vendor: Add --include-path-deps to include path dependencies

[stevenroose]

Fixes #9172, #10134.
Replacement of #10135.

I would just like to say that I personally think it's incorrect that path dependencies are skipped by default (especially without this being documented explicitly anywhere). I think #10135 is a more correct fix for this behavior that I consider a bug. However, since it seems that #10135 is not considered a bugfix by the cargo devs, I would like to propose this alternative solution to make a flag that explicitly includes path dependencies.

This means that using the flag will break with existing behavior, but using the flag will also fix the current documented behavior.

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[weihanglo]

While the effort is pretty much appreciated, the current approach doesn't seem to work.

As ehuss mentioned earlier, source replacement doesn't support path dependencies. The current output vendor-config is like

[source."path+file:///home/user/cargo/target/tmp/cit/t0/foo/bar"]
directory = "file:///home/user/cargo/target/tmp/cit/t0/foo/bar"
replace-with = "vendored-sources"

[source.vendored-sources]
directory = "vendor"

It makes bar a directory source at ~/cargo/target/tmp/cit/t0/foo/bar, but the bar is not really a directory source. If you add the config to your .cargo/config.toml and run cargo build --verbose, you'll see that cargo won't pick the vendored bar from vendor/bar.

We'd happy to discuss use cases, workflows and design first in #10134, and see which approach fits better with the community need and the current architecture of Cargo.

[bors]

☔ The latest upstream changes (presumably #12959) made this pull request unmergeable. Please resolve the merge conflicts.

[weihanglo]

I am going to close this and keep the alternative #13347 open. #13347 is a proof-of-concept that addresses the issue mentioned in #12858 (comment). It supports path sources in source replacement so that Cargo can pick up correct sources.

Thanks for the pull request!