Merge branch 'jn/merge-renormalize'

* jn/merge-renormalize:
  merge-recursive --renormalize
  rerere: never renormalize
  rerere: migrate to parse-options API
  t4200 (rerere): modernize style
  ll-merge: let caller decide whether to renormalize
  ll-merge: make flag easier to populate
  Documentation/technical: document ll_merge
  merge-trees: let caller decide whether to renormalize
  merge-trees: push choice to renormalize away from low level
  t6038 (merge.renormalize): check that it can be turned off
  t6038 (merge.renormalize): try checkout -m and cherry-pick
  t6038 (merge.renormalize): style nitpicks
  Don't expand CRLFs when normalizing text during merge
  Try normalizing files to avoid delete/modify conflicts when merging
  Avoid conflicts when merging branches with mixed normalization

Conflicts:
	builtin/rerere.c
	t/t4200-rerere.sh

1 files changed, 54 insertions, 3 deletions

diff --git a/merge-recursive.c b/merge-recursive.c
index df90be44a5..aadd48c4fc 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -644,7 +644,9 @@ static int merge_3way(struct merge_options *o,
 
 	merge_status = ll_merge(result_buf, a->path, &orig, base_name,
 				&src1, name1, &src2, name2,
-				(!!o->call_depth) | (favor << 1));
+				((o->call_depth ? LL_OPT_VIRTUAL_ANCESTOR : 0) |
+				 (o->renormalize ? LL_OPT_RENORMALIZE : 0) |
+				 create_ll_flag(favor)));
 
 	free(name1);
 	free(name2);
@@ -1062,6 +1064,53 @@ static unsigned char *stage_sha(const unsigned char *sha, unsigned mode)
 	return (is_null_sha1(sha) || mode == 0) ? NULL: (unsigned char *)sha;
 }
 
+static int read_sha1_strbuf(const unsigned char *sha1, struct strbuf *dst)
+{
+	void *buf;
+	enum object_type type;
+	unsigned long size;
+	buf = read_sha1_file(sha1, &type, &size);
+	if (!buf)
+		return error("cannot read object %s", sha1_to_hex(sha1));
+	if (type != OBJ_BLOB) {
+		free(buf);
+		return error("object %s is not a blob", sha1_to_hex(sha1));
+	}
+	strbuf_attach(dst, buf, size, size + 1);
+	return 0;
+}
+
+static int blob_unchanged(const unsigned char *o_sha,
+			  const unsigned char *a_sha,
+			  int renormalize, const char *path)
+{
+	struct strbuf o = STRBUF_INIT;
+	struct strbuf a = STRBUF_INIT;
+	int ret = 0; /* assume changed for safety */
+
+	if (sha_eq(o_sha, a_sha))
+		return 1;
+	if (!renormalize)
+		return 0;
+
+	assert(o_sha && a_sha);
+	if (read_sha1_strbuf(o_sha, &o) || read_sha1_strbuf(a_sha, &a))
+		goto error_return;
+	/*
+	 * Note: binary | is used so that both renormalizations are
+	 * performed.  Comparison can be skipped if both files are
+	 * unchanged since their sha1s have already been compared.
+	 */
+	if (renormalize_buffer(path, o.buf, o.len, &o) |
+	    renormalize_buffer(path, a.buf, o.len, &a))
+		ret = (o.len == a.len && !memcmp(o.buf, a.buf, o.len));
+
+error_return:
+	strbuf_release(&o);
+	strbuf_release(&a);
+	return ret;
+}
+
 /* Per entry merge function */
 static int process_entry(struct merge_options *o,
 			 const char *path, struct stage_data *entry)
@@ -1071,6 +1120,7 @@ static int process_entry(struct merge_options *o,
 	print_index_entry("\tpath: ", entry);
 	*/
 	int clean_merge = 1;
+	int normalize = o->renormalize;
 	unsigned o_mode = entry->stages[1].mode;
 	unsigned a_mode = entry->stages[2].mode;
 	unsigned b_mode = entry->stages[3].mode;
@@ -1082,8 +1132,8 @@ static int process_entry(struct merge_options *o,
 	if (o_sha && (!a_sha || !b_sha)) {
 		/* Case A: Deleted in one */
 		if ((!a_sha && !b_sha) ||
-		    (sha_eq(a_sha, o_sha) && !b_sha) ||
-		    (!a_sha && sha_eq(b_sha, o_sha))) {
+		    (!b_sha && blob_unchanged(o_sha, a_sha, normalize, path)) ||
+		    (!a_sha && blob_unchanged(o_sha, b_sha, normalize, path))) {
 			/* Deleted in both or deleted in one and
 			 * unchanged in the other */
 			if (a_sha)
@@ -1525,6 +1575,7 @@ void init_merge_options(struct merge_options *o)
 	o->buffer_output = 1;
 	o->diff_rename_limit = -1;
 	o->merge_rename_limit = -1;
+	o->renormalize = 0;
 	git_config(merge_recursive_config, o);
 	if (getenv("GIT_MERGE_VERBOSITY"))
 		o->verbosity =