[objective_c] Fix path resolving for test files on MacOS

[progamax]

Description
This PR fixes a build failure introduced in version 9.2.0 (native assets migration) when the package is fetched from a custom pub repository (e.g., Artifactory).

Issue
When using a custom pub host, the pub cache directory often contains URL-encoded characters (e.g., %47 or %25). The hook/build.dart script was handling file paths inconsistently:

• Source files (src/): Were retrieved using Directory.listSync(). The file.path property correctly returned the decoded OS file system path.

• Test files (test/util.c): Were retrieved using uri.resolve(path).path. This returned the encoded URI path (e.g., retaining %2547), causing clang to fail with no such file or directory.

Fix
I updated the resolution of testFiles to use File.fromUri(...).path. This ensures that the path is correctly decoded to the OS file system format, matching the behavior used for the source files.

fixes: #2990

---

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[dcharkes]

Thanks @progamax! 🙏

Could you please add a test to cover this? Either add a test or make it so that an existing test that runs in a temp dir runs in a subdir with characters that get encoded.

[github-actions]

PR Health

License Headers ✔️

// Copyright (c) 2026, the Dart project authors. Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

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Files
pkgs/hooks_runner/test_data/download_assets/hook/build.dart
pkgs/jni/test/debug_release_test.dart
pkgs/objective_c/example/command_line/lib/main.dart
pkgs/objective_c/lib/src/ns_input_stream.dart

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API leaks ⚠️

The following packages contain symbols visible in the public API, but not exported by the library. Export these symbols or remove them from your publicly visible API.

Package	Leaked API symbol	Leaking sources
objective_c	_FinalizablePointer	internal.dart::_ObjCReference::new::_finalizable

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Breaking changes ✔️

Package	Change	Current Version	New Version	Needed Version	Looking good?
objective_c	None	9.2.3	9.2.3	9.2.3	✔️

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[coveralls]

coverage: 81.942%. remained the same
when pulling c3b55c1 on progamax:progamax-patch-1
into 7f45c84 on dart-lang:main.

[progamax]

@dcharkes
I am not really sure of how to test the hook behavior. Would it be okay if I extract the method that resolves the test file ?
Otherwise, I am open to other suggestions

[dcharkes]

Ah, the fix is in the hook, not in package:native_toolchain_c. We have https://pub.dev/documentation/code_assets/latest/code_assets/testCodeBuildHook.html for testing hooks, but that one doesn't allow you to create a temp directory with a weird path currently.

If you want, you could try making a PR so that testCodeBuildHook will always select a temp directory with weird encodings. That way everyone using testCodeBuildHook will catch it.

@liamappelbe owns package:objective_c, I'll leave it to him whether he just wants to merge this PR as is or adopt testCodeBuildHook.

[liamappelbe]

Thanks for the PR, but there's already one in progress for this. #2996 (which is a re-upload of #2959).