Re: [RFC/PATCH 2/1] bash: eliminate dependency on bash_completion lib

From: Jonathan Nieder <jrnieder@gmail.com>
Date: Dec 3, 2010, 00:07 UTC
Message-ID: <20101203000723.GB8438@burratino>
In-Reply-To: <20101202234053.GB3577@neumann>

SZEDER Gábor wrote:

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> Bash's programmable completion provides the COMP_WORDS array variable,
> which holds the individual words in the current command line.  In Bash
> versions prior to v4 "words are split on shell metacharacters as the
> shell parser would separate them" (quote from bash v3.2.48's man
> page).  This behavior has changed with Bash v4, and the command line
> "is split into words as readline would split it, using COMP_WORDBREAKS
> as" "the set of characters that the readline library treats as word
> separators" (quote from bash v4's man page).
>
> Since COMP_WORDBREAKS contains the characters : and = by default, this
> behavior change in Bash also affects git's completion script.  For
> example, when using Bash v4 the completion script can't provide
> possible options for a command line argument (e.g. git log
> --pretty=<TAB><TAB> lists files, but it should list possible log
> formats).
> 
> 
> I would really, _really_ like to have the above text in the commit
> message (either in yours or in Peter's), because it took me weeks to
> figure this out ;)

Sounds good.

> (I'm still wondering what Bash v3.x was doing with COMP_WORDBREAKS,
> though...)

Based on v1.5.6.4~9^2 (bash completion: Resolve git show ref:path<tab> losing ref: portion, 2008-07-15) it seems COMP_WORDBREAKS determined the interpretation of COMPREPLY (result of completion). Of course it also governed standard filename completion.

> On Thu, Dec 02, 2010 at 03:02:07PM -0600, Jonathan Nieder wrote:

>> +++ b/contrib/completion/git-completion.bash
>> @@ -327,7 +327,102 @@ __gitcomp_1 ()

[...]

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>> +# This function can be used to access a tokenized list of words
>> +# on the command line:
>> +#
>> +#	__reassemble_comp_words_by_ref '=:'
>
> __git_reassemble_comp_words_by_ref?

[...]

>>  if ! type _get_comp_words_by_ref >/dev/null 2>&1; then
>> +if [[ -n $ZSH_VERSION ]]; then
>
> This should be ${ZSH_VERSION-} to keep 'set -u' environments happy.

Nice catches; thanks.