[bash] Enable fuzzy path completion for all commands (#3958)

All commands with no custom completion defined.

Close #3957

CHANGELOG.md

@@ -1,6 +1,17 @@
 CHANGELOG
 =========
 
+0.54.4
+------
+- [bash] Fuzzy path completion is enabled for all commands
+    - 1. If the default completion is not already set
+    - 2. And if the current bash supports `complete -D` option
+    - However, fuzzy completion for some commands can be "dynamically" disabled by the dynamic completion loader
+    - See the comment in `__fzf_default_completion` function for more information
+- Fixed `--tmux bottom` when the status line is not at the bottom
+- Fixed extra scroll offset in multi-line mode (`--read0` or `--wrap`)
+- Added fallback `ps` command for `kill` completion on Cygwin
+
 0.54.3
 ------
 - Fixed incompatibility of adaptive height specification and 'start:reload'

shell/completion.bash

@@ -289,7 +289,7 @@ __fzf_generic_path_completion() {
   fi
   COMPREPLY=()
   trigger=${FZF_COMPLETION_TRIGGER-'**'}
-  cur="${COMP_WORDS[COMP_CWORD]}"
+  [[ $COMP_CWORD -ge 0 ]] && cur="${COMP_WORDS[COMP_CWORD]}"
   if [[ "$cur" == *"$trigger" ]] && [[ $cur != *'$('* ]] && [[ $cur != *':='* ]] && [[ $cur != *'`'* ]]; then
     base=${cur:0:${#cur}-${#trigger}}
     eval "base=$base" 2> /dev/null || return
@@ -481,8 +481,31 @@ complete -o default -F _fzf_opts_completion fzf
 # fzf-tmux specific options (like `-w WIDTH`) are left as a future patch.
 complete -o default -F _fzf_opts_completion fzf-tmux
 
-d_cmds="${FZF_COMPLETION_DIR_COMMANDS-cd pushd rmdir}"
+# Default path completion
+__fzf_default_completion() {
+  __fzf_generic_path_completion _fzf_compgen_path "-m" "" "$@"
 
+  # Dynamic completion loader has updated the completion for the command
+  if [[ $? -eq 124 ]]; then
+    # We trigger _fzf_setup_completion so that fuzzy completion for the command
+    # still works. However, loader can update the completion for multiple
+    # commands at once, and fuzzy completion will no longer work for those
+    # other commands. e.g. pytest -> py.test, pytest-2, pytest-3, etc
+    _fzf_setup_completion path "$1"
+    return 124
+  fi
+}
+
+if complete | command grep -q __fzf_default_completion; then
+  : # Default completion already set up. Do nothing.
+elif ! complete | command grep -- '-D$' | command grep -qv _comp_complete_load &&
+       complete -D -F __fzf_default_completion -o default -o bashdefault 2> /dev/null; then
+  a_cmds=""
+else
+  # We can't set up default completion,
+  # 1. if it's already set up by another script
+  # 2. or if the current version of bash doesn't support -D option
+  #
   # NOTE: $FZF_COMPLETION_PATH_COMMANDS and $FZF_COMPLETION_VAR_COMMANDS are
   # undocumented and subject to change in the future.
   a_cmds="${FZF_COMPLETION_PATH_COMMANDS-"
@@ -494,6 +517,10 @@ a_cmds="${FZF_COMPLETION_PATH_COMMANDS-"
     find git grep gunzip gzip hg jar
     ln ls mv open rm rsync scp
     svn tar unzip zip"}"
+fi
+
+d_cmds="${FZF_COMPLETION_DIR_COMMANDS-cd pushd rmdir}"
+
 v_cmds="${FZF_COMPLETION_VAR_COMMANDS-export unset printenv}"
 
 # Preserve existing completion