git-rebase-subtree: support reverse operation

2 files changed, 65 insertions, 27 deletions

diff --git a/git-rebase-subtree/git-rebase-subtree.in b/git-rebase-subtree/git-rebase-subtree.in
index 1798942..3b3274d 100644
--- a/git-rebase-subtree/git-rebase-subtree.in
+++ b/git-rebase-subtree/git-rebase-subtree.in
@@ -40,14 +40,15 @@ set -e
 
 cmd() {
     echo "CMD>" "$@"
-    gitk --all
     "$@"
 }
 
 
 gf_init() {
+    configvar="rebase-subtree.subtree"
     echo "$self: Examining configuration"
-    git config follow.tree | while read from to restofline; do
+    test -n "$(git config "$configvar")" || die "Unset or empty git config var \"$configvar\""
+    git config "$configvar" | while read from to restofline; do
 	if test "x#" = "x$(echo "$from" | sed -n '1s/^\(.\).*/\1/p')"; then continue; fi
 	echo ""
 	echo "  From: $from"
@@ -84,50 +85,43 @@ gf_rmbranch() {
 
 
 gf_rebase_tree() {
+    reverse="no"
+    case "$1" in
+	--reverse) reverse=yes; shift ;;
+    esac
     newroot="$1"
     test "x$newroot" = "x" && die "Need <newroot> parameter"
     oldroot="$2"
     test "x$oldroot" = "x" && die "Need <oldroot> parameter"
     echo
     echo "$self: Preparing subtree rebase"
-    git config follow.tree | while read from to restofline; do
+    git config "$configvar" | while read from to restofline; do
 	if test "x#" = "x$(echo "$from" | sed -n '1s/^\(.\).*/\1/p')"; then continue; fi
 	gf_branch "$from"
 	gf_branch "$to"
     done
-    gitk --all
     echo
     echo "$self: Executing subtree rebase"
-    git config follow.tree | while read from to restofline; do
+    git config "$configvar" | while read from to restofline; do
 	if test "x#" = "x$(echo "$from" | sed -n '1s/^\(.\).*/\1/p')"; then continue; fi
-	cmd git-rebase --onto "$from" "follow-old/$from" "$to"
+	if test "x$reverse" = "xno" && test "x$from" = "x$oldroot"; then
+	    cmd git-rebase --onto "$newroot" "follow-old/$from" "$to"
+	elif test "x$reverse" = "xyes" && test "x$from" = "x$newroot"; then
+	    cmd git-rebase --onto "$newroot" "$oldroot" "$to"
+	else
+	    cmd git-rebase --onto "$from" "follow-old/$from" "$to"
+	fi
     done
-    gitk --all
     echo
     echo "$self: Cleaning up after subtree rebase"
-    git config follow.tree | while read from to restofline; do
+    git config "$configvar" | while read from to restofline; do
 	if test "x#" = "x$(echo "$from" | sed -n '1s/^\(.\).*/\1/p')"; then continue; fi
 	gf_rmbranch "$from"
 	gf_rmbranch "$to"
     done
-    gitk --all
 }
 
-
-# The great command case
-command="$1"
-if shift; then
-    case "$command" in
-	rebase-subtree)
-	    gf_init
-	    gf_rebase_tree "$@"
-	    ;;
-	*)
-	    die "Invalid command line parameter: \"$command\""
-	    ;;
-    esac
-else
-    gf_init
-fi
+gf_init
+gf_rebase_tree "$@"
 
 # End of file.
diff --git a/git-rebase-subtree/git-rebase-subtree.man.in b/git-rebase-subtree/git-rebase-subtree.man.in
index 295dfc5..01a21cb 100644
--- a/git-rebase-subtree/git-rebase-subtree.man.in
+++ b/git-rebase-subtree/git-rebase-subtree.man.in
@@ -5,6 +5,11 @@ git\-rebase\-subtree \- rebase set of interdependant git branches
 .B "git\-rebase\-subtree"
 .I "<origin-branch>"
 .I "<master-branch>"
+.PP
+.B "git\-rebase\-subtree"
+.I "\-\-reverse"
+.I "<master-branch>"
+.I "<master-branch-plus-x>"
 .SH DESCRIPTION
 So you are tracking some upstream's git repo and maintain your own set
 of interdependent feature branches ("branch subtree").
@@ -19,8 +24,8 @@ Note: Letters A\-Z are branch names, not revs.
 .PP
 Old tree:
 .nf
-                       *\-\-F
-                      /
+                        *\-\-F
+                       /
     origin=master\-\-A\-\-B\-\-G
                     \\
                      *\-\-D\-\-H
@@ -28,6 +33,18 @@ Old tree:
                           *\-\-*\-\-K
 .fi
 .PP
+Generate the following configuration using
+.I "git config rebase-subtree.subtree"
+.nf
+  master A
+  A B
+  B F
+  B G
+  A D
+  D H
+  D K
+.fi
+.PP
 After "git\-fetch \-v":
 .nf
                          *\-\-F
@@ -46,8 +63,35 @@ After hypothetical "git\-rebase\-subtree origin master":
    origin'=master'\-\-A'\-\-B'\-\-G'
                      \\
                       *'\-\-D'\-\-H'
+                           \\
+                            *'\-\-*'\-\-K'
+.fi
+.SS "REVERSE OPERATION"
+.PP
+Old tree:
+.nf
+                        *\-\-F
+                       /
+        master\-\-Y\-\-A\-\-B\-\-G
+                    \\
+                     *\-\-D\-\-H
+                         \\
+                          *\-\-*\-\-K
+.fi
+.PP
+After hypothetical "git\-rebase\-subtree \-\-reverse master Y":
+.nf
+                  Y      *'\-\-F'
+                 /      /
+           master\-\-A'\-\-B'\-\-G'
+                    \\
+                     *'\-\-D'\-\-H'
                           \\
                            *'\-\-*'\-\-K'
 .fi
+.SH "BUGS"
+.TP
+.B "Lacks generality (fixation about 'master')"
+Yes.
 .SH "SEE ALSO"
 git\-rebase(1).