flutter_build_with_compilation_error_test fails on Xcode 16 beta 3: stderr has moved to stdout

[jmagman]

On #151500 testing Xcode 16 beta 3, tools test flutter_build_with_compilation_error_test failed. The expected error is present, but is in the stdout and not stderr.

flutter/packages/flutter_tools/test/integration.shard/flutter_build_with_compilation_error_test.dart

Lines 68 to 70 in 43458fe

	const ProcessResultMatcher(
	exitCode: 1,
	stderrPattern: "A value of type 'String' can't be assigned to a variable of type 'int'.",

04:02 +26 ~4 -1: test/integration.shard/flutter_build_with_compilation_error_test.dart: flutter build ios shows dart compilation error in non-verbose [E]
  Expected: a process with exit code 1 and stderr: "A value of type 'String' can't be assigned to a variable of type 'int'."
    Actual: <Instance of 'ProcessResult'>
     Which: Actual stdout:
            Downloading ios tools...                                         1,634ms
            Downloading ios-profile tools...                                 1,184ms
            Downloading ios-release tools...                                   961ms
            Warning: Building for device with codesigning disabled. You will have to manually codesign before deploying to device.
            Building com.example.hello for device (ios-release)...
            Running Xcode build...                                          
            Xcode build done.                                            3.2s
            Failed to build iOS app
            Error output from Xcode build:
            ↳
                ** BUILD FAILED **
            
            
            Xcode's output:
            ↳
                Writing result bundle at path:
                	/Volumes/Work/s/w/ir/x/t/flutter_tools.OlXjrA/flutter_ios_build_temp_dirjszsu2/temporary_xcresult_bundle
            
                error: lib/main.dart:1:9: Error: A value of type 'String' can't be assigned to a variable of type 'int'.
                int x = 'String';
                        ^
                package:hello/main.dart: Error: No 'main' method found.
                Try adding a method named 'main' to your program.
                Target kernel_snapshot_program failed: Exception
                Failed to package /Volumes/Work/s/w/ir/x/t/flutter_build_compilation_error_test.3IDLED/hello.
                note: Disabling previews because SWIFT_VERSION is set and SWIFT_OPTIMIZATION_LEVEL=-O, expected -Onone (in target 'Runner' from project 'Runner')
                note: Run script build phase 'Run Script' will be run during every build because the option to run the script phase "Based on dependency analysis" is unchecked. (in target 'Runner' from project 'Runner')
                note: Run script build phase 'Thin Binary' will be run during every build because the option to run the script phase "Based on dependency analysis" is unchecked. (in target 'Runner' from project 'Runner')
            
            
            Actual stderr:
            Encountered error while building for device.

https://logs.chromium.org/logs/flutter/buildbucket/cr-buildbucket/8742848458823025121/+/u/run_test.dart_for_tool_integration_tests_shard_and_subshard_1_4/stdout

[jmagman]

stderr is:

** BUILD FAILED **

stdout is:

Writing result bundle at path:
	/var/folders/fm/wjzsj_z95ydgn4khxqgbtqx000mfq2/T/flutter_tools.PeJZlH/flutter_ios_build_temp_dirqmiKld/temporary_xcresult_bundle

error: lib/main.dart:13:11: Error: A value of type 'String' can't be assigned to a variable of type 'int'.
  int x = 'String';
          ^
Target kernel_snapshot_program failed: Exception
Failed to package /Users/m/Projects/test_create.
note: Disabling previews because SWIFT_VERSION is set and SWIFT_OPTIMIZATION_LEVEL=-O, expected -Onone (in target 'Runner' from project 'Runner')
note: Run script build phase 'Thin Binary' will be run during every build because the option to run the script phase "Based on dependency analysis" is unchecked. (in target 'Runner' from project 'Runner')
note: Run script build phase 'Run Script' will be run during every build because the option to run the script phase "Based on dependency analysis" is unchecked. (in target 'Runner' from project 'Runner')

The tool output of flutter build ios is:

Building com.example.testCreate for device (ios-release)...
Automatically signing iOS for device deployment using specified development team
in Xcode project: S8QB4VV633
Running Xcode build...
Xcode build done.                                           10.1s
Failed to build iOS app
Error output from Xcode build:
↳
    ** BUILD FAILED **


Xcode's output:
↳
    Writing result bundle at path:
    	/var/folders/fm/wjzsj_z95ydgn4khxqgbtqx000mfq2/T/flutter_tools.Dgnlxc/flutt
    	er_ios_build_temp_dirpKTDdk/temporary_xcresult_bundle

    error: lib/main.dart:13:11: Error: A value of type 'String' can't be
    assigned to a variable of type 'int'.
      int x = 'String';
              ^
    Target kernel_snapshot_program failed: Exception
    Failed to package /Users/magder/Projects/test_create.
    note: Disabling previews because SWIFT_VERSION is set and
    SWIFT_OPTIMIZATION_LEVEL=-O, expected -Onone (in target 'Runner' from
    project 'Runner')
    note: Run script build phase 'Run Script' will be run during every build
    because the option to run the script phase "Based on dependency analysis" is
    unchecked. (in target 'Runner' from project 'Runner')
    note: Run script build phase 'Thin Binary' will be run during every build
    because the option to run the script phase "Based on dependency analysis" is
    unchecked. (in target 'Runner' from project 'Runner')

Encountered error while building for device.

That seems okay, because the point is that you can see the int x = 'String'; error in the tool output. #72608 (comment)

I think just updating the test is sufficient without touching the tool.