Re: What's cooking in git.git (Aug 2008, #05; Tue, 19)

5 messages, 2 authors, 2016-06-15 · open the first message on its own page

Re: What's cooking in git.git (Aug 2008, #05; Tue, 19)

From: Junio C Hamano <hidden>
Date: 2016-06-15 22:45:11

Miklos Vajna [off-list ref] writes:

On Tue, Aug 19, 2008 at 12:19:09PM -0700, Junio C Hamano [off-list ref] wrote:

quoted

Since the latter is what everybody else ("checkout -m", "revert",
"cherry-pick", "am -3", "stash apply") should be using, I think it is
pretty much up to "git-merge" and "git-merge-recursive" implementations
how the caller of merge_recursive() function is structured.  I suspect
that you would not need two separate functions, _setup() and _generic(),
for these two codepaths, but I didn't look closely.

Sure, I can avoid _generic() and use merge_recursive() directly, that's
why I asked.

quoted

And make_virtual_commit() should become static inside merge_recursive.c;
use of these fake commits is strictly an internal implementation issue of
how merge_recursive() function works and does not concern the caller, does
it?

Not exactly. builtin-merge-recursive uses get_ref() - which should not
be in merge-recursive.c IMHO - and get_ref() uses make_virtual_commit().
merge_recursive() itself takes commits, so it can be only static if we
copy it builtin-merge-recursive as well, causing a code duplication. Or
have I missed something here?

I think you have.

Let's look at the call chain from cmd_merge_recursive() and think again.

    cmd_merge_recursive()
    -> merge_recursive_setup()
    -> merge_recursive_generic()
       -> merge_recursive()
          -> merge_recursive()
          -> merge_trees()

cmd_merge_recursive() takes subtree option and set of object names (two
commits and zero or more base commits), massages them and calls
merge_recursive().  merge_recursive_setup() and merge_recursive_generic()
are involved in this massaging process.

merge_recursive() computes the bases itself when given no base, and in a
multi-base situation, does its thing recursively to come up with a
consolidated base, using virtual commits.  After coming up with the three
(virtual or real) commits to use, it gives them to merge_trees(), which
operate solely on tree objects.

In addition, merge_recursive() currently *requires* the caller to wrap
bare tree objects in virtual commits, if the caller wants to do a simple
three-way merge of trees (in which case because there is no ancestry
information available you would naturally not do any recursive behaviour).
This "input must be commit" requirement is why you think you need to have
get_ref() that uses make_virtual_commit() in the caller.

But it does not have to be that way.  It is merely an artifact of the
current refactoring that kept the interface into merge_recursive() based
on commit objects.  You could further refine the refactoring so that:

 - merge_trees(), in addition to the three tree objects, takes options
   such as use of the subtree behaviour, descriptive names for heads to be
   used for conflict markers, verbosity level, and other future options
   (such as "use this lower rename detaction threshold").  Introduce
   "struct merge_options" for that and pass it around.  These show() and
   output() calls could even become callbacks, but I didn't look very
   carefully.

 - merge_recursive(), in addition to that "merge_options" structure, will
   take heads, and list of common ancestors.

 - merge_recursive_generic() can be a layer on top of merge_recursive() to
   allow the caller to feed tree objects.  Use of "const unsigned char *"
   to give raw object names (or even "const char *" to feed texual object
   names) would be easier for the callers.  Wrapping a tree into virtual
   commit can and should be done at this layer, hidden away inside
   merge-recursive.c from the callers.

   Alternatively, you can do away without such preparation step, and move
   the "wrap a tree into a virtual commit" inside merge_recursive()
   itself.  If you take that route, merge_recursive() will take heads and
   list of common ancestors all in "const unsigned char *" object names,
   in addition to the "merge_options" structure.

When you rewrite cmd_merge() to make direct call to bypass a subprocess,
your callchain would look like:

    cmd_merge()
    -> merge_recursive()
       -> merge_recursive()
       -> merge_trees()

cmd_merge() needs to do the same arrangement for "subtree" and any
possible future options, and feed the same set of object names to
merge_recursive().  You cannot give a bare tree to "git merge", so you do
not have to worry about having to wrap it in a virtual commit.

So my gut feeling is that the interface may look something like:

struct merge_options {
        const char *branch1_label;
        const char *branch2_label;
        unsigned subtree_merge : 1;
	int verbosity;
        /* other options here ... */
};

/* rename-detecting three-way merge, no recursion */
int merge_trees(struct merge_options *,
                struct tree *head,
                struct tree *merge,
                struct tree *common,
                struct tree **result);

/* merge_trees() but with recursive ancestor consolidation */
int merge_recursive(struct merge_options *,
                    struct commit *h1,
                    struct commit *h2,
                    struct commit_list *ca,
                    struct commit **result);

/*
 * "git-merge-recursive" can be fed trees; wrap them into
 * virtual commits and call merge_recursive() proper.
 */
int merge_recursive_generic(struct merge_options *,
                            const unsigned char *head,
                            const unsigned char *merge,
                            int num_ca,
                            const unsigned char **ca,
                            struct commit **result);

and the call chain would become:

    cmd_merge_recursive()
    -> merge_recursive_generic()
       -> merge_recursive()
          -> merge_recursive()
          -> merge_trees()

    cmd_merge()
    -> merge_recursive()
       -> merge_recursive()
       -> merge_trees()

    cmd_revert(), cmd_am(), cmd_checkout(), cmd_stash(), ...
    -> merge_trees()

Re: What's cooking in git.git (Aug 2008, #05; Tue, 19)

From: Miklos Vajna <hidden>
Date: 2016-06-15 22:45:11

On Tue, Aug 19, 2008 at 03:00:27PM -0700, Junio C Hamano [off-list ref] wrote:

quoted

Not exactly. builtin-merge-recursive uses get_ref() - which should not
be in merge-recursive.c IMHO - and get_ref() uses make_virtual_commit().
merge_recursive() itself takes commits, so it can be only static if we
copy it builtin-merge-recursive as well, causing a code duplication. Or
have I missed something here?

I think you have.

Let's look at the call chain from cmd_merge_recursive() and think again.

Thanks for the detailed answer. I just wanted to say that probably I
won't have time to implement this before the weekend; but I plan to do
so then.

[PATCH] merge-recursive: introduce merge_options

From: Miklos Vajna <hidden>
Date: 2016-06-15 22:45:13

This makes it possible to avoid passing the labels of branches as
arguments to merge_recursive(), merge_trees() and
merge_recursive_generic().

It also takes care of subtree merge, output buffering, verbosity, and
rename limits - these were global variables till now in
merge-recursive.c.

A new function, named init_merge_options(), is introduced as well, it
clears the struct merge_info, then initializes with default values,
finally updates the default values based on the config and environment
variables.

Signed-off-by: Miklos Vajna <redacted>
---

On Tue, Aug 19, 2008 at 03:00:27PM -0700, Junio C Hamano [off-list ref] wrote:

and the call chain would become:

    cmd_merge_recursive()
    -> merge_recursive_generic()
       -> merge_recursive()
          -> merge_recursive()
          -> merge_trees()

Actually I still left some extra function, as the merge_options
structure should be initialized, and that was done by just initializing
global variables before, but now we have to have a new function for it.

Other than that, I hope the patch looks like the way you imagined. ;-)

Notes:

1) This applies on top of 1c868d4 (merge-recursive.c: Add more generic
merge_recursive_generic()). I can rebase this (along with 1c868d4 and
1c868d4^) on top of current master, if this is a problem.

2) I know that this patch is huge, but we want to have the verbosity
flag in merge_options, so it has to be passed as an argument in many
places.

    cmd_merge()
    -> merge_recursive()
       -> merge_recursive()
       -> merge_trees()

    cmd_revert(), cmd_am(), cmd_checkout(), cmd_stash(), ...
    -> merge_trees()

builtin-checkout already used merge_trees(), so I modified it to use
merge_options, otherwise the patch would break the build. 'am' and
'stash' is not (yet) a builtin, so that is not interesting here. If this
patch looks OK, then I want to do the builtin-merge and builtin-revert
parts as well.

 builtin-checkout.c        |   11 ++-
 builtin-merge-recursive.c |   43 ++++----
 merge-recursive.c         |  242 ++++++++++++++++++++++----------------------
 merge-recursive.h         |   42 ++++++---
 4 files changed, 180 insertions(+), 158 deletions(-)

diff --git a/builtin-checkout.c b/builtin-checkout.c
index 411cc51..3627996 100644
--- a/builtin-checkout.c
+++ b/builtin-checkout.c

@@ -264,6 +264,7 @@ static int merge_working_tree(struct checkout_opts *opts,
 			 */
 			struct tree *result;
 			struct tree *work;
+			struct merge_options o;
 			if (!opts->merge)
 				return 1;
 			parse_commit(old->commit);

@@ -282,13 +283,17 @@ static int merge_working_tree(struct checkout_opts *opts,
 			 */
 
 			add_files_to_cache(NULL, NULL, 0);
-			work = write_tree_from_memory();
+			init_merge_options(&o);
+			o.verbosity = 0;
+			work = write_tree_from_memory(&o);
 
 			ret = reset_tree(new->commit->tree, opts, 1);
 			if (ret)
 				return ret;
-			merge_trees(new->commit->tree, work, old->commit->tree,
-				    new->name, "local", &result);
+			o.branch1 = new->name;
+			o.branch2 = "local";
+			merge_trees(&o, new->commit->tree, work,
+				old->commit->tree, &result);
 			ret = reset_tree(new->commit->tree, opts, 0);
 			if (ret)
 				return ret;

diff --git a/builtin-merge-recursive.c b/builtin-merge-recursive.c
index 25f540b..6b534c1 100644
--- a/builtin-merge-recursive.c
+++ b/builtin-merge-recursive.c

@@ -17,32 +17,33 @@ static const char *better_branch_name(const char *branch)
 
 int cmd_merge_recursive(int argc, const char **argv, const char *prefix)
 {
-	const char *bases[21];
+	const unsigned char *bases[21];
 	unsigned bases_count = 0;
 	int i, failed;
-	const char *branch1, *branch2;
 	unsigned char h1[20], h2[20];
-	int subtree_merge = 0;
+	struct merge_options o;
+	struct commit *result;
 
+	init_merge_options(&o);
 	if (argv[0]) {
 		int namelen = strlen(argv[0]);
 		if (8 < namelen &&
 		    !strcmp(argv[0] + namelen - 8, "-subtree"))
-			subtree_merge = 1;
+			o.subtree_merge = 1;
 	}
 
-	git_config(merge_recursive_config, NULL);
-	merge_recursive_setup(subtree_merge);
 	if (argc < 4)
 		die("Usage: %s <base>... -- <head> <remote> ...\n", argv[0]);
 
 	for (i = 1; i < argc; ++i) {
-		if (!strcmp(argv[i], "--")) {
-			bases[bases_count] = NULL;
+		if (!strcmp(argv[i], "--"))
 			break;
+		if (bases_count < ARRAY_SIZE(bases)-1) {
+			unsigned char *sha = xmalloc(20);
+			if (get_sha1(argv[i], sha))
+				die("Could not parse object '%s'", argv[i]);
+			bases[bases_count++] = sha;
 		}
-		if (bases_count < ARRAY_SIZE(bases)-1)
-			bases[bases_count++] = argv[i];
 		else
 			warning("Cannot handle more than %zu bases. "
 				"Ignoring %s.", ARRAY_SIZE(bases)-1, argv[i]);

@@ -50,21 +51,21 @@ int cmd_merge_recursive(int argc, const char **argv, const char *prefix)
 	if (argc - i != 3) /* "--" "<head>" "<remote>" */
 		die("Not handling anything other than two heads merge.");
 
-	branch1 = argv[++i];
-	branch2 = argv[++i];
+	o.branch1 = argv[++i];
+	o.branch2 = argv[++i];
 
-	if (get_sha1(branch1, h1))
-		die("Could not resolve ref '%s'", branch1);
-	if (get_sha1(branch2, h2))
-		die("Could not resolve ref '%s'", branch2);
+	if (get_sha1(o.branch1, h1))
+		die("Could not resolve ref '%s'", o.branch1);
+	if (get_sha1(o.branch2, h2))
+		die("Could not resolve ref '%s'", o.branch2);
 
-	branch1 = better_branch_name(branch1);
-	branch2 = better_branch_name(branch2);
+	o.branch1 = better_branch_name(o.branch1);
+	o.branch2 = better_branch_name(o.branch2);
 
-	if (merge_recursive_verbosity >= 3)
-		printf("Merging %s with %s\n", branch1, branch2);
+	if (o.verbosity >= 3)
+		printf("Merging %s with %s\n", o.branch1, o.branch2);
 
-	failed = merge_recursive_generic(bases, h1, branch1, h2, branch2);
+	failed = merge_recursive_generic(&o, h1, h2, bases_count, bases, &result);
 	if (failed < 0)
 		return 128; /* die() error code */
 	return failed;

diff --git a/merge-recursive.c b/merge-recursive.c
index 74a9fdc..ee23396 100644
--- a/merge-recursive.c
+++ b/merge-recursive.c

@@ -83,16 +83,11 @@ static struct string_list current_file_set = {NULL, 0, 0, 1};
 static struct string_list current_directory_set = {NULL, 0, 0, 1};
 
 static int call_depth = 0;
-int merge_recursive_verbosity = 2;
-static int diff_rename_limit = -1;
-static int merge_rename_limit = -1;
-static int buffer_output = 1;
 static struct strbuf obuf = STRBUF_INIT;
 
-static int show(int v)
+static int show(int v, struct merge_options *o)
 {
-	return (!call_depth && merge_recursive_verbosity >= v) ||
-		merge_recursive_verbosity >= 5;
+	return (!call_depth && o->verbosity >= v) || o->verbosity >= 5;
 }
 
 static void flush_output(void)

@@ -103,12 +98,12 @@ static void flush_output(void)
 	}
 }
 
-static void output(int v, const char *fmt, ...)
+static void output(int v, struct merge_options *o, const char *fmt, ...)
 {
 	int len;
 	va_list ap;
 
-	if (!show(v))
+	if (!show(v, o))
 		return;
 
 	strbuf_grow(&obuf, call_depth * 2 + 2);

@@ -132,7 +127,7 @@ static void output(int v, const char *fmt, ...)
 	}
 	strbuf_setlen(&obuf, obuf.len + len);
 	strbuf_add(&obuf, "\n", 1);
-	if (!buffer_output)
+	if (!o->buffer_output)
 		flush_output();
 }

@@ -219,17 +214,17 @@ static int git_merge_trees(int index_only,
 	return rc;
 }
 
-struct tree *write_tree_from_memory(void)
+struct tree *write_tree_from_memory(struct merge_options *o)
 {
 	struct tree *result = NULL;
 
 	if (unmerged_cache()) {
 		int i;
-		output(0, "There are unmerged index entries:");
+		output(0, o, "There are unmerged index entries:");
 		for (i = 0; i < active_nr; i++) {
 			struct cache_entry *ce = active_cache[i];
 			if (ce_stage(ce))
-				output(0, "%d %.*s", ce_stage(ce), ce_namelen(ce), ce->name);
+				output(0, o, "%d %.*s", ce_stage(ce), ce_namelen(ce), ce->name);
 		}
 		return NULL;
 	}

@@ -345,7 +340,8 @@ static struct string_list *get_renames(struct tree *tree,
 					struct tree *o_tree,
 					struct tree *a_tree,
 					struct tree *b_tree,
-					struct string_list *entries)
+					struct string_list *entries,
+					struct merge_options *o)
 {
 	int i;
 	struct string_list *renames;

@@ -355,8 +351,8 @@ static struct string_list *get_renames(struct tree *tree,
 	diff_setup(&opts);
 	DIFF_OPT_SET(&opts, RECURSIVE);
 	opts.detect_rename = DIFF_DETECT_RENAME;
-	opts.rename_limit = merge_rename_limit >= 0 ? merge_rename_limit :
-			    diff_rename_limit >= 0 ? diff_rename_limit :
+	opts.rename_limit = o->merge_rename_limit >= 0 ? o->merge_rename_limit :
+			    o->diff_rename_limit >= 0 ? o->diff_rename_limit :
 			    500;
 	opts.warn_on_too_large_rename = 1;
 	opts.output_format = DIFF_FORMAT_NO_OUTPUT;

@@ -720,7 +716,8 @@ static struct merge_file_info merge_file(struct diff_filespec *o,
 static void conflict_rename_rename(struct rename *ren1,
 				   const char *branch1,
 				   struct rename *ren2,
-				   const char *branch2)
+				   const char *branch2,
+				   struct merge_options *o)
 {
 	char *del[2];
 	int delp = 0;

@@ -730,13 +727,13 @@ static void conflict_rename_rename(struct rename *ren1,
 	const char *dst_name2 = ren2_dst;
 	if (string_list_has_string(&current_directory_set, ren1_dst)) {
 		dst_name1 = del[delp++] = unique_path(ren1_dst, branch1);
-		output(1, "%s is a directory in %s added as %s instead",
+		output(1, o, "%s is a directory in %s added as %s instead",
 		       ren1_dst, branch2, dst_name1);
 		remove_file(0, ren1_dst, 0);
 	}
 	if (string_list_has_string(&current_directory_set, ren2_dst)) {
 		dst_name2 = del[delp++] = unique_path(ren2_dst, branch2);
-		output(1, "%s is a directory in %s added as %s instead",
+		output(1, o, "%s is a directory in %s added as %s instead",
 		       ren2_dst, branch1, dst_name2);
 		remove_file(0, ren2_dst, 0);
 	}

@@ -758,10 +755,11 @@ static void conflict_rename_rename(struct rename *ren1,
 }
 
 static void conflict_rename_dir(struct rename *ren1,
-				const char *branch1)
+				const char *branch1,
+				struct merge_options *o)
 {
 	char *new_path = unique_path(ren1->pair->two->path, branch1);
-	output(1, "Renamed %s to %s instead", ren1->pair->one->path, new_path);
+	output(1, o, "Renamed %s to %s instead", ren1->pair->one->path, new_path);
 	remove_file(0, ren1->pair->two->path, 0);
 	update_file(0, ren1->pair->two->sha1, ren1->pair->two->mode, new_path);
 	free(new_path);

@@ -770,11 +768,12 @@ static void conflict_rename_dir(struct rename *ren1,
 static void conflict_rename_rename_2(struct rename *ren1,
 				     const char *branch1,
 				     struct rename *ren2,
-				     const char *branch2)
+				     const char *branch2,
+				     struct merge_options *o)
 {
 	char *new_path1 = unique_path(ren1->pair->two->path, branch1);
 	char *new_path2 = unique_path(ren2->pair->two->path, branch2);
-	output(1, "Renamed %s to %s and %s to %s instead",
+	output(1, o, "Renamed %s to %s and %s to %s instead",
 	       ren1->pair->one->path, new_path1,
 	       ren2->pair->one->path, new_path2);
 	remove_file(0, ren1->pair->two->path, 0);

@@ -786,8 +785,7 @@ static void conflict_rename_rename_2(struct rename *ren1,
 
 static int process_renames(struct string_list *a_renames,
 			   struct string_list *b_renames,
-			   const char *a_branch,
-			   const char *b_branch)
+			   struct merge_options *o)
 {
 	int clean_merge = 1, i, j;
 	struct string_list a_by_dst = {NULL, 0, 0, 0}, b_by_dst = {NULL, 0, 0, 0};

@@ -832,15 +830,15 @@ static int process_renames(struct string_list *a_renames,
 			renames1 = a_renames;
 			renames2 = b_renames;
 			renames2Dst = &b_by_dst;
-			branch1 = a_branch;
-			branch2 = b_branch;
+			branch1 = o->branch1;
+			branch2 = o->branch2;
 		} else {
 			struct rename *tmp;
 			renames1 = b_renames;
 			renames2 = a_renames;
 			renames2Dst = &a_by_dst;
-			branch1 = b_branch;
-			branch2 = a_branch;
+			branch1 = o->branch2;
+			branch2 = o->branch1;
 			tmp = ren2;
 			ren2 = ren1;
 			ren1 = tmp;

@@ -867,7 +865,7 @@ static int process_renames(struct string_list *a_renames,
 			ren2->processed = 1;
 			if (strcmp(ren1_dst, ren2_dst) != 0) {
 				clean_merge = 0;
-				output(1, "CONFLICT (rename/rename): "
+				output(1, o, "CONFLICT (rename/rename): "
 				       "Rename \"%s\"->\"%s\" in branch \"%s\" "
 				       "rename \"%s\"->\"%s\" in \"%s\"%s",
 				       src, ren1_dst, branch1,

@@ -878,7 +876,7 @@ static int process_renames(struct string_list *a_renames,
 					update_file(0, ren1->pair->one->sha1,
 						    ren1->pair->one->mode, src);
 				}
-				conflict_rename_rename(ren1, branch1, ren2, branch2);
+				conflict_rename_rename(ren1, branch1, ren2, branch2, o);
 			} else {
 				struct merge_file_info mfi;
 				remove_file(1, ren1_src, 1);

@@ -888,13 +886,13 @@ static int process_renames(struct string_list *a_renames,
 						 branch1,
 						 branch2);
 				if (mfi.merge || !mfi.clean)
-					output(1, "Renamed %s->%s", src, ren1_dst);
+					output(1, o, "Renamed %s->%s", src, ren1_dst);
 
 				if (mfi.merge)
-					output(2, "Auto-merged %s", ren1_dst);
+					output(2, o, "Auto-merged %s", ren1_dst);
 
 				if (!mfi.clean) {
-					output(1, "CONFLICT (content): merge conflict in %s",
+					output(1, o, "CONFLICT (content): merge conflict in %s",
 					       ren1_dst);
 					clean_merge = 0;

@@ -925,14 +923,14 @@ static int process_renames(struct string_list *a_renames,
 
 			if (string_list_has_string(&current_directory_set, ren1_dst)) {
 				clean_merge = 0;
-				output(1, "CONFLICT (rename/directory): Renamed %s->%s in %s "
+				output(1, o, "CONFLICT (rename/directory): Renamed %s->%s in %s "
 				       " directory %s added in %s",
 				       ren1_src, ren1_dst, branch1,
 				       ren1_dst, branch2);
-				conflict_rename_dir(ren1, branch1);
+				conflict_rename_dir(ren1, branch1, o);
 			} else if (sha_eq(src_other.sha1, null_sha1)) {
 				clean_merge = 0;
-				output(1, "CONFLICT (rename/delete): Renamed %s->%s in %s "
+				output(1, o, "CONFLICT (rename/delete): Renamed %s->%s in %s "
 				       "and deleted in %s",
 				       ren1_src, ren1_dst, branch1,
 				       branch2);

@@ -941,31 +939,31 @@ static int process_renames(struct string_list *a_renames,
 				const char *new_path;
 				clean_merge = 0;
 				try_merge = 1;
-				output(1, "CONFLICT (rename/add): Renamed %s->%s in %s. "
+				output(1, o, "CONFLICT (rename/add): Renamed %s->%s in %s. "
 				       "%s added in %s",
 				       ren1_src, ren1_dst, branch1,
 				       ren1_dst, branch2);
 				new_path = unique_path(ren1_dst, branch2);
-				output(1, "Added as %s instead", new_path);
+				output(1, o, "Added as %s instead", new_path);
 				update_file(0, dst_other.sha1, dst_other.mode, new_path);
 			} else if ((item = string_list_lookup(ren1_dst, renames2Dst))) {
 				ren2 = item->util;
 				clean_merge = 0;
 				ren2->processed = 1;
-				output(1, "CONFLICT (rename/rename): Renamed %s->%s in %s. "
+				output(1, o, "CONFLICT (rename/rename): Renamed %s->%s in %s. "
 				       "Renamed %s->%s in %s",
 				       ren1_src, ren1_dst, branch1,
 				       ren2->pair->one->path, ren2->pair->two->path, branch2);
-				conflict_rename_rename_2(ren1, branch1, ren2, branch2);
+				conflict_rename_rename_2(ren1, branch1, ren2, branch2, o);
 			} else
 				try_merge = 1;
 
 			if (try_merge) {
-				struct diff_filespec *o, *a, *b;
+				struct diff_filespec *one, *a, *b;
 				struct merge_file_info mfi;
 				src_other.path = (char *)ren1_src;
 
-				o = ren1->pair->one;
+				one = ren1->pair->one;
 				if (a_renames == renames1) {
 					a = ren1->pair->two;
 					b = &src_other;

@@ -973,8 +971,8 @@ static int process_renames(struct string_list *a_renames,
 					b = ren1->pair->two;
 					a = &src_other;
 				}
-				mfi = merge_file(o, a, b,
-						a_branch, b_branch);
+				mfi = merge_file(one, a, b,
+						o->branch1, o->branch2);
 
 				if (mfi.clean &&
 				    sha_eq(mfi.sha, ren1->pair->two->sha1) &&

@@ -984,20 +982,20 @@ static int process_renames(struct string_list *a_renames,
 					 * t6022 test. If you change
 					 * it update the test too.
 					 */
-					output(3, "Skipped %s (merged same as existing)", ren1_dst);
+					output(3, o, "Skipped %s (merged same as existing)", ren1_dst);
 				else {
 					if (mfi.merge || !mfi.clean)
-						output(1, "Renamed %s => %s", ren1_src, ren1_dst);
+						output(1, o, "Renamed %s => %s", ren1_src, ren1_dst);
 					if (mfi.merge)
-						output(2, "Auto-merged %s", ren1_dst);
+						output(2, o, "Auto-merged %s", ren1_dst);
 					if (!mfi.clean) {
-						output(1, "CONFLICT (rename/modify): Merge conflict in %s",
+						output(1, o, "CONFLICT (rename/modify): Merge conflict in %s",
 						       ren1_dst);
 						clean_merge = 0;
 
 						if (!index_only)
 							update_stages(ren1_dst,
-								      o, a, b, 1);
+								      one, a, b, 1);
 					}
 					update_file(mfi.clean, mfi.sha, mfi.mode, ren1_dst);
 				}

@@ -1017,8 +1015,7 @@ static unsigned char *stage_sha(const unsigned char *sha, unsigned mode)
 
 /* Per entry merge function */
 static int process_entry(const char *path, struct stage_data *entry,
-			 const char *branch1,
-			 const char *branch2)
+			 struct merge_options *o)
 {
 	/*
 	printf("processing entry, clean cache: %s\n", index_only ? "yes": "no");

@@ -1040,23 +1037,23 @@ static int process_entry(const char *path, struct stage_data *entry,
 			/* Deleted in both or deleted in one and
 			 * unchanged in the other */
 			if (a_sha)
-				output(2, "Removed %s", path);
+				output(2, o, "Removed %s", path);
 			/* do not touch working file if it did not exist */
 			remove_file(1, path, !a_sha);
 		} else {
 			/* Deleted in one and changed in the other */
 			clean_merge = 0;
 			if (!a_sha) {
-				output(1, "CONFLICT (delete/modify): %s deleted in %s "
+				output(1, o, "CONFLICT (delete/modify): %s deleted in %s "
 				       "and modified in %s. Version %s of %s left in tree.",
-				       path, branch1,
-				       branch2, branch2, path);
+				       path, o->branch1,
+				       o->branch2, o->branch2, path);
 				update_file(0, b_sha, b_mode, path);
 			} else {
-				output(1, "CONFLICT (delete/modify): %s deleted in %s "
+				output(1, o, "CONFLICT (delete/modify): %s deleted in %s "
 				       "and modified in %s. Version %s of %s left in tree.",
-				       path, branch2,
-				       branch1, branch1, path);
+				       path, o->branch2,
+				       o->branch1, o->branch1, path);
 				update_file(0, a_sha, a_mode, path);
 			}
 		}

@@ -1071,14 +1068,14 @@ static int process_entry(const char *path, struct stage_data *entry,
 		const char *conf;
 
 		if (a_sha) {
-			add_branch = branch1;
-			other_branch = branch2;
+			add_branch = o->branch1;
+			other_branch = o->branch2;
 			mode = a_mode;
 			sha = a_sha;
 			conf = "file/directory";
 		} else {
-			add_branch = branch2;
-			other_branch = branch1;
+			add_branch = o->branch2;
+			other_branch = o->branch1;
 			mode = b_mode;
 			sha = b_sha;
 			conf = "directory/file";

@@ -1086,13 +1083,13 @@ static int process_entry(const char *path, struct stage_data *entry,
 		if (string_list_has_string(&current_directory_set, path)) {
 			const char *new_path = unique_path(path, add_branch);
 			clean_merge = 0;
-			output(1, "CONFLICT (%s): There is a directory with name %s in %s. "
+			output(1, o, "CONFLICT (%s): There is a directory with name %s in %s. "
 			       "Added %s as %s",
 			       conf, path, other_branch, path, new_path);
 			remove_file(0, path, 0);
 			update_file(0, sha, mode, new_path);
 		} else {
-			output(2, "Added %s", path);
+			output(2, o, "Added %s", path);
 			update_file(1, sha, mode, path);
 		}
 	} else if (a_sha && b_sha) {

@@ -1100,32 +1097,32 @@ static int process_entry(const char *path, struct stage_data *entry,
 		/* case D: Modified in both, but differently. */
 		const char *reason = "content";
 		struct merge_file_info mfi;
-		struct diff_filespec o, a, b;
+		struct diff_filespec one, a, b;
 
 		if (!o_sha) {
 			reason = "add/add";
 			o_sha = (unsigned char *)null_sha1;
 		}
-		output(2, "Auto-merged %s", path);
-		o.path = a.path = b.path = (char *)path;
-		hashcpy(o.sha1, o_sha);
-		o.mode = o_mode;
+		output(2, o, "Auto-merged %s", path);
+		one.path = a.path = b.path = (char *)path;
+		hashcpy(one.sha1, o_sha);
+		one.mode = o_mode;
 		hashcpy(a.sha1, a_sha);
 		a.mode = a_mode;
 		hashcpy(b.sha1, b_sha);
 		b.mode = b_mode;
 
-		mfi = merge_file(&o, &a, &b,
-				 branch1, branch2);
+		mfi = merge_file(&one, &a, &b,
+				 o->branch1, o->branch2);
 
 		clean_merge = mfi.clean;
 		if (mfi.clean)
 			update_file(1, mfi.sha, mfi.mode, path);
 		else if (S_ISGITLINK(mfi.mode))
-			output(1, "CONFLICT (submodule): Merge conflict in %s "
+			output(1, o, "CONFLICT (submodule): Merge conflict in %s "
 			       "- needs %s", path, sha1_to_hex(b.sha1));
 		else {
-			output(1, "CONFLICT (%s): Merge conflict in %s",
+			output(1, o, "CONFLICT (%s): Merge conflict in %s",
 					reason, path);
 
 			if (index_only)

@@ -1146,11 +1143,10 @@ static int process_entry(const char *path, struct stage_data *entry,
 	return clean_merge;
 }
 
-int merge_trees(struct tree *head,
+int merge_trees(struct merge_options *o,
+		struct tree *head,
 		struct tree *merge,
 		struct tree *common,
-		const char *branch1,
-		const char *branch2,
 		struct tree **result)
 {
 	int code, clean;

@@ -1161,7 +1157,7 @@ int merge_trees(struct tree *head,
 	}
 
 	if (sha_eq(common->object.sha1, merge->object.sha1)) {
-		output(0, "Already uptodate!");
+		output(0, o, "Already uptodate!");
 		*result = head;
 		return 1;
 	}

@@ -1182,15 +1178,14 @@ int merge_trees(struct tree *head,
 		get_files_dirs(merge);
 
 		entries = get_unmerged();
-		re_head  = get_renames(head, common, head, merge, entries);
-		re_merge = get_renames(merge, common, head, merge, entries);
-		clean = process_renames(re_head, re_merge,
-				branch1, branch2);
+		re_head  = get_renames(head, common, head, merge, entries, o);
+		re_merge = get_renames(merge, common, head, merge, entries, o);
+		clean = process_renames(re_head, re_merge, o);
 		for (i = 0; i < entries->nr; i++) {
 			const char *path = entries->items[i].string;
 			struct stage_data *e = entries->items[i].util;
 			if (!e->processed
-				&& !process_entry(path, e, branch1, branch2))
+				&& !process_entry(path, e, o))
 				clean = 0;
 		}

@@ -1203,7 +1198,7 @@ int merge_trees(struct tree *head,
 		clean = 1;
 
 	if (index_only)
-		*result = write_tree_from_memory();
+		*result = write_tree_from_memory(o);
 
 	return clean;
 }

@@ -1223,10 +1218,9 @@ static struct commit_list *reverse_commit_list(struct commit_list *list)
  * Merge the commits h1 and h2, return the resulting virtual
  * commit object and a flag indicating the cleanness of the merge.
  */
-int merge_recursive(struct commit *h1,
+int merge_recursive(struct merge_options *o,
+		    struct commit *h1,
 		    struct commit *h2,
-		    const char *branch1,
-		    const char *branch2,
 		    struct commit_list *ca,
 		    struct commit **result)
 {

@@ -1235,8 +1229,8 @@ int merge_recursive(struct commit *h1,
 	struct tree *mrtree = mrtree;
 	int clean;
 
-	if (show(4)) {
-		output(4, "Merging:");
+	if (show(4, o)) {
+		output(4, o, "Merging:");
 		output_commit_title(h1);
 		output_commit_title(h2);
 	}

@@ -1246,8 +1240,8 @@ int merge_recursive(struct commit *h1,
 		ca = reverse_commit_list(ca);
 	}
 
-	if (show(5)) {
-		output(5, "found %u common ancestor(s):", commit_list_count(ca));
+	if (show(5, o)) {
+		output(5, o, "found %u common ancestor(s):", commit_list_count(ca));
 		for (iter = ca; iter; iter = iter->next)
 			output_commit_title(iter->item);
 	}

@@ -1264,6 +1258,7 @@ int merge_recursive(struct commit *h1,
 	}
 
 	for (iter = ca; iter; iter = iter->next) {
+		struct merge_options opts;
 		call_depth++;
 		/*
 		 * When the merge fails, the result contains files

@@ -1273,10 +1268,11 @@ int merge_recursive(struct commit *h1,
 		 * "conflicts" were already resolved.
 		 */
 		discard_cache();
-		merge_recursive(merged_common_ancestors, iter->item,
-				"Temporary merge branch 1",
-				"Temporary merge branch 2",
-				NULL,
+		memcpy(&opts, o, sizeof(struct merge_options));
+		opts.branch1 = "Temporary merge branch 1";
+		opts.branch2 = "Temporary merge branch 2";
+		merge_recursive(&opts, merged_common_ancestors,
+				iter->item, NULL,
 				&merged_common_ancestors);
 		call_depth--;

@@ -1291,8 +1287,8 @@ int merge_recursive(struct commit *h1,
 	} else
 		index_only = 1;
 
-	clean = merge_trees(h1->tree, h2->tree, merged_common_ancestors->tree,
-			    branch1, branch2, &mrtree);
+	clean = merge_trees(o, h1->tree, h2->tree, merged_common_ancestors->tree,
+			    &mrtree);
 
 	if (index_only) {
 		*result = make_virtual_commit(mrtree, "merged tree");

@@ -1319,35 +1315,33 @@ static struct commit *get_ref(const unsigned char *sha1, const char *name)
 	return (struct commit *)object;
 }
 
-int merge_recursive_generic(const char **base_list,
-		const unsigned char *head_sha1, const char *head_name,
-		const unsigned char *next_sha1, const char *next_name)
+int merge_recursive_generic(struct merge_options *o,
+			    const unsigned char *head,
+			    const unsigned char *merge,
+			    int num_base_list,
+			    const unsigned char **base_list,
+			    struct commit **result)
 {
 	int clean, index_fd;
 	struct lock_file *lock = xcalloc(1, sizeof(struct lock_file));
-	struct commit *result;
-	struct commit *head_commit = get_ref(head_sha1, head_name);
-	struct commit *next_commit = get_ref(next_sha1, next_name);
+	struct commit *head_commit = get_ref(head, o->branch1);
+	struct commit *next_commit = get_ref(merge, o->branch2);
 	struct commit_list *ca = NULL;
 
 	if (base_list) {
 		int i;
-		for (i = 0; base_list[i]; ++i) {
-			unsigned char sha[20];
+		for (i = 0; i < num_base_list; ++i) {
 			struct commit *base;
-			if (get_sha1(base_list[i], sha))
-				return error("Could not resolve ref '%s'",
-								base_list[i]);
-			if (!(base = get_ref(sha, base_list[i])))
+			if (!(base = get_ref(base_list[i], sha1_to_hex(base_list[i]))))
 				return error("Could not parse object '%s'",
-								base_list[i]);
+					sha1_to_hex(base_list[i]));
 			commit_list_insert(base, &ca);
 		}
 	}
 
 	index_fd = hold_locked_index(lock, 1);
-	clean = merge_recursive(head_commit, next_commit,
-				head_name, next_name, ca, &result);
+	clean = merge_recursive(o, head_commit, next_commit, ca,
+			result);
 	if (active_cache_changed &&
 			(write_cache(index_fd, active_cache, active_nr) ||
 			 commit_locked_index(lock)))

@@ -1356,29 +1350,35 @@ int merge_recursive_generic(const char **base_list,
 	return clean ? 0 : 1;
 }
 
-int merge_recursive_config(const char *var, const char *value, void *cb)
+static int merge_recursive_config(const char *var, const char *value, void *cb)
 {
+	struct merge_options *o = cb;
 	if (!strcasecmp(var, "merge.verbosity")) {
-		merge_recursive_verbosity = git_config_int(var, value);
+		o->verbosity = git_config_int(var, value);
 		return 0;
 	}
 	if (!strcasecmp(var, "diff.renamelimit")) {
-		diff_rename_limit = git_config_int(var, value);
+		o->diff_rename_limit = git_config_int(var, value);
 		return 0;
 	}
 	if (!strcasecmp(var, "merge.renamelimit")) {
-		merge_rename_limit = git_config_int(var, value);
+		o->merge_rename_limit = git_config_int(var, value);
 		return 0;
 	}
 	return git_default_config(var, value, cb);
 }
 
-void merge_recursive_setup(int is_subtree_merge)
+void init_merge_options(struct merge_options *o)
 {
+	memset(o, 0, sizeof(struct merge_options));
+	o->verbosity = 2;
+	o->buffer_output = 1;
+	o->diff_rename_limit = -1;
+	o->merge_rename_limit = -1;
+	git_config(merge_recursive_config, o);
 	if (getenv("GIT_MERGE_VERBOSITY"))
-		merge_recursive_verbosity =
+		o->verbosity =
 			strtol(getenv("GIT_MERGE_VERBOSITY"), NULL, 10);
-	if (merge_recursive_verbosity >= 5)
-		buffer_output = 0;
-	subtree_merge = is_subtree_merge;
+	if (o->verbosity >= 5)
+		o->buffer_output = 0;
 }

diff --git a/merge-recursive.h b/merge-recursive.h
index 4dd6476..72f0a28 100644
--- a/merge-recursive.h
+++ b/merge-recursive.h

@@ -1,26 +1,42 @@
 #ifndef MERGE_RECURSIVE_H
 #define MERGE_RECURSIVE_H
 
-int merge_recursive(struct commit *h1,
+struct merge_options {
+	const char *branch1;
+	const char *branch2;
+	unsigned subtree_merge : 1;
+	unsigned buffer_output : 1;
+	int verbosity;
+	int diff_rename_limit;
+	int merge_rename_limit;
+};
+
+/* merge_trees() but with recursive ancestor consolidation */
+int merge_recursive(struct merge_options *o,
+		    struct commit *h1,
 		    struct commit *h2,
-		    const char *branch1,
-		    const char *branch2,
 		    struct commit_list *ancestors,
 		    struct commit **result);
 
-int merge_trees(struct tree *head,
+/* rename-detecting three-way merge, no recursion */
+int merge_trees(struct merge_options *o,
+		struct tree *head,
 		struct tree *merge,
 		struct tree *common,
-		const char *branch1,
-		const char *branch2,
 		struct tree **result);
-extern int merge_recursive_generic(const char **base_list,
-		const unsigned char *head_sha1, const char *head_name,
-		const unsigned char *next_sha1, const char *next_name);
-int merge_recursive_config(const char *var, const char *value, void *cb);
-void merge_recursive_setup(int is_subtree_merge);
-struct tree *write_tree_from_memory(void);
 
-extern int merge_recursive_verbosity;
+/*
+ * "git-merge-recursive" can be fed trees; wrap them into
+ * virtual commits and call merge_recursive() proper.
+ */
+int merge_recursive_generic(struct merge_options *o,
+			    const unsigned char *head,
+			    const unsigned char *merge,
+			    int num_ca,
+			    const unsigned char **ca,
+			    struct commit **result);
+
+void init_merge_options(struct merge_options *o);
+struct tree *write_tree_from_memory(struct merge_options *o);
 
 #endif

-- 
1.6.0.rc3.17.gc14c8.dirty

Re: What's cooking in git.git (Aug 2008, #05; Tue, 19)

From: Miklos Vajna <hidden>
Date: 2016-06-15 22:45:16

On Tue, Aug 19, 2008 at 03:00:27PM -0700, Junio C Hamano [off-list ref] wrote:

and the call chain would become:
(...)
    cmd_revert(), cmd_am(), cmd_checkout(), cmd_stash(), ...
    -> merge_trees()

I tried to let cmd_revert() use merge_trees() only and not
merge_recursive_generic(), but something is fishy with it.

t3501-revert-cherry-pick passes fine, but t3404-rebase-interactive fail,
becase once we have a conflict, git diff --name-status says 'M' for the
given file and not 'U', which is obviously wrong.

I'm sending both patches: the one that works properly using
merge_recursive_generic() - and which one passes the testsuite here, and
the one that is elegant as it uses merge_trees(), but actually not
complete, at least regarding not adding the unmerged entries to the
index.

So, first here is my failed attempt to use merge_trees() inside
builtin-revert:

diff --git a/builtin-revert.c b/builtin-revert.c
index 3667705..3071518 100644
--- a/builtin-revert.c
+++ b/builtin-revert.c

@@ -12,6 +12,7 @@
 #include "diff.h"
 #include "revision.h"
 #include "rerere.h"
+#include "merge-recursive.h"
 
 /*
  * This implements the builtins revert and cherry-pick.

@@ -201,36 +202,6 @@ static void set_author_ident_env(const char *message)
 			sha1_to_hex(commit->object.sha1));
 }
 
-static int merge_recursive(const char *base_sha1,
-		const char *head_sha1, const char *head_name,
-		const char *next_sha1, const char *next_name)
-{
-	char buffer[256];
-	const char *argv[6];
-	int i = 0;
-
-	sprintf(buffer, "GITHEAD_%s", head_sha1);
-	setenv(buffer, head_name, 1);
-	sprintf(buffer, "GITHEAD_%s", next_sha1);
-	setenv(buffer, next_name, 1);
-
-	/*
-	 * This three way merge is an interesting one.  We are at
-	 * $head, and would want to apply the change between $commit
-	 * and $prev on top of us (when reverting), or the change between
-	 * $prev and $commit on top of us (when cherry-picking or replaying).
-	 */
-	argv[i++] = "merge-recursive";
-	if (base_sha1)
-		argv[i++] = base_sha1;
-	argv[i++] = "--";
-	argv[i++] = head_sha1;
-	argv[i++] = next_sha1;
-	argv[i++] = NULL;
-
-	return run_command_v_opt(argv, RUN_COMMAND_NO_STDIN | RUN_GIT_CMD);
-}
-
 static char *help_msg(const unsigned char *sha1)
 {
 	static char helpbuf[1024];

@@ -271,6 +242,8 @@ static int revert_or_cherry_pick(int argc, const char **argv)
 	char *oneline, *reencoded_message = NULL;
 	const char *message, *encoding;
 	const char *defmsg = xstrdup(git_path("MERGE_MSG"));
+	struct merge_options o;
+	struct tree *result;
 
 	git_config(git_default_config, NULL);
 	me = action == REVERT ? "revert" : "cherry-pick";

@@ -374,13 +347,16 @@ static int revert_or_cherry_pick(int argc, const char **argv)
 		}
 	}
 
-	if (merge_recursive(base == NULL ?
-				NULL : sha1_to_hex(base->object.sha1),
-				sha1_to_hex(head), "HEAD",
-				sha1_to_hex(next->object.sha1), oneline) ||
-			write_cache_as_tree(head, 0, NULL)) {
+	read_cache();
+	init_merge_options(&o);
+	o.branch1 = "HEAD";
+	o.branch2 = oneline;
+	parse_commit(next);
+	parse_commit(base);
+	if (!merge_trees(&o, lookup_commit_reference_gently(head, 0)->tree,
+				next->tree, base->tree, &result) ||
+		write_cache_as_tree(head, 0, NULL)) {
 		add_to_msg("\nConflicts:\n\n");
-		read_cache();
 		for (i = 0; i < active_nr;) {
 			struct cache_entry *ce = active_cache[i++];
 			if (ce_stage(ce)) {

[PATCH] builtin-revert: use merge_recursive_generic()

From: Miklos Vajna <hidden>
Date: 2016-06-15 22:45:16

We had a separate function to run merge-recursive in a separate process,
but this is not really necessary, since we have
merge_recursive_generic() to do the same, without wasting resources.

Signed-off-by: Miklos Vajna <redacted>
---

On Mon, Sep 01, 2008 at 03:06:12AM +0200, Miklos Vajna [off-list ref] wrote:

I'm sending both patches: the one that works properly using
merge_recursive_generic() - and which one passes the testsuite here

Here it is.

 builtin-revert.c |   55 ++++++++++++++++++-----------------------------------
 1 files changed, 19 insertions(+), 36 deletions(-)

diff --git a/builtin-revert.c b/builtin-revert.c
index 3667705..8d4ebcf 100644
--- a/builtin-revert.c
+++ b/builtin-revert.c

@@ -12,6 +12,7 @@
 #include "diff.h"
 #include "revision.h"
 #include "rerere.h"
+#include "merge-recursive.h"
 
 /*
  * This implements the builtins revert and cherry-pick.

@@ -201,36 +202,6 @@ static void set_author_ident_env(const char *message)
 			sha1_to_hex(commit->object.sha1));
 }
 
-static int merge_recursive(const char *base_sha1,
-		const char *head_sha1, const char *head_name,
-		const char *next_sha1, const char *next_name)
-{
-	char buffer[256];
-	const char *argv[6];
-	int i = 0;
-
-	sprintf(buffer, "GITHEAD_%s", head_sha1);
-	setenv(buffer, head_name, 1);
-	sprintf(buffer, "GITHEAD_%s", next_sha1);
-	setenv(buffer, next_name, 1);
-
-	/*
-	 * This three way merge is an interesting one.  We are at
-	 * $head, and would want to apply the change between $commit
-	 * and $prev on top of us (when reverting), or the change between
-	 * $prev and $commit on top of us (when cherry-picking or replaying).
-	 */
-	argv[i++] = "merge-recursive";
-	if (base_sha1)
-		argv[i++] = base_sha1;
-	argv[i++] = "--";
-	argv[i++] = head_sha1;
-	argv[i++] = next_sha1;
-	argv[i++] = NULL;
-
-	return run_command_v_opt(argv, RUN_COMMAND_NO_STDIN | RUN_GIT_CMD);
-}
-
 static char *help_msg(const unsigned char *sha1)
 {
 	static char helpbuf[1024];

@@ -266,12 +237,16 @@ static int index_is_dirty(void)
 static int revert_or_cherry_pick(int argc, const char **argv)
 {
 	unsigned char head[20];
+	unsigned const char *ca = NULL;
 	struct commit *base, *next, *parent;
-	int i;
+	int i, fail;
 	char *oneline, *reencoded_message = NULL;
 	const char *message, *encoding;
 	const char *defmsg = xstrdup(git_path("MERGE_MSG"));
+	struct merge_options o;
+	struct commit *result;
 
+	init_merge_options(&o);
 	git_config(git_default_config, NULL);
 	me = action == REVERT ? "revert" : "cherry-pick";
 	setenv(GIT_REFLOG_ACTION, me, 0);

@@ -374,11 +349,19 @@ static int revert_or_cherry_pick(int argc, const char **argv)
 		}
 	}
 
-	if (merge_recursive(base == NULL ?
-				NULL : sha1_to_hex(base->object.sha1),
-				sha1_to_hex(head), "HEAD",
-				sha1_to_hex(next->object.sha1), oneline) ||
-			write_cache_as_tree(head, 0, NULL)) {
+	if (base)
+		ca = base->object.sha1;
+	o.branch1 = "HEAD";
+	o.branch2 = oneline;
+	fail = merge_recursive_generic(&o,
+				head,
+				next->object.sha1,
+				ca ? 1 : 0,
+				&ca,
+				&result);
+	if (fail < 0)
+		exit(1);
+	if (fail || write_cache_as_tree(head, 0, NULL)) {
 		add_to_msg("\nConflicts:\n\n");
 		read_cache();
 		for (i = 0; i < active_nr;) {

-- 
1.6.0

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