Add Debug derive to std::process::Output

[webmobster-zz]

I didn't see any reason that debug couldn't be added to this object, since every field derives debug.

[rust-highfive]

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[sfackler]

Actually, I'm not sure the derived impl would be best here. Stdout and stderr are both Vec<u8>, so their output will be e.g. [32, 20, 39, 20, ...] which is not going to be great to look at.

[webmobster-zz]

What would be the alternative assume the stdout/stder will always be utf8 or ascii and convert the outputs to a utf8 string?

[sfackler]

String::from_utf8_lossy is one option. It could maybe also see if it's UTF8 and if not fall back to the raw output, possibly truncated?

[brson]

Since stdout/err doesn't need to be text I prefer @sfackler's latter option, printing text if utf8 and binary if not. Truncated in each case I guess.

[webmobster-zz]

If thats the consensus I can write up a debug implementation tomorrow (late here). I'll keep the pull request open till thats done I guess.

[sfackler]

Sounds good!

[webmobster-zz]

What should I put as the stability annotation on the function?

[sfackler]

The stability checking logic doesn't check trait implementations, so it's automatically stable.

[webmobster-zz]

I got a "src/libstd/process.rs:406:1: 429:2 error: This node does not have a stability attribute", on a build I ran myself

[petrochenkov]

@webmobster
#[stable(feature = "process_output_debug", since = "1.7.0")]
Even though these annotations are not checked now, they are still required for documentation and possible future checking.

[alexcrichton]

Stylistically there's typically a space after the //, and can you also format this comment to a maximum width of 80 chars? (the surrounding style)

[alexcrichton]

Looks good to me (including the stability annotation @petrochenkov mentioned)

[webmobster-zz]

Done

[alexcrichton]

@bors: r+ 21030f1

Thanks!

[bors]

⌛ Testing commit 21030f1 with merge 67a2d1f...

[bors]

☀️ Test successful - auto-linux-32-nopt-t, auto-linux-32-opt, auto-linux-64-debug-opt, auto-linux-64-nopt-t, auto-linux-64-opt, auto-linux-64-x-android-t, auto-linux-cross-opt, auto-linux-musl-64-opt, auto-mac-32-opt, auto-mac-64-nopt-t, auto-mac-64-opt, auto-win-gnu-32-nopt-t, auto-win-gnu-32-opt, auto-win-gnu-64-nopt-t, auto-win-gnu-64-opt, auto-win-msvc-32-opt, auto-win-msvc-64-opt