Merge with master for gitk and doc updates.

Documentation/Makefile

@@ -1,7 +1,7 @@
 MAN1_TXT=$(wildcard git-*.txt)
 MAN7_TXT=git.txt
 
-DOC_HTML=$(patsubst %.txt,%.html,$(MAN1_TXT) $(MAN7_TXT))
+DOC_HTML=$(patsubst %.txt,%.html,$(MAN1_TXT) $(MAN7_TXT)) glossary.html
 
 DOC_MAN1=$(patsubst %.txt,%.1,$(MAN1_TXT))
 DOC_MAN7=$(patsubst %.txt,%.7,$(MAN7_TXT))
@@ -54,3 +54,8 @@ clean:
 %.xml : %.txt
 	asciidoc -b docbook -d manpage $<
 
+glossary.html : glossary.txt sort_glossary.pl
+	cat $< | \
+	perl sort_glossary.pl | \
+	asciidoc -b xhtml11 - > glossary.html
+

Documentation/glossary.txt

@@ -3,21 +3,27 @@ object::
 	the SHA1 of its contents. Consequently, an object can not
 	be changed.
 
+object name::
+	The unique identifier of an object. The hash of the object's contents
+	using the Secure Hash Algorithm 1 and usually represented by the 40
+	character hexadecimal encoding of the hash of the object (possibly
+	followed by a white space).
+
 SHA1::
-	A 20-byte sequence (or 41-byte file containing the hex
+	Synonym for object name.
-	representation and a newline). It is calculated from the
+
-	contents of an object by the Secure Hash Algorithm 1.
+object identifier::
+	Synonym for object name.
+
+hash::
+	In git's context, synonym to object name.
 
 object database::
 	Stores a set of "objects", and an individial object is identified
-	by its SHA1 (its ref). The objects are either stored as single
+	by its object name. The object usually live in $GIT_DIR/objects/.
-	files, or live inside of packs.
-
-object name::
-	Synonym for SHA1.
 
 blob object::
-	Untyped object, i.e. the contents of a file.
+	Untyped object, e.g. the contents of a file.
 
 tree object::
 	An object containing a list of blob and/or tree objects.
@@ -29,42 +35,43 @@ tree::
 	dependent blob and tree objects (i.e. a stored representation
 	of a working tree).
 
-cache::
+index::
-	A collection of files whose contents are stored as objects.
+	A collection of files with stat information, whose contents are
-	The cache is a stored version of your working tree. Well, can
+	stored as objects. The cache is a stored version of your working
-	also contain a second, and even a third version of a working
+	tree. Truth be told, it can also contain a second, and even a third
-	tree, which are used when merging.
+	version of a working tree, which are used when merging.
 
-cache entry::
+index entry::
 	The information regarding a particular file, stored in the index.
-	A cache entry can be unmerged, if a merge was started, but not
+	An index entry can be unmerged, if a merge was started, but not
 	yet finished (i.e. if the cache contains multiple versions of
 	that file).
 
-index::
+unmerged index:
-	Contains information about the cache contents, in particular
+	An index which contains unmerged index entries.
-	timestamps and mode flags ("stat information") for the files
+
-	stored in the cache. An unmerged index is an index which contains
+cache::
-	unmerged cache entries.
+	Obsolete for: index.
 
 working tree::
-	The set of files and directories currently being worked on.
+	The set of files and directories currently being worked on,
-	Think "ls -laR"
+	i.e. you can work in your working tree without using git at all.
 
 directory::
 	The list you get with "ls" :-)
 
-checkout::
-	The action of updating the working tree to a revision which was
-	stored in the object database.
-
 revision::
 	A particular state of files and directories which was stored in
 	the object database. It is referenced by a commit object.
 
+checkout::
+	The action of updating the working tree to a revision which was
+	stored in the object database.
+
 commit::
-	The action of storing the current state of the cache in the
+	As a verb: The action of storing the current state of the cache in the
 	object database. The result is a revision.
+	As a noun: Short hand for commit object.
 
 commit object::
 	An object which contains the information about a particular
@@ -72,14 +79,15 @@ commit object::
 	tree object which corresponds to the top directory of the
 	stored revision.
 
+parent::
+	A commit object contains a (possibly empty) list of the logical
+	predecessor(s) in the line of development, i.e. its parents.
+
 changeset::
 	BitKeeper/cvsps speak for "commit". Since git does not store
 	changes, but states, it really does not make sense to use
 	the term "changesets" with git.
 
-ent::
-	Favorite synonym to "tree-ish" by some total geeks.
-
 clean::
 	A working tree is clean, if it corresponds to the revision
 	referenced by the current head.
@@ -94,13 +102,12 @@ head::
 
 branch::
 	A non-cyclical graph of revisions, i.e. the complete history of
-	a particular revision, which does not (yet) have children, which
+	a particular revision, which is called the branch head. The
-	is called the branch head. The branch heads are stored in
+	branch heads are stored in $GIT_DIR/refs/heads/.
-	$GIT_DIR/refs/heads/.
 
 ref::
 	A 40-byte hex representation of a SHA1 pointing to a particular
-	object. These are stored in $GIT_DIR/refs/.
+	object. These may be stored in $GIT_DIR/refs/.
 
 head ref::
 	A ref pointing to a head. Often, this is abbreviated to "head".
@@ -108,7 +115,10 @@ head ref::
 
 tree-ish::
 	A ref pointing to either a commit object, a tree object, or a
-	tag object pointing to a commit or tree object.
+	tag object pointing to a tag or commit or tree object.
+
+ent::
+	Favorite synonym to "tree-ish" by some total geeks.
 
 tag object::
 	An object containing a ref pointing to another object. It can
@@ -120,6 +130,8 @@ tag::
 	a tag is not changed by a commit. Tags (not tag objects) are
 	stored in $GIT_DIR/refs/tags/. A git tag has nothing to do with
 	a Lisp tag (which is called object type in git's context).
+	A tag is most typically used to mark a particular point in the
+	commit ancestry chain.
 
 merge::
 	To merge branches means to try to accumulate the changes since a
@@ -133,9 +145,18 @@ resolve::
 
 repository::
 	A collection of refs together with an object database containing
-	all objects, which are reachable from the refs. A repository can
+	all objects, which are reachable from the refs, possibly accompanied
+	by meta data from one or more porcelains. A repository can
 	share an object database with other repositories.
 
+git archive::
+	Synonym for repository (for arch people).
+
+file system::
+	Linus Torvalds originally designed git to be a user space file
+	system, i.e. the infrastructure to hold files and directories.
+	That ensured the efficiency and speed of git.
+
 alternate object database::
 	Via the alternates mechanism, a repository can inherit part of its
 	object database from another object database, which is called
@@ -150,10 +171,6 @@ chain::
 	reference to its successor (for example, the successor of a commit
 	could be one of its parents).
 
-parent::
-	A commit object contains a (possibly empty) list of the logical
-	predecessor(s) in the line of development, i.e. its parents.
-
 fetch::
 	Fetching a branch means to get the branch's head ref from a
 	remote repository, to find out which objects are missing from
@@ -176,8 +193,8 @@ pack::
 	space or to transmit them efficiently).
 
 pack index::
-	Contains offsets into a pack, so the pack can be used instead of
+	The list of identifiers, and other information, of the objects in a
-	the unpacked objects.
+	pack, to assist in efficiently accessing the contents of a pack. 
 
 plumbing::
 	Cute name for core git.
@@ -196,3 +213,4 @@ SCM::
 
 dircache::
 	You are *waaaaay* behind.
+

Documentation/howto/using-topic-branches.txt

@@ -70,8 +70,8 @@ them too:
 Now create the branches in which you are going to work, these start
 out at the current tip of the linus branch.
 
- $ git checkout -b test linus
+ $ git branch test linus
- $ git checkout -b release linus
+ $ git branch release linus
 
 These can be easily kept up to date by merging from the "linus" branch:
 
@@ -144,6 +144,11 @@ is empty.  At this point the branch can be deleted:
 
  $ rm .git/refs/heads/branchname
 
+Some changes are so trivial that it is not necessary to create a separate
+branch and then merge into each of the test and release branches.  For
+these changes, just apply directly to the "release" branch, and then
+merge that into the "test" branch.
+
 To create diffstat and shortlog summaries of changes to include in a "please
 pull" request to Linus you can use:
 
@@ -151,3 +156,109 @@ pull" request to Linus you can use:
 and
  $ git-whatchanged release ^linus | git-shortlog
 
+
+Here are some of the scripts that I use to simplify all this even further.
+
+==== update script ====
+# Update a branch in my GIT tree.  If the branch to be updated
+# is "linus", then pull from kernel.org.  Otherwise merge local
+# linus branch into test|release branch
+
+case "$1" in
+test|release)
+	git checkout $1 && git resolve $1 linus "Auto-update from upstream"
+	;;
+linus)
+	before=$(cat .git/HEAD)
+	git checkout linus && git pull linus
+	after=$(cat .git/HEAD)
+	if [ $before != $after ]
+	then
+		git-whatchanged $after ^$before | git-shortlog
+	fi
+	;;
+*)
+	echo "Usage: $0 linus|test|release" 1>&2
+	exit 1
+	;;
+esac
+
+==== merge script ====
+# Merge a branch into either the test or release branch
+
+pname=$0
+
+usage()
+{
+	echo "Usage: $pname branch test|release" 1>&2
+	exit 1
+}
+
+if [ ! -f .git/refs/heads/"$1" ]
+then
+	echo "Can't see branch <$1>" 1>&2
+	usage
+fi
+
+case "$2" in
+test|release)
+	if [ $(git-rev-list $1 ^$2 | wc -c) -eq 0 ]
+	then
+		echo $1 already merged into $2 1>&2
+		exit 1
+	fi
+	git checkout $2 && git resolve $2 $1 "Pull $1 into $2 branch"
+	;;
+*)
+	usage
+	;;
+esac
+
+==== status script ====
+# report on status of my ia64 GIT tree
+
+gb=$(tput setab 2)
+rb=$(tput setab 1)
+restore=$(tput setab 9)
+
+if [ `git-rev-tree release ^test | wc -c` -gt 0 ]
+then
+	echo $rb Warning: commits in release that are not in test $restore
+	git-whatchanged release ^test
+fi
+
+for branch in `ls .git/refs/heads`
+do
+	if [ $branch = linus -o $branch = test -o $branch = release ]
+	then
+		continue
+	fi
+
+	echo -n $gb ======= $branch ====== $restore " "
+	status=
+	for ref in test release linus
+	do
+		if [ `git-rev-tree $branch ^$ref | wc -c` -gt 0 ]
+		then
+			status=$status${ref:0:1}
+		fi
+	done
+	case $status in
+	trl)
+		echo $rb Need to pull into test $restore
+		;;
+	rl)
+		echo "In test"
+		;;
+	l)
+		echo "Waiting for linus"
+		;;
+	"")
+		echo $rb All done $restore
+		;;
+	*)
+		echo $rb "<$status>" $restore
+		;;
+	esac
+	git-whatchanged $branch ^linus | git-shortlog
+done

Documentation/sort_glossary.pl

@@ -0,0 +1,70 @@
+#!/usr/bin/perl
+
+%terms=();
+
+while(<>) {
+	if(/^(\S.*)::$/) {
+		my $term=$1;
+		if(defined($terms{$term})) {
+			die "$1 defined twice\n";
+		}
+		$terms{$term}="";
+		LOOP: while(<>) {
+			if(/^$/) {
+				last LOOP;
+			}
+			if(/^	\S/) {
+				$terms{$term}.=$_;
+			} else {
+				die "Error 1: $_";
+			}
+		}
+	}
+}
+
+sub format_tab_80 ($) {
+	my $text=$_[0];
+	my $result="";
+	$text=~s/\s+/ /g;
+	$text=~s/^\s+//;
+	while($text=~/^(.{1,72})(|\s+(\S.*)?)$/) {
+		$result.="	".$1."\n";
+		$text=$3;
+	}
+	return $result;
+}
+
+sub no_spaces ($) {
+	my $result=$_[0];
+	$result=~tr/ /_/;
+	return $result;
+}
+
+print 'GIT Glossary
+============
+Aug 2005
+
+This list is sorted alphabetically:
+
+';
+
+@keys=sort {uc($a) cmp uc($b)} keys %terms;
+$pattern='(\b'.join('\b|\b',reverse @keys).'\b)';
+foreach $key (@keys) {
+	$terms{$key}=~s/$pattern/sprintf "<<ref_".no_spaces($1).",$1>>";/eg;
+	print '[[ref_'.no_spaces($key).']]'.$key."::\n"
+		.format_tab_80($terms{$key})."\n";
+}
+
+print '
+
+Author
+------
+Written by Johannes Schindelin <Johannes.Schindelin@gmx.de> and
+the git-list <git@vger.kernel.org>.
+
+GIT
+---
+Part of the link:git.html[git] suite
+';
+

gitk

@@ -59,7 +59,7 @@ proc getcommits {rargs} {
 }
 
 proc getcommitlines {commfd}  {
-    global commits parents cdate children nchildren
+    global commits parents cdate children
     global commitlisted phase commitinfo nextupdate
     global stopped redisplaying leftover
 
@@ -156,6 +156,7 @@ proc readcommit {id} {
 
 proc parsecommit {id contents listed} {
     global commitinfo children nchildren parents nparents cdate ncleft
+    global grafts
 
     set inhdr 1
     set comment {}
@@ -171,13 +172,32 @@ proc parsecommit {id contents listed} {
     }
     set parents($id) {}
     set nparents($id) 0
+    set grafted 0
+    if {[info exists grafts($id)]} {
+	set grafted 1
+	set parents($id) $grafts($id)
+	set nparents($id) [llength $grafts($id)]
+	if {$listed} {
+	    foreach p $grafts($id) {
+		if {![info exists nchildren($p)]} {
+		    set children($p) [list $id]
+		    set nchildren($p) 1
+		    set ncleft($p) 1
+		} elseif {[lsearch -exact $children($p) $id] < 0} {
+		    lappend children($p) $id
+		    incr nchildren($p)
+		    incr ncleft($p)
+		}
+	    }
+	}
+    }
     foreach line [split $contents "\n"] {
 	if {$inhdr} {
 	    if {$line == {}} {
 		set inhdr 0
 	    } else {
 		set tag [lindex $line 0]
-		if {$tag == "parent"} {
+		if {$tag == "parent" && !$grafted} {
 		    set p [lindex $line 1]
 		    if {![info exists nchildren($p)]} {
 			set children($p) {}
@@ -273,6 +293,32 @@ proc readrefs {} {
     }
 }
 
+proc readgrafts {} {
+    global grafts env
+    catch {
+	set graftfile info/grafts
+	if {[info exists env(GIT_GRAFT_FILE)]} {
+	    set graftfile $env(GIT_GRAFT_FILE)
+	}
+	set fd [open [gitdir]/$graftfile r]
+	while {[gets $fd line] >= 0} {
+	    if {[string match "#*" $line]} continue
+	    set ok 1
+	    foreach x $line {
+		if {![regexp {^[0-9a-f]{40}$} $x]} {
+		    set ok 0
+		    break
+		}
+	    }
+	    if {$ok} {
+		set id [lindex $line 0]
+		set grafts($id) [lrange $line 1 end]
+	    }
+	}
+	close $fd
+    }
+}
+
 proc error_popup msg {
     set w .error
     toplevel $w
@@ -704,21 +750,24 @@ proc assigncolor {id} {
 }
 
 proc initgraph {} {
-    global canvy canvy0 lineno numcommits lthickness nextcolor linespc
+    global canvy canvy0 lineno numcommits nextcolor linespc
-    global mainline sidelines
+    global mainline mainlinearrow sidelines
     global nchildren ncleft
+    global displist nhyperspace
 
     allcanvs delete all
     set nextcolor 0
     set canvy $canvy0
     set lineno -1
     set numcommits 0
-    set lthickness [expr {int($linespc / 9) + 1}]
     catch {unset mainline}
+    catch {unset mainlinearrow}
     catch {unset sidelines}
     foreach id [array names nchildren] {
 	set ncleft($id) $nchildren($id)
     }
+    set displist {}
+    set nhyperspace 0
 }
 
 proc bindline {t id} {
@@ -730,19 +779,21 @@ proc bindline {t id} {
     $canv bind $t <Button-1> "lineclick %x %y $id 1"
 }
 
+# level here is an index in displist
 proc drawcommitline {level} {
-    global parents children nparents nchildren todo
+    global parents children nparents displist
     global canv canv2 canv3 mainfont namefont canvy linespc
     global lineid linehtag linentag linedtag commitinfo
     global colormap numcommits currentparents dupparents
-    global oldlevel oldnlines oldtodo
     global idtags idline idheads
-    global lineno lthickness mainline sidelines
+    global lineno lthickness mainline mainlinearrow sidelines
-    global commitlisted rowtextx idpos
+    global commitlisted rowtextx idpos lastuse displist
+    global oldnlines olddlevel olddisplist
 
     incr numcommits
     incr lineno
-    set id [lindex $todo $level]
+    set id [lindex $displist $level]
+    set lastuse($id) $lineno
     set lineid($lineno) $id
     set idline($id) $lineno
     set ofill [expr {[info exists commitlisted($id)]? "blue": "white"}]
@@ -773,8 +824,12 @@ proc drawcommitline {level} {
 	[list 0 0 0 [expr $y1 + 0.5 * $linespc + 2]]
     if {[info exists mainline($id)]} {
 	lappend mainline($id) $x $y1
+	if {$mainlinearrow($id) ne "none"} {
+	    set mainline($id) [trimdiagstart $mainline($id)]
+	}
 	set t [$canv create line $mainline($id) \
-		   -width $lthickness -fill $colormap($id)]
+		   -width $lthickness -fill $colormap($id) \
+		   -arrow $mainlinearrow($id)]
 	$canv lower $t
 	bindline $t $id
     }
@@ -782,8 +837,9 @@ proc drawcommitline {level} {
 	foreach ls $sidelines($id) {
 	    set coords [lindex $ls 0]
 	    set thick [lindex $ls 1]
+	    set arrow [lindex $ls 2]
 	    set t [$canv create line $coords -fill $colormap($id) \
-		       -width [expr {$thick * $lthickness}]]
+		       -width [expr {$thick * $lthickness}] -arrow $arrow]
 	    $canv lower $t
 	    bindline $t $id
 	}
@@ -794,7 +850,7 @@ proc drawcommitline {level} {
 	       -fill $ofill -outline black -width 1]
     $canv raise $t
     $canv bind $t <1> {selcanvline {} %x %y}
-    set xt [xcoord [llength $todo] $level $lineno]
+    set xt [xcoord [llength $displist] $level $lineno]
     if {[llength $currentparents] > 2} {
 	set xt [expr {$xt + ([llength $currentparents] - 2) * $linespc}]
     }
@@ -813,6 +869,10 @@ proc drawcommitline {level} {
 			       -text $name -font $namefont]
     set linedtag($lineno) [$canv3 create text 3 $y1 -anchor w \
 			       -text $date -font $mainfont]
+
+    set olddlevel $level
+    set olddisplist $displist
+    set oldnlines [llength $displist]
 }
 
 proc drawtags {id x xt y1} {
@@ -867,46 +927,11 @@ proc drawtags {id x xt y1} {
     return $xt
 }
 
-proc updatetodo {level noshortcut} {
-    global currentparents ncleft todo
-    global mainline oldlevel oldtodo oldnlines
-    global canvy linespc mainline
-    global commitinfo lineno xspc1
-
-    set oldlevel $level
-    set oldtodo $todo
-    set oldnlines [llength $todo]
-    if {!$noshortcut && [llength $currentparents] == 1} {
-	set p [lindex $currentparents 0]
-	if {$ncleft($p) == 1 && [lsearch -exact $todo $p] < 0} {
-	    set ncleft($p) 0
-	    set x [xcoord $level $level $lineno]
-	    set y [expr $canvy - $linespc]
-	    set mainline($p) [list $x $y]
-	    set todo [lreplace $todo $level $level $p]
-	    set xspc1([expr {$lineno + 1}]) $xspc1($lineno)
-	    return 0
-	}
-    }
-
-    set todo [lreplace $todo $level $level]
-    set i $level
-    foreach p $currentparents {
-	incr ncleft($p) -1
-	set k [lsearch -exact $todo $p]
-	if {$k < 0} {
-	    set todo [linsert $todo $i $p]
-	    incr i
-	}
-    }
-    return 1
-}
-
 proc notecrossings {id lo hi corner} {
-    global oldtodo crossings cornercrossings
+    global olddisplist crossings cornercrossings
 
     for {set i $lo} {[incr i] < $hi} {} {
-	set p [lindex $oldtodo $i]
+	set p [lindex $olddisplist $i]
 	if {$p == {}} continue
 	if {$i == $corner} {
 	    if {![info exists cornercrossings($id)]
@@ -942,37 +967,218 @@ proc xcoord {i level ln} {
     return $x
 }
 
-proc drawslants {level} {
+# it seems Tk can't draw arrows on the end of diagonal line segments...
-    global canv mainline sidelines canvx0 canvy xspc1 xspc2 lthickness
+proc trimdiagend {line} {
-    global oldlevel oldtodo todo currentparents dupparents
+    while {[llength $line] > 4} {
+	set x1 [lindex $line end-3]
+	set y1 [lindex $line end-2]
+	set x2 [lindex $line end-1]
+	set y2 [lindex $line end]
+	if {($x1 == $x2) != ($y1 == $y2)} break
+	set line [lreplace $line end-1 end]
+    }
+    return $line
+}
+
+proc trimdiagstart {line} {
+    while {[llength $line] > 4} {
+	set x1 [lindex $line 0]
+	set y1 [lindex $line 1]
+	set x2 [lindex $line 2]
+	set y2 [lindex $line 3]
+	if {($x1 == $x2) != ($y1 == $y2)} break
+	set line [lreplace $line 0 1]
+    }
+    return $line
+}
+
+proc drawslants {id needonscreen nohs} {
+    global canv mainline mainlinearrow sidelines
+    global canvx0 canvy xspc1 xspc2 lthickness
+    global currentparents dupparents
     global lthickness linespc canvy colormap lineno geometry
-    global maxgraphpct
+    global maxgraphpct maxwidth
+    global displist onscreen lastuse
+    global parents commitlisted
+    global oldnlines olddlevel olddisplist
+    global nhyperspace numcommits nnewparents
+
+    if {$lineno < 0} {
+	lappend displist $id
+	set onscreen($id) 1
+	return 0
+    }
+
+    set y1 [expr {$canvy - $linespc}]
+    set y2 $canvy
+
+    # work out what we need to get back on screen
+    set reins {}
+    if {$onscreen($id) < 0} {
+	# next to do isn't displayed, better get it on screen...
+	lappend reins [list $id 0]
+    }
+    # make sure all the previous commits's parents are on the screen
+    foreach p $currentparents {
+	if {$onscreen($p) < 0} {
+	    lappend reins [list $p 0]
+	}
+    }
+    # bring back anything requested by caller
+    if {$needonscreen ne {}} {
+	lappend reins $needonscreen
+    }
+
+    # try the shortcut
+    if {$currentparents == $id && $onscreen($id) == 0 && $reins eq {}} {
+	set dlevel $olddlevel
+	set x [xcoord $dlevel $dlevel $lineno]
+	set mainline($id) [list $x $y1]
+	set mainlinearrow($id) none
+	set lastuse($id) $lineno
+	set displist [lreplace $displist $dlevel $dlevel $id]
+	set onscreen($id) 1
+	set xspc1([expr {$lineno + 1}]) $xspc1($lineno)
+	return $dlevel
+    }
+
+    # update displist
+    set displist [lreplace $displist $olddlevel $olddlevel]
+    set j $olddlevel
+    foreach p $currentparents {
+	set lastuse($p) $lineno
+	if {$onscreen($p) == 0} {
+	    set displist [linsert $displist $j $p]
+	    set onscreen($p) 1
+	    incr j
+	}
+    }
+    if {$onscreen($id) == 0} {
+	lappend displist $id
+    }
+
+    # remove the null entry if present
+    set nullentry [lsearch -exact $displist {}]
+    if {$nullentry >= 0} {
+	set displist [lreplace $displist $nullentry $nullentry]
+    }
+
+    # bring back the ones we need now (if we did it earlier
+    # it would change displist and invalidate olddlevel)
+    foreach pi $reins {
+	# test again in case of duplicates in reins
+	set p [lindex $pi 0]
+	if {$onscreen($p) < 0} {
+	    set onscreen($p) 1
+	    set lastuse($p) $lineno
+	    set displist [linsert $displist [lindex $pi 1] $p]
+	    incr nhyperspace -1
+	}
+    }
+
+    set lastuse($id) $lineno
+
+    # see if we need to make any lines jump off into hyperspace
+    set displ [llength $displist]
+    if {$displ > $maxwidth} {
+	set ages {}
+	foreach x $displist {
+	    lappend ages [list $lastuse($x) $x]
+	}
+	set ages [lsort -integer -index 0 $ages]
+	set k 0
+	while {$displ > $maxwidth} {
+	    set use [lindex $ages $k 0]
+	    set victim [lindex $ages $k 1]
+	    if {$use >= $lineno - 5} break
+	    incr k
+	    if {[lsearch -exact $nohs $victim] >= 0} continue
+	    set i [lsearch -exact $displist $victim]
+	    set displist [lreplace $displist $i $i]
+	    set onscreen($victim) -1
+	    incr nhyperspace
+	    incr displ -1
+	    if {$i < $nullentry} {
+		incr nullentry -1
+	    }
+	    set x [lindex $mainline($victim) end-1]
+	    lappend mainline($victim) $x $y1
+	    set line [trimdiagend $mainline($victim)]
+	    set arrow "last"
+	    if {$mainlinearrow($victim) ne "none"} {
+		set line [trimdiagstart $line]
+		set arrow "both"
+	    }
+	    lappend sidelines($victim) [list $line 1 $arrow]
+	    unset mainline($victim)
+	}
+    }
+
+    set dlevel [lsearch -exact $displist $id]
+
+    # If we are reducing, put in a null entry
+    if {$displ < $oldnlines} {
+	# does the next line look like a merge?
+	# i.e. does it have > 1 new parent?
+	if {$nnewparents($id) > 1} {
+	    set i [expr {$dlevel + 1}]
+	} elseif {$nnewparents([lindex $olddisplist $olddlevel]) == 0} {
+	    set i $olddlevel
+	    if {$nullentry >= 0 && $nullentry < $i} {
+		incr i -1
+	    }
+	} elseif {$nullentry >= 0} {
+	    set i $nullentry
+	    while {$i < $displ
+		   && [lindex $olddisplist $i] == [lindex $displist $i]} {
+		incr i
+	    }
+	} else {
+	    set i $olddlevel
+	    if {$dlevel >= $i} {
+		incr i
+	    }
+	}
+	if {$i < $displ} {
+	    set displist [linsert $displist $i {}]
+	    incr displ
+	    if {$dlevel >= $i} {
+		incr dlevel
+	    }
+	}
+    }
 
     # decide on the line spacing for the next line
     set lj [expr {$lineno + 1}]
     set maxw [expr {$maxgraphpct * $geometry(canv1) / 100}]
-    set n [llength $todo]
+    if {$displ <= 1 || $canvx0 + $displ * $xspc2 <= $maxw} {
-    if {$n <= 1 || $canvx0 + $n * $xspc2 <= $maxw} {
 	set xspc1($lj) $xspc2
     } else {
-	set xspc1($lj) [expr {($maxw - $canvx0 - $xspc2) / ($n - 1)}]
+	set xspc1($lj) [expr {($maxw - $canvx0 - $xspc2) / ($displ - 1)}]
 	if {$xspc1($lj) < $lthickness} {
 	    set xspc1($lj) $lthickness
 	}
     }
 
-    set y1 [expr $canvy - $linespc]
+    foreach idi $reins {
-    set y2 $canvy
+	set id [lindex $idi 0]
+	set j [lsearch -exact $displist $id]
+	set xj [xcoord $j $dlevel $lj]
+	set mainline($id) [list $xj $y2]
+	set mainlinearrow($id) first
+    }
+
     set i -1
-    foreach id $oldtodo {
+    foreach id $olddisplist {
 	incr i
 	if {$id == {}} continue
-	set xi [xcoord $i $oldlevel $lineno]
+	if {$onscreen($id) <= 0} continue
-	if {$i == $oldlevel} {
+	set xi [xcoord $i $olddlevel $lineno]
+	if {$i == $olddlevel} {
 	    foreach p $currentparents {
-		set j [lsearch -exact $todo $p]
+		set j [lsearch -exact $displist $p]
 		set coords [list $xi $y1]
-		set xj [xcoord $j $level $lj]
+		set xj [xcoord $j $dlevel $lj]
 		if {$xj < $xi - $linespc} {
 		    lappend coords [expr {$xj + $linespc}] $y1
 		    notecrossings $p $j $i [expr {$j + 1}]
@@ -983,9 +1189,10 @@ proc drawslants {level} {
 		if {[lsearch -exact $dupparents $p] >= 0} {
 		    # draw a double-width line to indicate the doubled parent
 		    lappend coords $xj $y2
-		    lappend sidelines($p) [list $coords 2]
+		    lappend sidelines($p) [list $coords 2 none]
 		    if {![info exists mainline($p)]} {
 			set mainline($p) [list $xj $y2]
+			set mainlinearrow($p) none
 		    }
 		} else {
 		    # normal case, no parent duplicated
@@ -999,24 +1206,25 @@ proc drawslants {level} {
 			    lappend coords $xj $yb
 			}
 			set mainline($p) $coords
+			set mainlinearrow($p) none
 		    } else {
 			lappend coords $xj $yb
 			if {$yb < $y2} {
 			    lappend coords $xj $y2
 			}
-			lappend sidelines($p) [list $coords 1]
+			lappend sidelines($p) [list $coords 1 none]
 		    }
 		}
 	    }
 	} else {
 	    set j $i
-	    if {[lindex $todo $i] != $id} {
+	    if {[lindex $displist $i] != $id} {
-		set j [lsearch -exact $todo $id]
+		set j [lsearch -exact $displist $id]
 	    }
 	    if {$j != $i || $xspc1($lineno) != $xspc1($lj)
-		|| ($oldlevel <= $i && $i <= $level)
+		|| ($olddlevel <= $i && $i <= $dlevel)
-		|| ($level <= $i && $i <= $oldlevel)} {
+		|| ($dlevel <= $i && $i <= $olddlevel)} {
-		set xj [xcoord $j $level $lj]
+		set xj [xcoord $j $dlevel $lj]
 		set dx [expr {abs($xi - $xj)}]
 		set yb $y2
 		if {0 && $dx < $linespc} {
@@ -1026,21 +1234,152 @@ proc drawslants {level} {
 	    }
 	}
     }
+    return $dlevel
+}
+
+# search for x in a list of lists
+proc llsearch {llist x} {
+    set i 0
+    foreach l $llist {
+	if {$l == $x || [lsearch -exact $l $x] >= 0} {
+	    return $i
+	}
+	incr i
+    }
+    return -1
+}
+
+proc drawmore {reading} {
+    global displayorder numcommits ncmupdate nextupdate
+    global stopped nhyperspace parents commitlisted
+    global maxwidth onscreen displist currentparents olddlevel
+
+    set n [llength $displayorder]
+    while {$numcommits < $n} {
+	set id [lindex $displayorder $numcommits]
+	set ctxend [expr {$numcommits + 10}]
+	if {!$reading && $ctxend > $n} {
+	    set ctxend $n
+	}
+	set dlist {}
+	if {$numcommits > 0} {
+	    set dlist [lreplace $displist $olddlevel $olddlevel]
+	    set i $olddlevel
+	    foreach p $currentparents {
+		if {$onscreen($p) == 0} {
+		    set dlist [linsert $dlist $i $p]
+		    incr i
+		}
+	    }
+	}
+	set nohs {}
+	set reins {}
+	set isfat [expr {[llength $dlist] > $maxwidth}]
+	if {$nhyperspace > 0 || $isfat} {
+	    if {$ctxend > $n} break
+	    # work out what to bring back and
+	    # what we want to don't want to send into hyperspace
+	    set room 1
+	    for {set k $numcommits} {$k < $ctxend} {incr k} {
+		set x [lindex $displayorder $k]
+		set i [llsearch $dlist $x]
+		if {$i < 0} {
+		    set i [llength $dlist]
+		    lappend dlist $x
+		}
+		if {[lsearch -exact $nohs $x] < 0} {
+		    lappend nohs $x
+		}
+		if {$reins eq {} && $onscreen($x) < 0 && $room} {
+		    set reins [list $x $i]
+		}
+		set newp {}
+		if {[info exists commitlisted($x)]} {
+		    set right 0
+		    foreach p $parents($x) {
+			if {[llsearch $dlist $p] < 0} {
+			    lappend newp $p
+			    if {[lsearch -exact $nohs $p] < 0} {
+				lappend nohs $p
+			    }
+			    if {$reins eq {} && $onscreen($p) < 0 && $room} {
+				set reins [list $p [expr {$i + $right}]]
+			    }
+			}
+			set right 1
+		    }
+		}
+		set l [lindex $dlist $i]
+		if {[llength $l] == 1} {
+		    set l $newp
+		} else {
+		    set j [lsearch -exact $l $x]
+		    set l [concat [lreplace $l $j $j] $newp]
+		}
+		set dlist [lreplace $dlist $i $i $l]
+		if {$room && $isfat && [llength $newp] <= 1} {
+		    set room 0
+		}
+	    }
+	}
+
+	set dlevel [drawslants $id $reins $nohs]
+	drawcommitline $dlevel
+	if {[clock clicks -milliseconds] >= $nextupdate
+	    && $numcommits >= $ncmupdate} {
+	    doupdate $reading
+	    if {$stopped} break
+	}
+    }
+}
+
+# level here is an index in todo
+proc updatetodo {level noshortcut} {
+    global ncleft todo nnewparents
+    global commitlisted parents onscreen
+
+    set id [lindex $todo $level]
+    set olds {}
+    if {[info exists commitlisted($id)]} {
+	foreach p $parents($id) {
+	    if {[lsearch -exact $olds $p] < 0} {
+		lappend olds $p
+	    }
+	}
+    }
+    if {!$noshortcut && [llength $olds] == 1} {
+	set p [lindex $olds 0]
+	if {$ncleft($p) == 1 && [lsearch -exact $todo $p] < 0} {
+	    set ncleft($p) 0
+	    set todo [lreplace $todo $level $level $p]
+	    set onscreen($p) 0
+	    set nnewparents($id) 1
+	    return 0
+	}
+    }
+
+    set todo [lreplace $todo $level $level]
+    set i $level
+    set n 0
+    foreach p $olds {
+	incr ncleft($p) -1
+	set k [lsearch -exact $todo $p]
+	if {$k < 0} {
+	    set todo [linsert $todo $i $p]
+	    set onscreen($p) 0
+	    incr i
+	    incr n
+	}
+    }
+    set nnewparents($id) $n
+
+    return 1
 }
 
 proc decidenext {{noread 0}} {
-    global parents children nchildren ncleft todo
+    global ncleft todo
-    global canv canv2 canv3 mainfont namefont canvy linespc
     global datemode cdate
     global commitinfo
-    global currentparents oldlevel oldnlines oldtodo
-    global lineno lthickness
-
-    # remove the null entry if present
-    set nullentry [lsearch -exact $todo {}]
-    if {$nullentry >= 0} {
-	set todo [lreplace $todo $nullentry $nullentry]
-    }
 
     # choose which one to do next time around
     set todol [llength $todo]
@@ -1076,53 +1415,29 @@ proc decidenext {{noread 0}} {
 	return -1
     }
 
-    # If we are reducing, put in a null entry
-    if {$todol < $oldnlines} {
-	if {$nullentry >= 0} {
-	    set i $nullentry
-	    while {$i < $todol
-		   && [lindex $oldtodo $i] == [lindex $todo $i]} {
-		incr i
-	    }
-	} else {
-	    set i $oldlevel
-	    if {$level >= $i} {
-		incr i
-	    }
-	}
-	if {$i < $todol} {
-	    set todo [linsert $todo $i {}]
-	    if {$level >= $i} {
-		incr level
-	    }
-	}
-    }
     return $level
 }
 
 proc drawcommit {id} {
     global phase todo nchildren datemode nextupdate
-    global startcommits numcommits ncmupdate
+    global numcommits ncmupdate displayorder todo onscreen
 
     if {$phase != "incrdraw"} {
 	set phase incrdraw
-	set todo $id
+	set displayorder {}
-	set startcommits $id
+	set todo {}
 	initgraph
-	drawcommitline 0
+    }
-	updatetodo 0 $datemode
-    } else {
     if {$nchildren($id) == 0} {
 	lappend todo $id
-	    lappend startcommits $id
+	set onscreen($id) 0
     }
     set level [decidenext 1]
     if {$level == {} || $id != [lindex $todo $level]} {
 	return
     }
     while 1 {
-	    drawslants $level
+	lappend displayorder [lindex $todo $level]
-	    drawcommitline $level
 	if {[updatetodo $level $datemode]} {
 	    set level [decidenext 1]
 	    if {$level == {}} break
@@ -1131,18 +1446,12 @@ proc drawcommit {id} {
 	if {![info exists commitlisted($id)]} {
 	    break
 	}
-	    if {[clock clicks -milliseconds] >= $nextupdate
-		&& $numcommits >= $ncmupdate} {
-		doupdate 1
-		if {$stopped} break
-	    }
-	}
     }
+    drawmore 1
 }
 
 proc finishcommits {} {
     global phase
-    global startcommits
     global canv mainfont ctext maincursor textcursor
 
     if {$phase != "incrdraw"} {
@@ -1151,9 +1460,7 @@ proc finishcommits {} {
 	    -font $mainfont -tags textitems
 	set phase {}
     } else {
-	set level [decidenext]
+	drawrest
-	drawslants $level
-	drawrest $level [llength $startcommits]
     }
     . config -cursor $maincursor
     settextcursor $textcursor
@@ -1171,54 +1478,38 @@ proc settextcursor {c} {
 }
 
 proc drawgraph {} {
-    global nextupdate startmsecs startcommits todo ncmupdate
+    global nextupdate startmsecs ncmupdate
+    global displayorder onscreen
 
-    if {$startcommits == {}} return
+    if {$displayorder == {}} return
     set startmsecs [clock clicks -milliseconds]
     set nextupdate [expr $startmsecs + 100]
     set ncmupdate 1
     initgraph
-    set todo [lindex $startcommits 0]
+    foreach id $displayorder {
-    drawrest 0 1
+	set onscreen($id) 0
+    }
+    drawmore 0
 }
 
-proc drawrest {level startix} {
+proc drawrest {} {
     global phase stopped redisplaying selectedline
-    global datemode currentparents todo
+    global datemode todo displayorder
     global numcommits ncmupdate
-    global nextupdate startmsecs startcommits idline
+    global nextupdate startmsecs idline
 
+    set level [decidenext]
     if {$level >= 0} {
 	set phase drawgraph
-	set startid [lindex $startcommits $startix]
-	set startline -1
-	if {$startid != {}} {
-	    set startline $idline($startid)
-	}
 	while 1 {
-	    if {$stopped} break
+	    lappend displayorder [lindex $todo $level]
-	    drawcommitline $level
 	    set hard [updatetodo $level $datemode]
-	    if {$numcommits == $startline} {
-		lappend todo $startid
-		set hard 1
-		incr startix
-		set startid [lindex $startcommits $startix]
-		set startline -1
-		if {$startid != {}} {
-		    set startline $idline($startid)
-		}
-	    }
 	    if {$hard} {
 		set level [decidenext]
 		if {$level < 0} break
-		drawslants $level
-	    }
-	    if {[clock clicks -milliseconds] >= $nextupdate
-	        && $numcommits >= $ncmupdate} {
-		doupdate 0
 	    }
 	}
+	drawmore 0
     }
     set phase {}
     set drawmsecs [expr [clock clicks -milliseconds] - $startmsecs]
@@ -1730,7 +2021,7 @@ proc commit_descriptor {p} {
 proc selectline {l isnew} {
     global canv canv2 canv3 ctext commitinfo selectedline
     global lineid linehtag linentag linedtag
-    global canvy0 linespc parents nparents children nchildren
+    global canvy0 linespc parents nparents children
     global cflist currentid sha1entry
     global commentend idtags idline
 
@@ -2654,12 +2945,13 @@ proc listboxsel {} {
 
 proc setcoords {} {
     global linespc charspc canvx0 canvy0 mainfont
-    global xspc1 xspc2
+    global xspc1 xspc2 lthickness
 
     set linespc [font metrics $mainfont -linespace]
     set charspc [font measure $mainfont "m"]
     set canvy0 [expr 3 + 0.5 * $linespc]
     set canvx0 [expr 3 + 0.5 * $linespc]
+    set lthickness [expr {int($linespc / 9) + 1}]
     set xspc1(0) $linespc
     set xspc2 $linespc
 }
@@ -3170,6 +3462,7 @@ set textfont {Courier 9}
 set findmergefiles 0
 set gaudydiff 0
 set maxgraphpct 50
+set maxwidth 16
 
 set colors {green red blue magenta darkgrey brown orange}
 
@@ -3202,4 +3495,5 @@ set patchnum 0
 setcoords
 makewindow
 readrefs
+readgrafts
 getcommits $revtreeargs