[ImpellerC] Write a depfile when --shader-bundle is in use#186341
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bdero merged 2 commits intoMay 12, 2026
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Threads a dependency-collecting set through GenerateShaderBundleFlatbuffer, GenerateShaderFB, and GenerateShaderBackendFB. Each Compiler reports its included file names plus the primary shader source file into the set, which dedupes naturally across the five target-platform compiles per shader. After successful bundle generation, GenerateShaderBundle emits a Ninja-style depfile when --depfile is set, mirroring the format produced by Compiler::CreateDepfileContents on the single-shader compile path. Previously, --depfile was silently dropped in --shader-bundle mode because the early return into GenerateShaderBundle bypassed OutputDepfile. Build systems consuming impellerc for shader bundles (notably Dart's hooks framework, which flutter_gpu_shaders goes through) had no way to discover which source files and transitive #include headers contributed to the bundle, and therefore couldn't rerun the bundle build when any input changed. Tests confirm the dependency set contains the primary source files. Both the explicit-collector and null-collector paths are exercised. Existing shader bundle tests continue to pass unchanged. Fixes flutter#186340
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This pull request implements Ninja-style depfile generation for shader bundles by tracking source files and transitive includes during compilation. It updates the compilation pipeline to collect these dependencies, adds a utility to write them to disk, and includes unit tests to verify the new functionality. Review feedback recommends resolving paths relative to the specified working directory, simplifying string conversions in file operations, and using UTF-8 encoding for target paths to ensure cross-platform compatibility.
This was referenced May 12, 2026
This was referenced May 12, 2026
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Roll Flutter from 707dbc0420a3 to 23f6f5853f50 (149 revisions) flutter/flutter@707dbc0...23f6f58 2026-05-12 737941+loic-sharma@users.noreply.github.com Add 'cp: review' label to the manual cherrypick process (flutter/flutter#186158) 2026-05-12 engine-flutter-autoroll@skia.org Roll Packages from 19ec8b8 to 93cbed6 (3 revisions) (flutter/flutter#186401) 2026-05-12 30870216+gaaclarke@users.noreply.github.com Removes SDF option for macOS (always enabled) (flutter/flutter#186265) 2026-05-12 nico.reiab@gmail.com docs: fix typos in flutter_tools comments (flutter/flutter#186321) 2026-05-12 15619084+vashworth@users.noreply.github.com Pass XcodeBasedProject instead of String to functions in XcodeProjectInterpreter (flutter/flutter#186378) 2026-05-12 jason-simmons@users.noreply.github.com Update iOS scenario app test goldens to match changes from flutter/flutter#182662 (flutter/flutter#186390) 2026-05-12 engine-flutter-autoroll@skia.org Roll Skia from ad0aff15b9fa to 77a21bc723dc (2 revisions) (flutter/flutter#186396) 2026-05-12 32538273+ValentinVignal@users.noreply.github.com Migrate focus_node.unfocus.0.dart to use `RadioGroup` (flutter/flutter#183979) 2026-05-12 engine-flutter-autoroll@skia.org Roll Skia from 91d3c1e730af to ad0aff15b9fa (7 revisions) (flutter/flutter#186391) 2026-05-12 bdero@google.com [Flutter GPU] Allow customizing the vertex layout on a RenderPipeline (flutter/flutter#186310) 2026-05-12 97480502+b-luk@users.noreply.github.com Fix `EmbedderTest.CanRenderTextWithImpellerMetal` test breakage (flutter/flutter#186262) 2026-05-12 engine-flutter-autoroll@skia.org Roll Fuchsia Linux SDK from rFhU-YPqdCRCtCz7b... to z7ICmPtn4hspu02zk... (flutter/flutter#186384) 2026-05-12 bdero@google.com [Impeller] GLES: lazily allocate texture mip levels on first per-level write (flutter/flutter#186302) 2026-05-12 bdero@google.com [Android] Propagate --enable-flutter-gpu Intent extra to engine args (flutter/flutter#186298) 2026-05-11 47866232+chunhtai@users.noreply.github.com [ci] update no-response workflow to also look for old label name in e… (flutter/flutter#186373) 2026-05-11 bdero@google.com [ImpellerC] Write a depfile when --shader-bundle is in use (flutter/flutter#186341) 2026-05-11 nico.reiab@gmail.com docs: fix doubled-word typos in comments (flutter/flutter#186320) 2026-05-11 engine-flutter-autoroll@skia.org Roll Skia from 32281401997e to 91d3c1e730af (4 revisions) (flutter/flutter#186368) 2026-05-11 15619084+vashworth@users.noreply.github.com Show SwiftPM warnings right before iOS/macOS build (flutter/flutter#185984) 2026-05-11 15619084+vashworth@users.noreply.github.com Convert rebuilding-flutter-tool script to dart (flutter/flutter#185089) 2026-05-11 15619084+vashworth@users.noreply.github.com Use Xcode's LLDB (flutter/flutter#186273) 2026-05-11 mr-peipei@web.de Remove `currentMainUri` from `generateMainDartWithPluginRegistrant` (flutter/flutter#185907) 2026-05-11 engine-flutter-autoroll@skia.org Roll Skia from 2514f6b5f92b to 32281401997e (1 revision) (flutter/flutter#186349) 2026-05-11 engine-flutter-autoroll@skia.org Roll Packages from 92552b1 to 19ec8b8 (4 revisions) (flutter/flutter#186350) 2026-05-11 1063596+reidbaker@users.noreply.github.com Check for absolute paths in skills. (flutter/flutter#185632) 2026-05-11 engine-flutter-autoroll@skia.org Roll Skia from 9fb7d2814642 to 2514f6b5f92b (1 revision) (flutter/flutter#186347) 2026-05-11 engine-flutter-autoroll@skia.org Roll Skia from 8cafb209e836 to 9fb7d2814642 (4 revisions) (flutter/flutter#186335) 2026-05-10 engine-flutter-autoroll@skia.org Roll Fuchsia Linux SDK from sOBiPJb0xznDBZlf5... to rFhU-YPqdCRCtCz7b... (flutter/flutter#186328) 2026-05-10 engine-flutter-autoroll@skia.org Roll Skia from 05a03f99c74e to 8cafb209e836 (1 revision) (flutter/flutter#186315) 2026-05-10 bdero@google.com [Impeller] Vulkan: don't drop user-supplied viewport X, Y, and depth range (flutter/flutter#185886) 2026-05-09 mbrase@google.com Update Fuchsia tests to subpackage their child components (flutter/flutter#186259) 2026-05-09 victorsanniay@gmail.com Fix SelectableText crash with inline lambda contextMenuBuilder (flutter/flutter#184990) 2026-05-09 engine-flutter-autoroll@skia.org Roll Fuchsia Linux SDK from 5_TnhTsHSqtCx37o6... to sOBiPJb0xznDBZlf5... (flutter/flutter#186289) 2026-05-09 engine-flutter-autoroll@skia.org Roll Skia from dc78d4bd2efb to 05a03f99c74e (2 revisions) (flutter/flutter#186283) 2026-05-09 22373191+Hari-07@users.noreply.github.com Improve non rect platform view rendering (flutter/flutter#182662) 2026-05-08 engine-flutter-autoroll@skia.org Roll Skia from 31521f8508c7 to dc78d4bd2efb (1 revision) (flutter/flutter#186278) 2026-05-08 30870216+gaaclarke@users.noreply.github.com Moves wide_gamut_macos to arm64 (flutter/flutter#186214) 2026-05-08 98614782+auto-submit[bot]@users.noreply.github.com Reverts "[iOS] Migrate VSyncClient to a pure Obj-C implementation (#186166)" (flutter/flutter#186266) 2026-05-08 engine-flutter-autoroll@skia.org Roll Skia from a00db8749edb to 31521f8508c7 (2 revisions) (flutter/flutter#186264) 2026-05-08 97480502+b-luk@users.noreply.github.com Optimize compatible `DrawDiffRoundRect` calls to use `DrawRoundRect` (flutter/flutter#186203) 2026-05-08 bdero@google.com [triage] Add Flutter GPU as a triage team (flutter/flutter#186263) 2026-05-08 dmgr@google.com doc: Unified Check-Run User manual (flutter/flutter#186210) 2026-05-08 engine-flutter-autoroll@skia.org Roll Skia from 5f7adf4403d6 to a00db8749edb (1 revision) (flutter/flutter#186257) 2026-05-08 engine-flutter-autoroll@skia.org Roll Packages from 0411f1d to 92552b1 (1 revision) (flutter/flutter#186256) 2026-05-08 34871572+gmackall@users.noreply.github.com Add logging to figure out jvm crashes for `hot_mode_tests` (flutter/flutter#186107) 2026-05-08 engine-flutter-autoroll@skia.org Roll Skia from 926c09741ce2 to 5f7adf4403d6 (3 revisions) (flutter/flutter#186242) ...
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Fixes #186340
When
impellercis invoked with both--depfile=<path>and--shader-bundle=<json>, the depfile is silently dropped.impellerc_main.cctakes an early return intoGenerateShaderBundle(switches)when--shader-bundleis set, and the depfile-writing branch only runs on the non-bundle path. Build systems consuming impellerc for shader bundles (notably Dart'shooksframework, whichflutter_gpu_shaders'sbuildShaderBundleJsongoes through) have no way to discover which source files and transitive#includeheaders contributed to the produced bundle, and therefore cannot rerun the bundle build when any input changes. The user-visible effect is that editing a.fragreferenced by a shader bundle manifest does not invalidate the cached bundle output untilflutter cleanis run, which makes shader iteration painful and confuses new users.This change threads an optional
std::set<std::string>* out_dependenciesparameter throughGenerateShaderBundleFlatbuffer,GenerateShaderFB, andGenerateShaderBackendFB. EachCompilerinstance reports itsGetIncludedFileNames()plus the primary shader source file into the set, which dedupes naturally across the five target-platform compiles per shader. After successful bundle generation,GenerateShaderBundleemits a Ninja-style depfile when--depfileis set, mirroring the format produced byCompiler::CreateDepfileContentson the single-shader compile path.Manually verified end to end against a real bundle whose only shader transitively
#includes a header: the resulting depfile lists both files. The new unit tests cover both the explicit-collector path (set contains the primary source files) and the null-collector path (callers that don't pass a set get exactly today's behaviour). Existing shader-bundle unit tests continue to pass unchanged.Pre-launch Checklist
///).