Parser panics using global args and calling get_matches_from_safe_borrow() repeatedly

[tomprogrammer]

Rust Version

rustc 1.21.0 (3b72af97e 2017-10-09)

Affected Version of clap

v2.26.2

Expected Behavior Summary

A global argument (Arg::with_name("vm name").global(true)) should be usable when calling get_matches_from_safe_borrow() multiple times on the same App.

Actual Behavior Summary

The second time clap parses some input it panics and reports "Non-unique argument name: vm name is already in use". (See debug output)

Due to AppSetting::NoBinaryName and get_matches_from_safe_borrow() available I concluded it would be safe to reuse an App instance parsing many input lines. Except for the global arguments other features work well in my REPL-style cli application.

Alternatively I could clone the App and reset it before parsing another line of input. Do you consider reusing the App instance an API misuse and suggest to use clone() and reset, or is this an actual bug that should be fixed?

Steps to Reproduce the issue

• Clone https://github.com/tomprogrammer/clap-global-issue
• Run cargo run -- help
• Type help into the REPL
• The error occurs

Sample Code or Link to Sample Code

https://github.com/tomprogrammer/clap-global-issue

Debug output

https://gist.github.com/tomprogrammer/4063db64a246b3d2d4bf472cec94fbda

[kbknapp]

Would you mind testing this against the the current master branch? I just merged #1075 which deals with global args quite heavily and would like to know if that solves the issue.

[tomprogrammer]

I updated the demonstration repository to use the current master branch. Unfortunately the PR doesn't fix this issue. I also updated the debug log in the gist linked above.

[kbknapp]

👍

[kbknapp]

I have this fixed in a local branch, I'll upload and put in the PR once I get home today.

[tomprogrammer]

Thanks for the fast fix and this convenient and powerful crate!