feat(pex): support building PEX archives to inherit from the sys.path

[plobsing]

By default PEX archives are built to operate fully hermetically, which is usually a good idea. However, sometimes it is necessary to use packages from the hosting environment. One such example is AWS Lambda; the recommended approach for using PEX to run on Lambda is to build in this way.¹

Mapping of this flag through from the build system largely follows the equivalent feature in Pants.²

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Changes are visible to end-users: yes

• Searched for relevant documentation and updated as needed: yes
• Breaking change (forces users to change their own code or config):no
• Suggested release notes appear below: no

Test plan

• Covered by existing test cases
• Manual testing; please provide instructions so we can reproduce:

1. Edit //py/tests/py-pex-binary:print_modules_pex to have an explicit inherit_path of a chosen value (e.g. "prefer").
2. bazel build //py/tests/py-pex-binary:print_modules_pex.
3. tar xfO bazel-bin/py/tests/py-pex-binary/print_modules_pex.pex PEX-INFO | jq '.inherit_path'
4. Expect result: "prefer".

Do above except without passing an explicit inherit_path should give "false", which confirms the default semantics are preserved.

Footnotes

1. https://github.com/pex-tool/lambdex/blob/main/MIGRATING.md ↩

2. https://www.pantsbuild.org/stable/reference/targets/pex_binary#inherit_path ↩

[aspect-workflows]

Test

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