Add a spell checker for libcore/libstd documentation

[jyn514]

From #74141:

@pickfire: Did you go through this with some kind of type checkers like cargo-spellcheck?
@euclio: I made a super hacky custom rustdoc pass that ran a spellchecker over markdown compiled to plain text.

It would be great to have a tool that automated spell-checking for the docs. @pickfire suggested cargo spellcheck which had some trouble with bootstrap. Maybe we could somehow modify it to work with bootstrap so it runs as part of tidy?

[pickfire]

Maybe we should also ping the author here @drahnr. He may have some ideas?

[drahnr]

@pickfire @jyn514 glad to hear there is interest in using cargo-spellcheck!

The error you see is very most likely caused by an older version which had issues parsing args properly, note that I plan to release v0.3.0 is planned for this WE / early next week which should resolve quite a few issues.
In the meantime you could give yesterdays alpha.6 release a shot which should have the traversal + arg parse issues resolved (at least works in the CI https://ci.spearow.io/teams/main/pipelines/cargo-spellcheck/jobs/master-validate/builds/117 ) note that the garbled output for multiline comments is the biggest remaining topic for multiline comments in this alpha which will be fixed in v0.3.0

If there are specific issues I would be very happy to get things working for you :)

[pickfire]

It has a dependency on autotools and libtool which is unfortunate ... could we get them to avoid that somehow? -- @jyn514 #74141 (comment)

@drahnr What do you think?

[drahnr]

@drahnr What do you think?

@pickfire As @euclio already stated in #74141 (comment) - it should not be required anymore since v0.3.0-alpha.4 / c041dca66b966610d216ec23aeb4cf386adcf54a which incorporates the latest hunspell-sys which uses cc without any C-buildtools to create the static lib from hunspell source files, so that should be ☑️ if not please open a ticket :)

[pickfire]

It doesn't work and probably displayed the wrong error.

Error: Failed to parse manifest file /home/ivan/src/pickfire/rs/rust/src/bootstrap/Cargo.toml: No such file or directory (os error 2)

[drahnr]

@pickfire could you please open an issue with information on how to reproduce and commit sha / release so I can test / reproduce the issue?

[drahnr]

v0.3.0-beta.1 should resolve this and a few more issues with the rust lang code base, let me know if this is sufficient for the time being or if anything particular feature is badly needed.

[pickfire]

@drahnr I checked, a lot better but still not sufficient yet. Looks like UTF-8 handling still needs some tweak to make it work without panicking.

[drahnr]

Found the root cause, v0.3.0-beta.5 should do the trick 🎉

[jyn514]

I tried running it: it showed no output for ~three seconds then exited. With -vvvv I get the following output:

$ cargo spellcheck -vvvv
[2020-07-28T20:52:40Z WARN  cargo_spellcheck] Loading configuration from /home/joshua/.config/cargo_spellcheck/config.toml, due to: No such file or directory (os error 2)
[2020-07-28T20:52:40Z DEBUG cargo_spellcheck::traverse] Running on inputs ["/home/joshua/src/rust"] / recursive=true
[2020-07-28T20:52:40Z DEBUG cargo_spellcheck::traverse] Processing /home/joshua/src/rust -> /home/joshua/src/rust
[2020-07-28T20:52:40Z DEBUG cargo_spellcheck::traverse] Running on absolute dirs ["/home/joshua/src/rust"] 
[2020-07-28T20:52:40Z DEBUG cargo_spellcheck::traverse] Found a total of 1 files to check 
[2020-07-28T20:52:40Z DEBUG cargo_spellcheck::traverse] Failed to complete /home/joshua/src/rust/src/bootstrap/Cargo.toml from filesystem
[2020-07-28T20:52:40Z DEBUG cargo_spellcheck::traverse] Failed to complete /home/joshua/src/rust/src/rustc/Cargo.toml from filesystem
[2020-07-28T20:52:40Z DEBUG cargo_spellcheck::traverse] Failed to complete /home/joshua/src/rust/src/librustc_codegen_llvm/Cargo.toml from filesystem
[2020-07-28T20:52:40Z DEBUG cargo_spellcheck::traverse] Failed to complete /home/joshua/src/rust/src/tools/cargotest/Cargo.toml from filesystem
[2020-07-28T20:52:40Z DEBUG cargo_spellcheck::traverse] Failed to complete /home/joshua/src/rust/src/tools/error_index_generator/Cargo.toml from filesystem
[2020-07-28T20:52:40Z DEBUG cargo_spellcheck::traverse] Failed to complete /home/joshua/src/rust/src/tools/linkchecker/Cargo.toml from filesystem
[2020-07-28T20:52:40Z DEBUG cargo_spellcheck::traverse] Failed to complete /home/joshua/src/rust/src/tools/rust-demangler/Cargo.toml from filesystem
[2020-07-28T20:52:40Z DEBUG cargo_spellcheck::traverse] Failed to complete /home/joshua/src/rust/src/tools/rustdoc/Cargo.toml from filesystem
[2020-07-28T20:52:40Z DEBUG cargo_spellcheck::traverse] Failed to complete /home/joshua/src/rust/src/tools/rls/Cargo.toml from filesystem
[2020-07-28T20:52:40Z DEBUG cargo_spellcheck::traverse] Failed to complete /home/joshua/src/rust/src/tools/rustdoc-themes/Cargo.toml from filesystem
[2020-07-28T20:52:41Z DEBUG cargo_spellcheck::checker] Running Hunspell checks
[2020-07-28T20:52:41Z DEBUG cargo_spellcheck::checker::hunspell] Dictionary search path /usr/share/myspell/ is not a directory
[2020-07-28T20:52:41Z DEBUG cargo_spellcheck::checker::hunspell] Dictionary search path /usr/share/hunspell/ is not a directory
[2020-07-28T20:52:41Z DEBUG cargo_spellcheck::checker::hunspell] Dictionary search path /usr/share/myspell/dicts/ is not a directory

It looks like it's skipping almost all the directories? And not running checks on the ones that it did find, because the /usr/share/* paths weren't found? I would expect both of those to be warnings, not DEBUG logging.

I installed hunspell (with sudo apt install hunspell) and now it appears to at least be doing something:

error: spellcheck(Hunspell)
  --> /home/joshua/src/rust/src/tools/unicode-table-generator/src/skiplist.rs:7
   |
 7 |  This will get packed into a single u32 before inserting into the data set.
   |                                     ^^^
   |
   |
   |   Possible spelling mistake found.
   |

error: spellcheck(Hunspell)
   --> /home/joshua/src/rust/src/tools/unicode-table-generator/src/skiplist.rs:14
    |
 14 |  our largest sets are around ~1400 offsets long.
    |                              ^^^^^
    |
    |
    |   Possible spelling mistake found.
    |

However these warnings aren't particularly helpful - u32 is a builtin type and ~ is not a misspelling, it means approximation. @drahnr is there a way to add a whitelist of keywords or ignore symbols?