fix(bash_completion): support BASH_COMPLETION_COMPAT_IGNORE

We remove the workaround for the "acroread.sh" and instead expose a
customization point via the new shell variable
"BASH_COMPLETION_COMPAT_IGNORE" so that the user can specify the files
in "BASH_COMPLETION_COMPAT_DIR" to ignore.

Co-authored-by: Ville Skyttä <ville.skytta@iki.fi>

Author: akinomyoga

bash_completion

@@ -37,10 +37,6 @@ else
     set +v
 fi
 
-# Blacklisted completions, causing problems with our code.
-#
-_comp__init_blacklist_glob='@(acroread.sh)'
-
 # Turn on extended globbing and programmable completion
 shopt -s extglob progcomp
 
@@ -2519,11 +2515,11 @@ _comp_deprecate_func _xfunc _comp_xfunc
 _comp__init_compat_dir=${BASH_COMPLETION_COMPAT_DIR:-/etc/bash_completion.d}
 if [[ -d $_comp__init_compat_dir && -r $_comp__init_compat_dir && -x $_comp__init_compat_dir ]]; then
     for _comp__init_file in "$_comp__init_compat_dir"/*; do
-        [[ ${_comp__init_file##*/} != @($_comp_backup_glob|Makefile*|$_comp__init_blacklist_glob) &&
+        [[ ${_comp__init_file##*/} != @($_comp_backup_glob|Makefile*|${BASH_COMPLETION_COMPAT_IGNORE-}) &&
             -f $_comp__init_file && -r $_comp__init_file ]] && . "$_comp__init_file"
     done
 fi
-unset -v _comp__init_compat_dir _comp__init_file _comp__init_blacklist_glob
+unset -v _comp__init_compat_dir _comp__init_file
 
 # source user completion file
 #

doc/configuration.md

@@ -46,6 +46,32 @@ known hosts completion will omit hostnames from `HOSTFILE`. Omitting
 hostnames from `HOSTFILE` is useful if `HOSTFILE` contains many entries for
 local web development or ad-blocking.
 
+### `BASH_COMPLETION_COMPAT_IGNORE`
+
+Files in `BASH_COMPLETION_COMPAT_DIR` (the compat dir) to ignore, specified by
+a glob pattern.  The completion files in the compat dir whose basename matches
+with this pattern will not be sourced by `bash_completion` at its load time.
+This variable can be used to suppress the problematic completions.  Note that
+backup files and Makefiles in the compat dir are by default ignored regardless
+of this setting.
+
+One example is `acroread.sh` which is installed by some versions of Adobe
+Reader, overrides `_filedir` with an incompatible version, and causes
+various problems.  To recover this `_filedir`, another completion file
+`redefine_filedir` had been placed in the compat dir, which could also
+cause another incompatibility when the user uses their own version of
+bash-completion instead of the systemwide version.  To suppress these files
+one can set the following value:
+
+```bash
+export BASH_COMPLETION_COMPAT_IGNORE='@(acroread.sh|redefine_filedir)'
+```
+
+- <https://bugzilla.redhat.com/677446>
+- <http://forums.adobe.com/thread/745833>
+- <https://bugzilla.redhat.com/show_bug.cgi?id=1171396#c27>
+- <https://github.com/scop/bash-completion/pull/667>
+
 ### `BASH_COMPLETION_CMD_CONFIGURE_HINTS`
 
 If set and not null, `configure` completion will return the entire option

test/config/bashrc

@@ -41,6 +41,7 @@ export BASH_COMPLETION_USER_DIR=$(
 )
 # /var/empty isn't necessarily actually always empty :P
 export BASH_COMPLETION_COMPAT_DIR=/var/empty/bash_completion.d
+export BASH_COMPLETION_COMPAT_IGNORE='*'
 export XDG_DATA_DIRS=/var/empty
 
 # Make sure default settings are in effect