helpThe GNU Bourne-Again SHell - Support: sr #109251, Bash completion interaction with...


sr #109251: Bash completion interaction with quotes

Submitted by:  None
Submitted on:  Wed 08 Feb 2017 03:47:24 PM UTC  
Category:  None Priority:  5 - Normal
Severity:  3 - Normal Status:  In Progress
Privacy:  Public Assigned to:  None
Originator Email:  -email is unavailable- Open/Closed:  Open
Operating System:  GNU/Linux

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Sun 12 Feb 2017 12:06:20 AM UTC, comment #1:

Well, the issue is (again) mismatched expectations. The bash
documentation says that when computing COMP_WORDS, the line is
broken into words the way readline does it. You're expecting it to happen the way bash does it with a non-default $IFS.

I'm not opposed to changing this, but I will have to look at how
it might change whatever the existing versions of bash_completion

Chet Ramey <chet>
Project Administrator
Wed 08 Feb 2017 03:47:24 PM UTC, original submission:

There is a strange interaction between the completion and the use of single or double quotes in the command line. More precisely, when the quote is preceded by a delimiter, it is treated also as a common delimiter, ignoring that it has the distinctive feature that it opens a string.

This happens quite often when trying to complete commands such as:
`my_command --first-option="text_with_possible_spaces" --second-op<TAB>`

What happens is that COMP_WORDS contains ([my_command] [--first-option] [="] [text_with_possible_spaces" --second-op]), where the brackets delimit each word.

The function "split_at_words" in subst.c seems responsible for this behavior (especially lines 2299-2310 in Bash-4.4 patch 12). When a delimiter (here "=") is encountered, it tries to add as many consecutive delimiters as it can. And since the quotes are in COMP_WORDBREAKS, they are added to this word. And when the completion sees the second quote, it treats it as the opening of a string (since the first quote was ignored), creating the strange word [text_with_possible_spaces" --second-op], that obviously will not give interesting completions.

A solution could be to remove the quotes (' and ") from variable "d2", or to treat them in a specific way in lines 2299-2310. But probably there are other constraints that I am not aware of.



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