gitk: Fix bug causing the "can't unset idinlist(...)" error

Under some circumstances, having duplicate parents in a commit could
trigger a "can't unset idinlist" Tcl error.  This fixes the cause
(the logic in layoutrows could end up putting the same commit into
rowidlist twice) and also puts a catch around the unset to ignore
the error.

Thanks to Jeff King for coming up with a test script to generate a
repo that shows the problem.

Signed-off-by: Paul Mackerras <paulus@samba.org>

diff --git a/gitk b/gitk
index 6c2be3b7278927198bd937cbfb2dd7b0e3a0c481..44b04f017a0cadc56a1f3896d1d3d84657b21c58 100755 (executable)
--- a/gitk
+++ b/gitk
@@ -2880,6 +2880,7 @@ proc layoutrows {row endrow last} {
            } elseif {!$idinlist($p)} {
                lappend oldolds $p
            }
+           set idinlist($p) 1
        }
        set nev [expr {[llength $idlist] + [llength $newolds]
                       + [llength $oldolds] - $maxwidth + 1}]
@@ -2952,12 +2953,10 @@ proc layoutrows {row endrow last} {
            lset offs $col {}
        }
        foreach i $newolds {
-           set idinlist($i) 1
            set idrowranges($i) $id
        }
        incr col $l
        foreach oid $oldolds {
-           set idinlist($oid) 1
            set idlist [linsert $idlist $col $oid]
            set offs [linsert $offs $col $o]
            makeuparrow $oid $col $row $o
@@ -2998,7 +2997,7 @@ proc layouttail {} {
        set col [expr {[llength $idlist] - 1}]
        set id [lindex $idlist $col]
        addextraid $id $row
-       unset idinlist($id)
+       catch {unset idinlist($id)}
        lappend idrowranges($id) $id
        lappend rowrangelist $idrowranges($id)
        unset idrowranges($id)