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Abdulrahman QabboutandThomas Van Lenten
b6b6433ba2
## Summary This PR reduces the amount of vendored upstream protobuf/abseil source that SwiftPM clients need to check out when depending on SwiftProtobuf. It does this by pruning upstream files that are not used by SwiftProtobuf's package products: - upstream `protoc` built-in language generator implementations for C++, C#, Java, Kotlin, Objective-C, PHP, Python, Ruby, and Rust - upstream protobuf C++ test fixture directories that are not built by this SwiftPM package - upstream abseil/cctz timezone testdata used by upstream tests, not by SwiftProtobuf package products It also updates `scripts/UpdateProtobufSubtrees.py` so future vendored protobuf/abseil refreshes continue to prune the same unused files instead of reintroducing them. ## Motivation Xcode/SwiftPM package resolution can spend a noticeable amount of time checking out SwiftProtobuf when it appears as a transitive dependency in iOS projects. A meaningful part of the package payload comes from vendored upstream protobuf/abseil files. SwiftProtobuf's `protoc` executable target uses `Sources/protobuf/main.cc`, not upstream's full `compiler/main.cc`. That entry point enables external `protoc-*` plugins and does not register upstream's built-in language generators. The pruned generator trees therefore are not compiled or exposed by this package target. The Swift package also has its own test/reference/fuzz/compile-test inputs under `Tests/`, `Protos/`, `Reference/`, `FuzzTesting/`, and `CompileTests/`; the removed upstream C++ test fixtures are not part of the SwiftPM build/test graph. ## Local impact Measured locally after this change: - `Sources/protobuf` size dropped from about `34M` to `28M` - tracked files under `Sources/protobuf` dropped from `2733` to `1787` - total indexed tracked bytes dropped from about `57.2M` to `53.7M` This is intentionally a conservative reduction. It does not change public Swift APIs, package products, target names, or plugin behavior. ## Validation Ran locally on macOS with Apple Swift `6.3.1`: ```console swift package describe swift build --target protoc swift test ``` `swift test` result: ```console Executed 958 tests, with 0 failures (0 unexpected) ``` ## Notes and limitations This reduces checkout payload for future commits/releases that include the change. It cannot change the checkout behavior of already-published tags. A larger improvement would be to split runtime-only consumers from generator/tooling sources so iOS apps that only need the `SwiftProtobuf` runtime do not need to fetch `protoc` implementation sources at all. That would be a broader package-structure change; this PR keeps the current package structure and only removes files that are unused by the existing SwiftPM products. --------- Co-authored-by: Thomas Van Lenten <thomasvl@google.com>