fsck (receive-pack): allow demoting errors to warnings

For example, missing emails in commit and tag objects can be demoted to
mere warnings with

	git config receive.fsck.missingemail=warn

The value is actually a comma-separated list.

In case that the same key is listed in multiple receive.fsck.<msg-id>
lines in the config, the latter configuration wins (this can happen for
example when both $HOME/.gitconfig and .git/config contain message type
settings).

As git receive-pack does not actually perform the checks, it hands off
the setting to index-pack or unpack-objects in the form of an optional
argument to the --strict option.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/index-pack.c

@@ -1633,6 +1633,10 @@ int cmd_index_pack(int argc, const char **argv, const char *prefix)
 			} else if (!strcmp(arg, "--strict")) {
 				strict = 1;
 				do_fsck_object = 1;
+			} else if (skip_prefix(arg, "--strict=", &arg)) {
+				strict = 1;
+				do_fsck_object = 1;
+				fsck_set_msg_types(&fsck_options, arg);
 			} else if (!strcmp(arg, "--check-self-contained-and-connected")) {
 				strict = 1;
 				check_self_contained_and_connected = 1;

builtin/receive-pack.c

@@ -19,6 +19,7 @@
 #include "tag.h"
 #include "gpg-interface.h"
 #include "sigchain.h"
+#include "fsck.h"
 
 static const char receive_pack_usage[] = "git receive-pack <git-dir>";
 
@@ -36,6 +37,7 @@ static enum deny_action deny_current_branch = DENY_UNCONFIGURED;
 static enum deny_action deny_delete_current = DENY_UNCONFIGURED;
 static int receive_fsck_objects = -1;
 static int transfer_fsck_objects = -1;
+static struct strbuf fsck_msg_types = STRBUF_INIT;
 static int receive_unpack_limit = -1;
 static int transfer_unpack_limit = -1;
 static int advertise_atomic_push = 1;
@@ -115,6 +117,15 @@ static int receive_pack_config(const char *var, const char *value, void *cb)
 		return 0;
 	}
 
+	if (skip_prefix(var, "receive.fsck.", &var)) {
+		if (is_valid_msg_type(var, value))
+			strbuf_addf(&fsck_msg_types, "%c%s=%s",
+				fsck_msg_types.len ? ',' : '=', var, value);
+		else
+			warning("Skipping unknown msg id '%s'", var);
+		return 0;
+	}
+
 	if (strcmp(var, "receive.fsckobjects") == 0) {
 		receive_fsck_objects = git_config_bool(var, value);
 		return 0;
@@ -1490,7 +1501,8 @@ static const char *unpack(int err_fd, struct shallow_info *si)
 		if (quiet)
 			argv_array_push(&child.args, "-q");
 		if (fsck_objects)
-			argv_array_push(&child.args, "--strict");
+			argv_array_pushf(&child.args, "--strict%s",
+				fsck_msg_types.buf);
 		child.no_stdout = 1;
 		child.err = err_fd;
 		child.git_cmd = 1;
@@ -1508,7 +1520,8 @@ static const char *unpack(int err_fd, struct shallow_info *si)
 		argv_array_pushl(&child.args, "index-pack",
 				 "--stdin", hdr_arg, keep_arg, NULL);
 		if (fsck_objects)
-			argv_array_push(&child.args, "--strict");
+			argv_array_pushf(&child.args, "--strict%s",
+				fsck_msg_types.buf);
 		if (fix_thin)
 			argv_array_push(&child.args, "--fix-thin");
 		child.out = -1;

builtin/unpack-objects.c

@@ -530,6 +530,11 @@ int cmd_unpack_objects(int argc, const char **argv, const char *prefix)
 				strict = 1;
 				continue;
 			}
+			if (skip_prefix(arg, "--strict=", &arg)) {
+				strict = 1;
+				fsck_set_msg_types(&fsck_options, arg);
+				continue;
+			}
 			if (starts_with(arg, "--pack_header=")) {
 				struct pack_header *hdr;
 				char *c;

fsck.c

@@ -131,6 +131,14 @@ static int parse_msg_type(const char *str)
 		die("Unknown fsck message type: '%s'", str);
 }
 
+int is_valid_msg_type(const char *msg_id, const char *msg_type)
+{
+	if (parse_msg_id(msg_id) < 0)
+		return 0;
+	parse_msg_type(msg_type);
+	return 1;
+}
+
 void fsck_set_msg_type(struct fsck_options *options,
 		const char *msg_id, const char *msg_type)
 {

fsck.h

@@ -9,6 +9,7 @@ struct fsck_options;
 void fsck_set_msg_type(struct fsck_options *options,
 		const char *msg_id, const char *msg_type);
 void fsck_set_msg_types(struct fsck_options *options, const char *values);
+int is_valid_msg_type(const char *msg_id, const char *msg_type);
 
 /*
  * callback function for fsck_walk