Add `--with` option to cargo run

[vojtechkral]

Implementing what I had in mind in #1726

There are likely imperfections in design / implementation, I'm opening this PR mostly to get feedback :)

Motivation / usage examples:

$ cargo run -w gdb
     Running `gdb target/debug/hello`
GNU gdb (GDB) 7.9.1
<snip>
(gdb) r foobar
Starting program: target/debug/hello foobar
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/usr/lib/libthread_db.so.1".
Hello!
Arguments:
target/debug/hello foobar
[Inferior 1 (process 7568) exited normally]

$ cargo run -w strace -- -e trace=write {} foobar
     Running `strace -e trace=write target/debug/hello foobar`
write(1, "Hello!\nArguments:\n", 18Hello!
Arguments:
)    = 18
write(1, "target/debug/hello foob"..., 36target/debug/hello foobar
) = 36
+++ exited with 0 +++

[rust-highfive]

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[alexcrichton]

Nice idea! I'm somewhat uneasy about taking the unix-ism of {} == "self", but other than that this does seem like a pretty useful command.

Thoughts @rust-lang/tools?

[vojtechkral]

@alexcrichton Maybe I could argue it's std::fmt-ism, but honestly unix find command was my inspiration :)

[bors]

☔️ The latest upstream changes (presumably #1783) made this pull request unmergeable. Please resolve the merge conflicts.

[alexcrichton]

Another alternative for doing this is something along the lines of xargs which has -I arg where arg is then replaced with the name of the executable (basically making the {} configurable)

[vojtechkral]

I could implement that, not problem, but I'm a little concerned about an -I option only being relevant for the -w option...

[bors]

☔️ The latest upstream changes (presumably #1933) made this pull request unmergeable. Please resolve the merge conflicts.

[kanru]

@vojtechkral hi, are you still working on this?

[vojtechkral]

@kanru Well I haven't looked at this in a while because this PR hasn't really caught much attention :) but I could resolve the conflicts I suppose.

[kanru]

Just really want this feature so if you were not working on this, I'm gonna ;)

[vojtechkral]

@kanru I'll resolve the merge conflicts ASAP (wchich seems easy enough) and test if the implementation still works. Apart from that, what would you propose to do? If you have some comments/criticism concerning implementation, feel free to let me know.

[kanru]

@vojtechkral Instead of adding -I option I would add --with-args which specify the arguments for the --with option. So your example will become cargo run -w strace --with-args '-e trace=write' foobar. It's more intuitive, IMO.

[vojtechkral]

@kanru All of the arguments following -- are supposed to go to strace, refer to the line cargo outputs:

Running `strace -e trace=write target/debug/hello foobar`

[kanru]

@vojtechkral but foobar is actually the argument to hello. So one would normally do

cargo run foobar

When one wants to debug:

cargo run foobar -w strace --with-args '-e trace=write'

or

cargo run -w strace --with-args '-e trace=write' -- foobar

And --with-args is optional. What do you think?

[vojtechkral]

but foobar is actually the argument to hello.

Yes, but only because strace passes it to hello. cargo -w doesn't pass any arugments to hello at all, it actually can't since it doesn't run the hello process at all, it runs strace instead (in this example) and passes arguments to strace and then strace runs hello and passes some arguments to it. Same with gdb.

[bors]

☔️ The latest upstream changes (presumably #2192) made this pull request unmergeable. Please resolve the merge conflicts.

[alexcrichton]

This has been inactive for some time now, so I'm going to close, but feel free to resubmit with a rebase!