hmm I am pretty sure we need this in a non-test context somewhere which is why we had to add it. something like running the golden test .accept bin

Actually that works as with both bazel test //golden/file:test and bazel run //golden/file:test the TEST_* vars are set even in the bazel run case as it is a test target. The usage of TEST_TARGET is for the output

Update the golden file:

            bazel run ${debug ? '--compilation_mode=dbg ' : ''}${
          process.env['TEST_TARGET'].replace(/_bin$/, '')}.accept

which works in both bazel test and bazel run cases.

bazel run //golden/file:test.accept doesn't have the TEST_* vars set but it doesn't need them.

So in our repo we don't need BAZEL_TARGET set for any non-test targets.

I guess the question is if someone else is relying on this and if we should remove it or leave it and document it as a feature?

It can be useful in the run context to know which target is being run. A few others come to mind that would also be useful such as:

• BAZEL_WORKSPACE (to match TEST_WORKSPACE)
• BAZEL_BINARY (to match TEST_BINARY)
• BAZEL_SRCDIR (to match TEST_SRCDIR which is equal to RUNFILES)

Updating Angular to 1.0.0 yesterday I ran into the case where I needed all of these TEST_* vars to load the require.resolve loader patches in a bootstrap script since the bootstrap scripts are now being loaded with --node_options=--require=... and we're in an in-between state where the linker is not yet turned on for jasmine_node_test targets (also it would break on Windows).

/tools/testing/init_node_spec.ts in angular/angular#34589:

if (process.env['TEST_SRCDIR']) {
  // bootstrap the bazel require resolve patch since this
  // script is a bootstrap script loaded with --node_options=--require=...
  const path = require('path');
  require(path.posix.join(
      process.env['TEST_SRCDIR'], process.env['TEST_WORKSPACE'],
      (process.env['TEST_BINARY'] as string).replace(/\.(sh|bat)$/, '_loader.js'), ));
}

import 'zone.js/lib/node/rollup-main';
...

Ohhhh. The linker relies on TEST_* targets right now which would be a problem for non-test targets:

    const wksp = env['TEST_WORKSPACE'];
    const target = env['TEST_TARGET'];
    if (!!wksp && !!target) {
      // //path/to:target -> //path/to
      const pkg = target.split(':')[0];
      this.packagePath = path.posix.join(wksp, pkg);
    }

    // If under runfiles (and not unit testing) then don't add a bin to target for bin links
    this.noBin = !!env['TEST_TARGET'] && wksp !== 'build_bazel_rules_nodejs' &&
        target !== '//internal/linker/test:unit_tests';

Seems like the right way to go here is to set at least BAZEL_WORKSPACE, BAZEL_TARGET and document them. Possibly BAZEL_SRCDIR and BAZEL_BINARY as well.