cat-file: teach cat-file a '--allow-unknown-type' option

'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-unknown-type' option where it prints
the type or size of a broken/corrupt object without throwing
an error.

Modify '-t' and '-s' options to call sha1_object_info_extended()
directly to support the '--allow-unknown-type' option.

Add documentation for 'cat-file --allow-unknown-type'.

Helped-by: Junio C Hamano <gitster@pobox.com>
Helped-by: Eric Sunshine <sunshine@sunshineco.com>
Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
cat-file: add documentation for '--allow-unknown-type' option.

Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Documentation/git-cat-file.txt b/Documentation/git-cat-file.txt
index f6a16f4300b15669a518faa3d8a63d7586233258..499ae7b98a4d9bf48aa2c5a235608dfcffcc1c10 100644 (file)
--- a/Documentation/git-cat-file.txt
+++ b/Documentation/git-cat-file.txt
@@ -9,7 +9,7 @@ git-cat-file - Provide content or type and size information for repository objec
 SYNOPSIS
 --------
 [verse]
-'git cat-file' (-t | -s | -e | -p | <type> | --textconv ) <object>
+'git cat-file' (-t [--allow-unknown-type]| -s [--allow-unknown-type]| -e | -p | <type> | --textconv ) <object>
 'git cat-file' (--batch | --batch-check) < <list-of-objects>
 
 DESCRIPTION
@@ -69,6 +69,9 @@ OPTIONS
        not be combined with any other options or arguments.  See the
        section `BATCH OUTPUT` below for details.
 
+--allow-unknown-type::
+       Allow -s or -t to query broken/corrupt objects of unknown type.
+
 OUTPUT
 ------
 If '-t' is specified, one of the <type>.

diff --git a/builtin/cat-file.c b/builtin/cat-file.c
index 53b5376126887c2bec70b910cb6a5afb1909cc17..ecb488822f903c56b5d14bdec3130c71817e1b65 100644 (file)
--- 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 unknown_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 (unknown_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-unknown-type]|-s [--allow-unknown-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 unknown_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-unknown-type", &unknown_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 (unknown_type && opt != 't' && opt != 's')
+               die("git cat-file --allow-unknown-type: use with -s or -t");
+       return cat_one_file(opt, exp_type, obj_name, unknown_type);
 }