fix(complete): fix bash dynamic-engine COMP_WORDBREAKS word reassembly

The bash glue script emitted by the dynamic completion engine
(CompleteEnv / write_registration in env/shells.rs) passes
words[COMP_CWORD]="$2" to the completer. Bash tokenizes COMP_WORDS by
splitting on COMP_WORDBREAKS characters (= and : by default), so
--option=value arrives as three tokens ("--option", "=", "value")
instead of one. This breaks completion for --option=value style
arguments.

Fix: embed a word reassembly loop (adapted from git-completion and
bash-completion's _comp__reassemble_words) that re-merges tokens split
on = and : before passing words to the Rust completer. The loop tracks
_CLAP_COMPLETE_INDEX in parallel so the completer receives the correct
position in the reassembled array.

The reassembly is gated on bash >= 4 (same condition as the original
block) and only affects = and : characters from COMP_WORDBREAKS, leaving
all other tokenization unchanged.

Snapshot updated accordingly.

Testing:
- cargo test -p clap_complete: 9 passed, 0 failed
- cargo test -p clap_complete --features clap_complete/unstable-dynamic:
  109 passed, 0 failed
- Manual interactive test: sourced the generated completion script for
  the exhaustive example and verified TAB-completion works correctly.

Fixes #6363

Author: douzebis

clap_complete/src/env/shells.rs

@@ -39,7 +39,32 @@ _clap_complete_NAME() {
     fi
     local words=("${COMP_WORDS[@]}")
     if [[ "${BASH_VERSINFO[0]}" -ge 4 ]]; then
-        words[COMP_CWORD]="$2"
+        # Reassemble words that bash split on COMP_WORDBREAKS characters
+        # (typically = and :) so that --option=value arrives as one token.
+        # Based on the approach used by git-completion and bash-completion.
+        local _i _j=0 _line=$COMP_LINE _ref
+        local _wb="[${COMP_WORDBREAKS//[^=:]/}]"
+        words=()
+        _CLAP_COMPLETE_INDEX=$COMP_CWORD
+        for (( _i = 0; _i < ${#COMP_WORDS[@]}; _i++, _j++ )); do
+            while [[ _i -gt 0 && ${COMP_WORDS[_i]} == $_wb ]]; do
+                [[ $_line != [[:blank:]]* ]] && (( _j >= 2 )) && (( _j-- ))
+                _ref="words[$_j]"
+                printf -v "$_ref" %s "${!_ref-}${COMP_WORDS[_i]}"
+                (( _i == COMP_CWORD )) && _CLAP_COMPLETE_INDEX=$_j
+                _line=${_line#*"${COMP_WORDS[_i]}"}
+                if (( _i < ${#COMP_WORDS[@]} - 1 )); then
+                    (( _i++ ))
+                else
+                    break 2
+                fi
+                [[ $_line == [[:blank:]]* ]] && (( _j++ ))
+            done
+            _ref="words[$_j]"
+            printf -v "$_ref" %s "${!_ref-}${COMP_WORDS[_i]}"
+            _line=${_line#*"${COMP_WORDS[_i]}"}
+            (( _i == COMP_CWORD )) && _CLAP_COMPLETE_INDEX=$_j
+        done
     fi
     COMPREPLY=( $( \
         _CLAP_IFS="$IFS" \

clap_complete/tests/snapshots/home/dynamic-env/exhaustive/bash/.bashrc

@@ -12,7 +12,32 @@ _clap_complete_exhaustive() {
     fi
     local words=("${COMP_WORDS[@]}")
     if [[ "${BASH_VERSINFO[0]}" -ge 4 ]]; then
-        words[COMP_CWORD]="$2"
+        # Reassemble words that bash split on COMP_WORDBREAKS characters
+        # (typically = and :) so that --option=value arrives as one token.
+        # Based on the approach used by git-completion and bash-completion.
+        local _i _j=0 _line=$COMP_LINE _ref
+        local _wb="[${COMP_WORDBREAKS//[^=:]/}]"
+        words=()
+        _CLAP_COMPLETE_INDEX=$COMP_CWORD
+        for (( _i = 0; _i < ${#COMP_WORDS[@]}; _i++, _j++ )); do
+            while [[ _i -gt 0 && ${COMP_WORDS[_i]} == $_wb ]]; do
+                [[ $_line != [[:blank:]]* ]] && (( _j >= 2 )) && (( _j-- ))
+                _ref="words[$_j]"
+                printf -v "$_ref" %s "${!_ref-}${COMP_WORDS[_i]}"
+                (( _i == COMP_CWORD )) && _CLAP_COMPLETE_INDEX=$_j
+                _line=${_line#*"${COMP_WORDS[_i]}"}
+                if (( _i < ${#COMP_WORDS[@]} - 1 )); then
+                    (( _i++ ))
+                else
+                    break 2
+                fi
+                [[ $_line == [[:blank:]]* ]] && (( _j++ ))
+            done
+            _ref="words[$_j]"
+            printf -v "$_ref" %s "${!_ref-}${COMP_WORDS[_i]}"
+            _line=${_line#*"${COMP_WORDS[_i]}"}
+            (( _i == COMP_CWORD )) && _CLAP_COMPLETE_INDEX=$_j
+        done
     fi
     COMPREPLY=( $( \
         _CLAP_IFS="$IFS" \