[Bash-autocompletion] Check clang version in Bash

[yamaguchi]

Summary

Add check if user's clang version supports --autocomplete or not.
If not, we just autocomplete files.

[ruiu]

clang/utils/bash-autocomplete.sh

28 ↗

(On Diff #103881)

It is probably a bit better if you mention that it falls back to the default filename completion if --autocomplete is not available. How about this: If clang is old that it does not support --autocomplete, fall back to the filename completion.

31 ↗

(On Diff #103881)

If it is the same as just return, please remove 0.

33 ↗

(On Diff #103881)

nit: it is a bit easier to read if you insert a newline here to separate code blocks.

[yamaguchi]

Update patch.

[ruiu]

LGTM

[teemperor]

Works as intended, good job!

cfe/trunk/utils/bash-autocomplete.sh

 # Please add "source /path/to/bash-autocomplete.sh" to your .bashrc to use this.
 _clang()
 {
-  local cur prev words cword arg
+  local cur prev words cword arg flags
   _init_completion -n : || return
 
   # bash always separates '=' as a token even if there's no space before/after '='.
   # On the other hand, '=' is just a regular character for clang options that
   # contain '='. For example, "-stdlib=" is defined as is, instead of "-stdlib" and "=".
   # So, we need to partially undo bash tokenization here for integrity.
   local w1="${COMP_WORDS[$cword - 1]}"
   local w2="${COMP_WORDS[$cword - 2]}"
   if [[ "$cur" == -* ]]; then
     # -foo<tab>
     arg="$cur"
   elif [[ "$w1" == -*  && "$cur" == '=' ]]; then
     # -foo=<tab>
     arg="$w1=,"
   elif [[ "$w1" == -* ]]; then
     # -foo <tab> or -foo bar<tab>
     arg="$w1,$cur"
   elif [[ "$w2" == -* && "$w1" == '=' ]]; then
     # -foo=bar<tab>
     arg="$w2=,$cur"
   fi
 
-  local flags=$( clang --autocomplete="$arg" )
+  flags=$( clang --autocomplete="$arg" 2>/dev/null )
+  # If clang is old that it does not support --autocomplete,
+  # fall back to the filename completion.
+  if [[ "$?" != 0 ]]; then
+    _filedir
+    return
+  fi
+
   if [[ "$cur" == '=' ]]; then
     COMPREPLY=( $( compgen -W "$flags" -- "") )
   elif [[ "$flags" == "" || "$arg" == "" ]]; then
     _filedir
   else
     # Bash automatically appends a space after '=' by default.
     # Disable it so that it works nicely for options in the form of -foo=bar.
     [[ "${flags: -1}" == '=' ]] && compopt -o nospace
     COMPREPLY=( $( compgen -W "$flags" -- "$cur" ) )
   fi
 }
 complete -F _clang clang