git-merge: add support for --commit and --no-squash

These options can be used to override --no-commit and --squash, which is
needed since --no-commit and --squash now can be specified as default merge
options in $GIT_DIR/config.

The change also introduces slightly different behavior for --no-commit:
when specified, it explicitly overrides --squash. Earlier,
'git merge --squash --no-commit' would result in a squashed merge (i.e. no
$GIT_DIR/MERGE_HEAD was created) but with this patch the command will
behave as if --squash hadn't been specified.

Signed-off-by: Lars Hjemli <hjemli@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/Documentation/merge-options.txt b/Documentation/merge-options.txt
index d64c259..0464a34 100644
--- a/Documentation/merge-options.txt
+++ b/Documentation/merge-options.txt
@@ -10,6 +10,10 @@
 	not autocommit, to give the user a chance to inspect and
 	further tweak the merge result before committing.
 
+--commit::
+	Perform the merge and commit the result. This option can
+	be used to override --no-commit.
+
 --squash::
 	Produce the working tree and index state as if a real
 	merge happened, but do not actually make a commit or
@@ -19,6 +23,10 @@
 	top of the current branch whose effect is the same as
 	merging another branch (or more in case of an octopus).
 
+--no-squash::
+	Perform the merge and commit the result. This option can
+	be used to override --squash.
+
 -s <strategy>, \--strategy=<strategy>::
 	Use the given merge strategy; can be supplied more than
 	once to specify them in the order they should be tried.
diff --git a/git-merge.sh b/git-merge.sh
index a35b151..a0fc606 100755
--- a/git-merge.sh
+++ b/git-merge.sh
@@ -3,7 +3,7 @@
 # Copyright (c) 2005 Junio C Hamano
 #
 
-USAGE='[-n] [--summary] [--no-commit] [--squash] [-s <strategy>] [-m=<merge-message>] <commit>+'
+USAGE='[-n] [--summary] [--[no-]commit] [--[no-]squash] [-s <strategy>] [-m=<merge-message>] <commit>+'
 
 SUBDIRECTORY_OK=Yes
 . git-sh-setup
@@ -128,8 +128,12 @@
 		show_diffstat=t ;;
 	--sq|--squ|--squa|--squas|--squash)
 		squash=t no_commit=t ;;
+	--no-sq|--no-squ|--no-squa|--no-squas|--no-squash)
+		squash= no_commit= ;;
+	--c|--co|--com|--comm|--commi|--commit)
+		squash= no_commit= ;;
 	--no-c|--no-co|--no-com|--no-comm|--no-commi|--no-commit)
-		no_commit=t ;;
+		squash= no_commit=t ;;
 	-s=*|--s=*|--st=*|--str=*|--stra=*|--strat=*|--strate=*|\
 		--strateg=*|--strategy=*|\
 	-s|--s|--st|--str|--stra|--strat|--strate|--strateg|--strategy)
diff --git a/t/t7600-merge.sh b/t/t7600-merge.sh
index 110974c..b0ef488 100755
--- a/t/t7600-merge.sh
+++ b/t/t7600-merge.sh
@@ -395,4 +395,26 @@
 
 test_debug 'gitk --all'
 
+test_expect_success 'merge c1 with c2 (override --no-commit)' '
+	git reset --hard c1 &&
+	git config branch.master.mergeoptions "--no-commit" &&
+	test_tick &&
+	git merge --commit c2 &&
+	verify_merge file result.1-5 msg.1-5 &&
+	verify_parents $c1 $c2
+'
+
+test_debug 'gitk --all'
+
+test_expect_success 'merge c1 with c2 (override --squash)' '
+	git reset --hard c1 &&
+	git config branch.master.mergeoptions "--squash" &&
+	test_tick &&
+	git merge --no-squash c2 &&
+	verify_merge file result.1-5 msg.1-5 &&
+	verify_parents $c1 $c2
+'
+
+test_debug 'gitk --all'
+
 test_done