Merge branch 'mh/rebase-fixup' (early part)

* 'mh/rebase-fixup' (early part):
  rebase-i: Ignore comments and blank lines in peek_next_command
  lib-rebase: Allow comments and blank lines to be added to the rebase script
  lib-rebase: Provide clearer debugging info about what the editor did
  Add a command "fixup" to rebase --interactive
  t3404: Use test_commit to set up test repository

4 files changed, 137 insertions, 68 deletions

diff --git a/Documentation/git-rebase.txt b/Documentation/git-rebase.txt
index ca5e1e8653..9b648ece6e 100644
--- a/Documentation/git-rebase.txt
+++ b/Documentation/git-rebase.txt
@@ -382,9 +382,12 @@ If you just want to edit the commit message for a commit, replace the
 command "pick" with the command "reword".
 
 If you want to fold two or more commits into one, replace the command
-"pick" with "squash" for the second and subsequent commit.  If the
-commits had different authors, it will attribute the squashed commit to
-the author of the first commit.
+"pick" for the second and subsequent commits with "squash" or "fixup".
+If the commits had different authors, the folded commit will be
+attributed to the author of the first commit.  The suggested commit
+message for the folded commit is the concatenation of the commit
+messages of the first commit and of those with the "squash" command,
+but omits the commit messages of commits with the "fixup" command.
 
 'git-rebase' will stop when "pick" has been replaced with "edit" or
 when a command fails due to merge errors. When you are done editing
@@ -512,8 +515,8 @@ Easy case: The changes are literally the same.::
 Hard case: The changes are not the same.::
 
 	This happens if the 'subsystem' rebase had conflicts, or used
-	`\--interactive` to omit, edit, or squash commits; or if the
-	upstream used one of `commit \--amend`, `reset`, or
+	`\--interactive` to omit, edit, squash, or fixup commits; or
+	if the upstream used one of `commit \--amend`, `reset`, or
 	`filter-branch`.
 
 
diff --git a/git-rebase--interactive.sh b/git-rebase--interactive.sh
index 1560e84bd5..d0b59c96c4 100755
--- a/git-rebase--interactive.sh
+++ b/git-rebase--interactive.sh
@@ -302,7 +302,10 @@ nth_string () {
 
 make_squash_message () {
 	if test -f "$SQUASH_MSG"; then
-		COUNT=$(($(sed -n "s/^# This is [^0-9]*\([1-9][0-9]*\).*/\1/p" \
+		# We want to be careful about matching only the commit
+		# message comment lines generated by this function.
+		# "[snrt][tdh]" matches the nth_string endings.
+		COUNT=$(($(sed -n "s/^# Th[^0-9]*\([1-9][0-9]*\)[snrt][tdh] commit message.*:/\1/p" \
 			< "$SQUASH_MSG" | sed -ne '$p')+1))
 		echo "# This is a combination of $COUNT commits."
 		sed -e 1d -e '2,/^./{
@@ -315,10 +318,23 @@ make_squash_message () {
 		echo
 		git cat-file commit HEAD | sed -e '1,/^$/d'
 	fi
-	echo
-	echo "# This is the $(nth_string $COUNT) commit message:"
-	echo
-	git cat-file commit $1 | sed -e '1,/^$/d'
+	case $1 in
+	squash)
+		echo
+		echo "# This is the $(nth_string $COUNT) commit message:"
+		echo
+		git cat-file commit $2 | sed -e '1,/^$/d'
+		;;
+	fixup)
+		echo
+		echo "# The $(nth_string $COUNT) commit message will be skipped:"
+		echo
+		# Comment the lines of the commit message out using
+		# "#	" rather than "# " to make them less likely to
+		# confuse the sed regexp above.
+		git cat-file commit $2 | sed -e '1,/^$/d' -e 's/^/#	/'
+		;;
+	esac
 }
 
 peek_next_command () {
@@ -367,20 +383,28 @@ do_next () {
 		warn
 		exit 0
 		;;
-	squash|s)
-		comment_for_reflog squash
+	squash|s|fixup|f)
+		case "$command" in
+		squash|s)
+			squash_style=squash
+			;;
+		fixup|f)
+			squash_style=fixup
+			;;
+		esac
+		comment_for_reflog $squash_style
 
 		test -f "$DONE" && has_action "$DONE" ||
-			die "Cannot 'squash' without a previous commit"
+			die "Cannot '$squash_style' without a previous commit"
 
 		mark_action_done
-		make_squash_message $sha1 > "$MSG"
+		make_squash_message $squash_style $sha1 > "$MSG"
 		failed=f
 		author_script=$(get_author_ident_from_commit HEAD)
 		output git reset --soft HEAD^
 		pick_one -n $sha1 || failed=t
 		case "$(peek_next_command)" in
-		squash|s)
+		squash|s|fixup|f)
 			USE_OUTPUT=output
 			MSG_OPT=-F
 			EDIT_OR_FILE="$MSG"
@@ -787,6 +811,7 @@ first and then run 'git rebase --continue' again."
 #  r, reword = use commit, but edit the commit message
 #  e, edit = use commit, but stop for amending
 #  s, squash = use commit, but meld into previous commit
+#  f, fixup = like "squash", but discard this commit's log message
 #
 # If you remove a line here THAT COMMIT WILL BE LOST.
 # However, if you remove everything, the rebase will be aborted.
diff --git a/t/lib-rebase.sh b/t/lib-rebase.sh
index 62f452c8ea..0db8250c58 100644
--- a/t/lib-rebase.sh
+++ b/t/lib-rebase.sh
@@ -5,12 +5,20 @@
 # - override the commit message with $FAKE_COMMIT_MESSAGE,
 # - amend the commit message with $FAKE_COMMIT_AMEND
 # - check that non-commit messages have a certain line count with $EXPECT_COUNT
-# - rewrite a rebase -i script with $FAKE_LINES in the form
+# - rewrite a rebase -i script as directed by $FAKE_LINES.
+#   $FAKE_LINES consists of a sequence of words separated by spaces.
+#   The following word combinations are possible:
 #
-#	"[<lineno1>] [<lineno2>]..."
+#   "<lineno>" -- add a "pick" line with the SHA1 taken from the
+#       specified line.
 #
-#   If a line number is prefixed with "squash", "edit", or "reword", the
-#   respective line's command will be replaced with the specified one.
+#   "<cmd> <lineno>" -- add a line with the specified command
+#       ("squash", "fixup", "edit", or "reword") and the SHA1 taken
+#       from the specified line.
+#
+#   "#" -- Add a comment line.
+#
+#   ">" -- Add a blank line.
 
 set_fake_editor () {
 	echo "#!$SHELL_PATH" >fake-editor.sh
@@ -28,19 +36,24 @@ test -z "$EXPECT_COUNT" ||
 test -z "$FAKE_LINES" && exit
 grep -v '^#' < "$1" > "$1".tmp
 rm -f "$1"
+echo 'rebase -i script before editing:'
 cat "$1".tmp
 action=pick
 for line in $FAKE_LINES; do
 	case $line in
-	squash|edit|reword)
+	squash|fixup|edit|reword)
 		action="$line";;
+	"#")
+		echo '# comment' >> "$1";;
+	">")
+		echo >> "$1";;
 	*)
-		echo sed -n "${line}s/^pick/$action/p"
-		sed -n "${line}p" < "$1".tmp
 		sed -n "${line}s/^pick/$action/p" < "$1".tmp >> "$1"
 		action=pick;;
 	esac
 done
+echo 'rebase -i script after editing:'
+cat "$1"
 EOF
 
 	test_set_editor "$(pwd)/fake-editor.sh"
diff --git a/t/t3404-rebase-interactive.sh b/t/t3404-rebase-interactive.sh
index 3a37793c0d..d9382e41d3 100755
--- a/t/t3404-rebase-interactive.sh
+++ b/t/t3404-rebase-interactive.sh
@@ -16,53 +16,26 @@ set_fake_editor
 
 # set up two branches like this:
 #
-# A - B - C - D - E
+# A - B - C - D - E     (master)
 #   \
-#     F - G - H
+#     F - G - H         (branch1)
 #       \
-#         I
+#         I             (branch2)
 #
-# where B, D and G touch the same file.
+# where A, B, D and G touch the same file.
 
 test_expect_success 'setup' '
-	: > file1 &&
-	git add file1 &&
-	test_tick &&
-	git commit -m A &&
-	git tag A &&
-	echo 1 > file1 &&
-	test_tick &&
-	git commit -m B file1 &&
-	: > file2 &&
-	git add file2 &&
-	test_tick &&
-	git commit -m C &&
-	echo 2 > file1 &&
-	test_tick &&
-	git commit -m D file1 &&
-	: > file3 &&
-	git add file3 &&
-	test_tick &&
-	git commit -m E &&
+	test_commit A file1 &&
+	test_commit B file1 &&
+	test_commit C file2 &&
+	test_commit D file1 &&
+	test_commit E file3 &&
 	git checkout -b branch1 A &&
-	: > file4 &&
-	git add file4 &&
-	test_tick &&
-	git commit -m F &&
-	git tag F &&
-	echo 3 > file1 &&
-	test_tick &&
-	git commit -m G file1 &&
-	: > file5 &&
-	git add file5 &&
-	test_tick &&
-	git commit -m H &&
+	test_commit F file4 &&
+	test_commit G file1 &&
+	test_commit H file5 &&
 	git checkout -b branch2 F &&
-	: > file6 &&
-	git add file6 &&
-	test_tick &&
-	git commit -m I &&
-	git tag I
+	test_commit I file6
 '
 
 test_expect_success 'no changes are a nop' '
@@ -111,19 +84,20 @@ test_expect_success 'exchange two commits' '
 
 cat > expect << EOF
 diff --git a/file1 b/file1
-index e69de29..00750ed 100644
+index f70f10e..fd79235 100644
 --- a/file1
 +++ b/file1
-@@ -0,0 +1 @@
-+3
+@@ -1 +1 @@
+-A
++G
 EOF
 
 cat > expect2 << EOF
 <<<<<<< HEAD
-2
+D
 =======
-3
->>>>>>> b7ca976... G
+G
+>>>>>>> 91201e5... G
 EOF
 
 test_expect_success 'stop on conflicting pick' '
@@ -261,6 +235,60 @@ test_expect_success 'multi-squash only fires up editor once' '
 	test 1 = $(git show | grep ONCE | wc -l)
 '
 
+test_expect_success 'multi-fixup only fires up editor once' '
+	git checkout -b multi-fixup E &&
+	base=$(git rev-parse HEAD~4) &&
+	FAKE_COMMIT_AMEND="ONCE" FAKE_LINES="1 fixup 2 fixup 3 fixup 4" \
+		git rebase -i $base &&
+	test $base = $(git rev-parse HEAD^) &&
+	test 1 = $(git show | grep ONCE | wc -l) &&
+	git checkout to-be-rebased &&
+	git branch -D multi-fixup
+'
+
+cat > expect-squash-fixup << EOF
+B
+
+D
+
+ONCE
+EOF
+
+test_expect_success 'squash and fixup generate correct log messages' '
+	git checkout -b squash-fixup E &&
+	base=$(git rev-parse HEAD~4) &&
+	FAKE_COMMIT_AMEND="ONCE" FAKE_LINES="1 fixup 2 squash 3 fixup 4" \
+		git rebase -i $base &&
+	git cat-file commit HEAD | sed -e 1,/^\$/d > actual-squash-fixup &&
+	test_cmp expect-squash-fixup actual-squash-fixup &&
+	git checkout to-be-rebased &&
+	git branch -D squash-fixup
+'
+
+test_expect_success 'squash ignores comments' '
+	git checkout -b skip-comments E &&
+	base=$(git rev-parse HEAD~4) &&
+	FAKE_COMMIT_AMEND="ONCE" FAKE_LINES="# 1 # squash 2 # squash 3 # squash 4 #" \
+		EXPECT_HEADER_COUNT=4 \
+		git rebase -i $base &&
+	test $base = $(git rev-parse HEAD^) &&
+	test 1 = $(git show | grep ONCE | wc -l) &&
+	git checkout to-be-rebased &&
+	git branch -D skip-comments
+'
+
+test_expect_success 'squash ignores blank lines' '
+	git checkout -b skip-blank-lines E &&
+	base=$(git rev-parse HEAD~4) &&
+	FAKE_COMMIT_AMEND="ONCE" FAKE_LINES="> 1 > squash 2 > squash 3 > squash 4 >" \
+		EXPECT_HEADER_COUNT=4 \
+		git rebase -i $base &&
+	test $base = $(git rev-parse HEAD^) &&
+	test 1 = $(git show | grep ONCE | wc -l) &&
+	git checkout to-be-rebased &&
+	git branch -D skip-blank-lines
+'
+
 test_expect_success 'squash works as expected' '
 	for n in one two three four
 	do