Merge branch 'jc/merge-blobs'

Update the disused merge-tree proof-of-concept code.

* jc/merge-blobs:
  merge-tree: fix d/f conflicts
  merge-tree: add comments to clarify what these functions are doing
  merge-tree: lose unused "resolve_directories"
  merge-tree: lose unused "flags" from merge_list
  Which merge_file() function do you mean?

Makefile

@@ -766,7 +766,7 @@ LIB_OBJS += log-tree.o
 LIB_OBJS += mailmap.o
 LIB_OBJS += match-trees.o
 LIB_OBJS += merge.o
-LIB_OBJS += merge-file.o
+LIB_OBJS += merge-blobs.o
 LIB_OBJS += merge-recursive.o
 LIB_OBJS += mergesort.o
 LIB_OBJS += name-hash.o

builtin/merge-index.c

@@ -42,7 +42,7 @@ static int merge_entry(int pos, const char *path)
 	return found;
 }
 
-static void merge_file(const char *path)
+static void merge_one_path(const char *path)
 {
 	int pos = cache_name_pos(path, strlen(path));
 
@@ -102,7 +102,7 @@ int cmd_merge_index(int argc, const char **argv, const char *prefix)
 			}
 			die("git merge-index: unknown option %s", arg);
 		}
-		merge_file(arg);
+		merge_one_path(arg);
 	}
 	if (err && !quiet)
 		die("merge program failed");

builtin/merge-tree.c

@@ -3,17 +3,15 @@
 #include "xdiff-interface.h"
 #include "blob.h"
 #include "exec_cmd.h"
-#include "merge-file.h"
+#include "merge-blobs.h"
 
 static const char merge_tree_usage[] = "git merge-tree <base-tree> <branch1> <branch2>";
-static int resolve_directories = 1;
 
 struct merge_list {
 	struct merge_list *next;
 	struct merge_list *link;	/* other stages for this object */
 
-	unsigned int stage : 2,
-		     flags : 30;
+	unsigned int stage : 2;
 	unsigned int mode;
 	const char *path;
 	struct blob *blob;
@@ -27,7 +25,7 @@ static void add_merge_entry(struct merge_list *entry)
 	merge_result_end = &entry->next;
 }
 
-static void merge_trees(struct tree_desc t[3], const char *base);
+static void merge_trees_recursive(struct tree_desc t[3], const char *base, int df_conflict);
 
 static const char *explanation(struct merge_list *entry)
 {
@@ -76,7 +74,7 @@ static void *result(struct merge_list *entry, unsigned long *size)
 	their = NULL;
 	if (entry)
 		their = entry->blob;
-	return merge_file(path, base, our, their, size);
+	return merge_blobs(path, base, our, their, size);
 }
 
 static void *origin(struct merge_list *entry, unsigned long *size)
@@ -174,52 +172,53 @@ static char *traverse_path(const struct traverse_info *info, const struct name_e
 	return make_traverse_path(path, info, n);
 }
 
-static void resolve(const struct traverse_info *info, struct name_entry *branch1, struct name_entry *result)
+static void resolve(const struct traverse_info *info, struct name_entry *ours, struct name_entry *result)
 {
 	struct merge_list *orig, *final;
 	const char *path;
 
-	/* If it's already branch1, don't bother showing it */
-	if (!branch1)
+	/* If it's already ours, don't bother showing it */
+	if (!ours)
 		return;
 
 	path = traverse_path(info, result);
-	orig = create_entry(2, branch1->mode, branch1->sha1, path);
+	orig = create_entry(2, ours->mode, ours->sha1, path);
 	final = create_entry(0, result->mode, result->sha1, path);
 
 	final->link = orig;
 
 	add_merge_entry(final);
 }
 
-static int unresolved_directory(const struct traverse_info *info, struct name_entry n[3])
+static void unresolved_directory(const struct traverse_info *info, struct name_entry n[3],
+				 int df_conflict)
 {
 	char *newbase;
 	struct name_entry *p;
 	struct tree_desc t[3];
 	void *buf0, *buf1, *buf2;
 
-	if (!resolve_directories)
-		return 0;
-	p = n;
-	if (!p->mode) {
-		p++;
-		if (!p->mode)
-			p++;
+	for (p = n; p < n + 3; p++) {
+		if (p->mode && S_ISDIR(p->mode))
+			break;
 	}
-	if (!S_ISDIR(p->mode))
-		return 0;
+	if (n + 3 <= p)
+		return; /* there is no tree here */
+
 	newbase = traverse_path(info, p);
-	buf0 = fill_tree_descriptor(t+0, n[0].sha1);
-	buf1 = fill_tree_descriptor(t+1, n[1].sha1);
-	buf2 = fill_tree_descriptor(t+2, n[2].sha1);
-	merge_trees(t, newbase);
+
+#define ENTRY_SHA1(e) (((e)->mode && S_ISDIR((e)->mode)) ? (e)->sha1 : NULL)
+	buf0 = fill_tree_descriptor(t+0, ENTRY_SHA1(n + 0));
+	buf1 = fill_tree_descriptor(t+1, ENTRY_SHA1(n + 1));
+	buf2 = fill_tree_descriptor(t+2, ENTRY_SHA1(n + 2));
+#undef ENTRY_SHA1
+
+	merge_trees_recursive(t, newbase, df_conflict);
 
 	free(buf0);
 	free(buf1);
 	free(buf2);
 	free(newbase);
-	return 1;
 }
 
 
@@ -242,18 +241,26 @@ static struct merge_list *link_entry(unsigned stage, const struct traverse_info
 static void unresolved(const struct traverse_info *info, struct name_entry n[3])
 {
 	struct merge_list *entry = NULL;
+	int i;
+	unsigned dirmask = 0, mask = 0;
+
+	for (i = 0; i < 3; i++) {
+		mask |= (1 << 1);
+		if (n[i].mode && S_ISDIR(n[i].mode))
+			dirmask |= (1 << i);
+	}
 
-	if (unresolved_directory(info, n))
+	unresolved_directory(info, n, dirmask && (dirmask != mask));
+
+	if (dirmask == mask)
 		return;
 
-	/*
-	 * Do them in reverse order so that the resulting link
-	 * list has the stages in order - link_entry adds new
-	 * links at the front.
-	 */
-	entry = link_entry(3, info, n + 2, entry);
-	entry = link_entry(2, info, n + 1, entry);
-	entry = link_entry(1, info, n + 0, entry);
+	if (n[2].mode && !S_ISDIR(n[2].mode))
+		entry = link_entry(3, info, n + 2, entry);
+	if (n[1].mode && !S_ISDIR(n[1].mode))
+		entry = link_entry(2, info, n + 1, entry);
+	if (n[0].mode && !S_ISDIR(n[0].mode))
+		entry = link_entry(1, info, n + 0, entry);
 
 	add_merge_entry(entry);
 }
@@ -292,20 +299,29 @@ static int threeway_callback(int n, unsigned long mask, unsigned long dirmask, s
 	/* Same in both? */
 	if (same_entry(entry+1, entry+2)) {
 		if (entry[0].sha1) {
+			/* Modified identically */
 			resolve(info, NULL, entry+1);
 			return mask;
 		}
+		/* "Both added the same" is left unresolved */
 	}
 
 	if (same_entry(entry+0, entry+1)) {
 		if (entry[2].sha1 && !S_ISDIR(entry[2].mode)) {
+			/* We did not touch, they modified -- take theirs */
 			resolve(info, entry+1, entry+2);
 			return mask;
 		}
+		/*
+		 * If we did not touch a directory but they made it
+		 * into a file, we fall through and unresolved()
+		 * recurses down.  Likewise for the opposite case.
+		 */
 	}
 
 	if (same_entry(entry+0, entry+2)) {
 		if (entry[1].sha1 && !S_ISDIR(entry[1].mode)) {
+			/* We modified, they did not touch -- take ours */
 			resolve(info, NULL, entry+1);
 			return mask;
 		}
@@ -315,15 +331,21 @@ static int threeway_callback(int n, unsigned long mask, unsigned long dirmask, s
 	return mask;
 }
 
-static void merge_trees(struct tree_desc t[3], const char *base)
+static void merge_trees_recursive(struct tree_desc t[3], const char *base, int df_conflict)
 {
 	struct traverse_info info;
 
 	setup_traverse_info(&info, base);
+	info.data = &df_conflict;
 	info.fn = threeway_callback;
 	traverse_trees(3, t, &info);
 }
 
+static void merge_trees(struct tree_desc t[3], const char *base)
+{
+	merge_trees_recursive(t, base, 0);
+}
+
 static void *get_tree_descriptor(struct tree_desc *desc, const char *rev)
 {
 	unsigned char sha1[20];

merge-file.c → merge-blobs.c

@@ -3,7 +3,7 @@
 #include "xdiff-interface.h"
 #include "ll-merge.h"
 #include "blob.h"
-#include "merge-file.h"
+#include "merge-blobs.h"
 
 static int fill_mmfile_blob(mmfile_t *f, struct blob *obj)
 {
@@ -80,7 +80,7 @@ static int generate_common_file(mmfile_t *res, mmfile_t *f1, mmfile_t *f2)
 	return xdi_diff(f1, f2, &xpp, &xecfg, &ecb);
 }
 
-void *merge_file(const char *path, struct blob *base, struct blob *our, struct blob *their, unsigned long *size)
+void *merge_blobs(const char *path, struct blob *base, struct blob *our, struct blob *their, unsigned long *size)
 {
 	void *res = NULL;
 	mmfile_t f1, f2, common;

merge-blobs.h

@@ -0,0 +1,8 @@
+#ifndef MERGE_BLOBS_H
+#define MERGE_BLOBS_H
+
+#include "blob.h"
+
+extern void *merge_blobs(const char *, struct blob *, struct blob *, struct blob *, unsigned long *);
+
+#endif /* MERGE_BLOBS_H */

merge-recursive.c

@@ -976,7 +976,7 @@ merge_file_special_markers(struct merge_options *o,
 	return mfi;
 }
 
-static struct merge_file_info merge_file(struct merge_options *o,
+static struct merge_file_info merge_file_one(struct merge_options *o,
 					 const char *path,
 					 const unsigned char *o_sha, int o_mode,
 					 const unsigned char *a_sha, int a_mode,
@@ -1166,7 +1166,7 @@ static void conflict_rename_rename_1to2(struct merge_options *o,
 		struct merge_file_info mfi;
 		struct diff_filespec other;
 		struct diff_filespec *add;
-		mfi = merge_file(o, one->path,
+		mfi = merge_file_one(o, one->path,
 				 one->sha1, one->mode,
 				 a->sha1, a->mode,
 				 b->sha1, b->mode,
@@ -1450,7 +1450,7 @@ static int process_renames(struct merge_options *o,
 				       ren1_dst, branch2);
 				if (o->call_depth) {
 					struct merge_file_info mfi;
-					mfi = merge_file(o, ren1_dst, null_sha1, 0,
+					mfi = merge_file_one(o, ren1_dst, null_sha1, 0,
 							 ren1->pair->two->sha1, ren1->pair->two->mode,
 							 dst_other.sha1, dst_other.mode,
 							 branch1, branch2);

t/t4300-merge-tree.sh

@@ -254,4 +254,48 @@ EXPECTED
 	test_cmp expected actual
 '
 
+test_expect_success 'turn file to tree' '
+	git reset --hard initial &&
+	rm initial-file &&
+	mkdir initial-file &&
+	test_commit "turn-file-to-tree" "initial-file/ONE" "CCC" &&
+	git merge-tree initial initial turn-file-to-tree >actual &&
+	cat >expect <<-\EOF &&
+	added in remote
+	  their  100644 43aa4fdec31eb92e1fdc2f0ce6ea9ddb7c32bcf7 initial-file/ONE
+	@@ -0,0 +1 @@
+	+CCC
+	removed in remote
+	  base   100644 e79c5e8f964493290a409888d5413a737e8e5dd5 initial-file
+	  our    100644 e79c5e8f964493290a409888d5413a737e8e5dd5 initial-file
+	@@ -1 +0,0 @@
+	-initial
+	EOF
+	test_cmp expect actual
+'
+
+test_expect_success 'turn tree to file' '
+	git reset --hard initial &&
+	mkdir dir &&
+	test_commit "add-tree" "dir/path" "AAA" &&
+	test_commit "add-another-tree" "dir/another" "BBB" &&
+	rm -fr dir &&
+	test_commit "make-file" "dir" "CCC" &&
+	git merge-tree add-tree add-another-tree make-file >actual &&
+	cat >expect <<-\EOF &&
+	added in local
+	  our    100644 ba629238ca89489f2b350e196ca445e09d8bb834 dir/another
+	removed in remote
+	  base   100644 43d5a8ed6ef6c00ff775008633f95787d088285d dir/path
+	  our    100644 43d5a8ed6ef6c00ff775008633f95787d088285d dir/path
+	@@ -1 +0,0 @@
+	-AAA
+	added in remote
+	  their  100644 43aa4fdec31eb92e1fdc2f0ce6ea9ddb7c32bcf7 dir
+	@@ -0,0 +1 @@
+	+CCC
+	EOF
+	test_cmp expect actual
+'
+
 test_done