Merge branch 'jk/config-parsing-cleanup'

Configuration parsing for tar.* configuration variables were
broken. Introduce a new config-keyname parser API to make the
callers much less error prone.

* jk/config-parsing-cleanup:
  reflog: use parse_config_key in config callback
  help: use parse_config_key for man config
  submodule: simplify memory handling in config parsing
  submodule: use parse_config_key when parsing config
  userdiff: drop parse_driver function
  convert some config callbacks to parse_config_key
  archive-tar: use parse_config_key when parsing config
  config: add helper function for parsing key names

10 files changed, 117 insertions, 99 deletions

diff --git a/archive-tar.c b/archive-tar.c
index d1cce46e33..719b6298e6 100644
--- a/archive-tar.c
+++ b/archive-tar.c
@@ -327,20 +327,12 @@ static struct archiver *find_tar_filter(const char *name, int len)
 static int tar_filter_config(const char *var, const char *value, void *data)
 {
 	struct archiver *ar;
-	const char *dot;
 	const char *name;
 	const char *type;
 	int namelen;
 
-	if (prefixcmp(var, "tar."))
+	if (parse_config_key(var, "tar", &name, &namelen, &type) < 0 || !name)
 		return 0;
-	dot = strrchr(var, '.');
-	if (dot == var + 9)
-		return 0;
-
-	name = var + 4;
-	namelen = dot - name;
-	type = dot + 1;
 
 	ar = find_tar_filter(name, namelen);
 	if (!ar) {
diff --git a/builtin/help.c b/builtin/help.c
index 6067a6134b..d1d71816a9 100644
--- a/builtin/help.c
+++ b/builtin/help.c
@@ -236,21 +236,21 @@ static int add_man_viewer_cmd(const char *name,
 
 static int add_man_viewer_info(const char *var, const char *value)
 {
-	const char *name = var + 4;
-	const char *subkey = strrchr(name, '.');
+	const char *name, *subkey;
+	int namelen;
 
-	if (!subkey)
+	if (parse_config_key(var, "man", &name, &namelen, &subkey) < 0 || !name)
 		return 0;
 
-	if (!strcmp(subkey, ".path")) {
+	if (!strcmp(subkey, "path")) {
 		if (!value)
 			return config_error_nonbool(var);
-		return add_man_viewer_path(name, subkey - name, value);
+		return add_man_viewer_path(name, namelen, value);
 	}
-	if (!strcmp(subkey, ".cmd")) {
+	if (!strcmp(subkey, "cmd")) {
 		if (!value)
 			return config_error_nonbool(var);
-		return add_man_viewer_cmd(name, subkey - name, value);
+		return add_man_viewer_cmd(name, namelen, value);
 	}
 
 	return 0;
diff --git a/builtin/reflog.c b/builtin/reflog.c
index b3c9e27bde..1fedf66329 100644
--- a/builtin/reflog.c
+++ b/builtin/reflog.c
@@ -510,26 +510,27 @@ static int parse_expire_cfg_value(const char *var, const char *value, unsigned l
 
 static int reflog_expire_config(const char *var, const char *value, void *cb)
 {
-	const char *lastdot = strrchr(var, '.');
+	const char *pattern, *key;
+	int pattern_len;
 	unsigned long expire;
 	int slot;
 	struct reflog_expire_cfg *ent;
 
-	if (!lastdot || prefixcmp(var, "gc."))
+	if (parse_config_key(var, "gc", &pattern, &pattern_len, &key) < 0)
 		return git_default_config(var, value, cb);
 
-	if (!strcmp(lastdot, ".reflogexpire")) {
+	if (!strcmp(key, "reflogexpire")) {
 		slot = EXPIRE_TOTAL;
 		if (parse_expire_cfg_value(var, value, &expire))
 			return -1;
-	} else if (!strcmp(lastdot, ".reflogexpireunreachable")) {
+	} else if (!strcmp(key, "reflogexpireunreachable")) {
 		slot = EXPIRE_UNREACH;
 		if (parse_expire_cfg_value(var, value, &expire))
 			return -1;
 	} else
 		return git_default_config(var, value, cb);
 
-	if (lastdot == var + 2) {
+	if (!pattern) {
 		switch (slot) {
 		case EXPIRE_TOTAL:
 			default_reflog_expire = expire;
@@ -541,7 +542,7 @@ static int reflog_expire_config(const char *var, const char *value, void *cb)
 		return 0;
 	}
 
-	ent = find_cfg_ent(var + 3, lastdot - (var+3));
+	ent = find_cfg_ent(pattern, pattern_len);
 	if (!ent)
 		return -1;
 	switch (slot) {
diff --git a/cache.h b/cache.h
index 94ffcda8f6..9038fb500e 100644
--- a/cache.h
+++ b/cache.h
@@ -1170,6 +1170,21 @@ struct config_include_data {
 #define CONFIG_INCLUDE_INIT { 0 }
 extern int git_config_include(const char *name, const char *value, void *data);
 
+/*
+ * Match and parse a config key of the form:
+ *
+ *   section.(subsection.)?key
+ *
+ * (i.e., what gets handed to a config_fn_t). The caller provides the section;
+ * we return -1 if it does not match, 0 otherwise. The subsection and key
+ * out-parameters are filled by the function (and subsection is NULL if it is
+ * missing).
+ */
+extern int parse_config_key(const char *var,
+			    const char *section,
+			    const char **subsection, int *subsection_len,
+			    const char **key);
+
 extern int committer_ident_sufficiently_given(void);
 extern int author_ident_sufficiently_given(void);
 
diff --git a/config.c b/config.c
index 5a20de3fa6..aefd80b12a 100644
--- a/config.c
+++ b/config.c
@@ -1681,3 +1681,36 @@ int config_error_nonbool(const char *var)
 {
 	return error("Missing value for '%s'", var);
 }
+
+int parse_config_key(const char *var,
+		     const char *section,
+		     const char **subsection, int *subsection_len,
+		     const char **key)
+{
+	int section_len = strlen(section);
+	const char *dot;
+
+	/* Does it start with "section." ? */
+	if (prefixcmp(var, section) || var[section_len] != '.')
+		return -1;
+
+	/*
+	 * Find the key; we don't know yet if we have a subsection, but we must
+	 * parse backwards from the end, since the subsection may have dots in
+	 * it, too.
+	 */
+	dot = strrchr(var, '.');
+	*key = dot + 1;
+
+	/* Did we have a subsection at all? */
+	if (dot == var + section_len) {
+		*subsection = NULL;
+		*subsection_len = 0;
+	}
+	else {
+		*subsection = var + section_len + 1;
+		*subsection_len = dot - *subsection;
+	}
+
+	return 0;
+}
diff --git a/convert.c b/convert.c
index 66021550c3..3520252d3a 100644
--- a/convert.c
+++ b/convert.c
@@ -457,7 +457,7 @@ static struct convert_driver {
 
 static int read_convert_config(const char *var, const char *value, void *cb)
 {
-	const char *ep, *name;
+	const char *key, *name;
 	int namelen;
 	struct convert_driver *drv;
 
@@ -465,10 +465,8 @@ static int read_convert_config(const char *var, const char *value, void *cb)
 	 * External conversion drivers are configured using
 	 * "filter.<name>.variable".
 	 */
-	if (prefixcmp(var, "filter.") || (ep = strrchr(var, '.')) == var + 6)
+	if (parse_config_key(var, "filter", &name, &namelen, &key) < 0 || !name)
 		return 0;
-	name = var + 7;
-	namelen = ep - name;
 	for (drv = user_convert; drv; drv = drv->next)
 		if (!strncmp(drv->name, name, namelen) && !drv->name[namelen])
 			break;
@@ -479,8 +477,6 @@ static int read_convert_config(const char *var, const char *value, void *cb)
 		user_convert_tail = &(drv->next);
 	}
 
-	ep++;
-
 	/*
 	 * filter.<name>.smudge and filter.<name>.clean specifies
 	 * the command line:
@@ -490,13 +486,13 @@ static int read_convert_config(const char *var, const char *value, void *cb)
 	 * The command-line will not be interpolated in any way.
 	 */
 
-	if (!strcmp("smudge", ep))
+	if (!strcmp("smudge", key))
 		return git_config_string(&drv->smudge, var, value);
 
-	if (!strcmp("clean", ep))
+	if (!strcmp("clean", key))
 		return git_config_string(&drv->clean, var, value);
 
-	if (!strcmp("required", ep)) {
+	if (!strcmp("required", key)) {
 		drv->required = git_config_bool(var, value);
 		return 0;
 	}
diff --git a/ll-merge.c b/ll-merge.c
index acea33bf1b..fb61ea66a1 100644
--- a/ll-merge.c
+++ b/ll-merge.c
@@ -222,7 +222,7 @@ static const char *default_ll_merge;
 static int read_merge_config(const char *var, const char *value, void *cb)
 {
 	struct ll_merge_driver *fn;
-	const char *ep, *name;
+	const char *key, *name;
 	int namelen;
 
 	if (!strcmp(var, "merge.default")) {
@@ -236,15 +236,13 @@ static int read_merge_config(const char *var, const char *value, void *cb)
 	 * especially, we do not want to look at variables such as
 	 * "merge.summary", "merge.tool", and "merge.verbosity".
 	 */
-	if (prefixcmp(var, "merge.") || (ep = strrchr(var, '.')) == var + 5)
+	if (parse_config_key(var, "merge", &name, &namelen, &key) < 0 || !name)
 		return 0;
 
 	/*
 	 * Find existing one as we might be processing merge.<name>.var2
 	 * after seeing merge.<name>.var1.
 	 */
-	name = var + 6;
-	namelen = ep - name;
 	for (fn = ll_user_merge; fn; fn = fn->next)
 		if (!strncmp(fn->name, name, namelen) && !fn->name[namelen])
 			break;
@@ -256,16 +254,14 @@ static int read_merge_config(const char *var, const char *value, void *cb)
 		ll_user_merge_tail = &(fn->next);
 	}
 
-	ep++;
-
-	if (!strcmp("name", ep)) {
+	if (!strcmp("name", key)) {
 		if (!value)
 			return error("%s: lacks value", var);
 		fn->description = xstrdup(value);
 		return 0;
 	}
 
-	if (!strcmp("driver", ep)) {
+	if (!strcmp("driver", key)) {
 		if (!value)
 			return error("%s: lacks value", var);
 		/*
@@ -289,7 +285,7 @@ static int read_merge_config(const char *var, const char *value, void *cb)
 		return 0;
 	}
 
-	if (!strcmp("recursive", ep)) {
+	if (!strcmp("recursive", key)) {
 		if (!value)
 			return error("%s: lacks value", var);
 		fn->recursive = xstrdup(value);
diff --git a/submodule.c b/submodule.c
index 2f55436234..9ba1496543 100644
--- a/submodule.c
+++ b/submodule.c
@@ -126,45 +126,44 @@ void gitmodules_config(void)
 
 int parse_submodule_config_option(const char *var, const char *value)
 {
-	int len;
 	struct string_list_item *config;
-	struct strbuf submodname = STRBUF_INIT;
+	const char *name, *key;
+	int namelen;
 
-	var += 10;		/* Skip "submodule." */
+	if (parse_config_key(var, "submodule", &name, &namelen, &key) < 0 || !name)
+		return 0;
 
-	len = strlen(var);
-	if ((len > 5) && !strcmp(var + len - 5, ".path")) {
-		strbuf_add(&submodname, var, len - 5);
+	if (!strcmp(key, "path")) {
 		config = unsorted_string_list_lookup(&config_name_for_path, value);
 		if (config)
 			free(config->util);
 		else
 			config = string_list_append(&config_name_for_path, xstrdup(value));
-		config->util = strbuf_detach(&submodname, NULL);
-		strbuf_release(&submodname);
-	} else if ((len > 23) && !strcmp(var + len - 23, ".fetchrecursesubmodules")) {
-		strbuf_add(&submodname, var, len - 23);
-		config = unsorted_string_list_lookup(&config_fetch_recurse_submodules_for_name, submodname.buf);
+		config->util = xmemdupz(name, namelen);
+	} else if (!strcmp(key, "fetchrecursesubmodules")) {
+		char *name_cstr = xmemdupz(name, namelen);
+		config = unsorted_string_list_lookup(&config_fetch_recurse_submodules_for_name, name_cstr);
 		if (!config)
-			config = string_list_append(&config_fetch_recurse_submodules_for_name,
-						    strbuf_detach(&submodname, NULL));
+			config = string_list_append(&config_fetch_recurse_submodules_for_name, name_cstr);
+		else
+			free(name_cstr);
 		config->util = (void *)(intptr_t)parse_fetch_recurse_submodules_arg(var, value);
-		strbuf_release(&submodname);
-	} else if ((len > 7) && !strcmp(var + len - 7, ".ignore")) {
+	} else if (!strcmp(key, "ignore")) {
+		char *name_cstr;
+
 		if (strcmp(value, "untracked") && strcmp(value, "dirty") &&
 		    strcmp(value, "all") && strcmp(value, "none")) {
 			warning("Invalid parameter \"%s\" for config option \"submodule.%s.ignore\"", value, var);
 			return 0;
 		}
 
-		strbuf_add(&submodname, var, len - 7);
-		config = unsorted_string_list_lookup(&config_ignore_for_name, submodname.buf);
-		if (config)
+		name_cstr = xmemdupz(name, namelen);
+		config = unsorted_string_list_lookup(&config_ignore_for_name, name_cstr);
+		if (config) {
 			free(config->util);
-		else
-			config = string_list_append(&config_ignore_for_name,
-						    strbuf_detach(&submodname, NULL));
-		strbuf_release(&submodname);
+			free(name_cstr);
+		} else
+			config = string_list_append(&config_ignore_for_name, name_cstr);
 		config->util = xstrdup(value);
 		return 0;
 	}
diff --git a/t/t5000-tar-tree.sh b/t/t5000-tar-tree.sh
index e7c240fc1f..3fbd366ec3 100755
--- a/t/t5000-tar-tree.sh
+++ b/t/t5000-tar-tree.sh
@@ -212,7 +212,8 @@ test_expect_success 'git-archive --prefix=olde-' '
 test_expect_success 'setup tar filters' '
 	git config tar.tar.foo.command "tr ab ba" &&
 	git config tar.bar.command "tr ab ba" &&
-	git config tar.bar.remote true
+	git config tar.bar.remote true &&
+	git config tar.invalid baz
 '
 
 test_expect_success 'archive --list mentions user filter' '
diff --git a/userdiff.c b/userdiff.c
index ed958ef6b8..ea43a0306f 100644
--- a/userdiff.c
+++ b/userdiff.c
@@ -184,35 +184,6 @@ static struct userdiff_driver *userdiff_find_by_namelen(const char *k, int len)
 	return NULL;
 }
 
-static struct userdiff_driver *parse_driver(const char *var,
-		const char *value, const char *type)
-{
-	struct userdiff_driver *drv;
-	const char *dot;
-	const char *name;
-	int namelen;
-
-	if (prefixcmp(var, "diff."))
-		return NULL;
-	dot = strrchr(var, '.');
-	if (dot == var + 4)
-		return NULL;
-	if (strcmp(type, dot+1))
-		return NULL;
-
-	name = var + 5;
-	namelen = dot - name;
-	drv = userdiff_find_by_namelen(name, namelen);
-	if (!drv) {
-		ALLOC_GROW(drivers, ndrivers+1, drivers_alloc);
-		drv = &drivers[ndrivers++];
-		memset(drv, 0, sizeof(*drv));
-		drv->name = xmemdupz(name, namelen);
-		drv->binary = -1;
-	}
-	return drv;
-}
-
 static int parse_funcname(struct userdiff_funcname *f, const char *k,
 		const char *v, int cflags)
 {
@@ -240,20 +211,34 @@ static int parse_bool(int *b, const char *k, const char *v)
 int userdiff_config(const char *k, const char *v)
 {
 	struct userdiff_driver *drv;
+	const char *name, *type;
+	int namelen;
+
+	if (parse_config_key(k, "diff", &name, &namelen, &type) || !name)
+		return 0;
+
+	drv = userdiff_find_by_namelen(name, namelen);
+	if (!drv) {
+		ALLOC_GROW(drivers, ndrivers+1, drivers_alloc);
+		drv = &drivers[ndrivers++];
+		memset(drv, 0, sizeof(*drv));
+		drv->name = xmemdupz(name, namelen);
+		drv->binary = -1;
+	}
 
-	if ((drv = parse_driver(k, v, "funcname")))
+	if (!strcmp(type, "funcname"))
 		return parse_funcname(&drv->funcname, k, v, 0);
-	if ((drv = parse_driver(k, v, "xfuncname")))
+	if (!strcmp(type, "xfuncname"))
 		return parse_funcname(&drv->funcname, k, v, REG_EXTENDED);
-	if ((drv = parse_driver(k, v, "binary")))
+	if (!strcmp(type, "binary"))
 		return parse_tristate(&drv->binary, k, v);
-	if ((drv = parse_driver(k, v, "command")))
+	if (!strcmp(type, "command"))
 		return git_config_string(&drv->external, k, v);
-	if ((drv = parse_driver(k, v, "textconv")))
+	if (!strcmp(type, "textconv"))
 		return git_config_string(&drv->textconv, k, v);
-	if ((drv = parse_driver(k, v, "cachetextconv")))
+	if (!strcmp(type, "cachetextconv"))
 		return parse_bool(&drv->textconv_want_cache, k, v);
-	if ((drv = parse_driver(k, v, "wordregex")))
+	if (!strcmp(type, "wordregex"))
 		return git_config_string(&drv->word_regex, k, v);
 
 	return 0;