Subject: [PATCH] Re: Gitk --all error when there are more than 797 refs in a repository

From: Pat Thoyts <[email-masked]>
Date: 18 Sep 2009 15:06:17 +0100

"Murphy, John" <[email-masked]> writes:

>There is a error when running  gitk --all when there are more than 797 refs in a repository.
>We get an error message:
>
>Error reading commits: fatal ambiguous argument '3': unknown revision or path not in the working tree.
>Use '--' to separate paths from revisions.
>
>I believe issue is with this line of the code in proc parseviewrevs:
>
>       if {[catch {set ids [eval exec git rev-parse "$revs"]} err]}
>
>When there are more than 797 refs the output of git rev-parse is too large to fit into the string, ids.
>
>797 refs = 32,677 bytes.
>798 refs = 32,718 bytes my guess is a little too close for comfort to 32,768 bytes.
>
>As I was deleting refs locally the error message would change from '3' to any char [A-Z,0-9].
>
>I am a novice tcl programmer but is seems like ids could be an array.
>There are also many other areas in the code where git rev-parse is called and using array may also be necessary.
>

Tcl strings can eat all your memory. However, there is a limit to the
size of the command line argument passed to CreateProcess.  MSDN says
of the lpCommandLine parameter:
  "The maximum length of this string is 32K characters."
A solution for this case will be to use a pipe to read the responses
instead of having it all returned to the caller.
The following patch might be sufficient:

--- patch begins -----

[PATCH] Avoid command-line limits when executing git rev-parse on windows.

This patch solves the problem handling large numbers of references
reported by John Murphy that is due to limits in executing processes
in Windows by reading the rev-parse result over a pipe.

Signed-off-by: Pat Thoyts <[email-masked]>
---
 gitk |   14 ++++++++++++--
 1 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/gitk b/gitk
index 1306178..1bd7d65 100755
--- a/gitk
+++ b/gitk
@@ -236,13 +236,23 @@ proc parseviewargs {n arglist} {
     return $allknown
 }
 
+proc git-rev-parse {args} {
+    set ids {}
+    set pipe [open |[linsert $args 0 git rev-parse] r]
+    while {[gets $pipe line] != -1} {
+        lappend ids $line
+    }
+    close $pipe
+    return $ids
+}
+    
 proc parseviewrevs {view revs} {
     global vposids vnegids
 
     if {$revs eq {}} {
 	set revs HEAD
     }
-    if {[catch {set ids [eval exec git rev-parse $revs]} err]} {
+    if {[catch {set ids [git-rev-parse $revs]} err]} {
 	# we get stdout followed by stderr in $err
 	# for an unknown rev, git rev-parse echoes it and then errors out
 	set errlines [split $err "\n"]
@@ -273,7 +283,7 @@ proc parseviewrevs {view revs} {
     set pos {}
     set neg {}
     set sdm 0
-    foreach id [split $ids "\n"] {
+    foreach id $ids {
 	if {$id eq "--gitk-symmetric-diff-marker"} {
 	    set sdm 4
 	} elseif {[string match "^*" $id]} {
-- 
1.6.4.msysgit.0

-- 
Pat Thoyts                            http://www.patthoyts.tk/
PGP fingerprint 2C 6E 98 07 2C 59 C8 97  10 CE 11 E6 04 E0 B9 DD