Turn sufficiently old compatibility lints into hard errors

[petrochenkov]

It's been almost 7 months since #36894 was merged, so it's time to take the next step.

[breaking-change], needs crater run.

PRs/issues submitted to affected crates:
https://github.com/alexcrichton/ctest/pull/17
Sean1708/rusty-cheddar#55
m-r-r/helianto#3
azdle/virgil#1
rust-locale/rust-locale#24
mneumann/acyclic-network-rs#1
reem/rust-typemap#38

cc https://internals.rust-lang.org/t/moving-forward-on-forward-compatibility-lints/4204
cc #34537 #36887
Closes #36886
Closes #36888
Closes #36890
Closes #36891
Closes #36892
r? @nikomatsakis

[nikomatsakis]

Started crater run:

• Inspector link for (14f30da)
• Inspector link for 7df86e455fadd04cba822e28fe39e3491ef2987b
• Build crates
• Build crates

[nikomatsakis]

Crater report: https://gist.github.com/nikomatsakis/d52d52ad9593528326deda76fb8281e0

Not yet analyzed.

Coverage

• 9031 crates tested: 6575 working / 2086 broken / 152 regressed / 35 fixed / 183 unknown.

Regressions

• There are 51 root regressions
• There are 152 regressions

Root regressions, sorted by rank:

• tempdir-0.3.5 (before) (after)
• postgres-0.14.1 (before) (after)
• smallvec-0.4.0 (before) (after)
• plugin-0.2.6 (before) (after)
• chan-signal-0.2.0 (before) (after)
• rblas-0.0.13 (before) (after)
• timeit-0.1.2 (before) (after)
• cpp_utils-0.2.0 (before) (after)
• rusty-cheddar-0.3.3 (before) (after)
• lossyq-0.1.19 (before) (after)
• adler32-1.0.0 (before) (after)
• gluon_parser-0.4.0 (before) (after)
• magnet_core-0.0.1 (before) (after)
• elmesque-0.12.0 (before) (after)
• mongodb-0.2.9 (before) (after)
• console-0.4.2 (before) (after)
• locale-0.2.1 (before) (after)
• crusadertest1-0.1.0 (before) (after)
• winrt-0.2.1 (before) (after)
• hansard-0.1.3 (before) (after)
• helianto-0.1.0-beta1 (before) (after)
• identicon-0.1.1 (before) (after)
• kernel-1.1.0 (before) (after)
• baal-0.5.1 (before) (after)
• cppn-0.1.1 (before) (after)
• ctest-0.1.1 (before) (after)
• opensimplex-0.2.0 (before) (after)
• overflower-0.4.0 (before) (after)
• parser-haskell-0.1.0 (before) (after)
• pencil-0.3.0 (before) (after)
• practicum-0.0.0 (before) (after)
• repsheet_etl-0.0.4 (before) (after)
• rose_tree-0.1.2 (before) (after)
• rustv-0.5.1 (before) (after)
• aligner-0.1.5 (before) (after)
• sharp_pencil-0.4.3 (before) (after)
• sqlpop-0.3.0 (before) (after)
• systemd-jp-0.1.1 (before) (after)
• text-diff-0.4.0 (before) (after)
• tokio-serde-0.0.0 (before) (after)
• trafo-0.1.1 (before) (after)
• glium_shapes-0.1.1 (before) (after)
• virgil-0.2.1 (before) (after)
• gluon_c-api-0.4.0 (before) (after)
• gluon_language-server-0.4.0 (before) (after)
• gluon_repl-0.4.0 (before) (after)
• xhtmlchardet-2.0.0 (before) (after)
• cargo-travis-0.0.4 (before) (after)
• xorshift128plus-0.1.1 (before) (after)
• xswag-syntax-java-0.3.0 (before) (after)
• yaml_file_handler-0.1.4 (before) (after)

[Mark-Simulacrum]

Primary problems are petgraph and typemap, though there are a few others.

root cause          lint                                      recorded cause
acyclic-network     type param defaults                       cppn-0.1.1
chrono              illegal_struct_or_enum_constant_pattern   helianto-0.1.0-beta1
elfloader32         illegal_struct_or_enum_constant_pattern   rustv-0.5.1
locale              private in public                         locale-0.2.1
mustache            private in public                         virgil-0.2.1
petgraph            type param defaults                       gluon_c-api-0.4.0
petgraph            type param defaults                       gluon_language-server-0.4.0
petgraph            type param defaults                       gluon_parser-0.4.0
petgraph            type param defaults                       gluon_repl-0.4.0
petgraph            type param defaults                       kernel-1.1.0
petgraph            type param defaults                       parser-haskell-0.1.0
petgraph            type param defaults                       rose_tree-0.1.2
petgraph            type param defaults                       sqlpop-0.3.0
petgraph            type param defaults                       xswag-syntax-java-0.3.0
piston2d-graphics   type param defaults                       elmesque-0.12.0
syntex_syntax       illegal_struct_or_enum_constant_pattern   ctest-0.1.1
syntex_syntax       illegal_struct_or_enum_constant_pattern   rusty-cheddar-0.3.3
typemap             type param defaults                       magnet_core-0.0.1
typemap             type param defaults                       pencil-0.3.0
typemap             type param defaults                       plugin-0.2.6
typemap             type param defaults                       sharp_pencil-0.4.3

Legitimate failures:

• plugin-0.2.6 (before) (after): type param defaults: typemap
• rusty-cheddar-0.3.3 (before) (after): illegal_struct_or_enum_constant_pattern: syntex_syntax
• gluon_parser-0.4.0 (before) (after): type param defaults: petgraph
• magnet_core-0.0.1 (before) (after): type param defaults: typemap
• elmesque-0.12.0 (before) (after): type param defaults: piston2d-graphics
• locale-0.2.1 (before) (after): private in public: locale
• helianto-0.1.0-beta1 (before) (after): illegal_struct_or_enum_constant_pattern: chrono
• kernel-1.1.0 (before) (after): type param defaults: petgraph
• cppn-0.1.1 (before) (after): type param defaults: acyclic-network
• ctest-0.1.1 (before) (after): illegal_struct_or_enum_constant_pattern: syntex_syntax
• parser-haskell-0.1.0 (before) (after): type param defaults: petgraph
• pencil-0.3.0 (before) (after): type param defaults: typemap
• rose_tree-0.1.2 (before) (after): type param defaults: petgraph
• rustv-0.5.1 (before) (after): illegal_struct_or_enum_constant_pattern: elfloader32
• sharp_pencil-0.4.3 (before) (after): type param defaults: typemap
• sqlpop-0.3.0 (before) (after): type param defaults: petgraph
• virgil-0.2.1 (before) (after): private in public: mustache
• gluon_c-api-0.4.0 (before) (after): type param defaults: petgraph
• gluon_language-server-0.4.0 (before) (after): type param defaults: petgraph
• gluon_repl-0.4.0 (before) (after): type param defaults: petgraph
• xswag-syntax-java-0.3.0 (before) (after): type param defaults: petgraph

False positives:

• tempdir-0.3.5 (before) (after): network failure
• postgres-0.14.1 (before) (after): container didn't start
• smallvec-0.4.0 (before) (after): container didn't start
• chan-signal-0.2.0 (before) (after): network failure
• rblas-0.0.13 (before) (after): network failure
• timeit-0.1.2 (before) (after): network failure
• cpp_utils-0.2.0 (before) (after): network failure
• lossyq-0.1.19 (before) (after): network failure
• adler32-1.0.0 (before) (after): network failure
• mongodb-0.2.9 (before) (after): container didn't start
• console-0.4.2 (before) (after): container didn't start
• crusadertest1-0.1.0 (before) (after): container didn't start
• winrt-0.2.1 (before) (after): container didn't start
• hansard-0.1.3 (before) (after): container didn't start
• identicon-0.1.1 (before) (after): container failure
• baal-0.5.1 (before) (after): container failure
• opensimplex-0.2.0 (before) (after): container failure
• overflower-0.4.0 (before) (after): container failure
• practicum-0.0.0 (before) (after): container failure
• repsheet_etl-0.0.4 (before) (after): container failure
• aligner-0.1.5 (before) (after): container failure
• systemd-jp-0.1.1 (before) (after): container failure
• text-diff-0.4.0 (before) (after): container failure
• tokio-serde-0.0.0 (before) (after): container failure
• trafo-0.1.1 (before) (after): container failure
• glium_shapes-0.1.1 (before) (after): container failure
• xhtmlchardet-2.0.0 (before) (after): container failure
• cargo-travis-0.0.4 (before) (after): container failure
• xorshift128plus-0.1.1 (before) (after): container failure
• yaml_file_handler-0.1.4 (before) (after): container failure

[petrochenkov]

This is interesting, all the affected crates (except for abandoned locale) were fixed and published, but other crates still depend on older versions.
What would the best course of actions be?
Bump petgraph/typemap versions in dependent crates? Keep invalid_type_param_default a lint?

[nikomatsakis]

@petrochenkov

This is interesting, all the affected crates (except for abandoned locale) were fixed and published, but other crates still depend on older versions.

Yeah, this is a common scenario. Frustrating. I'm not sure what's the best fix. Another option is to encourage the crate authors to push a new minor version that fixes the lint; we have done that in the past for major cases.

[bors]

☔ The latest upstream changes (presumably #40847) made this pull request unmergeable. Please resolve the merge conflicts.

[nikomatsakis]

cc @rust-lang/compiler @alexcrichton @brson -- so what should we do here? There are a number of outdated dependencies in crater which means that if we "close the door" on these compatibility lints, they will break.

One option:

• Ping the authors here and encourage them to run cargo update and issue a new version, but land this code.
• Ping the authors here, wait for (most of) them to issue new versions, then land the code.
• Try to land PRs?

Seems like pinging authors is a good first step!

[petrochenkov]

Ping the authors here and encourage them to run cargo update and issue a new version, but land this code.
Ping the authors here, wait for (most of) them to issue new versions, then land the code.
Try to land PRs?

I've already submitted PRs to all affected crates except for those depending on typemap and petgraph.
Next I was going to turn invalid_type_param_default into a lint again (leave it for later), and then propose to land this PR without waiting.

[alexcrichton]

Thanks for the legwork here sending PRs @petrochenkov! It sounds like the major sources of breakage are or are about to all be mitigated? In that sense maybe leave invalid_type_param_default as a lint (warn for now to keep typemap/petgraph working) and then rerun crater?

[petrochenkov]

Next I was going to turn invalid_type_param_default into a lint again (leave it for later), and then propose to land this PR without waiting.

Done.

[Mark-Simulacrum]

@petrochenkov @nikomatsakis Does this need another crater run? The status tag wasn't removed after the last one and I'm not clear on the current status based on discussion.

[petrochenkov]

@Mark-Simulacrum
I'd say no. It'll take time (weeks at least, from previous experience) for people to react on PRs I sent, so it shouldn't block landing this.

[Mark-Simulacrum]

I'm a little confused by that; if we land this now, before the PRs are merged and published, presumably that would still break the ecosystem? Or am I missing something?

[petrochenkov]

@Mark-Simulacrum
"break the ecosystem" is kinda overestimation, from non-updated broken crates only rusty-cheddar has dependent crates.
I'm personally okay with this kind of breakage, crates that are important in the ecosystem are usually fixed long before this stage + the breakage is nightly only, there are some weeks ahead to push the authors if someone needs their crates.

[Mark-Simulacrum]

Ah, okay. Wasn't sure about the actual impact of these changes.

[bors]

☔ The latest upstream changes (presumably #41856) made this pull request unmergeable. Please resolve the merge conflicts.

[nikomatsakis]

r=me once rebased

[alexcrichton]

@petrochenkov for future tracking purposes if you've still got links to the PRs to fix upstream crates, mind throwing them into the PR description? That way if we see regressions crop up on crater we can quickly find the upstream PR to fix it.

[petrochenkov]

@bors r=nikomatsakis

[bors]

📌 Commit 26d5c0e has been approved by nikomatsakis

[bors]

⌛ Testing commit 26d5c0e with merge 67aa270...

[bors]

💔 Test failed - status-appveyor

[Mark-Simulacrum]

Error looks potentially spurious, but hard to tell.

@bors retry

[01:25:51] failures:
[01:25:51]
[01:25:51] ---- cargo_compile_simple_git_dep stdout ----
[01:25:51]  running `C:\projects\rust\build\x86_64-pc-windows-msvc\stage2-tools\x86_64-pc-windows-msvc\release\cargo.exe build`
[01:25:51] running `C:\projects\rust\build\x86_64-pc-windows-msvc\stage2-tools\x86_64-pc-windows-msvc\cit\t3\foo\target\debug\foo.exe`
[01:25:51] thread 'cargo_compile_simple_git_dep' panicked at '
[01:25:51] Expected: execs
[01:25:51]     but: differences:
[01:25:51]   0 - |hello world|
[01:25:51]     +
[01:25:51]
[01:25:51]
[01:25:51] other output:
[01:25:51] ``', C:\Users\appveyor\.cargo\registry\src\github.com-1ecc6299db9ec823\hamcrest-0.1.1\src\core.rs:31
[01:25:51] note: Run with `RUST_BACKTRACE=1` for a backtrace.
[01:25:51]
[01:25:51]
[01:25:51] failures:
[01:25:51]     cargo_compile_simple_git_dep
[01:25:51]
[01:25:51] test result: FAILED. 32 passed; 1 failed; 0 ignored; 0 measured; 0 filtered out

[alexcrichton]

My guess is #33434

[brson]

We're probably going to need writeups of all these for the release notes.