Auto merge of #136000 - matthiaskrgr:rollup-j6ge32r, r=matthiaskrgr

Rollup of 6 pull requests

Successful merges:

 - #135873 (coverage: Prepare for upcoming changes to counter creation)
 - #135926 (Implement `needs-subprocess` directive, and cleanup a bunch of tests to use `needs-{subprocess,threads}`)
 - #135950 (Tidy Python improvements)
 - #135956 (Make `Vec::pop_if` a bit more presentable)
 - #135966 ([AIX] Allow different sized load and store in `tests/assembly/powerpc64-struct-abi.rs`)
 - #135983 (Doc difference between extend and extend_from_slice)

r? `@ghost`
`@rustbot` modify labels: rollup

Author: bors

src/conventions.md

@@ -1,4 +1,4 @@
-This file offers some tips on the coding conventions for rustc.  This
+This file offers some tips on the coding conventions for rustc. This
 chapter covers [formatting](#formatting), [coding for correctness](#cc),
 [using crates from crates.io](#cio), and some tips on
 [structuring your PR for easy review](#er).
@@ -25,6 +25,7 @@ pass the <!-- date-check: nov 2022 --> `--edition=2021` argument yourself when c
 `rustfmt` directly.
 
 [fmt]: https://github.com/rust-dev-tools/fmt-rfcs
+
 [`rustfmt`]:https://github.com/rust-lang/rustfmt
 
 ## Formatting C++ code
@@ -40,6 +41,26 @@ When modifying that code, use this command to format it:
 This uses a pinned version of `clang-format`, to avoid relying on the local
 environment.
 
+## Formatting and linting Python code
+
+The Rust repository contains quite a lof of Python code. We try to keep
+it both linted and formatted by the [ruff][ruff] tool.
+
+When modifying Python code, use this command to format it:
+```sh
+./x test tidy --extra-checks=py:fmt --bless
+```
+
+and the following command to run lints:
+```sh
+./x test tidy --extra-checks=py:lint
+```
+
+This uses a pinned version of `ruff`, to avoid relying on the local
+environment.
+
+[ruff]: https://github.com/astral-sh/ruff
+
 <a id="copyright"></a>
 
 <!-- REUSE-IgnoreStart -->
@@ -84,7 +105,7 @@ Using `_` in a match is convenient, but it means that when new
 variants are added to the enum, they may not get handled correctly.
 Ask yourself: if a new variant were added to this enum, what's the
 chance that it would want to use the `_` code, versus having some
-other treatment?  Unless the answer is "low", then prefer an
+other treatment? Unless the answer is "low", then prefer an
 exhaustive match. (The same advice applies to `if let` and `while
 let`, which are effectively tests for a single variant.)
 
@@ -124,7 +145,7 @@ See the [crates.io dependencies][crates] section.
 # How to structure your PR
 
 How you prepare the commits in your PR can make a big difference for the
-reviewer.  Here are some tips.
+reviewer. Here are some tips.
 
 **Isolate "pure refactorings" into their own commit.** For example, if
 you rename a method, then put that rename into its own commit, along
@@ -165,4 +186,5 @@ to the compiler.
   crate-related, often the spelling is changed to `krate`.
 
 [tcx]: ./ty.md
+
 [crates]: ./crates-io.md

src/tests/directives.md

@@ -94,7 +94,7 @@ for more details.
 | Directive                         | Explanation                                                                                                              | Supported test suites                        | Possible values                                                                         |
 |-----------------------------------|--------------------------------------------------------------------------------------------------------------------------|----------------------------------------------|-----------------------------------------------------------------------------------------|
 | `check-run-results`               | Check run test binary `run-{pass,fail}` output snapshot                                                                  | `ui`, `crashes`, `incremental` if `run-pass` | N/A                                                                                     |
-| `error-pattern`                   | Check that output contains a specific string                                                                             | `ui`, `crashes`, `incremental` if `run-pass` | String                                                                                   |
+| `error-pattern`                   | Check that output contains a specific string                                                                             | `ui`, `crashes`, `incremental` if `run-pass` | String                                                                                  |
 | `regex-error-pattern`             | Check that output contains a regex pattern                                                                               | `ui`, `crashes`, `incremental` if `run-pass` | Regex                                                                                   |
 | `check-stdout`                    | Check `stdout` against `error-pattern`s from running test binary[^check_stdout]                                          | `ui`, `crashes`, `incremental`               | N/A                                                                                     |
 | `normalize-stderr-32bit`          | Normalize actual stderr (for 32-bit platforms) with a rule `"<raw>" -> "<normalized>"` before comparing against snapshot | `ui`, `incremental`                          | `"<RAW>" -> "<NORMALIZED>"`, `<RAW>`/`<NORMALIZED>` is regex capture and replace syntax |
@@ -176,6 +176,7 @@ settings:
 - `needs-rust-lld` — ignores if the rust lld support is not enabled (`rust.lld =
   true` in `config.toml`)
 - `needs-threads` — ignores if the target does not have threading support
+- `needs-subprocess`  — ignores if the target does not have subprocess support
 - `needs-symlink` — ignores if the target does not support symlinks. This can be
   the case on Windows if the developer did not enable privileged symlink
   permissions.