perf(package): only try to read files that exist

[andytom]

Description

Have refactored the package module to improve performance. Before this
change the module would try to open every single file that could contain
some package information until it found a valid version. This resulted
in a lot of unneeded disk IO. Have added a new fn, read_file_from_pwd
that uses the current context to check if that file already exists and
fast failing if it doesn't.

Motivation and Context

From my local testing this speeds up the package module from taking ~1ms to ~50µs in an empty directory.

Screenshots (if appropriate):

How Has This Been Tested?

• I have tested using MacOS
• I have tested using Linux
• I have tested using Windows

Checklist:

• I have updated the documentation accordingly.
• I have updated the tests accordingly.

[davidkna]

The changes themselves look good.

A few other files seem to have similar utils::read_file(context.current_dir.join("...")) calls, so this should perhaps also cover those.

[andytom]

The changes themselves look good.

A few other files seem to have similar utils::read_file(context.current_dir.join("...")) calls, so this should perhaps also cover those.

The only one I found from a quick check was the haskell module, which I have updated, but maybe I missed something.

Edit scratch that just noticed can update the node module.

[davidkna]

@andytom There's also the nodejs module has (base_dir is current_dir) and the terraform module (though it would be harder to replace there since it might read from a different location`).

[andytom]

Thanks for the review @davidkna