Undocumented behavior change since 2.x

[guimard]

Hi,

this simple program has 2 different behavior depending on commander version:

var p = require('commander');
p.option('-d, --debug [level]', 'debug level')
 .option('-m, --mangle [test]', 'mangle')
 .option('--out', 'output')
 
p.parse(process.argv);
console.error('Debug args:', p.opts());

Resuilt of node test.js -dm --out:

• 2.x : Debug args: { debug: true, mangle: true, out: true }
• 4.x : Debug args: { debug: 'm', mangle: undefined, out: true }

This has strange effect when using uglify-js.

Cheers,
Xavier

[shadowspawn]

Quick response: I think this is due to changes from #599 for #395, released in Commander 3.0.0

https://github.com/tj/commander.js/releases/tag/v3.0.0

Can call like this for consistent behaviour across versions:

node test.js -d -m --out

[shadowspawn]

The implementation of option parsing is refined further in Commander v5, and the updated README description is:

Multiple short flags may optionally be combined in a single argument following the dash: boolean flags, the last flag may take a value, and the value. For example -a -b -p 80 may be written as -ab -p80 or even -abp80.

commander.js/index.js

Line 1015 in 3cf8cff

if (option.required || option.optional) {

[guimard]

Hi,

commander 5.0.0-4 does not fix the problem!

Cheers,
Xavier

[guimard]

Following the doc:

Multiple short flags may optionally be combined in a single argument following the dash: boolean flags, the last flag may take a value, and the value. For example -a -b -p 80 may be written as -ab -p80 or even -abp80.

It becomes a bug

[shadowspawn]

Drat, the new wording is not as clear as I hoped! The behaviour is as intended in Command 5, but I will recheck the source documentation for behaviour and wording of description.

[shadowspawn]

The standard I consult is: https://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap12.html

Commander is more flexible with optional values than described there, but Commander is deliberately supporting the pattern that a value can directly follow the short flag, from item 2:

If the SYNOPSIS shows an optional option-argument (as with [ -f[ option_argument]] in the example), a conforming application shall place any option-argument for that option directly adjacent to the option in the same argument string, without intervening characters.

And Guideline 5:

One or more options without option-arguments, followed by at most one option that takes an option-argument, should be accepted when grouped behind one '-' delimiter.

[shadowspawn]

An answer was provided, and no further activity in a month. Closing this as resolved.

Feel free to open a new issue if it comes up again, with new information and renewed interest.

Thank you for your contributions.

[shadowspawn]

I think this behaviour change will be a problem for heavy users of optional values when they upgrade Commander, even though it is deliberate. Opened a PR to make it configurable.