completion-at-point + semantic : erroneous error

[Eric Ludlam <eric@siege-engine.com>]

Hi all,

I'm updating from Emacs 24 w/ CEDET from sourceforge to Emacs from git, 
using built-in cedet, and I encountered an unexpected error.  A 
simplified reproduction step is:

emacs -q
M-x semantic-mode
; visit a file supported by semantic, such as a C file
; put cursor in a blank space
M-x completion-at-point

It will error with: "Nothing to complete".

The underlying completion function has always issued this error, but the 
way it was brought into completion-at-point causes it to error mid way. 
I'm not completely familiar with completion-at-point behavior, but my 
assumption is it terminates navigating the list of completion functions.

This also showed up when using company-mode which seems to use the same 
underlying function list by default.  It is also especially annoying if 
'debug-on-error' is on with company mode, as the stack just keeps 
popping up when typing innocuous things.

The list of items in the list of completion functions include 
`semantic-analyze-completion-at-point-function' and a couple others.  I 
believe these functions, specific to completion-at-point, need to wrap 
their call the the underlying `semantic-analyze-possible-completions' so 
that errors aren't thrown, and it doesn't get in the way when debugging 
something completely different.

The below patch solved the problem for me.

Thanks
Eric


diff --git a/lisp/cedet/semantic/analyze.el b/lisp/cedet/semantic/analyze.el
index 6851ad556a..4e2d9d8728 100644
--- a/lisp/cedet/semantic/analyze.el
+++ b/lisp/cedet/semantic/analyze.el
@@ -827,7 +827,9 @@ semantic-analyze-completion-at-point-function
  This function can be used by `completion-at-point-functions'."
    (when (semantic-active-p)
      (let* ((ctxt (semantic-analyze-current-context))
-           (possible (semantic-analyze-possible-completions ctxt)))
+           (possible (condition-case nil
+                         (semantic-analyze-possible-completions ctxt)
+                       (error nil))))

        ;; The return from this is either:
        ;; nil - not applicable here.
@@ -846,7 +848,9 @@ semantic-analyze-notc-completion-at-point-function
  This function can be used by `completion-at-point-functions'."
    (when (semantic-active-p)
      (let* ((ctxt (semantic-analyze-current-context))
-           (possible (semantic-analyze-possible-completions ctxt 'no-tc)))
+           (possible (condition-case nil
+                         (semantic-analyze-possible-completions ctxt 
'no-tc)
+                       (error nil))))

        (when possible
          (list (car (oref ctxt bounds))
@@ -862,8 +866,10 @@ 
semantic-analyze-nolongprefix-completion-at-point-function
  This function can be used by `completion-at-point-functions'."
    (when (semantic-active-p)
      (let* ((ctxt (semantic-analyze-current-context))
-           (possible (semantic-analyze-possible-completions
-                      ctxt 'no-tc 'no-longprefix)))
+           (possible (condition-case nil
+                         (semantic-analyze-possible-completions
+                          ctxt 'no-tc 'no-longprefix)
+                       (error nil))))

        (when possible
          (list (car (oref ctxt bounds))