`x.py dist` builds tools twice due to dependency vendoring?

[matthiaskrgr]

There is this problem that x.py dist builds most of the tools twice.

It seems that during the initial build (which is the same as x.py build) we take the normal sources from $CARGO_HOME, but then there is some dependency vendoring taking place which seems to override some of the dependency paths to the vendored ones.

This causes fingerprints to change and some of the tools to be rebuilt:

   Vendoring xz2 v0.1.6 (/home/matthias/.cargo/registry/src/github.com-1ecc6299db9ec823/xz2-0.1.6) to vendor/xz2
   Vendoring yaml-merge-keys v0.4.1 (/home/matthias/.cargo/registry/src/github.com-1ecc6299db9ec823/yaml-merge-keys-0.4.1) to vendor/yaml-merge-keys
   Vendoring yaml-rust v0.3.5 (/home/matthias/.cargo/registry/src/github.com-1ecc6299db9ec823/yaml-rust-0.3.5) to vendor/yaml-rust-0.3.5
   Vendoring yaml-rust v0.4.4 (/home/matthias/.cargo/registry/src/github.com-1ecc6299db9ec823/yaml-rust-0.4.4) to vendor/yaml-rust
   Vendoring yansi-term v0.1.2 (/home/matthias/.cargo/registry/src/github.com-1ecc6299db9ec823/yansi-term-0.1.2) to vendor/yansi-term
To use vendored sources, add this to your .cargo/config.toml for this project:

[source.crates-io]
replace-with = "vendored-sources"

[source."https://github.com/bjorn3/rust-ar.git"]
git = "https://github.com/bjorn3/rust-ar.git"
branch = "do_not_remove_cg_clif_ranlib"
replace-with = "vendored-sources"

[source.vendored-sources]
directory = "vendor"
Dist rustc-1.60.0-dev-src
	finished in 283.091 seconds
Building stage1 tool cargo (x86_64-unknown-linux-gnu)
[2022-01-18T14:45:58Z INFO  cargo::core::compiler::fingerprint] stale: changed "/home/matthias/.cargo/registry/src/github.com-1ecc6299db9ec823/curl-sys-0.4.51+curl-7.80.0/curl"
[2022-01-18T14:45:58Z INFO  cargo::core::compiler::fingerprint]           (vs) "/home/matthias/vcs/github/rust/build/x86_64-unknown-linux-gnu/stage1-tools/x86_64-unknown-linux-gnu/release/build/curl-sys-92c84ce359fc681e/output"
[2022-01-18T14:45:58Z INFO  cargo::core::compiler::fingerprint]                FileTime { seconds: 1642516164, nanos: 851099564 } != FileTime { seconds: 1642516869, nanos: 931076291 }
[2022-01-18T14:45:58Z INFO  cargo::core::compiler::fingerprint] fingerprint error for cargo v0.60.0 (/home/matthias/vcs/github/rust/src/tools/cargo)/Build/TargetInner { ..: lib_target("cargo", ["lib"], "/home/matthias/vcs/github/rust/src/tools/cargo/src/cargo/lib.rs", Edition2021) }
[2022-01-18T14:45:58Z INFO  cargo::core::compiler::fingerprint]     err: current filesystem status shows we're outdated
[2022-01-18T14:45:58Z INFO  cargo::core::compiler::fingerprint] fingerprint error for cargo v0.60.0 (/home/matthias/vcs/github/rust/src/tools/cargo)/RunCustomBuild/TargetInner { ..: custom_build_target("build-script-build", "/home/matthias/vcs/github/rust/src/tools/cargo/build.rs", Edition2021) }
[2022-01-18T14:45:58Z INFO  cargo::core::compiler::fingerprint]     err: current filesystem status shows we're outdated
[2022-01-18T14:45:58Z INFO  cargo::core::compiler::fingerprint] fingerprint error for curl-sys v0.4.51+curl-7.80.0/RunCustomBuild/TargetInner { ..: custom_build_target("build-script-build", "/home/matthias/.cargo/registry/src/github.com-1ecc6299db9ec823/curl-sys-0.4.51+curl-7.80.0/build.rs", Edition2018) }
[2022-01-18T14:45:58Z INFO  cargo::core::compiler::fingerprint]     err: current filesystem status shows we're outdated
[2022-01-18T14:45:58Z INFO  cargo::core::compiler::fingerprint] fingerprint error for crates-io v0.33.1 (/home/matthias/vcs/github/rust/src/tools/cargo/crates/crates-io)/Build/TargetInner { ..: lib_target("crates_io", ["lib"], "/home/matthias/vcs/github/rust/src/tools/cargo/crates/crates-io/lib.rs", Edition2021) }
[2022-01-18T14:45:58Z INFO  cargo::core::compiler::fingerprint]     err: current filesystem status shows we're outdated
[2022-01-18T14:45:58Z INFO  cargo::core::compiler::fingerprint] fingerprint error for curl v0.4.41/Build/TargetInner { ..: lib_target("curl", ["lib"], "/home/matthias/.cargo/registry/src/github.com-1ecc6299db9ec823/curl-0.4.41/src/lib.rs", Edition2018) }
[2022-01-18T14:45:58Z INFO  cargo::core::compiler::fingerprint]     err: current filesystem status shows we're outdated
[2022-01-18T14:45:58Z INFO  cargo::core::compiler::fingerprint] fingerprint error for curl v0.4.41/RunCustomBuild/TargetInner { ..: custom_build_target("build-script-build", "/home/matthias/.cargo/registry/src/github.com-1ecc6299db9ec823/curl-0.4.41/build.rs", Edition2018) }
[2022-01-18T14:45:58Z INFO  cargo::core::compiler::fingerprint]     err: current filesystem status shows we're outdated
[2022-01-18T14:45:58Z INFO  cargo::core::compiler::fingerprint] fingerprint error for curl-sys v0.4.51+curl-7.80.0/Build/TargetInner { ..: lib_target("curl_sys", ["lib"], "/home/matthias/.cargo/registry/src/github.com-1ecc6299db9ec823/curl-sys-0.4.51+curl-7.80.0/lib.rs", Edition2018) }
[2022-01-18T14:45:58Z INFO  cargo::core::compiler::fingerprint]     err: current filesystem status shows we're outdated
[2022-01-18T14:45:58Z INFO  cargo::core::compiler::fingerprint] fingerprint error for git2-curl v0.14.1/Build/TargetInner { ..: lib_target("git2-curl", ["lib"], "/home/matthias/.cargo/registry/src/github.com-1ecc6299db9ec823/git2-curl-0.14.1/src/lib.rs", Edition2018) }
[2022-01-18T14:45:58Z INFO  cargo::core::compiler::fingerprint]     err: current filesystem status shows we're outdated
[2022-01-18T14:45:58Z INFO  cargo::core::compiler::fingerprint] fingerprint error for cargo v0.60.0 (/home/matthias/vcs/github/rust/src/tools/cargo)/Build/TargetInner { name: "cargo", tested: false, ..: with_path("/home/matthias/vcs/github/rust/src/tools/cargo/src/bin/cargo/main.rs", Edition2021) }
[2022-01-18T14:45:58Z INFO  cargo::core::compiler::fingerprint]     err: current filesystem status shows we're outdated
   Compiling curl-sys v0.4.51+curl-7.80.0
   Compiling curl v0.4.41
   Compiling cargo v0.60.0 (/home/matthias/vcs/github/rust/src/tools/cargo)
   Compiling crates-io v0.33.1 (/home/matthias/vcs/github/rust/src/tools/cargo/crates/crates-io)
   Compiling git2-curl v0.14.1
    Finished release [optimized] target(s) in 3m 17s
Building stage1 tool cargo-credential-1password (x86_64-unknown-linux-gnu)

[matthiaskrgr]

Commenting out the PlainSourceTarball step seems to make tools not be build again.

rust/src/bootstrap/builder.rs

Line 498 in 9ad5d82

dist::PlainSourceTarball,

[ehuss]

@matthiaskrgr Can you show which jobs are building tools multiple times?

The only one I know of is dist-x86_64-apple due to #90100. I don't think that is related to PlainSourceTarball, since dist-x86_64-apple does not build that step.

I am looking at dist-x86_64-linux, and it is building cargo twice (once as a tool, and once for RLS). There's a check that is supposed to prevent that, so I'm curious why that is happening.

[ehuss]

I determined why cargo is being built twice with RLS. It is due to rust-lang/cargo#10178, where CFG_COMMIT_HASH changes between the two. The way it is set causes it to change based on which tool is being built.

I'm uncertain how to fix that. I'll need to think about it.

[matthiaskrgr]

Oh then we talked about two different issues probably 😅

So when cargo is being built, it gets its own commithash from the rls repo, but then when we built cargo again as rls dependency, the commithash comes from the rls repo and we build both cargo (again, since hash changed) and rls with the commit hash from the rls repo?

Perhaps we can hack around like:
if we know that we are building in the rust repo, the cargo and rls could have a code branch that checks a different env var CFG_COMMIT_HASH_RLS and CFG_COMMIT_HASH_CARGO and bootstrap sets these accordingly.
This way CFG_COMMIT_HASH_RLS would always be set to the commit hash of the rls submodule (or later the rust repo, if rls gets subtree'd at some point?)

[ehuss]

I have posted rust-lang/cargo#10323 to fix the issue with cargo and rls. That should help shave a minute or two on the dist builders.

I'm still planning on looking at the issues with #90100.