Merge branch 'jc/mailmap-case-insensitivity'

The mailmap mechanism unnecessarily downcased the e-mail addresses
in the output, and also ignored the human name when it is a single
character name.

This now has become Eric Sunshine's series, even though it still is
under jc/ hierarchy.

* jc/mailmap-case-insensitivity:
  mailmap: style fixes
  mailmap: debug: avoid passing NULL to fprintf() '%s' conversion specification
  mailmap: debug: eliminate -Wformat field precision type warning
  mailmap: debug: fix malformed fprintf() format conversion specification
  mailmap: debug: fix out-of-order fprintf() arguments
  mailmap: do not downcase mailmap entries
  t4203: demonstrate loss of uppercase characters in canonical email
  mailmap: do not lose single-letter names
  t4203: demonstrate loss of single-character name in mailmap entry

2 files changed, 57 insertions, 28 deletions

diff --git a/mailmap.c b/mailmap.c
index 2a7b36628c..44614fc411 100644
--- a/mailmap.c
+++ b/mailmap.c
@@ -5,8 +5,10 @@
 #define DEBUG_MAILMAP 0
 #if DEBUG_MAILMAP
 #define debug_mm(...) fprintf(stderr, __VA_ARGS__)
+#define debug_str(X) ((X) ? (X) : "(none)")
 #else
 static inline void debug_mm(const char *format, ...) {}
+static inline const char *debug_str(const char *s) { return s; }
 #endif
 
 const char *git_mailmap_file;
@@ -29,7 +31,8 @@ struct mailmap_entry {
 static void free_mailmap_info(void *p, const char *s)
 {
 	struct mailmap_info *mi = (struct mailmap_info *)p;
-	debug_mm("mailmap: -- complex: '%s' -> '%s' <%s>\n", s, mi->name, mi->email);
+	debug_mm("mailmap: -- complex: '%s' -> '%s' <%s>\n",
+		 s, debug_str(mi->name), debug_str(mi->email));
 	free(mi->name);
 	free(mi->email);
 }
@@ -37,8 +40,11 @@ static void free_mailmap_info(void *p, const char *s)
 static void free_mailmap_entry(void *p, const char *s)
 {
 	struct mailmap_entry *me = (struct mailmap_entry *)p;
-	debug_mm("mailmap: removing entries for <%s>, with %d sub-entries\n", s, me->namemap.nr);
-	debug_mm("mailmap: - simple: '%s' <%s>\n", me->name, me->email);
+	debug_mm("mailmap: removing entries for <%s>, with %d sub-entries\n",
+		 s, me->namemap.nr);
+	debug_mm("mailmap: - simple: '%s' <%s>\n",
+		 debug_str(me->name), debug_str(me->email));
+
 	free(me->name);
 	free(me->email);
 
@@ -47,18 +53,11 @@ static void free_mailmap_entry(void *p, const char *s)
 }
 
 static void add_mapping(struct string_list *map,
-			char *new_name, char *new_email, char *old_name, char *old_email)
+			char *new_name, char *new_email,
+			char *old_name, char *old_email)
 {
 	struct mailmap_entry *me;
 	int index;
-	char *p;
-
-	if (old_email)
-		for (p = old_email; *p; p++)
-			*p = tolower(*p);
-	if (new_email)
-		for (p = new_email; *p; p++)
-			*p = tolower(*p);
 
 	if (old_email == NULL) {
 		old_email = new_email;
@@ -68,16 +67,21 @@ static void add_mapping(struct string_list *map,
 	if ((index = string_list_find_insert_index(map, old_email, 1)) < 0) {
 		/* mailmap entry exists, invert index value */
 		index = -1 - index;
+		me = (struct mailmap_entry *)map->items[index].util;
 	} else {
 		/* create mailmap entry */
-		struct string_list_item *item = string_list_insert_at_index(map, index, old_email);
-		item->util = xcalloc(1, sizeof(struct mailmap_entry));
-		((struct mailmap_entry *)item->util)->namemap.strdup_strings = 1;
+		struct string_list_item *item;
+
+		item = string_list_insert_at_index(map, index, old_email);
+		me = xcalloc(1, sizeof(struct mailmap_entry));
+		me->namemap.strdup_strings = 1;
+		me->namemap.cmp = strcasecmp;
+		item->util = me;
 	}
-	me = (struct mailmap_entry *)map->items[index].util;
 
 	if (old_name == NULL) {
-		debug_mm("mailmap: adding (simple) entry for %s at index %d\n", old_email, index);
+		debug_mm("mailmap: adding (simple) entry for %s at index %d\n",
+			 old_email, index);
 		/* Replace current name and new email for simple entry */
 		if (new_name) {
 			free(me->name);
@@ -89,7 +93,8 @@ static void add_mapping(struct string_list *map,
 		}
 	} else {
 		struct mailmap_info *mi = xcalloc(1, sizeof(struct mailmap_info));
-		debug_mm("mailmap: adding (complex) entry for %s at index %d\n", old_email, index);
+		debug_mm("mailmap: adding (complex) entry for %s at index %d\n",
+			 old_email, index);
 		if (new_name)
 			mi->name = xstrdup(new_name);
 		if (new_email)
@@ -98,11 +103,12 @@ static void add_mapping(struct string_list *map,
 	}
 
 	debug_mm("mailmap:  '%s' <%s> -> '%s' <%s>\n",
-		 old_name, old_email, new_name, new_email);
+		 debug_str(old_name), old_email,
+		 debug_str(new_name), debug_str(new_email));
 }
 
 static char *parse_name_and_email(char *buffer, char **name,
-		char **email, int allow_empty_email)
+				  char **email, int allow_empty_email)
 {
 	char *left, *right, *nstart, *nend;
 	*name = *email = NULL;
@@ -122,7 +128,7 @@ static char *parse_name_and_email(char *buffer, char **name,
 	while (nend > nstart && isspace(*nend))
 		--nend;
 
-	*name = (nstart < nend ? nstart : NULL);
+	*name = (nstart <= nend ? nstart : NULL);
 	*email = left+1;
 	*(nend+1) = '\0';
 	*right++ = '\0';
@@ -306,21 +312,25 @@ static struct string_list_item *lookup_prefix(struct string_list *map,
 }
 
 int map_user(struct string_list *map,
-			 const char **email, size_t *emaillen,
-			 const char **name, size_t *namelen)
+	     const char **email, size_t *emaillen,
+	     const char **name, size_t *namelen)
 {
 	struct string_list_item *item;
 	struct mailmap_entry *me;
 
 	debug_mm("map_user: map '%.*s' <%.*s>\n",
-		 *name, *namelen, *emaillen, *email);
+		 (int)*namelen, debug_str(*name),
+		 (int)*emaillen, debug_str(*email));
 
 	item = lookup_prefix(map, *email, *emaillen);
 	if (item != NULL) {
 		me = (struct mailmap_entry *)item->util;
 		if (me->namemap.nr) {
-			/* The item has multiple items, so we'll look up on name too */
-			/* If the name is not found, we choose the simple entry      */
+			/*
+			 * The item has multiple items, so we'll look up on
+			 * name too. If the name is not found, we choose the
+			 * simple entry.
+			 */
 			struct string_list_item *subitem;
 			subitem = lookup_prefix(&me->namemap, *name, *namelen);
 			if (subitem)
@@ -341,8 +351,9 @@ int map_user(struct string_list *map,
 				*name = mi->name;
 				*namelen = strlen(*name);
 		}
-		debug_mm("map_user:  to '%.*s' <.*%s>\n", *namelen, *name,
-				 *emaillen, *email);
+		debug_mm("map_user:  to '%.*s' <%.*s>\n",
+			 (int)*namelen, debug_str(*name),
+			 (int)*emaillen, debug_str(*email));
 		return 1;
 	}
 	debug_mm("map_user:  --\n");
diff --git a/t/t4203-mailmap.sh b/t/t4203-mailmap.sh
index 842b7549ec..c32df80f14 100755
--- a/t/t4203-mailmap.sh
+++ b/t/t4203-mailmap.sh
@@ -247,6 +247,24 @@ test_expect_success 'cleanup after mailmap.blob tests' '
 	rm -f .mailmap
 '
 
+test_expect_success 'single-character name' '
+	echo "     1	A <author@example.com>" >expect &&
+	echo "     1	nick1 <bugs@company.xx>" >>expect &&
+	echo "A <author@example.com>" >.mailmap &&
+	test_when_finished "rm .mailmap" &&
+	git shortlog -es HEAD >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success 'preserve canonical email case' '
+	echo "     1	A U Thor <AUTHOR@example.com>" >expect &&
+	echo "     1	nick1 <bugs@company.xx>" >>expect &&
+	echo "<AUTHOR@example.com> <author@example.com>" >.mailmap &&
+	test_when_finished "rm .mailmap" &&
+	git shortlog -es HEAD >actual &&
+	test_cmp expect actual
+'
+
 # Extended mailmap configurations should give us the following output for shortlog
 cat >expect <<\EOF
 A U Thor <author@example.com> (1):