Merge branch 'master-for-junio' of git://repo.or.cz/git/fastimport; branch 'maint'

* 'master-for-junio' of git://repo.or.cz/git/fastimport:
  fast-import: Fail if a non-existant commit is used for merge
  fast-import: Avoid infinite loop after reset

* maint:
  Fix diff-options references in git-diff and git-format-patch
  Add definition of <commit-ish> to the main git man page.
  Begin SubmittingPatches with a check list
  fast-import: Fail if a non-existant commit is used for merge
  fast-import: Avoid infinite loop after reset

Author: Junio C Hamano

Documentation/SubmittingPatches

@@ -1,3 +1,30 @@
+Checklist (and a short version for the impatient):
+
+	- make commits of logical units
+	- check for unnecessary whitespace with "git diff --check"
+	  before committing
+	- do not check in commented out code or unneeded files
+	- provide a meaningful commit message
+	- the first line of the commit message should be a short
+	  description and should skip the full stop
+	- if you want your work included in git.git, add a
+	  "Signed-off-by: Your Name <your@email.com>" line to the
+	  commit message (or just use the option "-s" when
+	  committing) to confirm that you agree to the Developer's
+	  Certificate of Origin
+	- do not PGP sign your patch
+	- use "git format-patch -M" to create the patch
+	- do not attach your patch, but read in the mail
+	  body, unless you cannot teach your mailer to
+	  leave the formatting of the patch alone.
+	- be careful doing cut & paste into your mailer, not to
+	  corrupt whitespaces.
+	- provide additional information (which is unsuitable for
+	  the commit message) between the "---" and the diffstat
+	- send the patch to the list _and_ the maintainer
+
+Long version:
+
 I started reading over the SubmittingPatches document for Linux
 kernel, primarily because I wanted to have a document similar to
 it for the core GIT to make sure people understand what they are

Documentation/git-diff.txt

@@ -8,7 +8,7 @@ git-diff - Show changes between commits, commit and working tree, etc
 
 SYNOPSIS
 --------
-'git-diff' [ --diff-options ] <commit>{0,2} [--] [<path>...]
+'git-diff' [<common diff options>] <commit>{0,2} [--] [<path>...]
 
 DESCRIPTION
 -----------

Documentation/git-format-patch.txt

@@ -9,8 +9,8 @@ git-format-patch - Prepare patches for e-mail submission
 SYNOPSIS
 --------
 [verse]
-'git-format-patch' [-n | -k] [-o <dir> | --stdout] [--attach] [--thread]
-	           [-s | --signoff] [--diff-options] [--start-number <n>]
+'git-format-patch' [<common diff options>] [-n | -k] [-o <dir> | --stdout]
+		   [--attach] [--thread] [-s | --signoff] [--start-number <n>]
 		   [--in-reply-to=Message-Id] [--suffix=.<sfx>]
 		   [--ignore-if-in-upstream]
 		   <since>[..<until>]
@@ -46,6 +46,8 @@ reference.
 
 OPTIONS
 -------
+include::diff-options.txt[]
+
 -o|--output-directory <dir>::
 	Use <dir> to store the resulting files, instead of the
 	current working directory.

Documentation/git.txt

@@ -241,6 +241,12 @@ Identifier Terminology
 	operate on a <tree> object but automatically dereferences
 	<commit> and <tag> objects that point at a <tree>.
 
+<commit-ish>::
+	Indicates a commit or tag object name.  A
+	command that takes a <commit-ish> argument ultimately wants to
+	operate on a <commit> object but automatically dereferences
+	<tag> objects that point at a <commit>.
+
 <type>::
 	Indicates that an object type is required.
 	Currently one of: `blob`, `tree`, `commit`, or `tag`.

fast-import.c

@@ -220,7 +220,8 @@ struct branch
 	const char *name;
 	struct tree_entry branch_tree;
 	uintmax_t last_commit;
-	unsigned int pack_id;
+	unsigned active : 1;
+	unsigned pack_id : PACK_ID_BITS;
 	unsigned char sha1[20];
 };
 
@@ -528,6 +529,7 @@ static struct branch *new_branch(const char *name)
 	b->table_next_branch = branch_table[hc];
 	b->branch_tree.versions[0].mode = S_IFDIR;
 	b->branch_tree.versions[1].mode = S_IFDIR;
+	b->active = 0;
 	b->pack_id = MAX_PACK_ID;
 	branch_table[hc] = b;
 	branch_count++;
@@ -1547,6 +1549,7 @@ static void unload_one_branch(void)
 			e = active_branches;
 			active_branches = e->active_next_branch;
 		}
+		e->active = 0;
 		e->active_next_branch = NULL;
 		if (e->branch_tree.tree) {
 			release_tree_content_recursive(e->branch_tree.tree);
@@ -1559,10 +1562,13 @@ static void unload_one_branch(void)
 static void load_branch(struct branch *b)
 {
 	load_tree(&b->branch_tree);
-	b->active_next_branch = active_branches;
-	active_branches = b;
-	cur_active_branches++;
-	branch_load_count++;
+	if (!b->active) {
+		b->active = 1;
+		b->active_next_branch = active_branches;
+		active_branches = b;
+		cur_active_branches++;
+		branch_load_count++;
+	}
 }
 
 static void file_change_m(struct branch *b)
@@ -1746,7 +1752,14 @@ static struct hash_list *cmd_merge(unsigned int *count)
 			if (oe->type != OBJ_COMMIT)
 				die("Mark :%" PRIuMAX " not a commit", idnum);
 			hashcpy(n->sha1, oe->sha1);
-		} else if (get_sha1(from, n->sha1))
+		} else if (!get_sha1(from, n->sha1)) {
+			unsigned long size;
+			char *buf = read_object_with_reference(n->sha1,
+				commit_type, &size, n->sha1);
+			if (!buf || size < 46)
+				die("Not a valid commit: %s", from);
+			free(buf);
+		} else
 			die("Invalid ref name or SHA1 expression: %s", from);
 
 		n->next = NULL;