fix(coverage): prevent issues when packages execute files in tmp dir.

Fixes bazel-contrib#2575

Author: BurnzZ

CHANGELOG.md

@@ -77,6 +77,8 @@ Unreleased changes template.
   The related issue is [#908](https://github.com/bazelbuild/rules_python/issue/908).
 * (sphinxdocs) Do not crash when `tag_class` does not have a populated `doc` value.
   Fixes ([#2579](https://github.com/bazelbuild/rules_python/issues/2579)).
+* (coverage) Prevent coveragepy report issues when packages execute files in tmp dir.
+  Fixes ([#2575](https://github.com/bazelbuild/rules_python/issues/2575)).
 
 {#v0-0-0-added}
 ### Added

python/private/python_bootstrap_template.txt

@@ -461,6 +461,9 @@ relative_files = True
     kparams['stdout'] = sys.stderr
     kparams['stderr'] = sys.stderr
 
+  # Prevent coveragepy report issues when packages execute files in tmp dir.
+  params.append('--omit="$TMPDIR/*"')
+
   ret_code = subprocess.call(
     params,
     **kparams