rubocop cache is not invalidated when file permissions change

[chrisdtaylor]

The Lint/ScriptPermission Cop checks that files that have a shebang line as their first line also have execute permissions. However, just adding execute permissions to the file does NOT invalidate the rubocop cache, so the check continues to fail.

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Expected behavior

Rubocop caches should be invalidated for any kind of file change, including permission changes.

Actual behavior

Permission changes do not invalidate the cache, meaning correcting Lint/ScriptPermission cop violations by adding execute permission to a file does not satisfy the cop unless the cache is manually invalidated or deleted.

Steps to reproduce the problem

create a script with a #! line and without execute permissions
run rubocop on it
fix permissions
run rubocop again
boom

Rubocop Version:

rubocop -V
0.49.1 (using Parser 2.4.0.0, running on ruby 2.3.0 x86_64-linux)

[pocke]

This problem has been fixed already.
#4530
#4469