Add suspicious_command_arg_space lint

[m-ou-se]

Fixes #10316

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changelog: New lint: [suspicious_command_arg_space]
#10317

[rustbot]

r? @Manishearth

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[Alexendoo]

I did a search to look at existing usages

There are results with = in like https://github.com/bytecodealliance/wasm-tools/blob/e5293d587f463e67d42ca26b151cd7afdc0a5e17/build.rs#L17 and https://github.com/kpcyrd/sh4d0wup/blob/7043379d0a26070ecb517b3162cef84dbfd64f5a/src/codegen/go.rs#L64. I think the current impl wouldn't flag these but it'd be good to have a test case

There are some short flag usages like https://github.com/PoC-Consortium/scavenger/blob/b38f6552c31d589a0433cb8ef52a44c87ce18725/src/utils.rs#L33 but all the ones I saw are worth linting, e.g. there the format gets a leading space which is unexpected

[Manishearth]

Yeah --foobar=some long string was one of the things i was thinking about which is handled but not tested

[m-ou-se]

Thanks! Added test cases.

[Manishearth]

error: the lint `SUSPICIOUS_COMMAND_ARG_SPACE` is not added to any `LintPass`
    --> src/methods/mod.rs:3166:1
     |
3166 | / declare_clippy_lint! {
3167 | |     /// ### What it does
3168 | |     ///
3169 | |     /// Checks for `Command::arg()` invocations that look like they
...    |
3189 | |     "single command line argument that looks like it should be multiple arguments"
3190 | | }
     | |_^
     |
     = help: for further information visit https://rust-lang.github.io/rust-clippy/master/index.html#lint_without_lint_pass
     = note: `-D clippy::lint-without-lint-pass` implied by `-D clippy::internal`
     = note: this error originates in the macro `declare_tool_lint` which comes from the expansion of the macro `declare_clippy_lint` (in Nightly builds, run with -Z macro-backtrace for more info)

Oh, right, you also need to construct the lint pass and register it in lib.rs

[m-ou-se]

Oh oops. Done.

[Manishearth]

@bors r+

thanks, this is great!

[bors]

📌 Commit 1f77866 has been approved by Manishearth

It is now in the queue for this repository.

[bors]

⌛ Testing commit 1f77866 with merge 298f139...

[bors]

☀️ Test successful - checks-action_dev_test, checks-action_remark_test, checks-action_test
Approved by: Manishearth
Pushing 298f139 to master...