Re: [PATCH v9 3/5] cat-file: teach cat-file a '--allow-unknown-type' option

> Karthik Nayak <karthik.188@gmail.com> writes:
>
>> Currently 'git cat-file' throws an error while trying to
>> print the type or size of a broken/corrupt object. This is
>> because these objects are usually of unknown types.
>>
>> Teach git cat-file a '--allow-unkown-type' option where it prints
>> the type or size of a broken/corrupt object without throwing
>> an error.
>
> Drop "Currently" from the description of the problem you are
> solving.  We know that the problem you have to solve in the code is
> current without being told.  This comment applies to all patches.

>
>> Modify '-t' and '-s' options to call sha1_object_info_extended()
>> directly to support the '--allow-unkown-type' option.
>>
>> Helped-by: Junio C Hamano <gitster@pobox.com>
>> Helped-by: Eric Sunshine <sunshine@sunshineco.com>
>> Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
>> ---
>>   builtin/cat-file.c | 38 ++++++++++++++++++++++++++------------
>>   1 file changed, 26 insertions(+), 12 deletions(-)
>>
>> diff --git a/builtin/cat-file.c b/builtin/cat-file.c
>> index 53b5376..299e2e5 100644
>> --- a/builtin/cat-file.c
>> +++ b/builtin/cat-file.c
>> @@ -9,13 +9,20 @@
>>   #include "userdiff.h"
>>   #include "streaming.h"
>>
>> -static int cat_one_file(int opt, const char *exp_type, const char *obj_name)
>> +static int cat_one_file(int opt, const char *exp_type, const char *obj_name,
>> +			int unkown_type)
>>   {
>>   	unsigned char sha1[20];
>>   	enum object_type type;
>>   	char *buf;
>>   	unsigned long size;
>>   	struct object_context obj_context;
>> +	struct object_info oi = {NULL};
>> +	struct strbuf sb = STRBUF_INIT;
>> +	unsigned flags = LOOKUP_REPLACE_OBJECT;
>> +
>> +	if (unkown_type)
>> +		flags |= LOOKUP_UNKNOWN_OBJECT;
>>
>>   	if (get_sha1_with_context(obj_name, 0, sha1, &obj_context))
>>   		die("Not a valid object name %s", obj_name);
>> @@ -23,20 +30,22 @@ static int cat_one_file(int opt, const char *exp_type, const char *obj_name)
>>   	buf = NULL;
>>   	switch (opt) {
>>   	case 't':
>> -		type = sha1_object_info(sha1, NULL);
>> -		if (type > 0) {
>> -			printf("%s\n", typename(type));
>> +		oi.typename = &sb;
>> +		if (sha1_object_info_extended(sha1, &oi, flags) < 0)
>> +			die("git cat-file: could not get object info");
>> +		if (sb.len) {
>> +			printf("%s\n", sb.buf);
>> +			strbuf_release(&sb);
>>   			return 0;
>>   		}
>>   		break;
>>
>>   	case 's':
>> -		type = sha1_object_info(sha1, &size);
>> -		if (type > 0) {
>> -			printf("%lu\n", size);
>> -			return 0;
>> -		}
>> -		break;
>> +		oi.sizep = &size;
>> +		if (sha1_object_info_extended(sha1, &oi, flags) < 0)
>> +			die("git cat-file: could not get object info");
>> +		printf("%lu\n", size);
>> +		return 0;
>>
>>   	case 'e':
>>   		return !has_sha1_file(sha1);
>> @@ -323,7 +332,7 @@ static int batch_objects(struct batch_options *opt)
>>   }
>>
>>   static const char * const cat_file_usage[] = {
>> -	N_("git cat-file (-t | -s | -e | -p | <type> | --textconv) <object>"),
>> +	N_("git cat-file (-t [--allow-unkown-type]|-s [--allow-unkown-type]|-e|-p|<type>|--textconv) <object>"),
>>   	N_("git cat-file (--batch | --batch-check) < <list-of-objects>"),
>>   	NULL
>>   };
>> @@ -359,6 +368,7 @@ int cmd_cat_file(int argc, const char **argv, const char *prefix)
>>   	int opt = 0;
>>   	const char *exp_type = NULL, *obj_name = NULL;
>>   	struct batch_options batch = {0};
>> +	int unkown_type = 0;
>>
>>   	const struct option options[] = {
>>   		OPT_GROUP(N_("<type> can be one of: blob, tree, commit, tag")),
>> @@ -369,6 +379,8 @@ int cmd_cat_file(int argc, const char **argv, const char *prefix)
>>   		OPT_CMDMODE('p', NULL, &opt, N_("pretty-print object's content"), 'p'),
>>   		OPT_CMDMODE(0, "textconv", &opt,
>>   			    N_("for blob objects, run textconv on object's content"), 'c'),
>> +		OPT_BOOL( 0, "allow-unkown-type", &unkown_type,
>> +			  N_("allow -s and -t to work with broken/corrupt objects")),
>>   		{ OPTION_CALLBACK, 0, "batch", &batch, "format",
>>   			N_("show info and content of objects fed from the standard input"),
>>   			PARSE_OPT_OPTARG, batch_option_callback },
>> @@ -402,5 +414,7 @@ int cmd_cat_file(int argc, const char **argv, const char *prefix)
>>   	if (batch.enabled)
>>   		return batch_objects(&batch);
>>
>> -	return cat_one_file(opt, exp_type, obj_name);
>> +	if (unkown_type && opt != 't' && opt != 's')
>> +		die("git cat-file --allow-unkown-type: use with -s or -t");
>> +	return cat_one_file(opt, exp_type, obj_name, unkown_type);
>>   }