Hi.

when displaying a bigger commit and then changing the view, gitk reports 

        can't read "treediffs(b107a60c5bed3002ecef93b4405a44d809776e6f)": no such variable
        can't read "treediffs(b107a60c5bed3002ecef93b4405a44d809776e6f)": no such variable
            while executing
        "lsearch -exact $treediffs($ids) $fname"
            (procedure "makediffhdr" line 7)
            invoked from within
        "makediffhdr $fname $ids"
            (procedure "parseblobdiffline" line 56)
            invoked from within
        "parseblobdiffline $ids $line"
            (procedure "getblobdiffline" line 16)
            invoked from within
        "getblobdiffline file6 b107a60c5bed3002ecef93b4405a44d809776e6f"
            ("eval" body line 1)
            invoked from within
        "eval $script"
            (procedure "dorunq" line 11)
            invoked from within
        "dorunq"
            ("after" script)

It is reproducible with:

        TCDIR=/tmp/testcase
        N=512

        rm -rf $TCDIR
        git init $TCDIR
        for i in `seq $N` ; do 
            dd if=/dev/random status=none bs=1024 count=16 | uuencode "" > $TCDIR/foo_$i 
        done
        git -C $TCDIR add . 
        git -C $TCDIR commit -m "commit" 

        cd $TCDIR
        gitk --all

followed by an immediate change to "All Files" in gitk menu "View".

The same issue has been mentioned here before: 
	https://stackoverflow.com/questions/17977996/gitk-cant-read-treediffs-error

Michael

---

diff --git a/gitk-git/gitk b/gitk-git/gitk
index 2730274966..f40bb1aa8c 100755
--- a/gitk-git/gitk
+++ b/gitk-git/gitk
@@ -281,10 +281,11 @@ proc gitworktree {} {
 # run before X event handlers, so reading from a fast source can
 # make the GUI completely unresponsive.
 proc run args {
-    global isonrunq runq currunq
+    global isonrunq runq currunq runq_active
 
     set script $args
     if {[info exists isonrunq($script)]} return
+    set $runq_active 1
     if {$runq eq {} && ![info exists currunq]} {
         after idle dorunq
     }
@@ -297,8 +298,9 @@ proc filerun {fd script} {
 }
 
 proc filereadable {fd script} {
-    global runq currunq
+    global runq currunq runq_active
 
+    set $runq_active 1
     fileevent $fd readable {}
     if {$runq eq {} && ![info exists currunq]} {
         after idle dorunq
@@ -318,12 +320,20 @@ proc nukefile {fd} {
     }
 }
 
+proc wait_runq_empty {} {
+    global runq runq_active
+    while {$runq ne {} || $runq_active > 0} {
+        dorunq
+    }
+}
+
 proc dorunq {} {
-    global isonrunq runq currunq
+    global isonrunq runq currunq runq_active
 
     set tstart [clock clicks -milliseconds]
     set t0 $tstart
     while {[llength $runq] > 0} {
+        set $runq_active 1
         set fd [lindex $runq 0 0]
         set script [lindex $runq 0 1]
         set currunq [lindex $runq 0]
@@ -343,6 +353,7 @@ proc dorunq {} {
         } elseif {$fd eq {}} {
             unset isonrunq($script)
         }
+        set $runq_active 0
         set t0 $t1
         if {$t1 - $tstart >= 80} break
     }
@@ -825,6 +836,7 @@ proc reloadcommits {} {
     global showneartags treediffs commitinterest cached_commitrow
     global targetid commitinfo
 
+    wait_runq_empty
     set selid {}
     if {$selectedline ne {}} {
         set selid $currentid
@@ -3660,6 +3672,7 @@ proc pop_flist_menu {w X Y x y} {
     global ctext cflist cmitmode flist_menu flist_menu_file
     global treediffs diffids
 
+    wait_runq_empty
     stopfinding
     set l [lindex [split [$w index "@$x,$y"] "."] 0]
     if {$l <= 1} return
@@ -4664,6 +4677,8 @@ proc showview {n} {
     global hlview selectedhlview commitinterest
 
     if {$n == $curview} return
+
+    wait_runq_empty
     set selid {}
     set ymax [lindex [$canv cget -scrollregion] 3]
     set span [$canv yview]
@@ -12909,6 +12924,7 @@ if {[file exists $themeloader]} {
 set appname "gitk"
 
 set runq {}
+set runq_active 0
 set history {}
 set historyindex 0
 set fh_serial 0

Re: gitk: race condition when changing view

Am 16.04.26 um 23:36 schrieb Michael Warmuth-Uhl:

> when displaying a bigger commit and then changing the view, gitk reports 
> 
>         can't read "treediffs(b107a60c5bed3002ecef93b4405a44d809776e6f)": no such variable
>         can't read "treediffs(b107a60c5bed3002ecef93b4405a44d809776e6f)": no such variable
>             while executing
>         "lsearch -exact $treediffs($ids) $fname"
>             (procedure "makediffhdr" line 7)
>             invoked from within
>         "makediffhdr $fname $ids"
>             (procedure "parseblobdiffline" line 56)
>             invoked from within
>         "parseblobdiffline $ids $line"
>             (procedure "getblobdiffline" line 16)
>             invoked from within
>         "getblobdiffline file6 b107a60c5bed3002ecef93b4405a44d809776e6f"
>             ("eval" body line 1)
>             invoked from within
>         "eval $script"
>             (procedure "dorunq" line 11)
>             invoked from within
>         "dorunq"
>             ("after" script)
> 
> It is reproducible with:
> 
>         TCDIR=/tmp/testcase
>         N=512
> 
>         rm -rf $TCDIR
>         git init $TCDIR
>         for i in `seq $N` ; do 
>             dd if=/dev/random status=none bs=1024 count=16 | uuencode "" > $TCDIR/foo_$i 
>         done
>         git -C $TCDIR add . 
>         git -C $TCDIR commit -m "commit" 
> 
>         cd $TCDIR
>         gitk --all
> 
> followed by an immediate change to "All Files" in gitk menu "View".
> 
> That happens because proc showview (and some others) clear treediffs which is 
> still needed by tasks pending in runq.
> 
> The patch below makes showview wait until runq is empty which is slow (waits for 
> useless operations) and feels wrong. I have no idea how to cleanly flush runq 
> instead.
> 
> The same issue has been mentioned here before: 
> 	https://stackoverflow.com/questions/17977996/gitk-cant-read-treediffs-error
> 
> Michael

Thank you for the report, the reproducer, and for digging into the issue.

I'll look into this further as time permits, but don't hold your breath.

-- Hannes

diff --git a/gitk b/gitk
index dc042a5..51d9fe5 100755
--- a/gitk
+++ b/gitk
@@ -4693,6 +4693,17 @@ proc showview {n} {
     }
     unselectline
     normalline
+    global runq
+    foreach curq $runq {
+        set fd [lindex $curq 0]
+        if {$fd ne {}} {
+            catch {close $fd}
+        } else {
+            set script [lindex $curq 1]
+            unset isonrunq($script)
+        }
+    }
+    set runq {}
     unset -nocomplain treediffs
     clear_display
     if {[info exists hlview] && $hlview == $n} {