Update cargo

[ehuss]

14 commits in aa6872140ab0fa10f641ab0b981d5330d419e927..974eb438da8ced6e3becda2bbf63d9b643eacdeb
2020-07-23 13:46:27 +0000 to 2020-07-29 16:15:05 +0000

• Fix O0 build scripts by default without [profile.release] (Fix O0 build scripts by default without [profile.release] cargo#8560)
• Emphasize git dependency version locking behavior. (Emphasize git dependency version locking behavior. cargo#8561)
• Update lock file encodings on changes (Update lock file encodings on changes cargo#8554)
• Fix sporadic lto test failures. (Fix sporadic lto test failures. cargo#8559)
• build-std: Fix libraries paths following upstream (build-std: Fix libraries paths following upstream cargo#8558)
• Flag git http errors as maybe spurious (Flag git http errors as maybe spurious cargo#8553)
• Display builtin aliases with cargo --list (Display builtin aliases with cargo --list cargo#8542)
• Check manifest for requiring nonexistent features (Check manifest for requiring nonexistent features cargo#7950)
• Clarify test name filter usage (Clarify test name filter usage cargo#8552)
• Revert Cargo Book changes for default edition (Revert Cargo Book changes for default edition cargo#8551)
• Prepare for not defaulting to master branch for git deps (Prepare for not defaulting to master branch for git deps cargo#8522)
• Include + for crates.io feature requirements in the Cargo Book section on features (Include + for crates.io feature requirements in the Cargo Book section on features cargo#8547)
• Update termcolor and fwdansi versions (Update termcolor and fwdansi versions cargo#8540)
• Cargo book nitpick in Manifest section (Cargo book nitpick in Manifest section cargo#8543)

[rust-highfive]

Updates src/tools/cargo.

cc @ehuss

[rust-highfive]

r? @Mark-Simulacrum

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[rust-highfive]

⚠️ Warning ⚠️

• These commits modify submodules.

[ehuss]

@bors p=1 rollup=never

Don't rollup, this includes several major changes.

Requesting review from @Mark-Simulacrum because this updates a dependency used by almost everything. I've run some tests, and I haven't run into any issues.

Unfortunately I don't remember why the update to termcolor was being delayed. I thought there were still some issues on Windows, but I did a few tests on Windows 8 and the colors looked OK.

[Mark-Simulacrum]

Hm, so there is this: #63725 (comment)

Do you happen to have Windows 7 or 8 handy to try and see if those issues have since been solved?

[ehuss]

Yes, I already tested on Windows 8, and the colors look OK to me. kennytm/fwdansi#1 got fixed (that's why it is updated here). My concern was kennytm/fwdansi#2, but I don't remember exactly why I filed that. I think Cargo (and rustc, etc.) uses simple enough colors that it isn't an issue.

[ehuss]

And once this lands on nightly, I'll do some more testing, and if everything looks good, I will close rust-lang/cargo#8089 and #55769.

[Mark-Simulacrum]

Okay. That's good enough for me -- I suspect getting this landed and rolled out to the community at large is the best way to determine if this breaks anyone's workflow anyway :)

@bors r+

[bors]

📌 Commit 89d7906 has been approved by Mark-Simulacrum

[bors]

⌛ Testing commit 89d7906 with merge 7986bf52e4c8ab2b61eb1931dbdf322b27f19b18...

[bors]

💔 Test failed - checks-actions

[ehuss]

@bors retry
flaky test: rust-lang/cargo#8564

[bors]

⌛ Testing commit 89d7906 with merge 6e50a22...

[bors]

☀️ Test successful - checks-actions, checks-azure
Approved by: Mark-Simulacrum
Pushing 6e50a22 to master...

[Mark-Simulacrum]

This was a performance regression, likely due to rust-lang/cargo#8560.

Looking at the results, it seems the two crates affected, cargo and script-servo, had a roughly 0.5s and 0.8s bump in macro expansion.

This is presumably an expected (if somewhat unfortunate) consequence of the above PR -- it was all but guaranteed to be a regression on perf.rust-lang.org, as we only benchmark "final binary/library" compilation rather than the whole build. rust-lang/cargo#8560 can only help full, post-cargo clean, builds.

[ehuss]

cc @alexcrichton ↑

Yea, it is difficult to get the defaults to accommodate all use cases. I would expect the negative effects to mostly happen for someone doing development with optimizations enabled. I'm curious how common that is. I suspect it is rare, but I've had a project where it was unusable without optimizations, so maybe not so rare.

FWIW, I did some benchmarking on a variety of real-world projects and a variety of parallel jobs, and the change was faster in every case for a from-scratch --release build.

If you want to restore the old behavior, you can set the env var CARGO_PROFILE_RELEASE_BUILD_OVERRIDE_OPT_LEVEL=3 (assuming the project doesn't override the default opt-level).

[Mark-Simulacrum]

I don't think I've ever had a Rust project that was more than a week long and didn't always need release mode, but I agree that it probably varies quite a bit.

I think that this is probably still the right call, though.

One thing we could try is splitting the build dependencies of proc macros and build scripts apart - the latter matter much less, and always run once. But proc macros used for in-workspace crates are essentially guaranteed to be run hundreds of times, so optimizing them to shave of a few milliseconds can be helpful.

I think from scratch builds will indeed always be faster for this, but we also don't have a great handle on whether that matters today (i.e., if you're on CI you probably only care about them, but locally you usually care about tiny incremental rebuilds).