Re: [PATCH] Teach parse_commit_buffer about grafting.

[Junio C Hamano <junkio@cox.net>]

Wolfgang Denk <wd@denx.de> writes:

> The display in gitk --all gets changed a bit (before the  branch  was
> the  leftmost  line,  now  it's  the rightmost one), but it's still a
> dangling head, and the selected  "merge  point"  (commit  24ee89)  is
> still  displayed  with  just  one parent (de180e) - I would expect to
> also see d9af3c listed as parent, and the branch merging in here?
>
> Am I missing something?

The graft info is not used by anything other than those that use
parse_commit() to figure out the commit ancestry information.

The list of commits that appear in the top pane of the gitk is
generated by git-rev-list which knows how to do it, but the
parent and child links, and the lines between nodes are drawn by
gitk using the information it reads directly from the commit
objects.

My Tcl/Tk is really rusty, and I do not like this patch, but
here is my stab at teaching the code that reads commit objects
how to use grafts as well.

------------
[PATCH] Teach gitk to use grafts info

Finding commits to draw is done by git-rev-list which knows how
to do the grafts, but the lines between commits and the
parent / child links needs to be drawn by reading from the
commit objects.  Teach that part of the code how to grok grafts
info so that "fake" ancestry is shown sensibly in gitk.

Signed-off-by: Junio C Hamano <junkio@cox.net>
---

 gitk |   36 +++++++++++++++++++++++++++++++++++-
 1 files changed, 35 insertions(+), 1 deletion(-)

diff --git a/gitk b/gitk
--- a/gitk
+++ b/gitk
@@ -155,7 +155,7 @@ proc readcommit {id} {
 }
 
 proc parsecommit {id contents listed} {
-    global commitinfo children nchildren parents nparents cdate ncleft
+    global commitinfo children nchildren parents nparents cdate ncleft grafts
 
     set inhdr 1
     set comment {}
@@ -171,6 +171,23 @@ proc parsecommit {id contents listed} {
     }
     set parents($id) {}
     set nparents($id) 0
+    set has_graft [array get grafts $id]
+    if {"" != $has_graft} {
+	set parents($id) $grafts($id)
+	set nparents($id) [llength $parents($id)]
+	foreach p $parents($id) {
+	    if {![info exists nchildren($p)]} {
+		set children($p) {}
+		set nchildren($p) 0
+		set ncleft($p) 0
+	    }
+	    if {$listed && [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 == {}} {
@@ -178,6 +195,9 @@ proc parsecommit {id contents listed} {
 	    } else {
 		set tag [lindex $line 0]
 		if {$tag == "parent"} {
+		    if {"" != $has_graft} {
+			continue
+		    }
 		    set p [lindex $line 1]
 		    if {![info exists nchildren($p)]} {
 			set children($p) {}
@@ -3194,6 +3214,20 @@ foreach arg $argv {
 
 set history {}
 set historyindex 0
+set grafts('') nothing
+array unset grafts ''
+if {![catch { set graft [exec cat [gitdir]/info/grafts] }]} {
+    global grafts
+    foreach line [split $graft "\n"] {
+	set commit [lindex $line 0]
+	set llen [llength $line]
+	set pp {}
+	for {set i 1} {$i < $llen} {incr i} {
+	    lappend pp [lindex $line $i]
+	}
+	set grafts($commit) $pp
+    }
+}
 
 set stopped 0
 set redisplaying 0