Try to fix paths in clang-tidy output [DIP-356]

[woodfell]

Not elegant, but look for bazel cache-y paths in the output of clang-tidy and strip out the prefix so that errors relate back to real files in the repository.

An example error output from before the change:

ERROR: /home/matt/work/clean/starling-core/public_types/BUILD.bazel:14:17: Run clang-tidy on public_types/src/snprintf.cc failed: (Exit 1): clang_tidy failed: error executing command (from target //public_types:public_types) bazel-out/k8-fastbuild/bin/external/rules_swiftnav/clang_tidy/clang_tidy external/x86_64-linux-llvm/bin/clang-tidy external/rules_swiftnav/clang_tidy/.clang-tidy ... (remaining 80 arguments skipped)

Use --sandbox_debug to see verbose messages from the sandbox and retain the sandbox build root for debugging
1543 warnings generated.
Suppressed 1558 warnings (1541 in non-user code, 16 NOLINT, 1 with check filters).
Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well.
/home/matt/.cache/bazel/_bazel_matt/88ca1cd2a9e383e37ba5e842f72d57ea/sandbox/linux-sandbox/150/execroot/starling-core/public_types/src/snprintf.cc:101:19: warning: consider replacing 'short' with 'int16' [google-runtime-int]
struct arg_traits<signed short> final {

And after:

ERROR: /home/matt/work/clean/starling-core/public_types/BUILD.bazel:14:17: Run clang-tidy on public_types/src/snprintf.cc failed: (Exit 1): clang_tidy failed: error executing command (from target //public_types:public_types) bazel-out/k8-fastbuild/bin/external/rules_swiftnav/clang_tidy/clang_tidy external/x86_64-linux-llvm/bin/clang-tidy external/rules_swiftnav/clang_tidy/.clang-tidy ... (remaining 80 arguments skipped)

Use --sandbox_debug to see verbose messages from the sandbox and retain the sandbox build root for debugging
1543 warnings generated.
Suppressed 1558 warnings (1541 in non-user code, 16 NOLINT, 1 with check filters).
Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well.
public_types/src/snprintf.cc:101:19: warning: consider replacing 'short' with 'int16' [google-runtime-int]
struct arg_traits<signed short> final {

Note how the first message mentions a file in ~/.cache/bazel/.... which is helpfully deleted as soon as the command fails. By stripping out this prefix and leaving just the relative path within the repository then, assuming the command is run from the repository root, the path matches the actual real file rather than bazel's copy. IDEs and other tooling can parse out the message and trace it back to where it actually came from

[woodfell]

@isaactorz as discussed in the build sync. Probably not an idiomatic solution but it solves my problem and makes the output of clang-tidy useable by other tooling

[jungleraptor]

@isaactorz as discussed in the build sync. Probably not an idiomatic solution but it solves my problem and makes the output of clang-tidy useable by other tooling

pinging myself to remember to take a look at it.

At first glance seems perfectly reasonable just want to take a closer look before approving.

[jungleraptor]

nit: can we leave a small comment here as a reminder of what this was for?