build_slim 0.4.0

A CLI tool and library to analyze and reduce the size of Flutter APK, AAB, and IPA build artifacts using best-practice optimizations.

Changelog

All notable changes to this project will be documented in this file.

The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.

0.4.0 - 2026-06-25

Added — advanced size strategies

• --aggressive flag: opt-in bundle of destructive optimizations. Every change ships with a .bak backup so users can roll back. Without the flag, build_slim keeps its historical, fully-safe behaviour.
  • PNG/JPEG → WebP conversion (WebPConverter): converts raster assets to WebP via cwebp and rewrites the references in lib/**/*.dart and pubspec.yaml. Atomic: if any conversion fails, no references are touched and the originals are preserved.
  • R8 full mode (android.enableR8.fullMode=true): injected into android/gradle.properties with backup. Removes substantially more unreachable code than the default safe mode.
  • Strict resource shrinking (res/raw/keep.xml with tools:shrinkMode="strict"): created only when absent; existing keep rules are never overwritten.
• --locales flag + auto-detection: injects Android resConfigs so third-party AARs (Play Services, AndroidX) no longer drag dozens of unused values-xx folders into the artifact. Locales are auto-detected from *.arb files and iOS .lproj directories when the flag is omitted.
• FindingSeverity.critical and Finding.breaking: new model fields surfaced by the console/HTML reporters with distinct styling so users immediately spot high-impact issues and changes that may break the build.

Added — passive findings (analyze-only safe)

• Heavy GIF audit: GIFs above 300KB are flagged as critical recommending Lottie/Rive vector animations.
• Font subsetting recommendation: .ttf/.otf files above 200KB emit a warning suggesting pyftsubset (a 600KB Latin font typically drops to ~30KB).
• Target-aware extractNativeLibs guidance: AAB targets now recommend extractNativeLibs="false" (Play Store requirement for uncompressed native libs); APK/legacy targets preserve the previous warning. No more contradictory advice.
• Deferred import suggestions: heavy packages imported eagerly in lib/ emit an info finding recommending import ... deferred as ... so App Bundles can ship them as on-demand splits.
• R8 full mode audit (--analyze-only): reports when the flag is missing, even without running the optimizer.

Changed

• OptimizerPipeline.run and ProjectAnalyzer now accept the build target so target-aware findings can be emitted. The target parameter is optional on the analyzer to preserve backwards compatibility for direct callers.
• pubspec.yaml version bumped to 0.4.0.

0.3.0 - 2026-06-22

Fixed

• Android optimizer now emits correct Kotlin DSL when patching build.gradle.kts. Previously it injected Groovy syntax (['arm64-v8a', ...] list literals, abiFilters.addAll(...), and bare minifyEnabled/ shrinkResources) that failed to compile under the Kotlin DSL.
  • abiFilters now uses ndk { abiFilters += listOf("arm64-v8a", "armeabi-v7a") }.
  • Property names use the is prefix (isMinifyEnabled, isShrinkResources).
  • Release-only scoping: edits are confined to the release { ... } build type via brace matching, so a preceding debug {} block is never mutated.
  • Word-boundary matching prevents the substring corruption that produced invalid identifiers like isminifyEnabled. Re-running the optimizer also repairs files corrupted by previous versions.
• NativeConfigAnalyzer.hasGradleBool now recognizes the Kotlin is-prefixed property form (isMinifyEnabled = true) so analyze and optimize agree.

Added

• Release signing resolution for Android targets (apk, aab) via a new SigningConfigurator. Follows the standard android/key.properties pattern with a deterministic, flag-driven flow (no interactive prompt — CI friendly).
  • --keystore, --store-password, --key-alias, --key-password generate android/key.properties from a keystore.
  • --signing-config debug temporarily signs the release build with the debug keystore (validation only) and creates a .bak backup.
  • Warns when key.properties is not covered by .gitignore.
  • Fails fast with actionable guidance when signing is unresolved.

Changed

• OptimizerPipeline.run and FakeOptimizerPipeline.run accept the new signing parameters (keystore, storePassword, keyAlias, keyPassword, debugSigning). Callers that override run must add the new parameters.
• Android optimizer applies patches to whichever Gradle file was found and names it explicitly in the applied-optimizations message.

0.2.0 - 2026-06-21

Added

• Comprehensive test suite: 279 tests covering all analyzers, optimizers, reporters, builders, CLI commands, and utilities (up from 17).
• End-to-end CLI tests that exercise the real dart --version and flutter --version probes against a fixture project.
• @visibleForTesting helpers on NativeConfigAnalyzer (normalizeGradle, hasGradleBool, parseVersion) to enable direct testing of fragile parsing.
• Injectable sink (StringSink? sink) on Logger to capture log output in tests without spawning real I/O.
• Optional dependency injection on OptimizeCommand, ReportCommand, and BuildSlimRunner for unit and integration testing of the CLI.
• MockProcessRunner improvements: responseFor callback, RecordedInvocation records (with working directory tracked separately), throwIfUnmatched.
• FakeOptimizerPipeline test helper.
• Pinned tests documenting known bugs (dead ternary in asset analyzer, non-monotonic _parseVersion for minor >= 100, Groovy-syntax detection gap, _compressWith adding success message on failure).

Changed

• Logger constructor is no longer const (accepts a runtime stdout sink by default). Existing call sites using const Logger(...) should drop the const keyword.

0.1.1 - 2026-06-21

Changed

• Bumped args lower bound to ^2.5.0.

0.1.0 - 2024-06-19

Added

• Initial release of build_slim.
• optimize command to analyze and build APK, AAB, and IPA artifacts.
• report command to compare before/after artifact sizes.
• Asset analyzer that detects unused assets and over-declared font weights.
• Dependency analyzer that flags known heavy transitive packages.
• Native configuration analyzers for Android (build.gradle) and iOS (Podfile, .xcconfig, .pbxproj).
• Dart optimizer that injects --tree-shake-icons, --obfuscate, and --split-debug-info.
• Android optimizer that patches Gradle settings and verifies ProGuard rules.
• iOS optimizer that injects safe .xcconfig settings and emits manual instructions.
• Asset optimizer that compresses PNG/JPEG/WebP assets when pngquant, optipng, or cwebp are available.
• Console, JSON, and HTML reporters.
• Comprehensive unit tests and fixture project for analyzers.