cherry-pick/revert: add support for -X/--strategy-option

For example, this would allow cherry-picking or reverting patches from
a piece of history with a different end-of-line style, like so:

	$ git revert -Xrenormalize old-problematic-commit

Currently that is possible with manual use of merge-recursive but the
cherry-pick/revert porcelain does not expose the functionality.

While at it, document the existing support for --strategy.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

2 files changed, 26 insertions, 9 deletions

diff --git a/builtin/merge.c b/builtin/merge.c
index 42fff387e..9403747b6 100644
--- a/builtin/merge.c
+++ b/builtin/merge.c
@@ -582,7 +582,8 @@ static void write_tree_trivial(unsigned char *sha1)
 		die("git write-tree failed to write a tree");
 }
 
-int try_merge_command(const char *strategy, struct commit_list *common,
+int try_merge_command(const char *strategy, size_t xopts_nr,
+		      const char **xopts, struct commit_list *common,
 		      const char *head_arg, struct commit_list *remotes)
 {
 	const char **args;
@@ -680,7 +681,8 @@ static int try_merge_strategy(const char *strategy, struct commit_list *common,
 		rollback_lock_file(lock);
 		return clean ? 0 : 1;
 	} else {
-		return try_merge_command(strategy, common, head_arg, remoteheads);
+		return try_merge_command(strategy, xopts_nr, xopts,
+						common, head_arg, remoteheads);
 	}
 }
 
diff --git a/builtin/revert.c b/builtin/revert.c
index bb6e9e83b..dc1b702ed 100644
--- a/builtin/revert.c
+++ b/builtin/revert.c
@@ -44,7 +44,11 @@ static const char **commit_argv;
 static int allow_rerere_auto;
 
 static const char *me;
+
+/* Merge strategy. */
 static const char *strategy;
+static const char **xopts;
+static size_t xopts_nr, xopts_alloc;
 
 #define GIT_REFLOG_ACTION "GIT_REFLOG_ACTION"
 
@@ -55,6 +59,17 @@ static const char * const *revert_or_cherry_pick_usage(void)
 	return action == REVERT ? revert_usage : cherry_pick_usage;
 }
 
+static int option_parse_x(const struct option *opt,
+			  const char *arg, int unset)
+{
+	if (unset)
+		return 0;
+
+	ALLOC_GROW(xopts, xopts_nr + 1, xopts_alloc);
+	xopts[xopts_nr++] = xstrdup(arg);
+	return 0;
+}
+
 static void parse_args(int argc, const char **argv)
 {
 	const char * const * usage_str = revert_or_cherry_pick_usage();
@@ -67,6 +82,8 @@ static void parse_args(int argc, const char **argv)
 		OPT_INTEGER('m', "mainline", &mainline, "parent number"),
 		OPT_RERERE_AUTOUPDATE(&allow_rerere_auto),
 		OPT_STRING(0, "strategy", &strategy, "strategy", "merge strategy"),
+		OPT_CALLBACK('X', "strategy-option", &xopts, "option",
+			"option for merge strategy", option_parse_x),
 		OPT_END(),
 		OPT_END(),
 		OPT_END(),
@@ -311,18 +328,13 @@ static int do_recursive_merge(struct commit *base, struct commit *next,
 	struct merge_options o;
 	struct tree *result, *next_tree, *base_tree, *head_tree;
 	int clean, index_fd;
+	const char **xopt;
 	static struct lock_file index_lock;
 
 	index_fd = hold_locked_index(&index_lock, 1);
 
 	read_cache();
 
-	/*
-	 * NEEDSWORK: cherry-picking between branches with
-	 * different end-of-line normalization is a pain;
-	 * plumb in an option to set o.renormalize?
-	 * (or better: arbitrary -X options)
-	 */
 	init_merge_options(&o);
 	o.ancestor = base ? base_label : "(empty tree)";
 	o.branch1 = "HEAD";
@@ -332,6 +344,9 @@ static int do_recursive_merge(struct commit *base, struct commit *next,
 	next_tree = next ? next->tree : empty_tree();
 	base_tree = base ? base->tree : empty_tree();
 
+	for (xopt = xopts; xopt != xopts + xopts_nr; xopt++)
+		parse_merge_opt(&o, *xopt);
+
 	clean = merge_trees(&o,
 			    head_tree,
 			    next_tree, base_tree, &result);
@@ -503,7 +518,7 @@ static int do_pick_commit(void)
 
 		commit_list_insert(base, &common);
 		commit_list_insert(next, &remotes);
-		res = try_merge_command(strategy, common,
+		res = try_merge_command(strategy, xopts_nr, xopts, common,
 					sha1_to_hex(head), remotes);
 		free_commit_list(common);
 		free_commit_list(remotes);