From: Junio C Hamano <gitster@pobox.com>
Date: Tue, 19 May 2015 20:17:57 +0000 (-0700)
Subject: Merge branch 'jc/merge'
X-Git-Tag: v2.5.0-rc0~107
X-Git-Url: https://git.lorimer.id.au/gitweb.git/diff_plain/bcd1ecd08a644a19adfebb31a72a4e608e077c6d?hp=-c

Merge branch 'jc/merge'

"git merge FETCH_HEAD" learned that the previous "git fetch" could
be to create an Octopus merge, i.e. recording multiple branches
that are not marked as "not-for-merge"; this allows us to lose an
old style invocation "git merge <msg> HEAD $commits..." in the
implementation of "git pull" script; the old style syntax can now
be deprecated.

* jc/merge:
merge: deprecate 'git merge <message> HEAD <commit>' syntax
merge: handle FETCH_HEAD internally
merge: decide if we auto-generate the message early in collect_parents()
merge: make collect_parents() auto-generate the merge message
merge: extract prepare_merge_message() logic out
merge: narrow scope of merge_names
merge: split reduce_parents() out of collect_parents()
merge: clarify collect_parents() logic
merge: small leakfix and code simplification
merge: do not check argc to determine number of remote heads
merge: clarify "pulling into void" special case
t5520: test pulling an octopus into an unborn branch
t5520: style fixes
merge: simplify code flow
merge: test the top-level merge driver
---

bcd1ecd08a644a19adfebb31a72a4e608e077c6d
diff --combined Documentation/git-merge.txt
index 1f94908e3c,d9aa6b6f11..273a1009be
--- a/Documentation/git-merge.txt
+++ b/Documentation/git-merge.txt
@@@ -104,6 -104,10 +104,10 @@@ commit or stash your changes before run
  If no commit is given from the command line, merge the remote-tracking
  branches that the current branch is configured to use as its upstream.
  See also the configuration section of this manual page.
+ +
+ When `FETCH_HEAD` (and no other commit) is specified, the branches
+ recorded in the `.git/FETCH_HEAD` file by the previous invocation
+ of `git fetch` for merging are merged to the current branch.
  
  
  PRE-MERGE CHECKS
@@@ -232,7 -236,7 +236,7 @@@ Barbie's remark on your side.  The onl
  side wants to say it is hard and you'd prefer to go shopping, while the
  other side wants to claim it is easy.
  
 -An alternative style can be used by setting the "merge.conflictstyle"
 +An alternative style can be used by setting the "merge.conflictStyle"
  configuration variable to "diff3".  In "diff3" style, the above conflict
  may look like this:
  
@@@ -329,7 -333,7 +333,7 @@@ CONFIGURATIO
  -------------
  include::merge-config.txt[]
  
 -branch.<name>.mergeoptions::
 +branch.<name>.mergeOptions::
  	Sets default options for merging into branch <name>. The syntax and
  	supported options are the same as those of 'git merge', but option
  	values containing whitespace characters are currently not supported.
diff --combined builtin/merge.c
index 3b0f8f96d4,67fbfafa02..f89f60e11a
--- a/builtin/merge.c
+++ b/builtin/merge.c
@@@ -29,7 -29,6 +29,7 @@@
  #include "remote.h"
  #include "fmt-merge-msg.h"
  #include "gpg-interface.h"
 +#include "sequencer.h"
  
  #define DEFAULT_TWOHEAD (1<<0)
  #define DEFAULT_OCTOPUS (1<<1)
@@@ -42,8 -41,8 +42,8 @@@ struct strategy 
  };
  
  static const char * const builtin_merge_usage[] = {
 -	N_("git merge [options] [<commit>...]"),
 -	N_("git merge [options] <msg> HEAD <commit>"),
 +	N_("git merge [<options>] [<commit>...]"),
 +	N_("git merge [<options>] <msg> HEAD <commit>"),
  	N_("git merge --abort"),
  	NULL
  };
@@@ -492,8 -491,7 +492,7 @@@ static void merge_name(const char *remo
  	}
  	if (len) {
  		struct strbuf truname = STRBUF_INIT;
- 		strbuf_addstr(&truname, "refs/heads/");
- 		strbuf_addstr(&truname, remote);
+ 		strbuf_addf(&truname, "refs/heads/%s", remote);
  		strbuf_setlen(&truname, truname.len - len);
  		if (ref_exists(truname.buf)) {
  			strbuf_addf(msg,
@@@ -504,28 -502,7 +503,7 @@@
  			strbuf_release(&truname);
  			goto cleanup;
  		}
- 	}
- 
- 	if (!strcmp(remote, "FETCH_HEAD") &&
- 			!access(git_path("FETCH_HEAD"), R_OK)) {
- 		const char *filename;
- 		FILE *fp;
- 		struct strbuf line = STRBUF_INIT;
- 		char *ptr;
- 
- 		filename = git_path("FETCH_HEAD");
- 		fp = fopen(filename, "r");
- 		if (!fp)
- 			die_errno(_("could not open '%s' for reading"),
- 				  filename);
- 		strbuf_getline(&line, fp, '\n');
- 		fclose(fp);
- 		ptr = strstr(line.buf, "\tnot-for-merge\t");
- 		if (ptr)
- 			strbuf_remove(&line, ptr-line.buf+1, 13);
- 		strbuf_addbuf(msg, &line);
- 		strbuf_release(&line);
- 		goto cleanup;
+ 		strbuf_release(&truname);
  	}
  
  	if (remote_head->util) {
@@@ -881,20 -858,28 +859,20 @@@ static int finish_automerge(struct comm
  	return 0;
  }
  
 -static int suggest_conflicts(int renormalizing)
 +static int suggest_conflicts(void)
  {
  	const char *filename;
  	FILE *fp;
 -	int pos;
 +	struct strbuf msgbuf = STRBUF_INIT;
  
  	filename = git_path("MERGE_MSG");
  	fp = fopen(filename, "a");
  	if (!fp)
  		die_errno(_("Could not open '%s' for writing"), filename);
 -	fprintf(fp, "\nConflicts:\n");
 -	for (pos = 0; pos < active_nr; pos++) {
 -		const struct cache_entry *ce = active_cache[pos];
 -
 -		if (ce_stage(ce)) {
 -			fprintf(fp, "\t%s\n", ce->name);
 -			while (pos + 1 < active_nr &&
 -					!strcmp(ce->name,
 -						active_cache[pos + 1]->name))
 -				pos++;
 -		}
 -	}
 +
 +	append_conflicts_hint(&msgbuf);
 +	fputs(msgbuf.buf, fp);
 +	strbuf_release(&msgbuf);
  	fclose(fp);
  	rerere(allow_rerere_auto);
  	printf(_("Automatic merge failed; "
@@@ -1037,28 -1022,24 +1015,24 @@@ static int default_edit_option(void
  		st_stdin.st_mode == st_stdout.st_mode);
  }
  
- static struct commit_list *collect_parents(struct commit *head_commit,
- 					   int *head_subsumed,
- 					   int argc, const char **argv)
+ static struct commit_list *reduce_parents(struct commit *head_commit,
+ 					  int *head_subsumed,
+ 					  struct commit_list *remoteheads)
  {
- 	int i;
- 	struct commit_list *remoteheads = NULL, *parents, *next;
- 	struct commit_list **remotes = &remoteheads;
+ 	struct commit_list *parents, *next, **remotes = &remoteheads;
  
- 	if (head_commit)
- 		remotes = &commit_list_insert(head_commit, remotes)->next;
- 	for (i = 0; i < argc; i++) {
- 		struct commit *commit = get_merge_parent(argv[i]);
- 		if (!commit)
- 			help_unknown_ref(argv[i], "merge",
- 					 "not something we can merge");
- 		remotes = &commit_list_insert(commit, remotes)->next;
- 	}
- 	*remotes = NULL;
+ 	/*
+ 	 * Is the current HEAD reachable from another commit being
+ 	 * merged?  If so we do not want to record it as a parent of
+ 	 * the resulting merge, unless --no-ff is given.  We will flip
+ 	 * this variable to 0 when we find HEAD among the independent
+ 	 * tips being merged.
+ 	 */
+ 	*head_subsumed = 1;
  
+ 	/* Find what parents to record by checking independent ones. */
  	parents = reduce_heads(remoteheads);
  
- 	*head_subsumed = 1; /* we will flip this to 0 when we find it */
  	for (remoteheads = NULL, remotes = &remoteheads;
  	     parents;
  	     parents = next) {
@@@ -1068,10 -1049,122 +1042,122 @@@
  			*head_subsumed = 0;
  		else
  			remotes = &commit_list_insert(commit, remotes)->next;
+ 		free(parents);
  	}
  	return remoteheads;
  }
  
+ static void prepare_merge_message(struct strbuf *merge_names, struct strbuf *merge_msg)
+ {
+ 	struct fmt_merge_msg_opts opts;
+ 
+ 	memset(&opts, 0, sizeof(opts));
+ 	opts.add_title = !have_message;
+ 	opts.shortlog_len = shortlog_len;
+ 	opts.credit_people = (0 < option_edit);
+ 
+ 	fmt_merge_msg(merge_names, merge_msg, &opts);
+ 	if (merge_msg->len)
+ 		strbuf_setlen(merge_msg, merge_msg->len - 1);
+ }
+ 
+ static void handle_fetch_head(struct commit_list **remotes, struct strbuf *merge_names)
+ {
+ 	const char *filename;
+ 	int fd, pos, npos;
+ 	struct strbuf fetch_head_file = STRBUF_INIT;
+ 
+ 	if (!merge_names)
+ 		merge_names = &fetch_head_file;
+ 
+ 	filename = git_path("FETCH_HEAD");
+ 	fd = open(filename, O_RDONLY);
+ 	if (fd < 0)
+ 		die_errno(_("could not open '%s' for reading"), filename);
+ 
+ 	if (strbuf_read(merge_names, fd, 0) < 0)
+ 		die_errno(_("could not read '%s'"), filename);
+ 	if (close(fd) < 0)
+ 		die_errno(_("could not close '%s'"), filename);
+ 
+ 	for (pos = 0; pos < merge_names->len; pos = npos) {
+ 		unsigned char sha1[20];
+ 		char *ptr;
+ 		struct commit *commit;
+ 
+ 		ptr = strchr(merge_names->buf + pos, '\n');
+ 		if (ptr)
+ 			npos = ptr - merge_names->buf + 1;
+ 		else
+ 			npos = merge_names->len;
+ 
+ 		if (npos - pos < 40 + 2 ||
+ 		    get_sha1_hex(merge_names->buf + pos, sha1))
+ 			commit = NULL; /* bad */
+ 		else if (memcmp(merge_names->buf + pos + 40, "\t\t", 2))
+ 			continue; /* not-for-merge */
+ 		else {
+ 			char saved = merge_names->buf[pos + 40];
+ 			merge_names->buf[pos + 40] = '\0';
+ 			commit = get_merge_parent(merge_names->buf + pos);
+ 			merge_names->buf[pos + 40] = saved;
+ 		}
+ 		if (!commit) {
+ 			if (ptr)
+ 				*ptr = '\0';
+ 			die("not something we can merge in %s: %s",
+ 			    filename, merge_names->buf + pos);
+ 		}
+ 		remotes = &commit_list_insert(commit, remotes)->next;
+ 	}
+ 
+ 	if (merge_names == &fetch_head_file)
+ 		strbuf_release(&fetch_head_file);
+ }
+ 
+ static struct commit_list *collect_parents(struct commit *head_commit,
+ 					   int *head_subsumed,
+ 					   int argc, const char **argv,
+ 					   struct strbuf *merge_msg)
+ {
+ 	int i;
+ 	struct commit_list *remoteheads = NULL;
+ 	struct commit_list **remotes = &remoteheads;
+ 	struct strbuf merge_names = STRBUF_INIT, *autogen = NULL;
+ 
+ 	if (merge_msg && (!have_message || shortlog_len))
+ 		autogen = &merge_names;
+ 
+ 	if (head_commit)
+ 		remotes = &commit_list_insert(head_commit, remotes)->next;
+ 
+ 	if (argc == 1 && !strcmp(argv[0], "FETCH_HEAD")) {
+ 		handle_fetch_head(remotes, autogen);
+ 		remoteheads = reduce_parents(head_commit, head_subsumed, remoteheads);
+ 	} else {
+ 		for (i = 0; i < argc; i++) {
+ 			struct commit *commit = get_merge_parent(argv[i]);
+ 			if (!commit)
+ 				help_unknown_ref(argv[i], "merge",
+ 						 "not something we can merge");
+ 			remotes = &commit_list_insert(commit, remotes)->next;
+ 		}
+ 		remoteheads = reduce_parents(head_commit, head_subsumed, remoteheads);
+ 		if (autogen) {
+ 			struct commit_list *p;
+ 			for (p = remoteheads; p; p = p->next)
+ 				merge_name(merge_remote_util(p->item)->name, autogen);
+ 		}
+ 	}
+ 
+ 	if (autogen) {
+ 		prepare_merge_message(autogen, merge_msg);
+ 		strbuf_release(autogen);
+ 	}
+ 
+ 	return remoteheads;
+ }
+ 
  int cmd_merge(int argc, const char **argv, const char *prefix)
  {
  	unsigned char result_tree[20];
@@@ -1158,61 -1251,62 +1244,62 @@@
  		option_commit = 0;
  	}
  
- 	if (!abort_current_merge) {
- 		if (!argc) {
- 			if (default_to_upstream)
- 				argc = setup_with_upstream(&argv);
- 			else
- 				die(_("No commit specified and merge.defaultToUpstream not set."));
- 		} else if (argc == 1 && !strcmp(argv[0], "-"))
- 			argv[0] = "@{-1}";
+ 	if (!argc) {
+ 		if (default_to_upstream)
+ 			argc = setup_with_upstream(&argv);
+ 		else
+ 			die(_("No commit specified and merge.defaultToUpstream not set."));
+ 	} else if (argc == 1 && !strcmp(argv[0], "-")) {
+ 		argv[0] = "@{-1}";
  	}
+ 
  	if (!argc)
  		usage_with_options(builtin_merge_usage,
  			builtin_merge_options);
  
- 	/*
- 	 * This could be traditional "merge <msg> HEAD <commit>..."  and
- 	 * the way we can tell it is to see if the second token is HEAD,
- 	 * but some people might have misused the interface and used a
- 	 * commit-ish that is the same as HEAD there instead.
- 	 * Traditional format never would have "-m" so it is an
- 	 * additional safety measure to check for it.
- 	 */
- 
- 	if (!have_message && head_commit &&
- 	    is_old_style_invocation(argc, argv, head_commit->object.sha1)) {
- 		strbuf_addstr(&merge_msg, argv[0]);
- 		head_arg = argv[1];
- 		argv += 2;
- 		argc -= 2;
- 		remoteheads = collect_parents(head_commit, &head_subsumed, argc, argv);
- 	} else if (!head_commit) {
+ 	if (!head_commit) {
  		struct commit *remote_head;
  		/*
  		 * If the merged head is a valid one there is no reason
  		 * to forbid "git merge" into a branch yet to be born.
  		 * We do the same for "git pull".
  		 */
- 		if (argc != 1)
- 			die(_("Can merge only exactly one commit into "
- 				"empty head"));
  		if (squash)
  			die(_("Squash commit into empty head not supported yet"));
  		if (fast_forward == FF_NO)
  			die(_("Non-fast-forward commit does not make sense into "
  			    "an empty head"));
- 		remoteheads = collect_parents(head_commit, &head_subsumed, argc, argv);
+ 		remoteheads = collect_parents(head_commit, &head_subsumed,
+ 					      argc, argv, NULL);
  		remote_head = remoteheads->item;
  		if (!remote_head)
  			die(_("%s - not something we can merge"), argv[0]);
+ 		if (remoteheads->next)
+ 			die(_("Can merge only exactly one commit into empty head"));
  		read_empty(remote_head->object.sha1, 0);
  		update_ref("initial pull", "HEAD", remote_head->object.sha1,
  			   NULL, 0, UPDATE_REFS_DIE_ON_ERR);
  		goto done;
- 	} else {
- 		struct strbuf merge_names = STRBUF_INIT;
+ 	}
  
+ 	/*
+ 	 * This could be traditional "merge <msg> HEAD <commit>..."  and
+ 	 * the way we can tell it is to see if the second token is HEAD,
+ 	 * but some people might have misused the interface and used a
+ 	 * commit-ish that is the same as HEAD there instead.
+ 	 * Traditional format never would have "-m" so it is an
+ 	 * additional safety measure to check for it.
+ 	 */
+ 	if (!have_message &&
+ 	    is_old_style_invocation(argc, argv, head_commit->object.sha1)) {
+ 		warning("old-style 'git merge <msg> HEAD <commit>' is deprecated.");
+ 		strbuf_addstr(&merge_msg, argv[0]);
+ 		head_arg = argv[1];
+ 		argv += 2;
+ 		argc -= 2;
+ 		remoteheads = collect_parents(head_commit, &head_subsumed,
+ 					      argc, argv, NULL);
+ 	} else {
  		/* We are invoked directly as the first-class UI. */
  		head_arg = "HEAD";
  
@@@ -1221,21 -1315,8 +1308,8 @@@
  		 * the standard merge summary message to be appended
  		 * to the given message.
  		 */
- 		remoteheads = collect_parents(head_commit, &head_subsumed, argc, argv);
- 		for (p = remoteheads; p; p = p->next)
- 			merge_name(merge_remote_util(p->item)->name, &merge_names);
- 
- 		if (!have_message || shortlog_len) {
- 			struct fmt_merge_msg_opts opts;
- 			memset(&opts, 0, sizeof(opts));
- 			opts.add_title = !have_message;
- 			opts.shortlog_len = shortlog_len;
- 			opts.credit_people = (0 < option_edit);
- 
- 			fmt_merge_msg(&merge_names, &merge_msg, &opts);
- 			if (merge_msg.len)
- 				strbuf_setlen(&merge_msg, merge_msg.len - 1);
- 		}
+ 		remoteheads = collect_parents(head_commit, &head_subsumed,
+ 					      argc, argv, &merge_msg);
  	}
  
  	if (!head_commit || !argc)
@@@ -1313,7 -1394,7 +1387,7 @@@
  	if (!remoteheads)
  		; /* already up-to-date */
  	else if (!remoteheads->next)
 -		common = get_merge_bases(head_commit, remoteheads->item, 1);
 +		common = get_merge_bases(head_commit, remoteheads->item);
  	else {
  		struct commit_list *list = remoteheads;
  		commit_list_insert(head_commit, &list);
@@@ -1410,7 -1491,7 +1484,7 @@@
  			 * merge_bases again, otherwise "git merge HEAD^
  			 * HEAD^^" would be missed.
  			 */
 -			common_one = get_merge_bases(head_commit, j->item, 1);
 +			common_one = get_merge_bases(head_commit, j->item);
  			if (hashcmp(common_one->item->object.sha1,
  				j->item->object.sha1)) {
  				up_to_date = 0;
@@@ -1543,7 -1624,7 +1617,7 @@@
  		fprintf(stderr, _("Automatic merge went well; "
  			"stopped before committing as requested\n"));
  	else
 -		ret = suggest_conflicts(option_renormalize);
 +		ret = suggest_conflicts();
  
  done:
  	free(branch_to_free);
diff --combined git-pull.sh
index ad442264cb,15d943190c..9ed01fd219
--- a/git-pull.sh
+++ b/git-pull.sh
@@@ -240,7 -240,7 +240,7 @@@ test true = "$rebase" && 
  	if ! git rev-parse -q --verify HEAD >/dev/null
  	then
  		# On an unborn branch
 -		if test -f "$GIT_DIR/index"
 +		if test -f "$(git rev-parse --git-path index)"
  		then
  			die "$(gettext "updating an unborn branch with changes added to the index")"
  		fi
@@@ -323,7 -323,6 +323,6 @@@ the
  	fi
  fi
  
- merge_name=$(git fmt-merge-msg $log_arg <"$GIT_DIR/FETCH_HEAD") || exit
  case "$rebase" in
  true)
  	eval="git-rebase $diffstat $strategy_args $merge_args $rebase_args $verbosity"
@@@ -334,7 -333,7 +333,7 @@@
  	eval="git-merge $diffstat $no_commit $verify_signatures $edit $squash $no_ff $ff_only"
  	eval="$eval $log_arg $strategy_args $merge_args $verbosity $progress"
  	eval="$eval $gpg_sign_args"
- 	eval="$eval \"\$merge_name\" HEAD $merge_head"
+ 	eval="$eval FETCH_HEAD"
  	;;
  esac
  eval "exec $eval"