[8.8.0] Fix launching executables whose path can't be shortened on Windows (https://github.com/bazelbuild/bazel/pull/29921)

[bazel-io]

Description

AsExecutablePathForCreateProcess shortens an executable's path with GetShortPathNameW so it fits CreateProcessW's MAX_PATH-bound command line, and currently fails outright when shortening can't bring it under MAX_PATH.
This change adds a fallback: it launches the executable through CreateProcessW's lpApplicationName, which is not subject to the MAX_PATH limit, in extended-length (\\?\) form.
Supplying lpApplicationName also lifts the MAX_PATH limit from the executable part of lpCommandLine, so the original path is kept there as argv[0].

Shortening is still attempted first, so the change is a pure superset of the current behavior: paths that shorten today are launched unchanged, and only the currently-failing ones take the fallback.
The fallback is limited to absolute, normalized paths to plain executables:

• a batch file is not a valid lpApplicationName as it must be run through a command interpreter,
• neither is a non-normalized path because its ./.. components would survive unresolved in the extended-length path.

The fix relies on \\?\ bypassing MAX_PATH at the path-parsing layer, independently of the LongPathsEnabled registry value and the longPathAware manifest.

Motivation

Fixes #19710.

Avoid errors like:

==================== Test output for //some/configuration/issues/invalidconfig:invalidconfig_test:
ERROR(tools/test/windows/tw.cc:1307) ERROR: src/main/native/windows/process.cc(82): WaitableProcess::Create(C:\user\execroot\_main\bazel-out\x64_windows-fastbuild-ST-000000000001\bin\some\configuration\issues\invalidconfig\invalidconfig_test_\invalidconfig_test.exe.runfiles\_main\some\configuration\issues\invalidconfig\invalidconfig_test_\invalidconfig_test.exe): ERROR: src/main/native/windows/util.cc(292): AsExecutablePathForCreateProcess(C:\user\execroot\_main\bazel-out\x64_windows-fastbuild-ST-000000000001\bin\some\configuration\issues\invalidconfig\invalidconfig_test_\invalidconfig_test.exe.runfiles\_main\some\configuration\issues\invalidconfig\invalidconfig_test_\invalidconfig_test.exe): ERROR: src/main/native/windows/util.cc(262): GetShortPathNameW(\\?\C:\user\execroot\_main\bazel-out\x64_windows-fastbuild-ST-000000000001\bin\some\configuration\issues\invalidconfig\invalidconfig_test_\invalidconfig_test.exe.runfiles\_main\some\configuration\issues\invalidconfig\invalidconfig_test_\invalidconfig_test.exe): cannot shorten the path enough
ERROR(tools/test/windows/tw.cc:1517) Failed to start test process (arg: C:\user\execroot\_main\bazel-out\x64_windows-fastbuild-ST-000000000001\bin\some\configuration\issues\invalidconfig\invalidconfig_test_\invalidconfig_test.exe.runfiles\_main\some\configuration\issues\invalidconfig\invalidconfig_test_\invalidconfig_test.exe)
================================================================================

Shortening fails in two situations, both handled here:

• 8dot3 short-name creation is disabled on the volume (common in containers, 8dot3name short name creation not persisted microsoft/Windows-Containers#507), so GetShortPathNameW is a no-op and a long runfiles executable path stays over MAX_PATH,
• the path is nested so deeply that even fully 8dot3-shortened it still overflows MAX_PATH.

Prior art: Rust's std::process::Command passes a verbatim \\?\ path as lpApplicationName for a >MAX_PATH executable and special-cases batch files the same way:

• Windows: Resolve process::Command program without using the current directory rust-lang/rust#87704,
• Use verbatim paths for process::Command if necessary rust-lang/rust#92519.

Build API Changes

No

Checklist

• I have added tests for the new use cases (if any).
• I have updated the documentation (if applicable).

Release Notes

RELNOTES: Fixed Bazel being unable to run a Windows executable whose path is too long to shorten under MAX_PATH, e.g. when 8dot3 short names are disabled (microsoft/Windows-Containers#507).

Closes #29921.

PiperOrigin-RevId: 937426905
Change-Id: Ia48d41e000622fc122d1b258ad15daa5018be75e

Commit 4a80d43