[PATCH 1/4] _git: fix __git_committish_range_{first,last} and __git_is_committish_range

[m0viefreak <m0viefreak.cm@xxxxxxxxxxxxxx>]

- Ranges with 3 dots would always fail, because the non-greedy
  expansion  %..(.|)* in __git_committish_range_first would only
  remove '..' and never three dots. 'a...b' would end up in 'a.'.
  Use ${${1%..*}%.} instead.
- Use a similar approach for __git_committish_range_last.
- Wrap them in another expansion to replace empty results with 'HEAD'.
  Git man-page states omitted range ending are being replaced with
  HEAD. This rule has to be followed to make completions like
  'git log foo.. -- <tab>' work properly.
- Add an additional check to make sure none of the extracted first/last
  parts contain additional '..' in invalied ranges such as 'a..b..c'.
  This gets rid of the 'TODO:' and ideally saves a few unneded
  calls to git rev-parse.
---
 Completion/Unix/Command/_git | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/Completion/Unix/Command/_git b/Completion/Unix/Command/_git
index c09f255..8562ab2 100644
--- a/Completion/Unix/Command/_git
+++ b/Completion/Unix/Command/_git
@@ -4798,12 +4798,12 @@ __git_command_successful () {
 
 (( $+functions[__git_committish_range_first] )) ||
 __git_committish_range_first () {
-  print -r -- ${1%..(.|)*}
+  print -r -- ${${${1%..*}%.}:-HEAD}
 }
 
 (( $+functions[__git_committish_range_last] )) ||
 __git_committish_range_last () {
-  print -r -- ${1##*..(.|)}
+  print -r -- ${${${1#*..}#.}:-HEAD}
 }
 
 (( $+functions[__git_pattern_escape] )) ||
@@ -4832,12 +4832,12 @@ __git_is_treeish () {
 
 (( $+functions[__git_is_committish_range] )) ||
 __git_is_committish_range () {
-  # TODO: This isn't quite right.  We would like to do parts=${(~s:..(.|))},
-  # but that doesn't work.  (This would allow us to make sure that parts only
-  # contains two elements and then apply __git_is_committish on them.
-  [[ $1 == *..(.|)* ]] &&
-    __git_is_committish $(__git_committish_range_first $1) &&
-    __git_is_committish $(__git_committish_range_last $1)
+  [[ $1 == *..(.|)* ]] || return 1
+  local first=$(__git_committish_range_first $1)
+  local last=$(__git_committish_range_last $1)
+  [[ $first != *..* && $last != *..* ]] && \
+    __git_is_committish $first && \
+    __git_is_committish $last
 }
 
 (( $+functions[__git_is_initial_commit] )) ||
-- 
1.9.0.1.g7244ca4