UX improvement: Enable --no-capture with --verbose.

[EvanCarroll]

Problem

This interface is unintuivie 100k people have viewed this question on StackOverflow,

https://stackoverflow.com/q/25106554/124486

It has 462 upvotes. The top answer has 533 upvotes. It makes using cargo more difficult, and presents a gotcha everyone must learn. The expectation of any user is going to be to display more information you enable --verbose. It seems highly likely that the information that they're going to want to see is either all of it, or specifically the information that's not shown.

Proposed Solution

A suggestion to fix this, is for verbose to take multiple options with the default being all.

• --verbose=all display everything you can.
• --verbose=subset for whatever the current --verbose does.

If this behavior isn't changed (please change it), perhaps we should at the very least add it to the FAQ. It's probably a contender for the most-asked question.

Notes

And, it'd be nice if the current behavior of --verbose was even documented.

[EvanCarroll]

If the proposed solution sounds acceptable, I'll volunteer to write the patch.

[weihanglo]

FWIW, the behaviour is indeed mentioned in cargo help test, which is right above --verbose flag.

[Muscraft]

The rustc book also mentions --nocapture and --show-output under Output options in the Tests page

[daweth]

This feature needs to be added, either as a command flag to cargo test or some other way, not being able to print natively makes it extremely difficult to debug tests

[tbu-]

This feature needs to be added, either as a command flag to cargo test or some other way, not being able to print natively makes it extremely difficult to debug tests

You can already do this, pass -- --nocapture or -- --show-output to cargo test.

[EvanCarroll]

Point was never that it couldn't be done. Worth pointing out that question on SO now has 150k+ views, meaning it's growing 50% year. People shouldn't have to learn this the hard way. The word "verbose" means more words. Not giving people words they print to stdout when they enable --verbose seems very much not-verbose.

[tbu-]

Point was never that it couldn't be done.

I was trying to respond to the post I quoted, which sounded to me like implying that it couldn't be done. I was trying to help that person. Is that a bad thing? ^^

[EvanCarroll]

Not at all, just trying to keep it on topic while you're helping him. ;) We need to make it such that the intuitive thing -- adding --verbose -- does what people expect. This is only a UX issue.

[SJonesy]

Stopping by to say that today I didn't understand why cargo test --verbose wouldn't tell me which assert in my test was failing. I googled it, found the referenced SO answer, and now I'm here.