gitk: Replace catch {unset foo} with unset -nocomplain foo

This generates better bytecode in Tcl 8.6 according to
http://wiki.tcl.tk/1506.

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

Author: paulusmack

gitk

@@ -600,18 +600,18 @@ proc reloadcommits {} {
     }
     resetvarcs $curview
     set selectedline {}
-    catch {unset currentid}
-    catch {unset thickerline}
-    catch {unset treediffs}
+    unset -nocomplain currentid
+    unset -nocomplain thickerline
+    unset -nocomplain treediffs
     readrefs
     changedrefs
     if {$showneartags} {
 	getallcommits
     }
     clear_display
-    catch {unset commitinterest}
-    catch {unset cached_commitrow}
-    catch {unset targetid}
+    unset -nocomplain commitinterest
+    unset -nocomplain cached_commitrow
+    unset -nocomplain targetid
     setcanvscroll
     getcommits $selid
     return 0
@@ -673,7 +673,7 @@ proc resetvarcs {view} {
     foreach vd [array names vseedcount $view,*] {
 	unset vseedcount($vd)
     }
-    catch {unset ordertok}
+    unset -nocomplain ordertok
 }
 
 # returns a list of the commits with no children
@@ -966,7 +966,7 @@ proc insertrow {id p v} {
     set vp $v,$p
     if {[llength [lappend children($vp) $id]] > 1} {
 	set children($vp) [lsort -command [list vtokcmp $v] $children($vp)]
-	catch {unset ordertok}
+	unset -nocomplain ordertok
     }
     fix_reversal $p $a $v
     incr commitidx($v)
@@ -1136,7 +1136,7 @@ proc update_arcrows {v} {
 	    set displayorder [lrange $displayorder 0 [expr {$vrowmod($v) - 1}]]
 	    set parentlist [lrange $parentlist 0 [expr {$vrowmod($v) - 1}]]
 	}
-	catch {unset cached_commitrow}
+	unset -nocomplain cached_commitrow
     }
     set narctot [expr {[llength $varctok($v)] - 1}]
     set a $varcmod($v)
@@ -1579,7 +1579,7 @@ proc getcommitlines {fd inst view updating}  {
 		    [vtokcmp $view [lindex $children($vp) end-1] $id] > 0} {
 		    set children($vp) [lsort -command [list vtokcmp $view] \
 					   $children($vp)]
-		    catch {unset ordertok}
+		    unset -nocomplain ordertok
 		}
 		if {[info exists varcid($view,$p)]} {
 		    fix_reversal $p $a $view
@@ -1778,7 +1778,7 @@ proc readrefs {} {
     global hideremotes
 
     foreach v {tagids idtags headids idheads otherrefids idotherrefs} {
-	catch {unset $v}
+	unset -nocomplain $v
     }
     set refd [open [list | git show-ref -d] r]
     while {[gets $refd line] >= 0} {
@@ -3389,7 +3389,7 @@ proc init_flist {first} {
 	set cflist_top 1
 	$cflist tag add highlight 1.0 "1.0 lineend"
     } else {
-	catch {unset cflist_top}
+	unset -nocomplain cflist_top
     }
     $cflist conf -state disabled
     set difffilestart {}
@@ -4438,15 +4438,15 @@ proc showview {n} {
     }
     unselectline
     normalline
-    catch {unset treediffs}
+    unset -nocomplain treediffs
     clear_display
     if {[info exists hlview] && $hlview == $n} {
 	unset hlview
 	set selectedhlview [mc "None"]
     }
-    catch {unset commitinterest}
-    catch {unset cached_commitrow}
-    catch {unset ordertok}
+    unset -nocomplain commitinterest
+    unset -nocomplain cached_commitrow
+    unset -nocomplain ordertok
 
     set curview $n
     set selectedview $n
@@ -4466,8 +4466,8 @@ proc showview {n} {
     set rowfinal {}
     set numcommits $commitidx($n)
 
-    catch {unset colormap}
-    catch {unset rowtextx}
+    unset -nocomplain colormap
+    unset -nocomplain rowtextx
     set nextcolor 0
     set canvxmax [$canv cget -width]
     set curview $n
@@ -4601,7 +4601,7 @@ proc delvhighlight {} {
 
     if {![info exists hlview]} return
     unset hlview
-    catch {unset vhighlights}
+    unset -nocomplain vhighlights
     unbolden
 }
 
@@ -4649,7 +4649,7 @@ proc hfiles_change {} {
 	# delete previous highlights
 	catch {close $filehighlight}
 	unset filehighlight
-	catch {unset fhighlights}
+	unset -nocomplain fhighlights
 	unbolden
 	unhighlight_filelist
     }
@@ -4710,7 +4710,7 @@ proc findcom_change args {
 	bolden_name $id mainfont
     }
     set boldnameids {}
-    catch {unset nhighlights}
+    unset -nocomplain nhighlights
     unbolden
     unmarkmatches
     if {$gdttype ne [mc "containing:"] || $findstring eq {}} {
@@ -4913,9 +4913,9 @@ proc rhighlight_sel {a} {
     global descendent desc_todo ancestor anc_todo
     global highlight_related
 
-    catch {unset descendent}
+    unset -nocomplain descendent
     set desc_todo [list $a]
-    catch {unset ancestor}
+    unset -nocomplain ancestor
     set anc_todo [list $a]
     if {$highlight_related ne [mc "None"]} {
 	rhighlight_none
@@ -4926,7 +4926,7 @@ proc rhighlight_sel {a} {
 proc rhighlight_none {} {
     global rhighlights
 
-    catch {unset rhighlights}
+    unset -nocomplain rhighlights
     unbolden
 }
 
@@ -5134,8 +5134,8 @@ proc initlayout {} {
     set rowisopt {}
     set rowfinal {}
     set canvxmax [$canv cget -width]
-    catch {unset colormap}
-    catch {unset rowtextx}
+    unset -nocomplain colormap
+    unset -nocomplain rowtextx
     setcanvscroll
 }
 
@@ -6368,17 +6368,17 @@ proc clear_display {} {
     global linehtag linentag linedtag boldids boldnameids
 
     allcanvs delete all
-    catch {unset iddrawn}
-    catch {unset linesegs}
-    catch {unset linehtag}
-    catch {unset linentag}
-    catch {unset linedtag}
+    unset -nocomplain iddrawn
+    unset -nocomplain linesegs
+    unset -nocomplain linehtag
+    unset -nocomplain linentag
+    unset -nocomplain linedtag
     set boldids {}
     set boldnameids {}
-    catch {unset vhighlights}
-    catch {unset fhighlights}
-    catch {unset nhighlights}
-    catch {unset rhighlights}
+    unset -nocomplain vhighlights
+    unset -nocomplain fhighlights
+    unset -nocomplain nhighlights
+    unset -nocomplain rhighlights
     set need_redisplay 0
     set nrows_drawn 0
 }
@@ -7226,7 +7226,7 @@ proc selectline {l isnew {desired_loc {}} {switch_to_patch 0}} {
     global autoselect autosellen jump_to_here
     global vinlinediff
 
-    catch {unset pending_select}
+    unset -nocomplain pending_select
     $canv delete hover
     normalline
     unsel_reflist
@@ -7424,7 +7424,7 @@ proc unselectline {} {
     global selectedline currentid
 
     set selectedline {}
-    catch {unset currentid}
+    unset -nocomplain currentid
     allcanvs delete secsel
     rhighlight_none
 }
@@ -7480,7 +7480,7 @@ proc unset_posvars {} {
     if {[info exists last_posvars]} {
 	foreach {var val} $last_posvars {
 	    global $var
-	    catch {unset $var}
+	    unset -nocomplain $var
 	}
 	unset last_posvars
     }
@@ -7548,7 +7548,7 @@ proc gettree {id} {
     global nullid nullid2
 
     set diffids $id
-    catch {unset diffmergeid}
+    unset -nocomplain diffmergeid
     if {![info exists treefilelist($id)]} {
 	if {![info exists treepending]} {
 	    if {$id eq $nullid} {
@@ -7704,7 +7704,7 @@ proc startdiff {ids} {
 
     settabs 1
     set diffids $ids
-    catch {unset diffmergeid}
+    unset -nocomplain diffmergeid
     if {![info exists treediffs($ids)] ||
 	[lsearch -exact $ids $nullid] >= 0 ||
 	[lsearch -exact $ids $nullid2] >= 0} {
@@ -8325,7 +8325,7 @@ proc clear_ctext {{first 1.0}} {
     }
     $ctext delete $first end
     if {$first eq "1.0"} {
-	catch {unset pendinglinks}
+	unset -nocomplain pendinglinks
     }
     set ctext_file_names {}
     set ctext_file_lines {}
@@ -8501,7 +8501,7 @@ proc scrolltext {f0 f1} {
 	highlightfile_for_scrollpos $topidx
     }
 
-    catch {unset suppress_highlighting_file_for_this_scrollpos}
+    unset -nocomplain suppress_highlighting_file_for_this_scrollpos
 
     .bleft.bottom.sb set $f0 $f1
     if {$searchstring ne {}} {
@@ -10103,9 +10103,9 @@ proc getallclines {fd} {
     }
     if {$nid > 0} {
 	global cached_dheads cached_dtags cached_atags
-	catch {unset cached_dheads}
-	catch {unset cached_dtags}
-	catch {unset cached_atags}
+	unset -nocomplain cached_dheads
+	unset -nocomplain cached_dtags
+	unset -nocomplain cached_atags
     }
     if {![eof $fd]} {
 	return [expr {$nid >= 1000? 2: 1}]
@@ -10345,7 +10345,7 @@ proc dropcache {err} {
     foreach v {arcnos arcout arcids arcstart arcend growing \
 		   arctags archeads allparents allchildren} {
 	global $v
-	catch {unset $v}
+	unset -nocomplain $v
     }
     set allcwait 0
     set nextarc 0
@@ -10996,8 +10996,8 @@ proc addedtag {id} {
     if {![info exists arcout($id)]} {
 	recalcarc [lindex $arcnos($id) 0]
     }
-    catch {unset cached_dtags}
-    catch {unset cached_atags}
+    unset -nocomplain cached_dtags
+    unset -nocomplain cached_atags
 }
 
 proc addedhead {hid head} {
@@ -11007,13 +11007,13 @@ proc addedhead {hid head} {
     if {![info exists arcout($hid)]} {
 	recalcarc [lindex $arcnos($hid) 0]
     }
-    catch {unset cached_dheads}
+    unset -nocomplain cached_dheads
 }
 
 proc removedhead {hid head} {
     global cached_dheads
 
-    catch {unset cached_dheads}
+    unset -nocomplain cached_dheads
 }
 
 proc movedhead {hid head} {
@@ -11023,7 +11023,7 @@ proc movedhead {hid head} {
     if {![info exists arcout($hid)]} {
 	recalcarc [lindex $arcnos($hid) 0]
     }
-    catch {unset cached_dheads}
+    unset -nocomplain cached_dheads
 }
 
 proc changedrefs {} {
@@ -11039,10 +11039,10 @@ proc changedrefs {} {
 	    }
 	}
     }
-    catch {unset cached_tagcontent}
-    catch {unset cached_dtags}
-    catch {unset cached_atags}
-    catch {unset cached_dheads}
+    unset -nocomplain cached_tagcontent
+    unset -nocomplain cached_dtags
+    unset -nocomplain cached_atags
+    unset -nocomplain cached_dheads
 }
 
 proc rereadrefs {} {
@@ -11628,7 +11628,7 @@ proc prefsok {} {
 	($perfile_attrs && !$oldprefs(perfile_attrs))} {
 	# treediffs elements are limited by path;
 	# won't have encodings cached if perfile_attrs was just turned on
-	catch {unset treediffs}
+	unset -nocomplain treediffs
     }
     if {$fontchanged || $maxwidth != $oldprefs(maxwidth)
 	|| $maxgraphpct != $oldprefs(maxgraphpct)} {