From: Junio C Hamano <gitster@pobox.com>
Date: Mon, 1 Jun 2015 19:45:16 +0000 (-0700)
Subject: Merge branch 'dt/cat-file-follow-symlinks'
X-Git-Tag: v2.5.0-rc0~62
X-Git-Url: https://git.lorimer.id.au/gitweb.git/diff_plain/67f0b6f3b2226ea858c616028375dcc3c46ccc37?ds=inline;hp=-c

Merge branch 'dt/cat-file-follow-symlinks'

"git cat-file --batch(-check)" learned the "--follow-symlinks"
option that follows an in-tree symbolic link when asked about an
object via extended SHA-1 syntax, e.g. HEAD:RelNotes that points at
Documentation/RelNotes/2.5.0.txt.  With the new option, the command
behaves as if HEAD:Documentation/RelNotes/2.5.0.txt was given as
input instead.

* dt/cat-file-follow-symlinks:
cat-file: add --follow-symlinks to --batch
sha1_name: get_sha1_with_context learns to follow symlinks
tree-walk: learn get_tree_entry_follow_symlinks
---

67f0b6f3b2226ea858c616028375dcc3c46ccc37
diff --combined Documentation/git-cat-file.txt
index 499ae7b98a,3568aff0de..319ab4cb08
--- a/Documentation/git-cat-file.txt
+++ b/Documentation/git-cat-file.txt
@@@ -9,8 -9,8 +9,8 @@@ git-cat-file - Provide content or type 
  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>
+ 'git cat-file' (--batch | --batch-check) [--follow-symlinks] < <list-of-objects>
  
  DESCRIPTION
  -----------
@@@ -69,9 -69,62 +69,65 @@@ OPTION
  	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.
 +
+ --follow-symlinks::
+ 	With --batch or --batch-check, follow symlinks inside the
+ 	repository when requesting objects with extended SHA-1
+ 	expressions of the form tree-ish:path-in-tree.  Instead of
+ 	providing output about the link itself, provide output about
+ 	the linked-to object.  If a symlink points outside the
+ 	tree-ish (e.g. a link to /foo or a root-level link to ../foo),
+ 	the portion of the link which is outside the tree will be
+ 	printed.
+ +
+ This option does not (currently) work correctly when an object in the
+ index is specified (e.g. `:link` instead of `HEAD:link`) rather than
+ one in the tree.
+ +
+ This option cannot (currently) be used unless `--batch` or
+ `--batch-check` is used.
+ +
+ For example, consider a git repository containing:
+ +
+ --
+ 	f: a file containing "hello\n"
+ 	link: a symlink to f
+ 	dir/link: a symlink to ../f
+ 	plink: a symlink to ../f
+ 	alink: a symlink to /etc/passwd
+ --
+ +
+ For a regular file `f`, `echo HEAD:f | git cat-file --batch` would print
+ +
+ --
+ 	ce013625030ba8dba906f756967f9e9ca394464a blob 6
+ --
+ +
+ And `echo HEAD:link | git cat-file --batch --follow-symlinks` would
+ print the same thing, as would `HEAD:dir/link`, as they both point at
+ `HEAD:f`.
+ +
+ Without `--follow-symlinks`, these would print data about the symlink
+ itself.  In the case of `HEAD:link`, you would see
+ +
+ --
+ 	4d1ae35ba2c8ec712fa2a379db44ad639ca277bd blob 1
+ --
+ +
+ Both `plink` and `alink` point outside the tree, so they would
+ respectively print:
+ +
+ --
+ 	symlink 4
+ 	../f
+ 
+ 	symlink 11
+ 	/etc/passwd
+ --
+ 
+ 
  OUTPUT
  ------
  If '-t' is specified, one of the <type>.
@@@ -151,6 -204,47 +207,47 @@@ the repository, then `cat-file` will ig
  <object> SP missing LF
  ------------
  
+ If --follow-symlinks is used, and a symlink in the repository points
+ outside the repository, then `cat-file` will ignore any custom format
+ and print:
+ 
+ ------------
+ symlink SP <size> LF
+ <symlink> LF
+ ------------
+ 
+ The symlink will either be absolute (beginning with a /), or relative
+ to the tree root.  For instance, if dir/link points to ../../foo, then
+ <symlink> will be ../foo.  <size> is the size of the symlink in bytes.
+ 
+ If --follow-symlinks is used, the following error messages will be
+ displayed:
+ 
+ ------------
+ <object> SP missing LF
+ ------------
+ is printed when the initial symlink requested does not exist.
+ 
+ ------------
+ dangling SP <size> LF
+ <object> LF
+ ------------
+ is printed when the initial symlink exists, but something that
+ it (transitive-of) points to does not.
+ 
+ ------------
+ loop SP <size> LF
+ <object> LF
+ ------------
+ is printed for symlink loops (or any symlinks that
+ require more than 40 link resolutions to resolve).
+ 
+ ------------
+ notdir SP <size> LF
+ <object> LF
+ ------------
+ is printed when, during symlink resolution, a file is used as a
+ directory name.
  
  CAVEATS
  -------
diff --combined builtin/cat-file.c
index ecb488822f,43338bb7de..049a95f1f1
--- a/builtin/cat-file.c
+++ b/builtin/cat-file.c
@@@ -8,21 -8,15 +8,22 @@@
  #include "parse-options.h"
  #include "userdiff.h"
  #include "streaming.h"
+ #include "tree-walk.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);
@@@ -30,22 -24,20 +31,22 @@@
  	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);
@@@ -233,6 -225,7 +234,7 @@@ static void print_object_or_die(int fd
  
  struct batch_options {
  	int enabled;
+ 	int follow_symlinks;
  	int print_contents;
  	const char *format;
  };
@@@ -241,12 -234,44 +243,44 @@@ static int batch_one_object(const char 
  			    struct expand_data *data)
  {
  	struct strbuf buf = STRBUF_INIT;
+ 	struct object_context ctx;
+ 	int flags = opt->follow_symlinks ? GET_SHA1_FOLLOW_SYMLINKS : 0;
+ 	enum follow_symlinks_result result;
  
  	if (!obj_name)
  	   return 1;
  
- 	if (get_sha1(obj_name, data->sha1)) {
- 		printf("%s missing\n", obj_name);
+ 	result = get_sha1_with_context(obj_name, flags, data->sha1, &ctx);
+ 	if (result != FOUND) {
+ 		switch (result) {
+ 		case MISSING_OBJECT:
+ 			printf("%s missing\n", obj_name);
+ 			break;
+ 		case DANGLING_SYMLINK:
+ 			printf("dangling %"PRIuMAX"\n%s\n",
+ 			       (uintmax_t)strlen(obj_name), obj_name);
+ 			break;
+ 		case SYMLINK_LOOP:
+ 			printf("loop %"PRIuMAX"\n%s\n",
+ 			       (uintmax_t)strlen(obj_name), obj_name);
+ 			break;
+ 		case NOT_DIR:
+ 			printf("notdir %"PRIuMAX"\n%s\n",
+ 			       (uintmax_t)strlen(obj_name), obj_name);
+ 			break;
+ 		default:
+ 			die("BUG: unknown get_sha1_with_context result %d\n",
+ 			       result);
+ 			break;
+ 		}
+ 		fflush(stdout);
+ 		return 0;
+ 	}
+ 
+ 	if (ctx.mode == 0) {
+ 		printf("symlink %"PRIuMAX"\n%s\n",
+ 		       (uintmax_t)ctx.symlink_path.len,
+ 		       ctx.symlink_path.buf);
  		fflush(stdout);
  		return 0;
  	}
@@@ -332,8 -357,8 +366,8 @@@ static int batch_objects(struct batch_o
  }
  
  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>"),
+ 	N_("git cat-file (--batch | --batch-check) [--follow-symlinks] < <list-of-objects>"),
  	NULL
  };
  
@@@ -351,9 -376,8 +385,8 @@@ static int batch_option_callback(const 
  {
  	struct batch_options *bo = opt->value;
  
- 	if (unset) {
- 		memset(bo, 0, sizeof(*bo));
- 		return 0;
+ 	if (bo->enabled) {
+ 		return 1;
  	}
  
  	bo->enabled = 1;
@@@ -368,30 -392,32 +401,32 @@@ int cmd_cat_file(int argc, const char *
  	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")),
 -		OPT_SET_INT('t', NULL, &opt, N_("show object type"), 't'),
 -		OPT_SET_INT('s', NULL, &opt, N_("show object size"), 's'),
 -		OPT_SET_INT('e', NULL, &opt,
 +		OPT_CMDMODE('t', NULL, &opt, N_("show object type"), 't'),
 +		OPT_CMDMODE('s', NULL, &opt, N_("show object size"), 's'),
 +		OPT_CMDMODE('e', NULL, &opt,
  			    N_("exit with zero when there's no error"), 'e'),
 -		OPT_SET_INT('p', NULL, &opt, N_("pretty-print object's content"), 'p'),
 -		OPT_SET_INT(0, "textconv", &opt,
 +		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 },
  		{ OPTION_CALLBACK, 0, "batch-check", &batch, "format",
  			N_("show info about objects fed from the standard input"),
  			PARSE_OPT_OPTARG, batch_option_callback },
+ 		OPT_BOOL(0, "follow-symlinks", &batch.follow_symlinks,
+ 			 N_("follow in-tree symlinks (used with --batch or --batch-check)")),
  		OPT_END()
  	};
  
  	git_config(git_cat_file_config, NULL);
  
 -	if (argc != 3 && argc != 2)
 -		usage_with_options(cat_file_usage, options);
 -
  	argc = parse_options(argc, argv, prefix, options, cat_file_usage, 0);
  
  	if (opt) {
@@@ -411,10 -437,12 +446,14 @@@
  		usage_with_options(cat_file_usage, options);
  	}
  
+ 	if (batch.follow_symlinks && !batch.enabled) {
+ 		usage_with_options(cat_file_usage, options);
+ 	}
+ 
  	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);
  }
diff --combined cache.h
index 9da9784824,ec8d142d9f..571c98f5e2
--- a/cache.h
+++ b/cache.h
@@@ -297,11 -297,8 +297,11 @@@ static inline unsigned int canon_mode(u
  #define RESOLVE_UNDO_CHANGED	(1 << 4)
  #define CACHE_TREE_CHANGED	(1 << 5)
  #define SPLIT_INDEX_ORDERED	(1 << 6)
 +#define UNTRACKED_CHANGED	(1 << 7)
  
  struct split_index;
 +struct untracked_cache;
 +
  struct index_state {
  	struct cache_entry **cache;
  	unsigned int version;
@@@ -315,7 -312,6 +315,7 @@@
  	struct hashmap name_hash;
  	struct hashmap dir_hash;
  	unsigned char sha1[20];
 +	struct untracked_cache *untracked;
  };
  
  extern struct index_state the_index;
@@@ -382,7 -378,6 +382,7 @@@ static inline enum object_type object_t
  
  /* Double-check local_repo_env below if you add to this list. */
  #define GIT_DIR_ENVIRONMENT "GIT_DIR"
 +#define GIT_COMMON_DIR_ENVIRONMENT "GIT_COMMON_DIR"
  #define GIT_NAMESPACE_ENVIRONMENT "GIT_NAMESPACE"
  #define GIT_WORK_TREE_ENVIRONMENT "GIT_WORK_TREE"
  #define GIT_PREFIX_ENVIRONMENT "GIT_PREFIX"
@@@ -436,13 -431,11 +436,13 @@@ extern int is_inside_git_dir(void)
  extern char *git_work_tree_cfg;
  extern int is_inside_work_tree(void);
  extern const char *get_git_dir(void);
 +extern const char *get_git_common_dir(void);
  extern int is_git_directory(const char *path);
  extern char *get_object_directory(void);
  extern char *get_index_file(void);
  extern char *get_graft_file(void);
  extern int set_git_dir(const char *path);
 +extern int get_common_dir(struct strbuf *sb, const char *gitdir);
  extern const char *get_git_namespace(void);
  extern const char *strip_namespace(const char *namespaced_ref);
  extern const char *get_git_work_tree(void);
@@@ -567,8 -560,6 +567,8 @@@ extern void fill_stat_data(struct stat_
   * INODE_CHANGED, and DATA_CHANGED.
   */
  extern int match_stat_data(const struct stat_data *sd, struct stat *st);
 +extern int match_stat_data_racy(const struct index_state *istate,
 +				const struct stat_data *sd, struct stat *st);
  
  extern void fill_stat_cache_info(struct cache_entry *ce, struct stat *st);
  
@@@ -629,7 -620,6 +629,7 @@@ extern int core_apply_sparse_checkout
  extern int precomposed_unicode;
  extern int protect_hfs;
  extern int protect_ntfs;
 +extern int git_db_env, git_index_env, git_graft_env, git_common_dir_env;
  
  /*
   * Include broken refs in all ref iterations, which will
@@@ -700,19 -690,18 +700,19 @@@ extern int check_repository_format(void
  
  extern char *mksnpath(char *buf, size_t n, const char *fmt, ...)
  	__attribute__((format (printf, 3, 4)));
 -extern char *git_snpath(char *buf, size_t n, const char *fmt, ...)
 -	__attribute__((format (printf, 3, 4)));
 +extern void strbuf_git_path(struct strbuf *sb, const char *fmt, ...)
 +	__attribute__((format (printf, 2, 3)));
  extern char *git_pathdup(const char *fmt, ...)
  	__attribute__((format (printf, 1, 2)));
  extern char *mkpathdup(const char *fmt, ...)
  	__attribute__((format (printf, 1, 2)));
  
  /* Return a statically allocated filename matching the sha1 signature */
 -extern char *mkpath(const char *fmt, ...) __attribute__((format (printf, 1, 2)));
 -extern char *git_path(const char *fmt, ...) __attribute__((format (printf, 1, 2)));
 -extern char *git_path_submodule(const char *path, const char *fmt, ...)
 +extern const char *mkpath(const char *fmt, ...) __attribute__((format (printf, 1, 2)));
 +extern const char *git_path(const char *fmt, ...) __attribute__((format (printf, 1, 2)));
 +extern const char *git_path_submodule(const char *path, const char *fmt, ...)
  	__attribute__((format (printf, 2, 3)));
 +extern void report_linked_checkout_garbage(void);
  
  /*
   * Return the name of the file in the local object database that would
@@@ -857,6 -846,7 +857,6 @@@ enum scld_error safe_create_leading_dir
  enum scld_error safe_create_leading_directories_const(const char *path);
  
  int mkdir_in_gitdir(const char *path);
 -extern void home_config_paths(char **global, char **xdg, char *file);
  extern char *expand_user_path(const char *path);
  const char *enter_repo(const char *path, int strict);
  static inline int is_absolute_path(const char *path)
@@@ -876,16 -866,8 +876,16 @@@ char *strip_path_suffix(const char *pat
  int daemon_avoid_alias(const char *path);
  extern int is_ntfs_dotgit(const char *name);
  
 +/**
 + * Return a newly allocated string with the evaluation of
 + * "$XDG_CONFIG_HOME/git/$filename" if $XDG_CONFIG_HOME is non-empty, otherwise
 + * "$HOME/.config/git/$filename". Return NULL upon error.
 + */
 +extern char *xdg_config_home(const char *filename);
 +
  /* object replacement */
  #define LOOKUP_REPLACE_OBJECT 1
 +#define LOOKUP_UNKNOWN_OBJECT 2
  extern void *read_sha1_file_extended(const unsigned char *sha1, enum object_type *type, unsigned long *size, unsigned flag);
  static inline void *read_sha1_file(const unsigned char *sha1, enum object_type *type, unsigned long *size)
  {
@@@ -922,7 -904,6 +922,7 @@@ static inline const unsigned char *look
  extern int sha1_object_info(const unsigned char *, unsigned long *);
  extern int hash_sha1_file(const void *buf, unsigned long len, const char *type, unsigned char *sha1);
  extern int write_sha1_file(const void *buf, unsigned long len, const char *type, unsigned char *return_sha1);
 +extern int hash_sha1_file_literally(const void *buf, unsigned long len, const char *type, unsigned char *sha1, unsigned flags);
  extern int pretend_sha1_file(void *, unsigned long, enum object_type, unsigned char *);
  extern int force_object_loose(const unsigned char *sha1, time_t mtime);
  extern int git_open_noatime(const char *name);
@@@ -971,15 -952,21 +971,21 @@@ struct object_context 
  	unsigned char tree[20];
  	char path[PATH_MAX];
  	unsigned mode;
+ 	/*
+ 	 * symlink_path is only used by get_tree_entry_follow_symlinks,
+ 	 * and only for symlinks that point outside the repository.
+ 	 */
+ 	struct strbuf symlink_path;
  };
  
- #define GET_SHA1_QUIETLY        01
- #define GET_SHA1_COMMIT         02
- #define GET_SHA1_COMMITTISH     04
- #define GET_SHA1_TREE          010
- #define GET_SHA1_TREEISH       020
- #define GET_SHA1_BLOB	       040
- #define GET_SHA1_ONLY_TO_DIE 04000
+ #define GET_SHA1_QUIETLY           01
+ #define GET_SHA1_COMMIT            02
+ #define GET_SHA1_COMMITTISH        04
+ #define GET_SHA1_TREE             010
+ #define GET_SHA1_TREEISH          020
+ #define GET_SHA1_BLOB             040
+ #define GET_SHA1_FOLLOW_SYMLINKS 0100
+ #define GET_SHA1_ONLY_TO_DIE    04000
  
  extern int get_sha1(const char *str, unsigned char *sha1);
  extern int get_sha1_commit(const char *str, unsigned char *sha1);
@@@ -1358,7 -1345,6 +1364,7 @@@ struct object_info 
  	unsigned long *sizep;
  	unsigned long *disk_sizep;
  	unsigned char *delta_base_sha1;
 +	struct strbuf *typename;
  
  	/* Response */
  	enum {
@@@ -1547,13 -1533,9 +1553,13 @@@ extern const char *git_mailmap_blob
  extern void maybe_flush_or_die(FILE *, const char *);
  __attribute__((format (printf, 2, 3)))
  extern void fprintf_or_die(FILE *, const char *fmt, ...);
 +
 +#define COPY_READ_ERROR (-2)
 +#define COPY_WRITE_ERROR (-3)
  extern int copy_fd(int ifd, int ofd);
  extern int copy_file(const char *dst, const char *src, int mode);
  extern int copy_file_with_time(const char *dst, const char *src, int mode);
 +
  extern void write_or_die(int fd, const void *buf, size_t count);
  extern int write_or_whine(int fd, const void *buf, size_t count, const char *msg);
  extern int write_or_whine_pipe(int fd, const void *buf, size_t count, const char *msg);
@@@ -1567,8 -1549,6 +1573,8 @@@ static inline ssize_t write_str_in_full
  {
  	return write_in_full(fd, str, strlen(str));
  }
 +__attribute__((format (printf, 3, 4)))
 +extern int write_file(const char *path, int fatal, const char *fmt, ...);
  
  /* pager.c */
  extern void setup_pager(void);
diff --combined sha1_name.c
index 6de8c87c8a,0c26515010..46218ba02c
--- a/sha1_name.c
+++ b/sha1_name.c
@@@ -6,7 -6,6 +6,7 @@@
  #include "tree-walk.h"
  #include "refs.h"
  #include "remote.h"
 +#include "dir.h"
  
  static int get_sha1_oneline(const char *, unsigned char *, struct commit_list *);
  
@@@ -1238,13 -1237,14 +1238,13 @@@ static void diagnose_invalid_sha1_path(
  				       const char *object_name,
  				       int object_name_len)
  {
 -	struct stat st;
  	unsigned char sha1[20];
  	unsigned mode;
  
  	if (!prefix)
  		prefix = "";
  
 -	if (!lstat(filename, &st))
 +	if (file_exists(filename))
  		die("Path '%s' exists on disk, but not in '%.*s'.",
  		    filename, object_name_len, object_name);
  	if (errno == ENOENT || errno == ENOTDIR) {
@@@ -1271,6 -1271,7 +1271,6 @@@ static void diagnose_invalid_index_path
  					const char *prefix,
  					const char *filename)
  {
 -	struct stat st;
  	const struct cache_entry *ce;
  	int pos;
  	unsigned namelen = strlen(filename);
@@@ -1313,7 -1314,7 +1313,7 @@@
  			    ce_stage(ce), filename);
  	}
  
 -	if (!lstat(filename, &st))
 +	if (file_exists(filename))
  		die("Path '%s' exists on disk, but not in the index.", filename);
  	if (errno == ENOENT || errno == ENOTDIR)
  		die("Path '%s' does not exist (neither on disk nor in the index).",
@@@ -1433,11 -1434,19 +1433,19 @@@ static int get_sha1_with_context_1(cons
  			new_filename = resolve_relative_path(filename);
  			if (new_filename)
  				filename = new_filename;
- 			ret = get_tree_entry(tree_sha1, filename, sha1, &oc->mode);
- 			if (ret && only_to_die) {
- 				diagnose_invalid_sha1_path(prefix, filename,
- 							   tree_sha1,
- 							   name, len);
+ 			if (flags & GET_SHA1_FOLLOW_SYMLINKS) {
+ 				ret = get_tree_entry_follow_symlinks(tree_sha1,
+ 					filename, sha1, &oc->symlink_path,
+ 					&oc->mode);
+ 			} else {
+ 				ret = get_tree_entry(tree_sha1, filename,
+ 						     sha1, &oc->mode);
+ 				if (ret && only_to_die) {
+ 					diagnose_invalid_sha1_path(prefix,
+ 								   filename,
+ 								   tree_sha1,
+ 								   name, len);
+ 				}
  			}
  			hashcpy(oc->tree, tree_sha1);
  			strlcpy(oc->path, filename, sizeof(oc->path));
@@@ -1468,5 -1477,7 +1476,7 @@@ void maybe_die_on_misspelt_object_name(
  
  int get_sha1_with_context(const char *str, unsigned flags, unsigned char *sha1, struct object_context *orc)
  {
+ 	if (flags & GET_SHA1_FOLLOW_SYMLINKS && flags & GET_SHA1_ONLY_TO_DIE)
+ 		die("BUG: incompatible flags for get_sha1_with_context");
  	return get_sha1_with_context_1(str, flags, NULL, sha1, orc);
  }
diff --combined t/t1006-cat-file.sh
index 4f225db9a7,a494013ed3..93a4794930
--- a/t/t1006-cat-file.sh
+++ b/t/t1006-cat-file.sh
@@@ -47,18 -47,6 +47,18 @@@ $content
  	test_cmp expect actual
      '
  
 +    test_expect_success "Type of $type is correct using --allow-unknown-type" '
 +	echo $type >expect &&
 +	git cat-file -t --allow-unknown-type $sha1 >actual &&
 +	test_cmp expect actual
 +    '
 +
 +    test_expect_success "Size of $type is correct using --allow-unknown-type" '
 +	echo $size >expect &&
 +	git cat-file -s --allow-unknown-type $sha1 >actual &&
 +	test_cmp expect actual
 +    '
 +
      test -z "$content" ||
      test_expect_success "Content of $type is correct" '
  	maybe_remove_timestamp "$content" $no_ts >expect &&
@@@ -201,6 -189,13 +201,13 @@@ d
      '
  done
  
+ for opt in t s e p
+ do
+     test_expect_success "Passing -$opt with --follow-symlinks fails" '
+ 	    test_must_fail git cat-file --follow-symlinks -$opt $hello_sha1
+ 	'
+ done
+ 
  test_expect_success "--batch-check for a non-existent named object" '
      test "foobar42 missing
  foobar84 missing" = \
@@@ -308,37 -303,202 +315,236 @@@ test_expect_success '%(deltabase) repor
  	}
  '
  
 +bogus_type="bogus"
 +bogus_content="bogus"
 +bogus_size=$(strlen "$bogus_content")
 +bogus_sha1=$(echo_without_newline "$bogus_content" | git hash-object -t $bogus_type --literally -w --stdin)
 +
 +test_expect_success "Type of broken object is correct" '
 +	echo $bogus_type >expect &&
 +	git cat-file -t --allow-unknown-type $bogus_sha1 >actual &&
 +	test_cmp expect actual
 +'
 +
 +test_expect_success "Size of broken object is correct" '
 +	echo $bogus_size >expect &&
 +	git cat-file -s --allow-unknown-type $bogus_sha1 >actual &&
 +	test_cmp expect actual
 +'
 +bogus_type="abcdefghijklmnopqrstuvwxyz1234679"
 +bogus_content="bogus"
 +bogus_size=$(strlen "$bogus_content")
 +bogus_sha1=$(echo_without_newline "$bogus_content" | git hash-object -t $bogus_type --literally -w --stdin)
 +
 +test_expect_success "Type of broken object is correct when type is large" '
 +	echo $bogus_type >expect &&
 +	git cat-file -t --allow-unknown-type $bogus_sha1 >actual &&
 +	test_cmp expect actual
 +'
 +
 +test_expect_success "Size of large broken object is correct when type is large" '
 +	echo $bogus_size >expect &&
 +	git cat-file -s --allow-unknown-type $bogus_sha1 >actual &&
 +	test_cmp expect actual
 +'
 +
+ # Tests for git cat-file --follow-symlinks
+ test_expect_success 'prep for symlink tests' '
+ 	echo_without_newline "$hello_content" >morx &&
+ 	test_ln_s_add morx same-dir-link &&
+ 	test_ln_s_add dir link-to-dir &&
+ 	test_ln_s_add ../fleem out-of-repo-link &&
+ 	test_ln_s_add .. out-of-repo-link-dir &&
+ 	test_ln_s_add same-dir-link link-to-link &&
+ 	test_ln_s_add nope broken-same-dir-link &&
+ 	mkdir dir &&
+ 	test_ln_s_add ../morx dir/parent-dir-link &&
+ 	test_ln_s_add .. dir/link-dir &&
+ 	test_ln_s_add ../../escape dir/out-of-repo-link &&
+ 	test_ln_s_add ../.. dir/out-of-repo-link-dir &&
+ 	test_ln_s_add nope dir/broken-link-in-dir &&
+ 	mkdir dir/subdir &&
+ 	test_ln_s_add ../../morx dir/subdir/grandparent-dir-link &&
+ 	test_ln_s_add ../../../great-escape dir/subdir/out-of-repo-link &&
+ 	test_ln_s_add ../../.. dir/subdir/out-of-repo-link-dir &&
+ 	test_ln_s_add ../../../ dir/subdir/out-of-repo-link-dir-trailing &&
+ 	test_ln_s_add ../parent-dir-link dir/subdir/parent-dir-link-to-link &&
+ 	echo_without_newline "$hello_content" >dir/subdir/ind2 &&
+ 	echo_without_newline "$hello_content" >dir/ind1 &&
+ 	test_ln_s_add dir dirlink &&
+ 	test_ln_s_add dir/subdir subdirlink &&
+ 	test_ln_s_add subdir/ind2 dir/link-to-child &&
+ 	test_ln_s_add dir/link-to-child link-to-down-link &&
+ 	test_ln_s_add dir/.. up-down &&
+ 	test_ln_s_add dir/../ up-down-trailing &&
+ 	test_ln_s_add dir/../morx up-down-file &&
+ 	test_ln_s_add dir/../../morx up-up-down-file &&
+ 	test_ln_s_add subdirlink/../../morx up-two-down-file &&
+ 	test_ln_s_add loop1 loop2 &&
+ 	test_ln_s_add loop2 loop1 &&
+ 	git add morx dir/subdir/ind2 dir/ind1 &&
+ 	git commit -am "test" &&
+ 	echo $hello_sha1 blob $hello_size >found
+ '
+ 
+ test_expect_success 'git cat-file --batch-check --follow-symlinks works for non-links' '
+ 	echo HEAD:morx | git cat-file --batch-check --follow-symlinks >actual &&
+ 	test_cmp found actual &&
+ 	echo HEAD:nope missing >expect &&
+ 	echo HEAD:nope | git cat-file --batch-check --follow-symlinks >actual &&
+ 	test_cmp expect actual
+ '
+ 
+ test_expect_success 'git cat-file --batch-check --follow-symlinks works for in-repo, same-dir links' '
+ 	echo HEAD:same-dir-link | git cat-file --batch-check --follow-symlinks >actual &&
+ 	test_cmp found actual
+ '
+ 
+ test_expect_success 'git cat-file --batch-check --follow-symlinks works for in-repo, links to dirs' '
+ 	echo HEAD:link-to-dir/ind1 | git cat-file --batch-check --follow-symlinks >actual &&
+ 	test_cmp found actual
+ '
+ 
+ 
+ test_expect_success 'git cat-file --batch-check --follow-symlinks works for broken in-repo, same-dir links' '
+ 	echo dangling 25 >expect &&
+ 	echo HEAD:broken-same-dir-link >>expect &&
+ 	echo HEAD:broken-same-dir-link | git cat-file --batch-check --follow-symlinks >actual &&
+ 	test_cmp expect actual
+ '
+ 
+ test_expect_success 'git cat-file --batch-check --follow-symlinks works for same-dir links-to-links' '
+ 	echo HEAD:link-to-link | git cat-file --batch-check --follow-symlinks >actual &&
+ 	test_cmp found actual
+ '
+ 
+ test_expect_success 'git cat-file --batch-check --follow-symlinks works for parent-dir links' '
+ 	echo HEAD:dir/parent-dir-link | git cat-file --batch-check --follow-symlinks >actual &&
+ 	test_cmp found actual &&
+ 	echo notdir 29 >expect &&
+ 	echo HEAD:dir/parent-dir-link/nope >>expect &&
+ 	echo HEAD:dir/parent-dir-link/nope | git cat-file --batch-check --follow-symlinks >actual &&
+ 	test_cmp expect actual
+ '
+ 
+ test_expect_success 'git cat-file --batch-check --follow-symlinks works for .. links' '
+ 	echo dangling 22 >expect &&
+ 	echo HEAD:dir/link-dir/nope >>expect &&
+ 	echo HEAD:dir/link-dir/nope | git cat-file --batch-check --follow-symlinks >actual &&
+ 	test_cmp expect actual &&
+ 	echo HEAD:dir/link-dir/morx | git cat-file --batch-check --follow-symlinks >actual &&
+ 	test_cmp found actual &&
+ 	echo dangling 27 >expect &&
+ 	echo HEAD:dir/broken-link-in-dir >>expect &&
+ 	echo HEAD:dir/broken-link-in-dir | git cat-file --batch-check --follow-symlinks >actual &&
+ 	test_cmp expect actual
+ '
+ 
+ test_expect_success 'git cat-file --batch-check --follow-symlinks works for ../.. links' '
+ 	echo notdir 41 >expect &&
+ 	echo HEAD:dir/subdir/grandparent-dir-link/nope >>expect &&
+ 	echo HEAD:dir/subdir/grandparent-dir-link/nope | git cat-file --batch-check --follow-symlinks >actual &&
+ 	test_cmp expect actual &&
+ 	echo HEAD:dir/subdir/grandparent-dir-link | git cat-file --batch-check --follow-symlinks >actual &&
+ 	test_cmp found actual &&
+ 	echo HEAD:dir/subdir/parent-dir-link-to-link | git cat-file --batch-check --follow-symlinks >actual &&
+ 	test_cmp found actual
+ '
+ 
+ test_expect_success 'git cat-file --batch-check --follow-symlinks works for dir/ links' '
+ 	echo dangling 17 >expect &&
+ 	echo HEAD:dirlink/morx >>expect &&
+ 	echo HEAD:dirlink/morx | git cat-file --batch-check --follow-symlinks >actual &&
+ 	test_cmp expect actual &&
+ 	echo $hello_sha1 blob $hello_size >expect &&
+ 	echo HEAD:dirlink/ind1 | git cat-file --batch-check --follow-symlinks >actual &&
+ 	test_cmp expect actual
+ '
+ 
+ test_expect_success 'git cat-file --batch-check --follow-symlinks works for dir/subdir links' '
+ 	echo dangling 20 >expect &&
+ 	echo HEAD:subdirlink/morx >>expect &&
+ 	echo HEAD:subdirlink/morx | git cat-file --batch-check --follow-symlinks >actual &&
+ 	test_cmp expect actual &&
+ 	echo HEAD:subdirlink/ind2 | git cat-file --batch-check --follow-symlinks >actual &&
+ 	test_cmp found actual
+ '
+ 
+ test_expect_success 'git cat-file --batch-check --follow-symlinks works for dir ->subdir links' '
+ 	echo notdir 27 >expect &&
+ 	echo HEAD:dir/link-to-child/morx >>expect &&
+ 	echo HEAD:dir/link-to-child/morx | git cat-file --batch-check --follow-symlinks >actual &&
+ 	test_cmp expect actual &&
+ 	echo HEAD:dir/link-to-child | git cat-file --batch-check --follow-symlinks >actual &&
+ 	test_cmp found actual &&
+ 	echo HEAD:link-to-down-link | git cat-file --batch-check --follow-symlinks >actual &&
+ 	test_cmp found actual
+ '
+ 
+ test_expect_success 'git cat-file --batch-check --follow-symlinks works for out-of-repo symlinks' '
+ 	echo symlink 8 >expect &&
+ 	echo ../fleem >>expect &&
+ 	echo HEAD:out-of-repo-link | git cat-file --batch-check --follow-symlinks >actual &&
+ 	test_cmp expect actual &&
+ 	echo symlink 2 >expect &&
+ 	echo .. >>expect &&
+ 	echo HEAD:out-of-repo-link-dir | git cat-file --batch-check --follow-symlinks >actual &&
+ 	test_cmp expect actual
+ '
+ 
+ test_expect_success 'git cat-file --batch-check --follow-symlinks works for out-of-repo symlinks in dirs' '
+ 	echo symlink 9 >expect &&
+ 	echo ../escape >>expect &&
+ 	echo HEAD:dir/out-of-repo-link | git cat-file --batch-check --follow-symlinks >actual &&
+ 	test_cmp expect actual &&
+ 	echo symlink 2 >expect &&
+ 	echo .. >>expect &&
+ 	echo HEAD:dir/out-of-repo-link-dir | git cat-file --batch-check --follow-symlinks >actual &&
+ 	test_cmp expect actual
+ '
+ 
+ test_expect_success 'git cat-file --batch-check --follow-symlinks works for out-of-repo symlinks in subdirs' '
+ 	echo symlink 15 >expect &&
+ 	echo ../great-escape >>expect &&
+ 	echo HEAD:dir/subdir/out-of-repo-link | git cat-file --batch-check --follow-symlinks >actual &&
+ 	test_cmp expect actual &&
+ 	echo symlink 2 >expect &&
+ 	echo .. >>expect &&
+ 	echo HEAD:dir/subdir/out-of-repo-link-dir | git cat-file --batch-check --follow-symlinks >actual &&
+ 	test_cmp expect actual &&
+ 	echo symlink 3 >expect &&
+ 	echo ../ >>expect &&
+ 	echo HEAD:dir/subdir/out-of-repo-link-dir-trailing | git cat-file --batch-check --follow-symlinks >actual &&
+ 	test_cmp expect actual
+ '
+ 
+ test_expect_success 'git cat-file --batch-check --follow-symlinks works for symlinks with internal ..' '
+ 	echo HEAD: | git cat-file --batch-check >expect &&
+ 	echo HEAD:up-down | git cat-file --batch-check --follow-symlinks >actual &&
+ 	test_cmp expect actual &&
+ 	echo HEAD:up-down-trailing | git cat-file --batch-check --follow-symlinks >actual &&
+ 	test_cmp expect actual &&
+ 	echo HEAD:up-down-file | git cat-file --batch-check --follow-symlinks >actual &&
+ 	test_cmp found actual &&
+ 	echo symlink 7 >expect &&
+ 	echo ../morx >>expect &&
+ 	echo HEAD:up-up-down-file | git cat-file --batch-check --follow-symlinks >actual &&
+ 	test_cmp expect actual &&
+ 	echo HEAD:up-two-down-file | git cat-file --batch-check --follow-symlinks >actual &&
+ 	test_cmp found actual
+ '
+ 
+ test_expect_success 'git cat-file --batch-check --follow-symlink breaks loops' '
+ 	echo loop 10 >expect &&
+ 	echo HEAD:loop1 >>expect &&
+ 	echo HEAD:loop1 | git cat-file --batch-check --follow-symlinks >actual &&
+ 	test_cmp expect actual
+ '
+ 
+ test_expect_success 'git cat-file --batch --follow-symlink returns correct sha and mode' '
+ 	echo HEAD:morx | git cat-file --batch >expect &&
+ 	echo HEAD:morx | git cat-file --batch --follow-symlinks >actual &&
+ 	test_cmp expect actual
+ '
++
  test_done