalize-engine-xr

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[coderabbitai]

🧹 Nitpick comments (1)

rollup.config.mjs (1)

153-168: Add a CI size budget gate for dist/miniprogram.js.

Given this regression persisted across multiple releases, add a CI check that fails when miniprogram output exceeds a threshold (for example, ~150 KB) so future externalization regressions are caught pre-release.

🤖 Prompt for AI Agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

In `@rollup.config.mjs` around lines 153 - 168, Add a CI size budget gate for the
dist/miniprogram.js build output. The rollup configuration generates
miniprogram.js but there is no automated check to prevent size regressions.
Implement a size check in your CI workflow that runs after the build step and
fails the build if dist/miniprogram.js exceeds approximately 150 KB, capturing
size violations before they reach release. This can be done through a dedicated
size checking tool (such as bundlesize or similar CI plugins) or by adding a
post-build script that compares the actual output size against your threshold
and exits with an error code if exceeded.

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Nitpick comments:
In `@rollup.config.mjs`:
- Around line 153-168: Add a CI size budget gate for the dist/miniprogram.js
build output. The rollup configuration generates miniprogram.js but there is no
automated check to prevent size regressions. Implement a size check in your CI
workflow that runs after the build step and fails the build if
dist/miniprogram.js exceeds approximately 150 KB, capturing size violations
before they reach release. This can be done through a dedicated size checking
tool (such as bundlesize or similar CI plugins) or by adding a post-build script
that compares the actual output size against your threshold and exits with an
error code if exceeded.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Repository UI

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Run ID: 7f8d5abb-2d69-4398-9a53-87b2e04c03d7

📥 Commits

Reviewing files that changed from the base of the PR and between b89bb15 and 095ea5b.

📒 Files selected for processing (2)

• rollup.config.mjs
• rollup.miniprogram.plugin.mjs