[bash] Update the completion setting after _completion_loader

[akinomyoga]

Original problem

This is a fix for an issue reported at scop/bash-completion#1123. The original problem is that the fzf completion setting does not fully preserve the completion settings of cd set by bash-completion-2.12. More specifically, bash-completion completes also variable names through the -v option of complete when shopt -s autocd shopt -s cdable_vars is specified, but the -v option is lost for bash-completion 2.12 when Fzf's completion setting is present. See the original thread for the details.

Description of the problem

The problem is that when the completion setting is loaded by _fzf_handle_dynamic_completion using bash-completion's _completion_loader, only the function specified by -F is used by fzf. The completion settings specified by other complete options are ignored.

The problem does not arise when the completion setting already exists when Fzf's completion.bash is loaded or when _fzf_setup_completion is called. This is because __fzf_defc preserves the other complete options. The reason that the problem was not observed with bash-completion 2.11 is that bash-completion 2.12 started to load the completion setting of cd dynamically.

Solution

When the completion settings are loaded using _completion_loader, the other complete options should be applied to the completion setting in the same way as __fzf_defc does.

The main fix is in commit c732298.

Associated refactoring

To reuse existing codes, there is a refactoring commit (0214e50) before the main commit. In the current codebase, for the original completion settings, the pieces of the codes to determine the variable name and access the stored data are scattered. In this commit, we define functions to access these variables. The functions are used in the main fix of this PR.

This refactoring also resolves an inconsistent escaping of $cmd: $cmd is escaped as ${...//[^A-Za-z0-9_]/_} in some places, but it is escaped as ${...//[^A-Za-z0-9_=]/_} in some other places. The latter leaves the character = in the command name, which causes an issue because = cannot be a part of a variable name. For example, the following test case produces an error message:

$ COMP_WORDBREAKS=${COMP_WORDBREAKS//=}
$ _test1() { COMPREPLY=(); }
$ complete -vF _test1 cmd.v=1.0
$ _fzf_setup_completion path cmd.v=1.0
$ cmd.v=1.0 [TAB]
bash: _fzf_orig_completion_cmd_v=1_0: invalid variable name

The behavior of leaving = was present from the beginning when saving the original completion is introduced in commit 9140151, and this does not seem to have specific reasoning. We replace = as well as the other non-identifier characters.

Note: In the new functions, the variable REPLY is used to return values. This design is to make it useful with the value substitutions, which is a new Bash feature of the next release 5.3, and was originally the feature introduced by mksh.

[junegunn]

Thanks for the excellent analysis and the patch! 👍

[akinomyoga]

Thank you!