Support showing notes from more than one notes tree

With this patch, you can set notes.displayRef to a glob that points at
your favourite notes refs, e.g.,

[notes]
	displayRef = refs/notes/*

Then git-log and friends will show notes from all trees.

Thanks to Junio C Hamano for lots of feedback, which greatly
influenced the design of the entire series and this commit in
particular.

Signed-off-by: Thomas Rast <trast@student.ethz.ch>
Acked-by: Johan Herland <johan@herland.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/config.txt

@@ -500,10 +500,12 @@ check that makes sure that existing object files will not get overwritten.
 core.notesRef::
 	When showing commit messages, also show notes which are stored in
 	the given ref.  This ref is expected to contain files named
-	after the full SHA-1 of the commit they annotate.
+	after the full SHA-1 of the commit they annotate.  The ref
+	must be fully qualified.
 +
 If such a file exists in the given ref, the referenced blob is read, and
-appended to the commit message, separated by a "Notes:" line.  If the
+appended to the commit message, separated by a "Notes (<refname>):"
+line (shortened to "Notes:" in the case of "refs/notes/commits").  If the
 given ref itself does not exist, it is not an error, but means that no
 notes should be printed.
 +
@@ -1286,6 +1288,23 @@ mergetool.keepTemporaries::
 mergetool.prompt::
 	Prompt before each invocation of the merge resolution program.
 
+notes.displayRef::
+	The (fully qualified) refname from which to show notes when
+	showing commit messages.  The value of this variable can be set
+	to a glob, in which case notes from all matching refs will be
+	shown.  You may also specify this configuration variable
+	several times.  A warning will be issued for refs that do not
+	exist, but a glob that does not match any refs is silently
+	ignored.
++
+This setting can be overridden with the `GIT_NOTES_DISPLAY_REF`
+environment variable, which must be a colon separated list of refs or
+globs.
++
+The effective value of "core.notesRef" (possibly overridden by
+GIT_NOTES_REF) is also implicitly added to the list of refs to be
+displayed.
+
 pack.window::
 	The size of the window used by linkgit:git-pack-objects[1] when no
 	window size is given on the command line. Defaults to 10.

Documentation/git-notes.txt

@@ -27,12 +27,13 @@ A typical use of notes is to extend a commit message without having
 to change the commit itself. Such commit notes can be shown by `git log`
 along with the original commit message. To discern these notes from the
 message stored in the commit object, the notes are indented like the
-message, after an unindented line saying "Notes:".
+message, after an unindented line saying "Notes (<refname>):" (or
+"Notes:" for the default setting).
 
-To disable notes, you have to set the config variable core.notesRef to
-the empty string.  Alternatively, you can set it to a different ref,
-something like "refs/notes/bugzilla".  This setting can be overridden
-by the environment variable "GIT_NOTES_REF".
+This command always manipulates the notes specified in "core.notesRef"
+(see linkgit:git-config[1]), which can be overridden by GIT_NOTES_REF.
+To change which notes are shown by 'git-log', see the
+"notes.displayRef" configuration.
 
 
 SUBCOMMANDS

Documentation/pretty-options.txt

@@ -30,9 +30,18 @@ people using 80-column terminals.
 	defaults to UTF-8.
 
 --no-notes::
---show-notes::
+--show-notes[=<ref>]::
 	Show the notes (see linkgit:git-notes[1]) that annotate the
 	commit, when showing the commit log message.  This is the default
 	for `git log`, `git show` and `git whatchanged` commands when
 	there is no `--pretty`, `--format` nor `--oneline` option is
 	given on the command line.
++
+With an optional argument, add this ref to the list of notes.  The ref
+is taken to be in `refs/notes/` if it is not qualified.
+
+--[no-]standard-notes::
+	Enable or disable populating the notes ref list from the
+	'core.notesRef' and 'notes.displayRef' variables (or
+	corresponding environment overrides).  Enabled by default.
+	See linkgit:git-config[1].

builtin-log.c

@@ -60,6 +60,8 @@ static void cmd_log_init(int argc, const char **argv, const char *prefix,
 
 	if (!rev->show_notes_given && !rev->pretty_given)
 		rev->show_notes = 1;
+	if (rev->show_notes)
+		init_display_notes(&rev->notes_opt);
 
 	if (rev->diffopt.pickaxe || rev->diffopt.filter)
 		rev->always_show_header = 0;
@@ -1059,6 +1061,9 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
 	if (!DIFF_OPT_TST(&rev.diffopt, TEXT) && !no_binary_diff)
 		DIFF_OPT_SET(&rev.diffopt, BINARY);
 
+	if (rev.show_notes)
+		init_display_notes(&rev.notes_opt);
+
 	if (!use_stdout)
 		output_directory = set_outdir(prefix, output_directory);
 

cache.h

@@ -385,6 +385,7 @@ static inline enum object_type object_type(unsigned int mode)
 #define ATTRIBUTE_MACRO_PREFIX "[attr]"
 #define GIT_NOTES_REF_ENVIRONMENT "GIT_NOTES_REF"
 #define GIT_NOTES_DEFAULT_REF "refs/notes/commits"
+#define GIT_NOTES_DISPLAY_REF_ENVIRONMENT "GIT_NOTES_DISPLAY_REF"
 
 extern int is_bare_repository_cfg;
 extern int is_bare_repository(void);

notes.c

@@ -5,6 +5,8 @@
 #include "utf8.h"
 #include "strbuf.h"
 #include "tree-walk.h"
+#include "string-list.h"
+#include "refs.h"
 
 /*
  * Use a non-balancing simple 16-tree structure with struct int_node as
@@ -68,6 +70,9 @@ struct non_note {
 
 struct notes_tree default_notes_tree;
 
+static struct string_list display_notes_refs;
+static struct notes_tree **display_notes_trees;
+
 static void load_subtree(struct notes_tree *t, struct leaf_node *subtree,
 		struct int_node *node, unsigned int n);
 
@@ -828,6 +833,83 @@ int combine_notes_ignore(unsigned char *cur_sha1,
 	return 0;
 }
 
+static int string_list_add_one_ref(const char *path, const unsigned char *sha1,
+				   int flag, void *cb)
+{
+	struct string_list *refs = cb;
+	if (!unsorted_string_list_has_string(refs, path))
+		string_list_append(path, refs);
+	return 0;
+}
+
+void string_list_add_refs_by_glob(struct string_list *list, const char *glob)
+{
+	if (has_glob_specials(glob)) {
+		for_each_glob_ref(string_list_add_one_ref, glob, list);
+	} else {
+		unsigned char sha1[20];
+		if (get_sha1(glob, sha1))
+			warning("notes ref %s is invalid", glob);
+		if (!unsorted_string_list_has_string(list, glob))
+			string_list_append(glob, list);
+	}
+}
+
+void string_list_add_refs_from_colon_sep(struct string_list *list,
+					 const char *globs)
+{
+	struct strbuf globbuf = STRBUF_INIT;
+	struct strbuf **split;
+	int i;
+
+	strbuf_addstr(&globbuf, globs);
+	split = strbuf_split(&globbuf, ':');
+
+	for (i = 0; split[i]; i++) {
+		if (!split[i]->len)
+			continue;
+		if (split[i]->buf[split[i]->len-1] == ':')
+			strbuf_setlen(split[i], split[i]->len-1);
+		string_list_add_refs_by_glob(list, split[i]->buf);
+	}
+
+	strbuf_list_free(split);
+	strbuf_release(&globbuf);
+}
+
+static int string_list_add_refs_from_list(struct string_list_item *item,
+					  void *cb)
+{
+	struct string_list *list = cb;
+	string_list_add_refs_by_glob(list, item->string);
+	return 0;
+}
+
+static int notes_display_config(const char *k, const char *v, void *cb)
+{
+	int *load_refs = cb;
+
+	if (*load_refs && !strcmp(k, "notes.displayref")) {
+		if (!v)
+			config_error_nonbool(k);
+		string_list_add_refs_by_glob(&display_notes_refs, v);
+	}
+
+	return 0;
+}
+
+static const char *default_notes_ref(void)
+{
+	const char *notes_ref = NULL;
+	if (!notes_ref)
+		notes_ref = getenv(GIT_NOTES_REF_ENVIRONMENT);
+	if (!notes_ref)
+		notes_ref = notes_ref_name; /* value of core.notesRef config */
+	if (!notes_ref)
+		notes_ref = GIT_NOTES_DEFAULT_REF;
+	return notes_ref;
+}
+
 void init_notes(struct notes_tree *t, const char *notes_ref,
 		combine_notes_fn combine_notes, int flags)
 {
@@ -840,11 +922,7 @@ void init_notes(struct notes_tree *t, const char *notes_ref,
 	assert(!t->initialized);
 
 	if (!notes_ref)
-		notes_ref = getenv(GIT_NOTES_REF_ENVIRONMENT);
-	if (!notes_ref)
-		notes_ref = notes_ref_name; /* value of core.notesRef config */
-	if (!notes_ref)
-		notes_ref = GIT_NOTES_DEFAULT_REF;
+		notes_ref = default_notes_ref();
 
 	if (!combine_notes)
 		combine_notes = combine_notes_concatenate;
@@ -868,6 +946,63 @@ void init_notes(struct notes_tree *t, const char *notes_ref,
 	load_subtree(t, &root_tree, t->root, 0);
 }
 
+struct load_notes_cb_data {
+	int counter;
+	struct notes_tree **trees;
+};
+
+static int load_one_display_note_ref(struct string_list_item *item,
+				     void *cb_data)
+{
+	struct load_notes_cb_data *c = cb_data;
+	struct notes_tree *t = xcalloc(1, sizeof(struct notes_tree));
+	init_notes(t, item->string, combine_notes_ignore, 0);
+	c->trees[c->counter++] = t;
+	return 0;
+}
+
+struct notes_tree **load_notes_trees(struct string_list *refs)
+{
+	struct notes_tree **trees;
+	struct load_notes_cb_data cb_data;
+	trees = xmalloc((refs->nr+1) * sizeof(struct notes_tree *));
+	cb_data.counter = 0;
+	cb_data.trees = trees;
+	for_each_string_list(load_one_display_note_ref, refs, &cb_data);
+	trees[cb_data.counter] = NULL;
+	return trees;
+}
+
+void init_display_notes(struct display_notes_opt *opt)
+{
+	char *display_ref_env;
+	int load_config_refs = 0;
+	display_notes_refs.strdup_strings = 1;
+
+	assert(!display_notes_trees);
+
+	if (!opt || !opt->suppress_default_notes) {
+		string_list_append(default_notes_ref(), &display_notes_refs);
+		display_ref_env = getenv(GIT_NOTES_DISPLAY_REF_ENVIRONMENT);
+		if (display_ref_env) {
+			string_list_add_refs_from_colon_sep(&display_notes_refs,
+							    display_ref_env);
+			load_config_refs = 0;
+		} else
+			load_config_refs = 1;
+	}
+
+	git_config(notes_display_config, &load_config_refs);
+
+	if (opt && opt->extra_notes_refs)
+		for_each_string_list(string_list_add_refs_from_list,
+				     opt->extra_notes_refs,
+				     &display_notes_refs);
+
+	display_notes_trees = load_notes_trees(&display_notes_refs);
+	string_list_clear(&display_notes_refs, 0);
+}
+
 void add_note(struct notes_tree *t, const unsigned char *object_sha1,
 		const unsigned char *note_sha1, combine_notes_fn combine_notes)
 {
@@ -1016,8 +1151,18 @@ void format_note(struct notes_tree *t, const unsigned char *object_sha1,
 	if (msglen && msg[msglen - 1] == '\n')
 		msglen--;
 
-	if (flags & NOTES_SHOW_HEADER)
-		strbuf_addstr(sb, "\nNotes:\n");
+	if (flags & NOTES_SHOW_HEADER) {
+		const char *ref = t->ref;
+		if (!ref || !strcmp(ref, GIT_NOTES_DEFAULT_REF)) {
+			strbuf_addstr(sb, "\nNotes:\n");
+		} else {
+			if (!prefixcmp(ref, "refs/"))
+				ref += 5;
+			if (!prefixcmp(ref, "notes/"))
+				ref += 6;
+			strbuf_addf(sb, "\nNotes (%s):\n", ref);
+		}
+	}
 
 	for (msg_p = msg; msg_p < msg + msglen; msg_p += linelen + 1) {
 		linelen = strchrnul(msg_p, '\n') - msg_p;
@@ -1030,3 +1175,13 @@ void format_note(struct notes_tree *t, const unsigned char *object_sha1,
 
 	free(msg);
 }
+
+void format_display_notes(const unsigned char *object_sha1,
+			  struct strbuf *sb, const char *output_encoding, int flags)
+{
+	int i;
+	assert(display_notes_trees);
+	for (i = 0; display_notes_trees[i]; i++)
+		format_note(display_notes_trees[i], object_sha1, sb,
+			    output_encoding, flags);
+}

notes.h

@@ -198,4 +198,59 @@ void free_notes(struct notes_tree *t);
 void format_note(struct notes_tree *t, const unsigned char *object_sha1,
 		struct strbuf *sb, const char *output_encoding, int flags);
 
+
+struct string_list;
+
+struct display_notes_opt {
+	int suppress_default_notes:1;
+	struct string_list *extra_notes_refs;
+};
+
+/*
+ * Load the notes machinery for displaying several notes trees.
+ *
+ * If 'opt' is not NULL, then it specifies additional settings for the
+ * displaying:
+ *
+ * - suppress_default_notes indicates that the notes from
+ *   core.notesRef and notes.displayRef should not be loaded.
+ *
+ * - extra_notes_refs may contain a list of globs (in the same style
+ *   as notes.displayRef) where notes should be loaded from.
+ */
+void init_display_notes(struct display_notes_opt *opt);
+
+/*
+ * Append notes for the given 'object_sha1' from all trees set up by
+ * init_display_notes() to 'sb'.  The 'flags' are a bitwise
+ * combination of
+ *
+ * - NOTES_SHOW_HEADER: add a 'Notes (refname):' header
+ *
+ * - NOTES_INDENT: indent the notes by 4 places
+ *
+ * You *must* call init_display_notes() before using this function.
+ */
+void format_display_notes(const unsigned char *object_sha1,
+			  struct strbuf *sb, const char *output_encoding, int flags);
+
+/*
+ * Load the notes tree from each ref listed in 'refs'.  The output is
+ * an array of notes_tree*, terminated by a NULL.
+ */
+struct notes_tree **load_notes_trees(struct string_list *refs);
+
+/*
+ * Add all refs that match 'glob' to the 'list'.
+ */
+void string_list_add_refs_by_glob(struct string_list *list, const char *glob);
+
+/*
+ * Add all refs from a colon-separated glob list 'globs' to the end of
+ * 'list'.  Empty components are ignored.  This helper is used to
+ * parse GIT_NOTES_DISPLAY_REF style environment variables.
+ */
+void string_list_add_refs_from_colon_sep(struct string_list *list,
+					 const char *globs);
+
 #endif

pretty.c

@@ -775,7 +775,7 @@ static size_t format_commit_one(struct strbuf *sb, const char *placeholder,
 		}
 		return 0;	/* unknown %g placeholder */
 	case 'N':
-		format_note(NULL, commit->object.sha1, sb,
+		format_display_notes(commit->object.sha1, sb,
 			    git_log_output_encoding ? git_log_output_encoding
 						    : git_commit_encoding, 0);
 		return 1;
@@ -1096,8 +1096,8 @@ void pretty_print_commit(enum cmit_fmt fmt, const struct commit *commit,
 		strbuf_addch(sb, '\n');
 
 	if (context->show_notes)
-		format_note(NULL, commit->object.sha1, sb, encoding,
-			    NOTES_SHOW_HEADER | NOTES_INDENT);
+		format_display_notes(commit->object.sha1, sb, encoding,
+				     NOTES_SHOW_HEADER | NOTES_INDENT);
 
 	free(reencoded);
 }