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[PATCH v3 2/3] Try normalizing files to avoid delete/modify conflicts when merging

From
Eyvind Bernhardsen <eyvind.bernhardsen@gmail.com>
Date
Jun 24, 2010, 20:44 UTC
Message-ID
<eeb2d5a91ac0e443e74c5866c9c331639b72b7a4.1277408598.git.eyvind.bernhardsen@gmail.com>
In-Reply-To
<cover.1277408598.git.eyvind.bernhardsen@gmail.com>

If a file is modified due to normalization on one branch, and deleted on another, a merge of the two branches will result in a delete/modify conflict for that file even if it is otherwise unchanged.

Try to avoid the conflict by normalizing and comparing the "base" file and the modified file when their sha1s differ. If they compare equal, the file is considered unmodified and is deleted.

Signed-off-by: Eyvind Bernhardsen <eyvind.bernhardsen@gmail.com>
---
 merge-recursive.c          |   42 ++++++++++++++++++++++++++++++++++++++++--
 t/t6038-merge-text-auto.sh |    2 +-
 2 files changed, 41 insertions(+), 3 deletions(-)
diff --git a/merge-recursive.c b/merge-recursive.c
index 206c103..95edc3e 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c
@@ -1056,6 +1056,42 @@ 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 *sha, const char *path,
+			    struct strbuf *dst) {
+	void *buf;
+	enum object_type type;
+	unsigned long size;
+	buf = read_sha1_file(sha, &type, &size);
+	if (!buf)
+		return 0;
+	if (type != OBJ_BLOB) {
+		free(buf);
+		return 0;
+	}
+	strbuf_attach(dst, buf, size, size + 1);
+	return 1;
+}
+
+static int normalized_eq(const unsigned char *a_sha,
+			 const unsigned char *b_sha,
+			 const char *path) {
+	struct strbuf a = STRBUF_INIT;
+	struct strbuf b = STRBUF_INIT;
+	int ret = 0;
+	if (a_sha && b_sha &&
+	    read_sha1_strbuf(a_sha, path, &a) &&
+	    read_sha1_strbuf(b_sha, path, &b)) {
+		/* Both files must be normalized, so we can't use || */
+		if ((renormalize_buffer(path, a.buf, a.len, &a) |
+		     renormalize_buffer(path, b.buf, b.len, &b)) &&
+		    (a.len == b.len))
+			ret = memcmp(a.buf, b.buf, a.len) == 0;
+	}
+	strbuf_release(&a);
+	strbuf_release(&b);
+	return ret;
+}
+
 /* Per entry merge function */
 static int process_entry(struct merge_options *o,
 			 const char *path, struct stage_data *entry)
@@ -1075,8 +1111,10 @@ 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 && sha_eq(a_sha, o_sha) ||
+		     normalized_eq(a_sha, o_sha, path)) ||
+		    (!a_sha && sha_eq(b_sha, o_sha) ||
+		     normalized_eq(b_sha, o_sha, path))) {
 			/* Deleted in both or deleted in one and
 			 * unchanged in the other */
 			if (a_sha)
diff --git a/t/t6038-merge-text-auto.sh b/t/t6038-merge-text-auto.sh
index 44e6003..5e45256 100755
--- a/t/t6038-merge-text-auto.sh
+++ b/t/t6038-merge-text-auto.sh
@@ -45,7 +45,7 @@ test_expect_success 'Check merging addition of text=auto' '
 	test_cmp file file.temp
 '
 
-test_expect_failure 'Test delete/normalize conflict' '
+test_expect_success 'Test delete/normalize conflict' '
 	git checkout side &&
 	git reset --hard initial &&
 	git rm file &&
-- 
1.7.1.575.g383de
Previous: Eyvind BernhardsenNext: Eyvind Bernhardsen
Message 3 of 9 in “Help merging when text has been normalized”
  1. 0/3 Help merging when text has been normalizedEyvind Bernhardsen, Jun 24, 2010
  2. 1/3 Avoid conflicts when merging branches with mixed normalizationEyvind Bernhardsen, Jun 24, 2010
  3. 2/3 Try normalizing files to avoid delete/modify conflicts when mergingEyvind Bernhardsen, Jun 24, 2010
  4. 3/3 Don't expand CRLFs when normalizing text during mergeEyvind Bernhardsen, Jun 24, 2010
  5. Johannes SixtJun 25, 2010
  6. Eyvind BernhardsenJun 25, 2010
  7. Johannes SixtJun 25, 2010
  8. Eyvind BernhardsenJun 25, 2010
  9. Finn Arne GangstadJun 25, 2010

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