[sunnylqm]

Problem

BundledResourceCopier finds patch copies by CRC among the APKs installed on the device. A density split install (Google Play, or bundletool) only has the variants its split_config.<density>.apk carries, so copies of every other density are never found and the whole patch fails with Bundled resource content mismatch (crc32). On an app with @2x and @3x images, 9 of 17 copies were missing at every density tested, so its Play users could not take a pdiff at all.

Fix

When a copy's CRC is not found, its targets are filled from the variant Android resolves for that resource, only if all of these hold:

• the install has density splits;
• every target is a drawable-* path whose density is not installed;
• the path match did not already show drift;
• the resource resolves to an installed variant, of a different density than the target.

A copy of an installed density, a resource that was removed, and content that moved into an installed density still fail as before.

The filled file holds the installed variant, so a later density change reads an existing file instead of hitting ENOENT. Its pixel size may not match its directory.

Verification

• BundledResourceCopierTest (new, not run by CI): 6 cases on the density decision.
• Probe app, split installs on API 26 and 34, crunchPngs on and off: unfixed fails, fixed succeeds; switching among xhdpi/xxhdpi/xxxhdpi loads every image; drift, removal and moved content fail; only changing a density that is not installed succeeds, as intended; plain APK unchanged; AAB baseline passes.
• Production app config (R8, shrinkResources, crunchPngs false), sideload APK as baseline, Play AAB split installed by bundletool, API 34: unfixed fails on 9 entries; fixed succeeds on xhdpi, xxhdpi and xxxhdpi, and images load after density changes.

Not covered: splits delivered by Play itself (to be checked on an internal track after release), API 24/25.

🤖 Generated with Claude Code

Summary by CodeRabbit

• Bug Fixes
  • Android installations using density-specific APK splits can now use an available bundled image variant when the requested density is missing. Missing resources or content mismatches still cause the update to fail.
• Documentation
  • Clarified how density-specific resources are handled during bundle hash checks.

[coderabbitai]

Caution

Review failed

The pull request is closed.

Walkthrough

The Android resource copier detects installed density splits. When a requested source is absent without CRC drift, it can use eligible bundled resources at another density to populate target paths.

Changes: Android density-variant fallback

Layer / File(s)	Summary
Density metadata and eligibility android/src/main/java/cn/reactnative/modules/update/BundledResourceCopier.java, android/src/test/java/cn/reactnative/modules/update/BundledResourceCopierTest.java	The copier extracts installed density qualifiers, retains resolved resource density and target paths, and checks whether all targets have a matching bundled resource at another density. Tests cover split-name parsing and substitution eligibility.
Fallback copy and drift handling android/src/main/java/cn/reactnative/modules/update/BundledResourceCopier.java, docs/BUNDLEHASH_MIGRATION.md	The copier does not substitute after a path match fails CRC validation. If the source is absent without CRC drift, it writes eligible substitutes, records write failures, and logs successful substitutions. The migration documentation describes this behavior.

Estimated code review effort: 3 (Moderate) | ~20 minutes

Change: Bug fix

Sequence Diagram(s)

sequenceDiagram
  participant BundledResourceCopier
  participant InstalledApkPaths
  participant BundledResourceArchive
  participant TargetPaths
  BundledResourceCopier->>InstalledApkPaths: Extract installed density qualifiers
  BundledResourceCopier->>BundledResourceArchive: Resolve eligible resource at another density
  BundledResourceArchive-->>BundledResourceCopier: Return matching archive entry
  BundledResourceCopier->>TargetPaths: Write substitute resources

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Merge Risk: Low · previous review 90ff8

Some night-mode images could display the day variant after a density-split patch. Restricting substitution to density-only targets would address this bounded risk.

Pre-merge checks: 4 · 1

Failed checks: 1 warning

Check name	Status	Explanation	Resolution
Docstring Coverage		Docstring coverage is 22.22% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff with cyclomatic complexity of at least 2. Documenta…	Write docstrings for the functions missing them to satisfy the coverage threshold.

Passed checks: 4 passed

Check name	Status	Explanation
Description Check		Check skipped - CodeRabbit’s high-level summary is enabled.
Title check		The title "fix(android): keep pdiff working on density split installs" names the main change: a fix for patch failures on Android density-split installs. The raw summary and PR objectives both describ…
Linked Issues check		Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check		Check skipped because no linked issues were found for this pull request.

Full details: Title check

Explanation

The title "fix(android): keep pdiff working on density split installs" names the main change: a fix for patch failures on Android density-split installs. The raw summary and PR objectives both describe filling missing density-split resource copies from the installed density variant, so the title matches the changeset. It uses the conventional commit prefix and is 58 characters, within a concise length. It does not name the specific mechanism (substitution of installed density variants), but it is not overly broad for the primary purpose.

Full details: Docstring Coverage

Explanation

Docstring coverage is 22.22% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff with cyclomatic complexity of at least 2. Documentation-only edits and deletions within surviving functions are included; unchanged diff context and fully deleted functions are excluded. Analyzed 9 functions across 2 files. (1 skipped: 1 unsupported.)

Resolution

Write docstrings for the functions missing them to satisfy the coverage threshold.

• Autofix · Keep fixing CodeRabbit findings and required CI, and resolving merge conflicts

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Commits

Reviewing files that changed from the base of the PR and between 4620119 and 90ff8d9.

Files selected for processing: 3

• android/src/main/java/cn/reactnative/modules/update/BundledResourceCopier.java
• android/src/test/java/cn/reactnative/modules/update/BundledResourceCopierTest.java
• docs/BUNDLEHASH_MIGRATION.md

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