Merge branch 'ap/merge-backend-opts'

* ap/merge-backend-opts:
  Document that merge strategies can now take their own options
  Extend merge-subtree tests to test -Xsubtree=dir.
  Make "subtree" part more orthogonal to the rest of merge-recursive.
  pull: Fix parsing of -X<option>
  Teach git-pull to pass -X<option> to git-merge
  git merge -X<option>
  git-merge-file --ours, --theirs

Conflicts:
	git-compat-util.h

Documentation/git-merge-file.txt

@@ -10,7 +10,8 @@ SYNOPSIS
 --------
 [verse]
 'git merge-file' [-L <current-name> [-L <base-name> [-L <other-name>]]]
-	[-p|--stdout] [-q|--quiet] <current-file> <base-file> <other-file>
+	[--ours|--theirs] [-p|--stdout] [-q|--quiet]
+	<current-file> <base-file> <other-file>
 
 
 DESCRIPTION
@@ -34,7 +35,9 @@ normally outputs a warning and brackets the conflict with lines containing
 	>>>>>>> B
 
 If there are conflicts, the user should edit the result and delete one of
-the alternatives.
+the alternatives.  When `--ours` or `--theirs` option is in effect, however,
+these conflicts are resolved favouring lines from `<current-file>` or
+lines from `<other-file>` respectively.
 
 The exit value of this program is negative on error, and the number of
 conflicts otherwise. If the merge was clean, the exit value is 0.
@@ -62,6 +65,11 @@ OPTIONS
 -q::
 	Quiet; do not warn about conflicts.
 
+--ours::
+--theirs::
+	Instead of leaving conflicts in the file, resolve conflicts
+	favouring our (or their) side of the lines.
+
 
 EXAMPLES
 --------

Documentation/merge-options.txt

@@ -74,3 +74,8 @@ option can be used to override --squash.
 -v::
 --verbose::
 	Be verbose.
+
+-X <option>::
+--strategy-option=<option>::
+	Pass merge strategy specific option through to the merge
+	strategy.

Documentation/merge-strategies.txt

@@ -1,6 +1,11 @@
 MERGE STRATEGIES
 ----------------
 
+The merge mechanism ('git-merge' and 'git-pull' commands) allows the
+backend 'merge strategies' to be chosen with `-s` option.  Some strategies
+can also take their own options, which can be passed by giving `-X<option>`
+arguments to 'git-merge' and/or 'git-pull'.
+
 resolve::
 	This can only resolve two heads (i.e. the current branch
 	and another branch you pulled from) using a 3-way merge
@@ -20,6 +25,27 @@ recursive::
 	Additionally this can detect and handle merges involving
 	renames.  This is the default merge strategy when
 	pulling or merging one branch.
++
+The 'recursive' strategy can take the following options:
+
+ours;;
+	This option forces conflicting hunks to be auto-resolved cleanly by
+	favoring 'our' version.  Changes from the other tree that do not
+	conflict with our side are reflected to the merge result.
++
+This should not be confused with the 'ours' merge strategy, which does not
+even look at what the other tree contains at all.  It discards everything
+the other tree did, declaring 'our' history contains all that happened in it.
+
+theirs;;
+	This is opposite of 'ours'.
+
+subtree[=path];;
+	This option is a more advanced form of 'subtree' strategy, where
+	the strategy makes a guess on how two trees must be shifted to
+	match with each other when merging.  Instead, the specified path
+	is prefixed (or stripped from the beginning) to make the shape of
+	two trees to match.
 
 octopus::
 	This resolves cases with more than two heads, but refuses to do
@@ -33,7 +59,8 @@ ours::
 	merge is always that of the current branch head, effectively
 	ignoring all changes from all other branches.  It is meant to
 	be used to supersede old development history of side
-	branches.
+	branches.  Note that this is different from the -Xours option to
+	the 'recursive' merge strategy.
 
 subtree::
 	This is a modified recursive strategy. When merging trees A and

builtin-merge-file.c

@@ -27,13 +27,18 @@ int cmd_merge_file(int argc, const char **argv, const char *prefix)
 	mmbuffer_t result = {NULL, 0};
 	xpparam_t xpp = {XDF_NEED_MINIMAL};
 	int ret = 0, i = 0, to_stdout = 0;
-	int merge_level = XDL_MERGE_ZEALOUS_ALNUM;
-	int merge_style = 0, quiet = 0;
+	int level = XDL_MERGE_ZEALOUS_ALNUM;
+	int style = 0, quiet = 0;
+	int favor = 0;
 	int nongit;
 
 	struct option options[] = {
 		OPT_BOOLEAN('p', "stdout", &to_stdout, "send results to standard output"),
-		OPT_SET_INT(0, "diff3", &merge_style, "use a diff3 based merge", XDL_MERGE_DIFF3),
+		OPT_SET_INT(0, "diff3", &style, "use a diff3 based merge", XDL_MERGE_DIFF3),
+		OPT_SET_INT(0, "ours", &favor, "for conflicts, use our version",
+			    XDL_MERGE_FAVOR_OURS),
+		OPT_SET_INT(0, "theirs", &favor, "for conflicts, use their version",
+			    XDL_MERGE_FAVOR_THEIRS),
 		OPT__QUIET(&quiet),
 		OPT_CALLBACK('L', NULL, names, "name",
 			     "set labels for file1/orig_file/file2", &label_cb),
@@ -45,7 +50,7 @@ int cmd_merge_file(int argc, const char **argv, const char *prefix)
 		/* Read the configuration file */
 		git_config(git_xmerge_config, NULL);
 		if (0 <= git_xmerge_style)
-			merge_style = git_xmerge_style;
+			style = git_xmerge_style;
 	}
 
 	argc = parse_options(argc, argv, prefix, options, merge_file_usage, 0);
@@ -68,7 +73,7 @@ int cmd_merge_file(int argc, const char **argv, const char *prefix)
 	}
 
 	ret = xdl_merge(mmfs + 1, mmfs + 0, names[0], mmfs + 2, names[2],
-			&xpp, merge_level | merge_style, &result);
+			&xpp, XDL_MERGE_FLAGS(level, style, favor), &result);
 
 	for (i = 0; i < 3; i++)
 		free(mmfs[i].ptr);

builtin-merge-recursive.c

@@ -25,19 +25,30 @@ int cmd_merge_recursive(int argc, const char **argv, const char *prefix)
 	struct commit *result;
 
 	init_merge_options(&o);
-	if (argv[0]) {
-		int namelen = strlen(argv[0]);
-		if (8 < namelen &&
-		    !strcmp(argv[0] + namelen - 8, "-subtree"))
-			o.subtree_merge = 1;
-	}
+	if (argv[0] && !suffixcmp(argv[0], "-subtree"))
+		o.subtree_shift = "";
 
 	if (argc < 4)
 		usagef("%s <base>... -- <head> <remote> ...", argv[0]);
 
 	for (i = 1; i < argc; ++i) {
-		if (!strcmp(argv[i], "--"))
-			break;
+		const char *arg = argv[i];
+
+		if (!prefixcmp(arg, "--")) {
+			if (!arg[2])
+				break;
+			if (!strcmp(arg+2, "ours"))
+				o.recursive_variant = MERGE_RECURSIVE_OURS;
+			else if (!strcmp(arg+2, "theirs"))
+				o.recursive_variant = MERGE_RECURSIVE_THEIRS;
+			else if (!strcmp(arg+2, "subtree"))
+				o.subtree_shift = "";
+			else if (!prefixcmp(arg+2, "subtree="))
+				o.subtree_shift = arg + 10;
+			else
+				die("Unknown option %s", arg);
+			continue;
+		}
 		if (bases_count < ARRAY_SIZE(bases)-1) {
 			unsigned char *sha = xmalloc(20);
 			if (get_sha1(argv[i], sha))

builtin-merge.c

@@ -51,6 +51,8 @@ static struct commit_list *remoteheads;
 static unsigned char head[20], stash[20];
 static struct strategy **use_strategies;
 static size_t use_strategies_nr, use_strategies_alloc;
+static const char **xopts;
+static size_t xopts_nr, xopts_alloc;
 static const char *branch;
 static int verbosity;
 static int allow_rerere_auto;
@@ -148,6 +150,17 @@ static int option_parse_strategy(const struct option *opt,
 	return 0;
 }
 
+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 int option_parse_n(const struct option *opt,
 			  const char *arg, int unset)
 {
@@ -175,6 +188,8 @@ static struct option builtin_merge_options[] = {
 	OPT_RERERE_AUTOUPDATE(&allow_rerere_auto),
 	OPT_CALLBACK('s', "strategy", &use_strategies, "strategy",
 		"merge strategy to use", option_parse_strategy),
+	OPT_CALLBACK('X', "strategy-option", &xopts, "option=value",
+		"option for selected merge strategy", option_parse_x),
 	OPT_CALLBACK('m', "message", &merge_msg, "message",
 		"message to be used for the merge commit (if any)",
 		option_parse_message),
@@ -537,7 +552,7 @@ static int try_merge_strategy(const char *strategy, struct commit_list *common,
 			      const char *head_arg)
 {
 	const char **args;
-	int i = 0, ret;
+	int i = 0, x = 0, ret;
 	struct commit_list *j;
 	struct strbuf buf = STRBUF_INIT;
 	int index_fd;
@@ -566,7 +581,20 @@ static int try_merge_strategy(const char *strategy, struct commit_list *common,
 
 		init_merge_options(&o);
 		if (!strcmp(strategy, "subtree"))
-			o.subtree_merge = 1;
+			o.subtree_shift = "";
+
+		for (x = 0; x < xopts_nr; x++) {
+			if (!strcmp(xopts[x], "ours"))
+				o.recursive_variant = MERGE_RECURSIVE_OURS;
+			else if (!strcmp(xopts[x], "theirs"))
+				o.recursive_variant = MERGE_RECURSIVE_THEIRS;
+			else if (!strcmp(xopts[x], "subtree"))
+				o.subtree_shift = "";
+			else if (!prefixcmp(xopts[x], "subtree="))
+				o.subtree_shift = xopts[x]+8;
+			else
+				die("Unknown option for merge-recursive: -X%s", xopts[x]);
+		}
 
 		o.branch1 = head_arg;
 		o.branch2 = remoteheads->item->util;
@@ -584,10 +612,16 @@ static int try_merge_strategy(const char *strategy, struct commit_list *common,
 		rollback_lock_file(lock);
 		return clean ? 0 : 1;
 	} else {
-		args = xmalloc((4 + commit_list_count(common) +
+		args = xmalloc((4 + xopts_nr + commit_list_count(common) +
 					commit_list_count(remoteheads)) * sizeof(char *));
 		strbuf_addf(&buf, "merge-%s", strategy);
 		args[i++] = buf.buf;
+		for (x = 0; x < xopts_nr; x++) {
+			char *s = xmalloc(strlen(xopts[x])+2+1);
+			strcpy(s, "--");
+			strcpy(s+2, xopts[x]);
+			args[i++] = s;
+		}
 		for (j = common; j; j = j->next)
 			args[i++] = xstrdup(sha1_to_hex(j->item->object.sha1));
 		args[i++] = "--";
@@ -598,6 +632,8 @@ static int try_merge_strategy(const char *strategy, struct commit_list *common,
 		ret = run_command_v_opt(args, RUN_GIT_CMD);
 		strbuf_release(&buf);
 		i = 1;
+		for (x = 0; x < xopts_nr; x++)
+			free((void *)args[i++]);
 		for (j = common; j; j = j->next)
 			free((void *)args[i++]);
 		i += 2;

cache.h

@@ -1007,6 +1007,7 @@ extern int diff_auto_refresh_index;
 
 /* match-trees.c */
 void shift_tree(const unsigned char *, const unsigned char *, unsigned char *, int);
+void shift_tree_by(const unsigned char *, const unsigned char *, unsigned char *, const char *);
 
 /*
  * whitespace rules.

contrib/examples/git-merge.sh

@@ -31,10 +31,11 @@ LF='
 '
 
 all_strategies='recur recursive octopus resolve stupid ours subtree'
+all_strategies="$all_strategies recursive-ours recursive-theirs"
 default_twohead_strategies='recursive'
 default_octopus_strategies='octopus'
 no_fast_forward_strategies='subtree ours'
-no_trivial_strategies='recursive recur subtree ours'
+no_trivial_strategies='recursive recur subtree ours recursive-ours recursive-theirs'
 use_strategies=
 
 allow_fast_forward=t

git-compat-util.h

@@ -199,6 +199,7 @@ extern void warning(const char *err, ...) __attribute__((format (printf, 1, 2)))
 extern void set_die_routine(NORETURN_PTR void (*routine)(const char *err, va_list params));
 
 extern int prefixcmp(const char *str, const char *prefix);
+extern int suffixcmp(const char *str, const char *suffix);
 
 static inline const char *skip_prefix(const char *str, const char *prefix)
 {

git-pull.sh

@@ -39,6 +39,7 @@ test -f "$GIT_DIR/MERGE_HEAD" && die_merge
 
 strategy_args= diffstat= no_commit= squash= no_ff= ff_only=
 log_arg= verbosity=
+merge_args=
 curr_branch=$(git symbolic-ref -q HEAD)
 curr_branch_short=$(echo "$curr_branch" | sed "s|refs/heads/||")
 rebase=$(git config --bool branch.$curr_branch_short.rebase)
@@ -83,6 +84,18 @@ do
 		esac
 		strategy_args="${strategy_args}-s $strategy "
 		;;
+	-X*)
+		case "$#,$1" in
+		1,-X)
+			usage ;;
+		*,-X)
+			xx="-X $(git rev-parse --sq-quote "$2")"
+			shift ;;
+		*,*)
+			xx=$(git rev-parse --sq-quote "$1") ;;
+		esac
+		merge_args="$merge_args$xx "
+		;;
 	-r|--r|--re|--reb|--reba|--rebas|--rebase)
 		rebase=true
 		;;
@@ -254,8 +267,15 @@ then
 fi
 
 merge_name=$(git fmt-merge-msg $log_arg <"$GIT_DIR/FETCH_HEAD") || exit
-test true = "$rebase" &&
-	exec git-rebase $diffstat $strategy_args --onto $merge_head \
-	${oldremoteref:-$merge_head}
-exec git-merge $diffstat $no_commit $squash $no_ff $ff_only $log_arg $strategy_args \
-	"$merge_name" HEAD $merge_head $verbosity
+case "$rebase" in
+true)
+	eval="git-rebase $diffstat $strategy_args $merge_args"
+	eval="$eval --onto $merge_head ${oldremoteref:-$merge_head}"
+	;;
+*)
+	eval="git-merge $diffstat $no_commit $squash $no_ff $ff_only"
+	eval="$eval  $log_arg $strategy_args $merge_args"
+	eval="$eval \"$merge_name\" HEAD $merge_head $verbosity"
+	;;
+esac
+eval "exec $eval"

git.c

@@ -332,6 +332,8 @@ static void handle_internal_command(int argc, const char **argv)
 		{ "merge-file", cmd_merge_file },
 		{ "merge-ours", cmd_merge_ours, RUN_SETUP },
 		{ "merge-recursive", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
+		{ "merge-recursive-ours", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
+		{ "merge-recursive-theirs", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
 		{ "merge-subtree", cmd_merge_recursive, RUN_SETUP | NEED_WORK_TREE },
 		{ "mktree", cmd_mktree, RUN_SETUP },
 		{ "mv", cmd_mv, RUN_SETUP | NEED_WORK_TREE },