[elpa] master 4f2aa15 05/36: Only kill snippets for text length change

[Noam Postavsky]

branch: master
commit 4f2aa1526a3a630a984bc00c45204ee35a7ba556
Author: Noam Postavsky <address@hidden>
Commit: Noam Postavsky <address@hidden>

    Only kill snippets for text length change
    
    of protection overlay.  Changes that keep the same length of text are
    probably harmless (e.g. just change of text properties).  It's possible
    that some harmful changes don't change text length, but the protection
    overlays are already unable to catch all important changes since they
    only cover 1 character each at the edges.
    
    cc-mode modifies text properties in the buffer to cache parsing results,
    therefore it's important that yasnippet not kill yasnippets when parsing
    is triggered by a function that only wants to parse the
    buffer (e.g. which-function-mode).
    
    * yasnippet.el (yas--on-protection-overlay-modification): Check length
    of text change to decide if change is harmful.  Fix docstring.
---
 yasnippet.el |    9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/yasnippet.el b/yasnippet.el
index 9bdb5f9..f91e130 100644
--- a/yasnippet.el
+++ b/yasnippet.el
@@ -3467,12 +3467,11 @@ Move the overlays, or create them if they do not exit."
              ;; (overlay-put ov 'evaporate t)
              (overlay-put ov 'modification-hooks 
'(yas--on-protection-overlay-modification)))))))
 
-(defun yas--on-protection-overlay-modification (_overlay after? _beg _end 
&optional _length)
-  "Signals a snippet violation, then issues error.
-
-The error should be ignored in `debug-ignored-errors'"
+(defun yas--on-protection-overlay-modification (_overlay after? beg end 
&optional length)
+  "Commit the snippet if the protection overlay is being killed."
   (unless (or yas--inhibit-overlay-hooks
-              after?
+              (not after?)
+              (= length (- end beg)) ; deletion or insertion
               (yas--undo-in-progress))
     (let ((snippets (yas--snippets-at-point)))
       (yas--message 3 "Comitting snippets. Action would destroy a protection 
overlay.")