Add check to ensure error code explanations are not removed anymore even if not emitted

[GuillaumeGomez]

The error explanations are useful in case you use older version of the compiler. Even more if they had an explanation. If they are not emitted, their explanations should be updated but not removed (as we did for a few of them, like E0001).

r? @Mark-Simulacrum

[GuillaumeGomez]

Moved the check into validate-toolstate.sh in mingw-check.

[Mark-Simulacrum]

This is unrelated to validating toolstate, so it should go in a separate file.

[GuillaumeGomez]

Created a new bash script I'm now calling in the Dockerfile.

[Mark-Simulacrum]

Please push a temp commit to make sure this works (mingw-check should fail on the PR) and also we may need to somehow skip this script in local docker invocations (where FETCH_HEAD is meaningless). I'm not sure what the best way of doing that would be, but it may also be OK to not worry too much about it -- if you could check that src/ci/docker/run.sh mingw-check works locally that would be sufficient for me (it may not actually detect deleted error codes but that's OK, just shouldn't fail).

[GuillaumeGomez]

$ src/ci/docker/run.sh mingw-check
...
Build completed successfully in 0:00:33
+ /scripts/validate-toolstate.sh
Cloning into 'rust-toolstate'...
<Nothing changed>
+ /scripts/validate-error-codes.sh
/scripts/validate-error-codes.sh: line 6: BASE_COMMIT: unbound variable
+ es-check es5 ../src/librustdoc/html/static/main.js ../src/librustdoc/html/static/search.js ../src/librustdoc/html/static/settings.js ../src/librustdoc/html/static/source-script.js ../src/librustdoc/html/static/storage.js
ES-Check: there were no ES version matching errors!  🎉
+ eslint ../src/librustdoc/html/static/main.js ../src/librustdoc/html/static/search.js ../src/librustdoc/html/static/settings.js ../src/librustdoc/html/static/source-script.js ../src/librustdoc/html/static/storage.js
Compile requests               237
Compile requests executed      215
Cache hits                      13
Cache misses                   202
Cache timeouts                   0
Cache read errors                0
Forced recaches                  0
Cache write errors               0
Compilation failures             0
Cache errors                     0
Non-cacheable compilations       0
Non-cacheable calls             18
Non-compilation calls            4
Unsupported compiler calls       0
Average cache write          0.000 s
Average cache read miss      0.105 s
Average cache read hit       0.000 s
Cache location             Local disk: "/sccache"
Cache size                     491 KiB
Max cache size                  10 GiB
== clock drift check ==
  local time: Mon Jun 28 19:08:09 UTC 2021
  network time: Mon, 28 Jun 2021 01:34:02 GMT
== end clock drift check ==

So this part is working fine apparently. Even with:

/scripts/validate-error-codes.sh: line 6: BASE_COMMIT: unbound variable

[Mark-Simulacrum]

It looks like CI here is passing, but the E0001 code is deleted so presumably CI should fail. My guess is that the BASE_COMMIT variable is not set in the script -- you'll need to find a way to pipe it through. I'm not sure where it gets set, though, so there's likely some investigation that needs to be done.

[GuillaumeGomez]

IT WORKS! 🎉

Removing unwanted commit and it's good to go. :)

[GuillaumeGomez]

@Mark-Simulacrum This is now ready.

[GuillaumeGomez]

Updated! Only setting BASE_COMMIT if on CI. Then the error code removal checker only runs if the variable is not empty (so if it doesn't exist, it doesn't run either).

[GuillaumeGomez]

@Mark-Simulacrum Should be ready now.

[Mark-Simulacrum]

@bors r+ rollup

[bors]

📌 Commit d6962ff has been approved by Mark-Simulacrum