fetch: implement fetch.fsck.*

Implement support for fetch.fsck.* corresponding with the existing
receive.fsck.*. This allows for pedantically cloning repositories with
specific issues without turning off fetch.fsckObjects.

One such repository is https://github.com/robbyrussell/oh-my-zsh.git
which before this change will emit this error when cloned with
fetch.fsckObjects:

    error: object 2b7227859263b6aabcc28355b0b994995b7148b6: zeroPaddedFilemode: contains zero-padded file modes
    fatal: Error in object
    fatal: index-pack failed

Now with fetch.fsck.zeroPaddedFilemode=warn we'll warn about that
issue, but the clone will succeed:

    warning: object 2b7227859263b6aabcc28355b0b994995b7148b6: zeroPaddedFilemode: contains zero-padded file modes
    warning: object a18c4d13c2a5fa2d4ecd5346c50e119b999b807d: zeroPaddedFilemode: contains zero-padded file modes
    warning: object 84df066176c8da3fd59b13731a86d90f4f1e5c9d: zeroPaddedFilemode: contains zero-padded file modes

The motivation for this is to be able to turn on fetch.fsckObjects
globally across a fleet of computers but still be able to manually
clone various legacy repositories by either white-listing specific
issues, or better yet whitelist specific objects.

The use of --git-dir=* instead of -C in the tests could be considered
somewhat archaic, but the tests I'm adding here are duplicating the
corresponding receive.* tests with as few changes as possible.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 30 insertions, 2 deletions

diff --git a/fetch-pack.c b/fetch-pack.c
index 7ccb9c0d45..aea2f6cf26 100644
--- a/fetch-pack.c
+++ b/fetch-pack.c
@@ -21,6 +21,7 @@
 #include "packfile.h"
 #include "object-store.h"
 #include "connected.h"
+#include "fsck.h"
 
 static int transfer_unpack_limit = -1;
 static int fetch_unpack_limit = -1;
@@ -35,6 +36,7 @@ static int agent_supported;
 static int server_supports_filtering;
 static struct lock_file shallow_lock;
 static const char *alternate_shallow_file;
+static struct strbuf fsck_msg_types = STRBUF_INIT;
 
 /* Remember to update object flag allocation in object.h */
 #define COMPLETE	(1U << 0)
@@ -937,7 +939,8 @@ static int get_pack(struct fetch_pack_args *args,
 			 */
 			argv_array_push(&cmd.args, "--fsck-objects");
 		else
-			argv_array_push(&cmd.args, "--strict");
+			argv_array_pushf(&cmd.args, "--strict%s",
+					 fsck_msg_types.buf);
 	}
 
 	cmd.in = demux.out;
@@ -1458,6 +1461,31 @@ static struct ref *do_fetch_pack_v2(struct fetch_pack_args *args,
 	return ref;
 }
 
+static int fetch_pack_config_cb(const char *var, const char *value, void *cb)
+{
+	if (strcmp(var, "fetch.fsck.skiplist") == 0) {
+		const char *path;
+
+		if (git_config_pathname(&path, var, value))
+			return 1;
+		strbuf_addf(&fsck_msg_types, "%cskiplist=%s",
+			fsck_msg_types.len ? ',' : '=', path);
+		free((char *)path);
+		return 0;
+	}
+
+	if (skip_prefix(var, "fetch.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;
+	}
+
+	return git_default_config(var, value, cb);
+}
+
 static void fetch_pack_config(void)
 {
 	git_config_get_int("fetch.unpacklimit", &fetch_unpack_limit);
@@ -1466,7 +1494,7 @@ static void fetch_pack_config(void)
 	git_config_get_bool("fetch.fsckobjects", &fetch_fsck_objects);
 	git_config_get_bool("transfer.fsckobjects", &transfer_fsck_objects);
 
-	git_config(git_default_config, NULL);
+	git_config(fetch_pack_config_cb, NULL);
 }
 
 static void fetch_pack_setup(void)