Re: [PATCH 1/8] git-gui: rework handling of diff header

>The fix in ca53c3f (Fix diff parsing for lines starting with "--" or "++",
>2008-09-05) got a bug report from Johannes Sixt, that new files in the
>index now looks like:
>
>new file mode 100644
>--- /dev/null
>+++ b/foo
>@@ -0,0 +1 @@
>+foo

>
>The introduced problem was that the 'in-diff-header'-flag was unconditially
>disabled. Now it is only disabled when a hunk line is detected. And also
>re-enabled when we encounter a new diff header.
>
>The second part solves also the issue reported by me for diffs with file
>type changes (i.e. the ''error: Unhandled 2 way diff marker: {d}"', which
>comes from the second 'diff --git' line).
>
>Reported-by: Johannes Sixt <j.sixt@viscovery.net>
>Reported-by: Bert Wesarg <bert.wesarg@googlemail.com>
>Signed-off-by: Bert Wesarg <bert.wesarg@googlemail.com>
>
>---
>
>Cc: Johannes Sixt <j.sixt@viscovery.net>
>---
> foo          |    1 +
> lib/diff.tcl |   18 +++++++++++++++---
> 2 files changed, 16 insertions(+), 3 deletions(-)
> create mode 100644 foo
>
>diff --git a/foo b/foo
>new file mode 100644
>index 0000000..257cc56
>--- /dev/null
>+++ b/foo
>@@ -0,0 +1 @@
>+foo

>diff --git a/lib/diff.tcl b/lib/diff.tcl
>index 9d0dc07..dae6ca6 100644
>--- a/lib/diff.tcl
>+++ b/lib/diff.tcl
>@@ -382,23 +382,35 @@ proc read_diff {fd conflict_size cont_info} {
> 		foreach {line markup} [parse_color_line $line] break
> 		set line [string map {\033 ^} $line]
> 
>-		# -- Cleanup uninteresting diff header lines.
>+		# -- Check for start of diff header.
>+		if {   [string match {diff --git *}      $line]
>+		    || [string match {diff --cc *}       $line]
>+		    || [string match {diff --combined *} $line]} {
>+			set ::current_diff_inheader 1
>+		}
>+
>+		# -- Check for end of diff header (any hunk line will do this).
> 		#
>+		if {[regexp {^@@+ } $line]} {set ::current_diff_inheader 0}
>+
> 		if {$::current_diff_inheader} {
>+			append current_diff_header $line "\n"
>+
>+			# -- Cleanup uninteresting diff header lines.
>+			#
> 			if {   [string match {diff --git *}      $line]
> 			    || [string match {diff --cc *}       $line]
> 			    || [string match {diff --combined *} $line]
> 			    || [string match {--- *}             $line]
> 			    || [string match {+++ *}             $line]} {
>-				append current_diff_header $line "\n"
> 				continue
> 			}
> 		}
>+
> 		if {[string match {index *} $line]} continue
> 		if {$line eq {deleted file mode 120000}} {
> 			set line "deleted symlink"
> 		}
>-		set ::current_diff_inheader 0
> 
> 		# -- Automatically detect if this is a 3 way diff.
> 		#