Merge branch 'cc/replace'
authorJunio C Hamano <gitster@pobox.com>
Sat, 22 Aug 2009 01:47:53 +0000 (18:47 -0700)
committerJunio C Hamano <gitster@pobox.com>
Sat, 22 Aug 2009 01:47:53 +0000 (18:47 -0700)
* cc/replace:
t6050: check pushing something based on a replaced commit
Documentation: add documentation for "git replace"
Add git-replace to .gitignore
builtin-replace: use "usage_msg_opt" to give better error messages
parse-options: add new function "usage_msg_opt"
builtin-replace: teach "git replace" to actually replace
Add new "git replace" command
environment: add global variable to disable replacement
mktag: call "check_sha1_signature" with the replacement sha1
replace_object: add a test case
object: call "check_sha1_signature" with the replacement sha1
sha1_file: add a "read_sha1_file_repl" function
replace_object: add mechanism to replace objects found in "refs/replace/"
refs: add a "for_each_replace_ref" function

23 files changed:
.gitignore
Documentation/git-replace.txt [new file with mode: 0644]
Makefile
builtin-fsck.c
builtin-pack-objects.c
builtin-prune.c
builtin-replace.c [new file with mode: 0644]
builtin-unpack-objects.c
builtin.h
cache.h
commit.h
environment.c
git.c
mktag.c
object.c
parse-options.c
parse-options.h
refs.c
refs.h
replace_object.c [new file with mode: 0644]
sha1_file.c
t/t6050-replace.sh [new file with mode: 0755]
upload-pack.c
index 41c0b20a76ce0fd47c7cafc51777336ce99ce1b0..10808e3a734c2fdcee523e49bf1e8a6694002cc1 100644 (file)
@@ -105,6 +105,7 @@ git-reflog
 git-relink
 git-remote
 git-repack
+git-replace
 git-repo-config
 git-request-pull
 git-rerere
diff --git a/Documentation/git-replace.txt b/Documentation/git-replace.txt
new file mode 100644 (file)
index 0000000..915cb77
--- /dev/null
@@ -0,0 +1,71 @@
+git-replace(1)
+==============
+
+NAME
+----
+git-replace - Create, list, delete refs to replace objects
+
+SYNOPSIS
+--------
+[verse]
+'git replace' [-f] <object> <replacement>
+'git replace' -d <object>...
+'git replace' -l [<pattern>]
+
+DESCRIPTION
+-----------
+Adds a 'replace' reference in `.git/refs/replace/`
+
+The name of the 'replace' reference is the SHA1 of the object that is
+replaced. The content of the replace reference is the SHA1 of the
+replacement object.
+
+Unless `-f` is given, the replace reference must not yet exist in
+`.git/refs/replace/` directory.
+
+OPTIONS
+-------
+-f::
+       If an existing replace ref for the same object exists, it will
+       be overwritten (instead of failing).
+
+-d::
+       Delete existing replace refs for the given objects.
+
+-l <pattern>::
+       List replace refs for objects that match the given pattern (or
+       all if no pattern is given).
+       Typing "git replace" without arguments, also lists all replace
+       refs.
+
+BUGS
+----
+Comparing blobs or trees that have been replaced with those that
+replace them will not work properly. And using 'git reset --hard' to
+go back to a replaced commit will move the branch to the replacement
+commit instead of the replaced commit.
+
+There may be other problems when using 'git rev-list' related to
+pending objects. And of course things may break if an object of one
+type is replaced by an object of another type (for example a blob
+replaced by a commit).
+
+SEE ALSO
+--------
+linkgit:git-tag[1]
+linkgit:git-branch[1]
+
+Author
+------
+Written by Christian Couder <chriscool@tuxfamily.org> and Junio C
+Hamano <gitster@pobox.com>, based on 'git tag' by Kristian Hogsberg
+<krh@redhat.com> and Carlos Rica <jasampler@gmail.com>.
+
+Documentation
+--------------
+Documentation by Christian Couder <chriscool@tuxfamily.org> and the
+git-list <git@vger.kernel.org>, based on 'git tag' documentation.
+
+GIT
+---
+Part of the linkgit:git[1] suite
index e6df8ecde68edbfddf7266de3aa11912df63b30e..66eedeff428986e2d5850ac84c98cd0ab7a44081 100644 (file)
--- a/Makefile
+++ b/Makefile
@@ -536,6 +536,7 @@ LIB_OBJS += read-cache.o
 LIB_OBJS += reflog-walk.o
 LIB_OBJS += refs.o
 LIB_OBJS += remote.o
+LIB_OBJS += replace_object.o
 LIB_OBJS += rerere.o
 LIB_OBJS += revision.o
 LIB_OBJS += run-command.o
@@ -625,6 +626,7 @@ BUILTIN_OBJS += builtin-read-tree.o
 BUILTIN_OBJS += builtin-receive-pack.o
 BUILTIN_OBJS += builtin-reflog.o
 BUILTIN_OBJS += builtin-remote.o
+BUILTIN_OBJS += builtin-replace.o
 BUILTIN_OBJS += builtin-rerere.o
 BUILTIN_OBJS += builtin-reset.o
 BUILTIN_OBJS += builtin-rev-list.o
index b3d38fa277b3d0024b9c46a62cf15bc2448cc1e7..c58b0e337ed434ffb90cfb5c80540531d94a4a6a 100644 (file)
@@ -589,6 +589,7 @@ int cmd_fsck(int argc, const char **argv, const char *prefix)
        struct alternate_object_database *alt;
 
        errors_found = 0;
+       read_replace_refs = 0;
 
        argc = parse_options(argc, argv, prefix, fsck_opts, fsck_usage, 0);
        if (write_lost_and_found) {
index 9cc8a8451d21840b315d1355207293a1b0bcbf2c..c4337480fd3ebbe86919b3014316143ecfa0ccaf 100644 (file)
@@ -2098,6 +2098,8 @@ int cmd_pack_objects(int argc, const char **argv, const char *prefix)
        int rp_ac_alloc = 64;
        int rp_ac;
 
+       read_replace_refs = 0;
+
        rp_av = xcalloc(rp_ac_alloc, sizeof(*rp_av));
 
        rp_av[0] = "pack-objects";
index 0ed9cce4a23aa575c1e131a808cedd4f8bb542f4..8459aec8e8ea9d24a13448cf950d2e160361fd9d 100644 (file)
@@ -140,6 +140,7 @@ int cmd_prune(int argc, const char **argv, const char *prefix)
        char *s;
 
        save_commit_buffer = 0;
+       read_replace_refs = 0;
        init_revisions(&revs, prefix);
 
        argc = parse_options(argc, argv, prefix, options, prune_usage, 0);
diff --git a/builtin-replace.c b/builtin-replace.c
new file mode 100644 (file)
index 0000000..fe3a647
--- /dev/null
@@ -0,0 +1,159 @@
+/*
+ * Builtin "git replace"
+ *
+ * Copyright (c) 2008 Christian Couder <chriscool@tuxfamily.org>
+ *
+ * Based on builtin-tag.c by Kristian Høgsberg <krh@redhat.com>
+ * and Carlos Rica <jasampler@gmail.com> that was itself based on
+ * git-tag.sh and mktag.c by Linus Torvalds.
+ */
+
+#include "cache.h"
+#include "builtin.h"
+#include "refs.h"
+#include "parse-options.h"
+
+static const char * const git_replace_usage[] = {
+       "git replace [-f] <object> <replacement>",
+       "git replace -d <object>...",
+       "git replace -l [<pattern>]",
+       NULL
+};
+
+static int show_reference(const char *refname, const unsigned char *sha1,
+                         int flag, void *cb_data)
+{
+       const char *pattern = cb_data;
+
+       if (!fnmatch(pattern, refname, 0))
+               printf("%s\n", refname);
+
+       return 0;
+}
+
+static int list_replace_refs(const char *pattern)
+{
+       if (pattern == NULL)
+               pattern = "*";
+
+       for_each_replace_ref(show_reference, (void *) pattern);
+
+       return 0;
+}
+
+typedef int (*each_replace_name_fn)(const char *name, const char *ref,
+                                   const unsigned char *sha1);
+
+static int for_each_replace_name(const char **argv, each_replace_name_fn fn)
+{
+       const char **p;
+       char ref[PATH_MAX];
+       int had_error = 0;
+       unsigned char sha1[20];
+
+       for (p = argv; *p; p++) {
+               if (snprintf(ref, sizeof(ref), "refs/replace/%s", *p)
+                                       >= sizeof(ref)) {
+                       error("replace ref name too long: %.*s...", 50, *p);
+                       had_error = 1;
+                       continue;
+               }
+               if (!resolve_ref(ref, sha1, 1, NULL)) {
+                       error("replace ref '%s' not found.", *p);
+                       had_error = 1;
+                       continue;
+               }
+               if (fn(*p, ref, sha1))
+                       had_error = 1;
+       }
+       return had_error;
+}
+
+static int delete_replace_ref(const char *name, const char *ref,
+                             const unsigned char *sha1)
+{
+       if (delete_ref(ref, sha1, 0))
+               return 1;
+       printf("Deleted replace ref '%s'\n", name);
+       return 0;
+}
+
+static int replace_object(const char *object_ref, const char *replace_ref,
+                         int force)
+{
+       unsigned char object[20], prev[20], repl[20];
+       char ref[PATH_MAX];
+       struct ref_lock *lock;
+
+       if (get_sha1(object_ref, object))
+               die("Failed to resolve '%s' as a valid ref.", object_ref);
+       if (get_sha1(replace_ref, repl))
+               die("Failed to resolve '%s' as a valid ref.", replace_ref);
+
+       if (snprintf(ref, sizeof(ref),
+                    "refs/replace/%s",
+                    sha1_to_hex(object)) > sizeof(ref) - 1)
+               die("replace ref name too long: %.*s...", 50, ref);
+       if (check_ref_format(ref))
+               die("'%s' is not a valid ref name.", ref);
+
+       if (!resolve_ref(ref, prev, 1, NULL))
+               hashclr(prev);
+       else if (!force)
+               die("replace ref '%s' already exists", ref);
+
+       lock = lock_any_ref_for_update(ref, prev, 0);
+       if (!lock)
+               die("%s: cannot lock the ref", ref);
+       if (write_ref_sha1(lock, repl, NULL) < 0)
+               die("%s: cannot update the ref", ref);
+
+       return 0;
+}
+
+int cmd_replace(int argc, const char **argv, const char *prefix)
+{
+       int list = 0, delete = 0, force = 0;
+       struct option options[] = {
+               OPT_BOOLEAN('l', NULL, &list, "list replace refs"),
+               OPT_BOOLEAN('d', NULL, &delete, "delete replace refs"),
+               OPT_BOOLEAN('f', NULL, &force, "replace the ref if it exists"),
+               OPT_END()
+       };
+
+       argc = parse_options(argc, argv, prefix, options, git_replace_usage, 0);
+
+       if (list && delete)
+               usage_msg_opt("-l and -d cannot be used together",
+                             git_replace_usage, options);
+
+       if (force && (list || delete))
+               usage_msg_opt("-f cannot be used with -d or -l",
+                             git_replace_usage, options);
+
+       /* Delete refs */
+       if (delete) {
+               if (argc < 1)
+                       usage_msg_opt("-d needs at least one argument",
+                                     git_replace_usage, options);
+               return for_each_replace_name(argv, delete_replace_ref);
+       }
+
+       /* Replace object */
+       if (!list && argc) {
+               if (argc != 2)
+                       usage_msg_opt("bad number of arguments",
+                                     git_replace_usage, options);
+               return replace_object(argv[0], argv[1], force);
+       }
+
+       /* List refs, even if "list" is not set */
+       if (argc > 1)
+               usage_msg_opt("only one pattern can be given with -l",
+                             git_replace_usage, options);
+       if (force)
+               usage_msg_opt("-f needs some arguments",
+                             git_replace_usage, options);
+
+       return list_replace_refs(argv[0]);
+}
index 557148a693c058f51222cb3d996c309791d43d8b..968fda7219807de9985c06eccd0812da04a149ae 100644 (file)
@@ -495,6 +495,8 @@ int cmd_unpack_objects(int argc, const char **argv, const char *prefix)
        int i;
        unsigned char sha1[20];
 
+       read_replace_refs = 0;
+
        git_config(git_default_config, NULL);
 
        quiet = !isatty(2);
index 9993dfcf99f7ad47a1a0a052d591cfc06a9f614d..51e4ba7f360338e5cd666c01c2f3b8c31e9b5a3e 100644 (file)
--- a/builtin.h
+++ b/builtin.h
@@ -111,5 +111,6 @@ extern int cmd_write_tree(int argc, const char **argv, const char *prefix);
 extern int cmd_verify_pack(int argc, const char **argv, const char *prefix);
 extern int cmd_show_ref(int argc, const char **argv, const char *prefix);
 extern int cmd_pack_refs(int argc, const char **argv, const char *prefix);
+extern int cmd_replace(int argc, const char **argv, const char *prefix);
 
 #endif
diff --git a/cache.h b/cache.h
index eee717c81b5882bd59009fb52d0484f0fb1041cb..f7937893773a4b015df7fafc605e2d561139c86b 100644 (file)
--- a/cache.h
+++ b/cache.h
@@ -520,6 +520,7 @@ extern size_t packed_git_window_size;
 extern size_t packed_git_limit;
 extern size_t delta_base_cache_limit;
 extern int auto_crlf;
+extern int read_replace_refs;
 extern int fsync_object_files;
 extern int core_preload_index;
 
@@ -656,7 +657,11 @@ char *strip_path_suffix(const char *path, const char *suffix);
 
 /* Read and unpack a sha1 file into memory, write memory to a sha1 file */
 extern int sha1_object_info(const unsigned char *, unsigned long *);
-extern void * read_sha1_file(const unsigned char *sha1, enum object_type *type, unsigned long *size);
+extern void *read_sha1_file_repl(const unsigned char *sha1, enum object_type *type, unsigned long *size, const unsigned char **replacement);
+static inline void *read_sha1_file(const unsigned char *sha1, enum object_type *type, unsigned long *size)
+{
+       return read_sha1_file_repl(sha1, type, size, NULL);
+}
 extern int hash_sha1_file(const void *buf, unsigned long len, const char *type, unsigned char *sha1);
 extern int write_sha1_file(void *buf, unsigned long len, const char *type, unsigned char *return_sha1);
 extern int pretend_sha1_file(void *, unsigned long, enum object_type, unsigned char *);
index 4886544b631bd6b79ad8410fa369e41975c0ff23..d1674d7f16465b6288fe5e20b03f77dd3a403546 100644 (file)
--- a/commit.h
+++ b/commit.h
@@ -123,6 +123,8 @@ struct commit_graft *read_graft_line(char *buf, int len);
 int register_commit_graft(struct commit_graft *, int);
 struct commit_graft *lookup_commit_graft(const unsigned char *sha1);
 
+const unsigned char *lookup_replace_object(const unsigned char *sha1);
+
 extern struct commit_list *get_merge_bases(struct commit *rev1, struct commit *rev2, int cleanup);
 extern struct commit_list *get_merge_bases_many(struct commit *one, int n, struct commit **twos, int cleanup);
 extern struct commit_list *get_octopus_merge_bases(struct commit_list *in);
index 3cf88f58c4adad2aef67cd8ced121fef9cd8bab0..5de683784039f20b55f58ef36cb04a11f6a10610 100644 (file)
@@ -39,6 +39,7 @@ int pager_use_color = 1;
 const char *editor_program;
 const char *excludes_file;
 int auto_crlf = 0;     /* 1: both ways, -1: only when adding git objects */
+int read_replace_refs = 1;
 enum safe_crlf safe_crlf = SAFE_CRLF_WARN;
 unsigned whitespace_rule_cfg = WS_DEFAULT_RULE;
 enum branch_track git_branch_track = BRANCH_TRACK_REMOTE;
diff --git a/git.c b/git.c
index 4588a8bac21a12240c84eac4b24d68cb72920d80..5da6c65697dfd198e27b5b693566158bf772ab88 100644 (file)
--- a/git.c
+++ b/git.c
@@ -339,6 +339,7 @@ static void handle_internal_command(int argc, const char **argv)
                { "receive-pack", cmd_receive_pack },
                { "reflog", cmd_reflog, RUN_SETUP },
                { "remote", cmd_remote, RUN_SETUP },
+               { "replace", cmd_replace, RUN_SETUP },
                { "repo-config", cmd_config },
                { "rerere", cmd_rerere, RUN_SETUP },
                { "reset", cmd_reset, RUN_SETUP },
diff --git a/mktag.c b/mktag.c
index a609e3ebd106ed985fa2065dc4af6565e5a379a6..a3b4270c18ea78fa36f7243de5a9e05e2066e030 100644 (file)
--- a/mktag.c
+++ b/mktag.c
 /*
  * We refuse to tag something we can't verify. Just because.
  */
-static int verify_object(unsigned char *sha1, const char *expected_type)
+static int verify_object(const unsigned char *sha1, const char *expected_type)
 {
        int ret = -1;
        enum object_type type;
        unsigned long size;
-       void *buffer = read_sha1_file(sha1, &type, &size);
+       const unsigned char *repl;
+       void *buffer = read_sha1_file_repl(sha1, &type, &size, &repl);
 
        if (buffer) {
                if (type == type_from_string(expected_type))
-                       ret = check_sha1_signature(sha1, buffer, size, expected_type);
+                       ret = check_sha1_signature(repl, buffer, size, expected_type);
                free(buffer);
        }
        return ret;
index a6ef439192c1083e367f0a86cb10d93564fc9481..fe8eaaf19f71b48d9acba83594d918fc4875f5c4 100644 (file)
--- a/object.c
+++ b/object.c
@@ -188,17 +188,18 @@ struct object *parse_object(const unsigned char *sha1)
        unsigned long size;
        enum object_type type;
        int eaten;
-       void *buffer = read_sha1_file(sha1, &type, &size);
+       const unsigned char *repl;
+       void *buffer = read_sha1_file_repl(sha1, &type, &size, &repl);
 
        if (buffer) {
                struct object *obj;
-               if (check_sha1_signature(sha1, buffer, size, typename(type)) < 0) {
+               if (check_sha1_signature(repl, buffer, size, typename(type)) < 0) {
                        free(buffer);
-                       error("sha1 mismatch %s\n", sha1_to_hex(sha1));
+                       error("sha1 mismatch %s\n", sha1_to_hex(repl));
                        return NULL;
                }
 
-               obj = parse_object_buffer(sha1, type, size, buffer, &eaten);
+               obj = parse_object_buffer(repl, type, size, buffer, &eaten);
                if (!eaten)
                        free(buffer);
                return obj;
index 3b71fbb5410332a3f11ca0e450a614b3345a687b..a64a4d6ee267cf2a691f546f668f3f644616408c 100644 (file)
@@ -549,6 +549,14 @@ void usage_with_options(const char * const *usagestr,
        exit(129);
 }
 
+void usage_msg_opt(const char *msg,
+                  const char * const *usagestr,
+                  const struct option *options)
+{
+       fprintf(stderr, "%s\n\n", msg);
+       usage_with_options(usagestr, options);
+}
+
 int parse_options_usage(const char * const *usagestr,
                        const struct option *opts)
 {
index b32587ad7cbf5ac3923764d68d1ccd197955e660..f295a2cf858f4dbebc62e956878544ffdb7fbe58 100644 (file)
@@ -145,6 +145,10 @@ extern int parse_options(int argc, const char **argv, const char *prefix,
 extern NORETURN void usage_with_options(const char * const *usagestr,
                                         const struct option *options);
 
+extern NORETURN void usage_msg_opt(const char *msg,
+                                  const char * const *usagestr,
+                                  const struct option *options);
+
 /*----- incremental advanced APIs -----*/
 
 enum {
diff --git a/refs.c b/refs.c
index dd9c9ba3f6cb1b7e742adaee89cc406c44d77367..24865cf5a6c937834b2a98ccd8d80a652ae5541e 100644 (file)
--- a/refs.c
+++ b/refs.c
@@ -668,6 +668,11 @@ int for_each_remote_ref(each_ref_fn fn, void *cb_data)
        return for_each_ref_in("refs/remotes/", fn, cb_data);
 }
 
+int for_each_replace_ref(each_ref_fn fn, void *cb_data)
+{
+       return do_for_each_ref("refs/replace/", fn, 13, 0, cb_data);
+}
+
 int for_each_rawref(each_ref_fn fn, void *cb_data)
 {
        return do_for_each_ref("refs/", fn, 0,
diff --git a/refs.h b/refs.h
index c11f6a6d588d1bd737fa60241b9c67308f4c14cc..777b5b7ca6c08ef63f44abbf0236fc180cb9c6d1 100644 (file)
--- a/refs.h
+++ b/refs.h
@@ -24,6 +24,7 @@ extern int for_each_ref_in(const char *, each_ref_fn, void *);
 extern int for_each_tag_ref(each_ref_fn, void *);
 extern int for_each_branch_ref(each_ref_fn, void *);
 extern int for_each_remote_ref(each_ref_fn, void *);
+extern int for_each_replace_ref(each_ref_fn, void *);
 
 /* can be used to learn about broken ref and symref */
 extern int for_each_rawref(each_ref_fn, void *);
diff --git a/replace_object.c b/replace_object.c
new file mode 100644 (file)
index 0000000..eb59604
--- /dev/null
@@ -0,0 +1,114 @@
+#include "cache.h"
+#include "sha1-lookup.h"
+#include "refs.h"
+
+static struct replace_object {
+       unsigned char sha1[2][20];
+} **replace_object;
+
+static int replace_object_alloc, replace_object_nr;
+
+static const unsigned char *replace_sha1_access(size_t index, void *table)
+{
+       struct replace_object **replace = table;
+       return replace[index]->sha1[0];
+}
+
+static int replace_object_pos(const unsigned char *sha1)
+{
+       return sha1_pos(sha1, replace_object, replace_object_nr,
+                       replace_sha1_access);
+}
+
+static int register_replace_object(struct replace_object *replace,
+                                  int ignore_dups)
+{
+       int pos = replace_object_pos(replace->sha1[0]);
+
+       if (0 <= pos) {
+               if (ignore_dups)
+                       free(replace);
+               else {
+                       free(replace_object[pos]);
+                       replace_object[pos] = replace;
+               }
+               return 1;
+       }
+       pos = -pos - 1;
+       if (replace_object_alloc <= ++replace_object_nr) {
+               replace_object_alloc = alloc_nr(replace_object_alloc);
+               replace_object = xrealloc(replace_object,
+                                         sizeof(*replace_object) *
+                                         replace_object_alloc);
+       }
+       if (pos < replace_object_nr)
+               memmove(replace_object + pos + 1,
+                       replace_object + pos,
+                       (replace_object_nr - pos - 1) *
+                       sizeof(*replace_object));
+       replace_object[pos] = replace;
+       return 0;
+}
+
+static int register_replace_ref(const char *refname,
+                               const unsigned char *sha1,
+                               int flag, void *cb_data)
+{
+       /* Get sha1 from refname */
+       const char *slash = strrchr(refname, '/');
+       const char *hash = slash ? slash + 1 : refname;
+       struct replace_object *repl_obj = xmalloc(sizeof(*repl_obj));
+
+       if (strlen(hash) != 40 || get_sha1_hex(hash, repl_obj->sha1[0])) {
+               free(repl_obj);
+               warning("bad replace ref name: %s", refname);
+               return 0;
+       }
+
+       /* Copy sha1 from the read ref */
+       hashcpy(repl_obj->sha1[1], sha1);
+
+       /* Register new object */
+       if (register_replace_object(repl_obj, 1))
+               die("duplicate replace ref: %s", refname);
+
+       return 0;
+}
+
+static void prepare_replace_object(void)
+{
+       static int replace_object_prepared;
+
+       if (replace_object_prepared)
+               return;
+
+       for_each_replace_ref(register_replace_ref, NULL);
+       replace_object_prepared = 1;
+}
+
+/* We allow "recursive" replacement. Only within reason, though */
+#define MAXREPLACEDEPTH 5
+
+const unsigned char *lookup_replace_object(const unsigned char *sha1)
+{
+       int pos, depth = MAXREPLACEDEPTH;
+       const unsigned char *cur = sha1;
+
+       if (!read_replace_refs)
+               return sha1;
+
+       prepare_replace_object();
+
+       /* Try to recursively replace the object */
+       do {
+               if (--depth < 0)
+                       die("replace depth too high for object %s",
+                           sha1_to_hex(sha1));
+
+               pos = replace_object_pos(cur);
+               if (0 <= pos)
+                       cur = replace_object[pos]->sha1[1];
+       } while (0 <= pos);
+
+       return cur;
+}
index 1d996a199036c115d46c1d630d53edf29b3b78e7..4ea0b18d0aaeca48ed75ed21863195c5ce830cbc 100644 (file)
@@ -2144,13 +2144,26 @@ static void *read_object(const unsigned char *sha1, enum object_type *type,
        return read_packed_sha1(sha1, type, size);
 }
 
-void *read_sha1_file(const unsigned char *sha1, enum object_type *type,
-                    unsigned long *size)
+void *read_sha1_file_repl(const unsigned char *sha1,
+                         enum object_type *type,
+                         unsigned long *size,
+                         const unsigned char **replacement)
 {
-       void *data = read_object(sha1, type, size);
+       const unsigned char *repl = lookup_replace_object(sha1);
+       void *data = read_object(repl, type, size);
+
+       /* die if we replaced an object with one that does not exist */
+       if (!data && repl != sha1)
+               die("replacement %s not found for %s",
+                   sha1_to_hex(repl), sha1_to_hex(sha1));
+
        /* legacy behavior is to die on corrupted objects */
-       if (!data && (has_loose_object(sha1) || has_packed_and_bad(sha1)))
-               die("object %s is corrupted", sha1_to_hex(sha1));
+       if (!data && (has_loose_object(repl) || has_packed_and_bad(repl)))
+               die("object %s is corrupted", sha1_to_hex(repl));
+
+       if (replacement)
+               *replacement = repl;
+
        return data;
 }
 
diff --git a/t/t6050-replace.sh b/t/t6050-replace.sh
new file mode 100755 (executable)
index 0000000..8b8bd81
--- /dev/null
@@ -0,0 +1,200 @@
+#!/bin/sh
+#
+# Copyright (c) 2008 Christian Couder
+#
+test_description='Tests replace refs functionality'
+
+exec </dev/null
+
+. ./test-lib.sh
+
+add_and_commit_file()
+{
+    _file="$1"
+    _msg="$2"
+
+    git add $_file || return $?
+    test_tick || return $?
+    git commit --quiet -m "$_file: $_msg"
+}
+
+HASH1=
+HASH2=
+HASH3=
+HASH4=
+HASH5=
+HASH6=
+HASH7=
+
+test_expect_success 'set up buggy branch' '
+     echo "line 1" >> hello &&
+     echo "line 2" >> hello &&
+     echo "line 3" >> hello &&
+     echo "line 4" >> hello &&
+     add_and_commit_file hello "4 lines" &&
+     HASH1=$(git rev-parse --verify HEAD) &&
+     echo "line BUG" >> hello &&
+     echo "line 6" >> hello &&
+     echo "line 7" >> hello &&
+     echo "line 8" >> hello &&
+     add_and_commit_file hello "4 more lines with a BUG" &&
+     HASH2=$(git rev-parse --verify HEAD) &&
+     echo "line 9" >> hello &&
+     echo "line 10" >> hello &&
+     add_and_commit_file hello "2 more lines" &&
+     HASH3=$(git rev-parse --verify HEAD) &&
+     echo "line 11" >> hello &&
+     add_and_commit_file hello "1 more line" &&
+     HASH4=$(git rev-parse --verify HEAD) &&
+     sed -e "s/BUG/5/" hello > hello.new &&
+     mv hello.new hello &&
+     add_and_commit_file hello "BUG fixed" &&
+     HASH5=$(git rev-parse --verify HEAD) &&
+     echo "line 12" >> hello &&
+     echo "line 13" >> hello &&
+     add_and_commit_file hello "2 more lines" &&
+     HASH6=$(git rev-parse --verify HEAD)
+     echo "line 14" >> hello &&
+     echo "line 15" >> hello &&
+     echo "line 16" >> hello &&
+     add_and_commit_file hello "again 3 more lines" &&
+     HASH7=$(git rev-parse --verify HEAD)
+'
+
+test_expect_success 'replace the author' '
+     git cat-file commit $HASH2 | grep "author A U Thor" &&
+     R=$(git cat-file commit $HASH2 | sed -e "s/A U/O/" | git hash-object -t commit --stdin -w) &&
+     git cat-file commit $R | grep "author O Thor" &&
+     git update-ref refs/replace/$HASH2 $R &&
+     git show HEAD~5 | grep "O Thor" &&
+     git show $HASH2 | grep "O Thor"
+'
+
+cat >tag.sig <<EOF
+object $HASH2
+type commit
+tag mytag
+tagger T A Gger <> 0 +0000
+
+EOF
+
+test_expect_success 'tag replaced commit' '
+     git mktag <tag.sig >.git/refs/tags/mytag 2>message
+'
+
+test_expect_success '"git fsck" works' '
+     git fsck master > fsck_master.out &&
+     grep "dangling commit $R" fsck_master.out &&
+     grep "dangling tag $(cat .git/refs/tags/mytag)" fsck_master.out &&
+     test -z "$(git fsck)"
+'
+
+test_expect_success 'repack, clone and fetch work' '
+     git repack -a -d &&
+     git clone --no-hardlinks . clone_dir &&
+     cd clone_dir &&
+     git show HEAD~5 | grep "A U Thor" &&
+     git show $HASH2 | grep "A U Thor" &&
+     git cat-file commit $R &&
+     git repack -a -d &&
+     test_must_fail git cat-file commit $R &&
+     git fetch ../ "refs/replace/*:refs/replace/*" &&
+     git show HEAD~5 | grep "O Thor" &&
+     git show $HASH2 | grep "O Thor" &&
+     git cat-file commit $R &&
+     cd ..
+'
+
+test_expect_success '"git replace" listing and deleting' '
+     test "$HASH2" = "$(git replace -l)" &&
+     test "$HASH2" = "$(git replace)" &&
+     aa=${HASH2%??????????????????????????????????????} &&
+     test "$HASH2" = "$(git replace -l "$aa*")" &&
+     test_must_fail git replace -d $R &&
+     test_must_fail git replace -d &&
+     test_must_fail git replace -l -d $HASH2 &&
+     git replace -d $HASH2 &&
+     git show $HASH2 | grep "A U Thor" &&
+     test -z "$(git replace -l)"
+'
+
+test_expect_success '"git replace" replacing' '
+     git replace $HASH2 $R &&
+     git show $HASH2 | grep "O Thor" &&
+     test_must_fail git replace $HASH2 $R &&
+     git replace -f $HASH2 $R &&
+     test_must_fail git replace -f &&
+     test "$HASH2" = "$(git replace)"
+'
+
+# This creates a side branch where the bug in H2
+# does not appear because P2 is created by applying
+# H2 and squashing H5 into it.
+# P3, P4 and P6 are created by cherry-picking H3, H4
+# and H6 respectively.
+#
+# At this point, we should have the following:
+#
+#    P2--P3--P4--P6
+#   /
+# H1-H2-H3-H4-H5-H6-H7
+#
+# Then we replace H6 with P6.
+#
+test_expect_success 'create parallel branch without the bug' '
+     git replace -d $HASH2 &&
+     git show $HASH2 | grep "A U Thor" &&
+     git checkout $HASH1 &&
+     git cherry-pick $HASH2 &&
+     git show $HASH5 | git apply &&
+     git commit --amend -m "hello: 4 more lines WITHOUT the bug" hello &&
+     PARA2=$(git rev-parse --verify HEAD) &&
+     git cherry-pick $HASH3 &&
+     PARA3=$(git rev-parse --verify HEAD) &&
+     git cherry-pick $HASH4 &&
+     PARA4=$(git rev-parse --verify HEAD) &&
+     git cherry-pick $HASH6 &&
+     PARA6=$(git rev-parse --verify HEAD) &&
+     git replace $HASH6 $PARA6 &&
+     git checkout master &&
+     cur=$(git rev-parse --verify HEAD) &&
+     test "$cur" = "$HASH7" &&
+     git log --pretty=oneline | grep $PARA2 &&
+     git remote add cloned ./clone_dir
+'
+
+test_expect_success 'push to cloned repo' '
+     git push cloned $HASH6^:refs/heads/parallel &&
+     cd clone_dir &&
+     git checkout parallel &&
+     git log --pretty=oneline | grep $PARA2 &&
+     cd ..
+'
+
+test_expect_success 'push branch with replacement' '
+     git cat-file commit $PARA3 | grep "author A U Thor" &&
+     S=$(git cat-file commit $PARA3 | sed -e "s/A U/O/" | git hash-object -t commit --stdin -w) &&
+     git cat-file commit $S | grep "author O Thor" &&
+     git replace $PARA3 $S &&
+     git show $HASH6~2 | grep "O Thor" &&
+     git show $PARA3 | grep "O Thor" &&
+     git push cloned $HASH6^:refs/heads/parallel2 &&
+     cd clone_dir &&
+     git checkout parallel2 &&
+     git log --pretty=oneline | grep $PARA3 &&
+     git show $PARA3 | grep "A U Thor" &&
+     cd ..
+'
+
+test_expect_success 'fetch branch with replacement' '
+     git branch tofetch $HASH6 &&
+     cd clone_dir &&
+     git fetch origin refs/heads/tofetch:refs/heads/parallel3
+     git log --pretty=oneline parallel3 | grep $PARA3
+     git show $PARA3 | grep "A U Thor"
+     cd ..
+'
+
+#
+#
+test_done
index f7d308a411d22cf350a6ac4512ee2ebb195f87d7..4d8be834ff45ba869bb84f0fa8a424a3c469a200 100644 (file)
@@ -651,6 +651,7 @@ int main(int argc, char **argv)
        int strict = 0;
 
        git_extract_argv0_path(argv[0]);
+       read_replace_refs = 0;
 
        for (i = 1; i < argc; i++) {
                char *arg = argv[i];