From b3cfc4066d87476726e8711a8b5fc3b721aba41c Mon Sep 17 00:00:00 2001 From: Josh Triplett Date: Tue, 5 Jul 2011 10:54:21 -0700 Subject: [PATCH 1/5] Fix prefix handling in ref iteration functions The do_for_each_ref iteration function accepts a prefix and a trim, and checks for the prefix on each ref before passing in that ref; it also supports trimming off part of the ref before passing it. However, do_for_each_ref used trim as the length of the prefix to check, ignoring the actual length of the prefix. Switch to using prefixcmp, checking the entire length of the prefix string, to properly support a trim value different than the length of the prefix. Several callers passed a prefix of "refs/" to filter out everything outside of refs/, but a trim of 0 to avoid trimming off the "refs/"; the trim of 0 meant that the filter of "refs/" no longer applied. Change these callers to pass an empty prefix instead, to avoid changing the existing behavior. Various callers count on this lack of filtering, such as receive-pack which uses add_extra_ref to add alternates as refs named ".have"; adding filtering would break that, causing t5501-fetch-push-alternates.sh to fail. That lack of filtering doesn't currently have any other effect, since the loose ref functions can never supply refs outside of "refs/", and packed-refs will not normally include such refs unless manually edited. Signed-off-by: Josh Triplett Signed-off-by: Jamey Sharp Signed-off-by: Junio C Hamano --- refs.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/refs.c b/refs.c index e3c05110e5..858cf92cf1 100644 --- a/refs.c +++ b/refs.c @@ -584,7 +584,7 @@ int read_ref(const char *ref, unsigned char *sha1) static int do_one_ref(const char *base, each_ref_fn fn, int trim, int flags, void *cb_data, struct ref_list *entry) { - if (strncmp(base, entry->name, trim)) + if (prefixcmp(entry->name, base)) return 0; if (!(flags & DO_FOR_EACH_INCLUDE_BROKEN)) { @@ -728,12 +728,12 @@ int head_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data) int for_each_ref(each_ref_fn fn, void *cb_data) { - return do_for_each_ref(NULL, "refs/", fn, 0, 0, cb_data); + return do_for_each_ref(NULL, "", fn, 0, 0, cb_data); } int for_each_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data) { - return do_for_each_ref(submodule, "refs/", fn, 0, 0, cb_data); + return do_for_each_ref(submodule, "", fn, 0, 0, cb_data); } int for_each_ref_in(const char *prefix, each_ref_fn fn, void *cb_data) @@ -819,7 +819,7 @@ int for_each_glob_ref(each_ref_fn fn, const char *pattern, void *cb_data) int for_each_rawref(each_ref_fn fn, void *cb_data) { - return do_for_each_ref(NULL, "refs/", fn, 0, + return do_for_each_ref(NULL, "", fn, 0, DO_FOR_EACH_INCLUDE_BROKEN, cb_data); } From a1bea2c1fc5e5243e873919248940dd5fff593a4 Mon Sep 17 00:00:00 2001 From: Josh Triplett Date: Tue, 5 Jul 2011 10:54:44 -0700 Subject: [PATCH 2/5] ref namespaces: infrastructure Add support for dividing the refs of a single repository into multiple namespaces, each of which can have its own branches, tags, and HEAD. Git can expose each namespace as an independent repository to pull from and push to, while sharing the object store, and exposing all the refs to operations such as git-gc. Storing multiple repositories as namespaces of a single repository avoids storing duplicate copies of the same objects, such as when storing multiple branches of the same source. The alternates mechanism provides similar support for avoiding duplicates, but alternates do not prevent duplication between new objects added to the repositories without ongoing maintenance, while namespaces do. To specify a namespace, set the GIT_NAMESPACE environment variable to the namespace. For each ref namespace, git stores the corresponding refs in a directory under refs/namespaces/. For example, GIT_NAMESPACE=foo will store refs under refs/namespaces/foo/. You can also specify namespaces via the --namespace option to git. Note that namespaces which include a / will expand to a hierarchy of namespaces; for example, GIT_NAMESPACE=foo/bar will store refs under refs/namespaces/foo/refs/namespaces/bar/. This makes paths in GIT_NAMESPACE behave hierarchically, so that cloning with GIT_NAMESPACE=foo/bar produces the same result as cloning with GIT_NAMESPACE=foo and cloning from that repo with GIT_NAMESPACE=bar. It also avoids ambiguity with strange namespace paths such as foo/refs/heads/, which could otherwise generate directory/file conflicts within the refs directory. Add the infrastructure for ref namespaces: handle the GIT_NAMESPACE environment variable and --namespace option, and support iterating over refs in a namespace. Signed-off-by: Josh Triplett Signed-off-by: Jamey Sharp Signed-off-by: Junio C Hamano --- cache.h | 3 ++ contrib/completion/git-completion.bash | 1 + environment.c | 41 ++++++++++++++++++++++++++ git.c | 18 +++++++++-- refs.c | 25 ++++++++++++++++ refs.h | 3 ++ 6 files changed, 89 insertions(+), 2 deletions(-) diff --git a/cache.h b/cache.h index 28a921dffc..26310c464e 100644 --- a/cache.h +++ b/cache.h @@ -379,6 +379,7 @@ static inline enum object_type object_type(unsigned int mode) } #define GIT_DIR_ENVIRONMENT "GIT_DIR" +#define GIT_NAMESPACE_ENVIRONMENT "GIT_NAMESPACE" #define GIT_WORK_TREE_ENVIRONMENT "GIT_WORK_TREE" #define DEFAULT_GIT_DIR_ENVIRONMENT ".git" #define DB_ENVIRONMENT "GIT_OBJECT_DIRECTORY" @@ -419,6 +420,8 @@ 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 const char *get_git_namespace(void); +extern const char *strip_namespace(const char *namespaced_ref); extern const char *get_git_work_tree(void); extern const char *read_gitfile_gently(const char *path); extern void set_git_work_tree(const char *tree); diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash index bb8d7d0878..32eb9cb4ff 100755 --- a/contrib/completion/git-completion.bash +++ b/contrib/completion/git-completion.bash @@ -2639,6 +2639,7 @@ _git () --exec-path --html-path --work-tree= + --namespace= --help " ;; diff --git a/environment.c b/environment.c index 94d58fd244..aad274b37d 100644 --- a/environment.c +++ b/environment.c @@ -8,6 +8,7 @@ * are. */ #include "cache.h" +#include "refs.h" char git_default_email[MAX_GITNAME]; char git_default_name[MAX_GITNAME]; @@ -65,6 +66,9 @@ int core_preload_index = 0; char *git_work_tree_cfg; static char *work_tree; +static const char *namespace; +static size_t namespace_len; + static const char *git_dir; static char *git_object_dir, *git_index_file, *git_graft_file; @@ -86,6 +90,27 @@ const char * const local_repo_env[LOCAL_REPO_ENV_SIZE + 1] = { NULL }; +static char *expand_namespace(const char *raw_namespace) +{ + struct strbuf buf = STRBUF_INIT; + struct strbuf **components, **c; + + if (!raw_namespace || !*raw_namespace) + return xstrdup(""); + + strbuf_addstr(&buf, raw_namespace); + components = strbuf_split(&buf, '/'); + strbuf_reset(&buf); + for (c = components; *c; c++) + if (strcmp((*c)->buf, "/") != 0) + strbuf_addf(&buf, "refs/namespaces/%s", (*c)->buf); + strbuf_list_free(components); + if (check_ref_format(buf.buf) != CHECK_REF_FORMAT_OK) + die("bad git namespace path \"%s\"", raw_namespace); + strbuf_addch(&buf, '/'); + return strbuf_detach(&buf, NULL); +} + static void setup_git_env(void) { git_dir = getenv(GIT_DIR_ENVIRONMENT); @@ -111,6 +136,8 @@ static void setup_git_env(void) git_graft_file = git_pathdup("info/grafts"); if (getenv(NO_REPLACE_OBJECTS_ENVIRONMENT)) read_replace_refs = 0; + namespace = expand_namespace(getenv(GIT_NAMESPACE_ENVIRONMENT)); + namespace_len = strlen(namespace); } int is_bare_repository(void) @@ -131,6 +158,20 @@ const char *get_git_dir(void) return git_dir; } +const char *get_git_namespace(void) +{ + if (!namespace) + setup_git_env(); + return namespace; +} + +const char *strip_namespace(const char *namespaced_ref) +{ + if (prefixcmp(namespaced_ref, get_git_namespace()) != 0) + return NULL; + return namespaced_ref + namespace_len; +} + static int git_work_tree_initialized; /* diff --git a/git.c b/git.c index a5ef3c69ff..ad95efe5b3 100644 --- a/git.c +++ b/git.c @@ -7,8 +7,8 @@ const char git_usage_string[] = "git [--version] [--exec-path[=]] [--html-path] [--man-path] [--info-path]\n" - " [-p|--paginate|--no-pager] [--no-replace-objects]\n" - " [--bare] [--git-dir=] [--work-tree=]\n" + " [-p|--paginate|--no-pager] [--no-replace-objects] [--bare]\n" + " [--git-dir=] [--work-tree=] [--namespace=]\n" " [-c name=value] [--help]\n" " []"; @@ -127,6 +127,20 @@ static int handle_options(const char ***argv, int *argc, int *envchanged) setenv(GIT_DIR_ENVIRONMENT, cmd + 10, 1); if (envchanged) *envchanged = 1; + } else if (!strcmp(cmd, "--namespace")) { + if (*argc < 2) { + fprintf(stderr, "No namespace given for --namespace.\n" ); + usage(git_usage_string); + } + setenv(GIT_NAMESPACE_ENVIRONMENT, (*argv)[1], 1); + if (envchanged) + *envchanged = 1; + (*argv)++; + (*argc)--; + } else if (!prefixcmp(cmd, "--namespace=")) { + setenv(GIT_NAMESPACE_ENVIRONMENT, cmd + 12, 1); + if (envchanged) + *envchanged = 1; } else if (!strcmp(cmd, "--work-tree")) { if (*argc < 2) { fprintf(stderr, "No directory given for --work-tree.\n" ); diff --git a/refs.c b/refs.c index 858cf92cf1..e83bbf804a 100644 --- a/refs.c +++ b/refs.c @@ -782,6 +782,31 @@ int for_each_replace_ref(each_ref_fn fn, void *cb_data) return do_for_each_ref(NULL, "refs/replace/", fn, 13, 0, cb_data); } +int head_ref_namespaced(each_ref_fn fn, void *cb_data) +{ + struct strbuf buf = STRBUF_INIT; + int ret = 0; + unsigned char sha1[20]; + int flag; + + strbuf_addf(&buf, "%sHEAD", get_git_namespace()); + if (resolve_ref(buf.buf, sha1, 1, &flag)) + ret = fn(buf.buf, sha1, flag, cb_data); + strbuf_release(&buf); + + return ret; +} + +int for_each_namespaced_ref(each_ref_fn fn, void *cb_data) +{ + struct strbuf buf = STRBUF_INIT; + int ret; + strbuf_addf(&buf, "%srefs/", get_git_namespace()); + ret = do_for_each_ref(NULL, buf.buf, fn, 0, 0, cb_data); + strbuf_release(&buf); + return ret; +} + int for_each_glob_ref_in(each_ref_fn fn, const char *pattern, const char *prefix, void *cb_data) { diff --git a/refs.h b/refs.h index 5e7a9a59f5..9a5c9e02fb 100644 --- a/refs.h +++ b/refs.h @@ -36,6 +36,9 @@ extern int for_each_tag_ref_submodule(const char *submodule, each_ref_fn fn, voi extern int for_each_branch_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data); extern int for_each_remote_ref_submodule(const char *submodule, each_ref_fn fn, void *cb_data); +extern int head_ref_namespaced(each_ref_fn fn, void *cb_data); +extern int for_each_namespaced_ref(each_ref_fn fn, void *cb_data); + static inline const char *has_glob_specials(const char *pattern) { return strpbrk(pattern, "?*["); From 6b01ecfe22f0b6ccb9665cd8d85d78a381fecffc Mon Sep 17 00:00:00 2001 From: Josh Triplett Date: Fri, 8 Jul 2011 16:13:32 -0700 Subject: [PATCH 3/5] ref namespaces: Support remote repositories via upload-pack and receive-pack Change upload-pack and receive-pack to use the namespace-prefixed refs when working with the repository, and use the unprefixed refs when talking to the client, maintaining the masquerade. This allows clone, pull, fetch, and push to work with a suitably configured GIT_NAMESPACE. receive-pack advertises refs outside the current namespace as .have refs (as it currently does for refs in alternates), so that the client can use them to minimize data transfer but will otherwise ignore them. With appropriate configuration, this also allows http-backend to expose namespaces as multiple repositories with different paths. This only requires setting GIT_NAMESPACE, which http-backend passes through to upload-pack and receive-pack. Signed-off-by: Josh Triplett Signed-off-by: Jamey Sharp Signed-off-by: Junio C Hamano --- builtin/receive-pack.c | 45 ++++++++++++++++++++++++++++++++++++------ upload-pack.c | 15 +++++++------- 2 files changed, 47 insertions(+), 13 deletions(-) diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c index e1ba4dc697..e589082b31 100644 --- a/builtin/receive-pack.c +++ b/builtin/receive-pack.c @@ -119,9 +119,25 @@ static int show_ref(const char *path, const unsigned char *sha1, int flag, void return 0; } +static int show_ref_cb(const char *path, const unsigned char *sha1, int flag, void *cb_data) +{ + path = strip_namespace(path); + /* + * Advertise refs outside our current namespace as ".have" + * refs, so that the client can use them to minimize data + * transfer but will otherwise ignore them. This happens to + * cover ".have" that are thrown in by add_one_alternate_ref() + * to mark histories that are complete in our alternates as + * well. + */ + if (!path) + path = ".have"; + return show_ref(path, sha1, flag, cb_data); +} + static void write_head_info(void) { - for_each_ref(show_ref, NULL); + for_each_ref(show_ref_cb, NULL); if (!sent_capabilities) show_ref("capabilities^{}", null_sha1, 0, NULL); @@ -332,6 +348,8 @@ static void refuse_unconfigured_deny_delete_current(void) static const char *update(struct command *cmd) { const char *name = cmd->ref_name; + struct strbuf namespaced_name_buf = STRBUF_INIT; + const char *namespaced_name; unsigned char *old_sha1 = cmd->old_sha1; unsigned char *new_sha1 = cmd->new_sha1; struct ref_lock *lock; @@ -342,7 +360,10 @@ static const char *update(struct command *cmd) return "funny refname"; } - if (is_ref_checked_out(name)) { + strbuf_addf(&namespaced_name_buf, "%s%s", get_git_namespace(), name); + namespaced_name = strbuf_detach(&namespaced_name_buf, NULL); + + if (is_ref_checked_out(namespaced_name)) { switch (deny_current_branch) { case DENY_IGNORE: break; @@ -370,7 +391,7 @@ static const char *update(struct command *cmd) return "deletion prohibited"; } - if (!strcmp(name, head_name)) { + if (!strcmp(namespaced_name, head_name)) { switch (deny_delete_current) { case DENY_IGNORE: break; @@ -426,14 +447,14 @@ static const char *update(struct command *cmd) rp_warning("Allowing deletion of corrupt ref."); old_sha1 = NULL; } - if (delete_ref(name, old_sha1, 0)) { + if (delete_ref(namespaced_name, old_sha1, 0)) { rp_error("failed to delete %s", name); return "failed to delete"; } return NULL; /* good */ } else { - lock = lock_any_ref_for_update(name, old_sha1, 0); + lock = lock_any_ref_for_update(namespaced_name, old_sha1, 0); if (!lock) { rp_error("failed to lock %s", name); return "failed to lock"; @@ -490,17 +511,29 @@ static void run_update_post_hook(struct command *commands) static void check_aliased_update(struct command *cmd, struct string_list *list) { + struct strbuf buf = STRBUF_INIT; + const char *dst_name; struct string_list_item *item; struct command *dst_cmd; unsigned char sha1[20]; char cmd_oldh[41], cmd_newh[41], dst_oldh[41], dst_newh[41]; int flag; - const char *dst_name = resolve_ref(cmd->ref_name, sha1, 0, &flag); + strbuf_addf(&buf, "%s%s", get_git_namespace(), cmd->ref_name); + dst_name = resolve_ref(buf.buf, sha1, 0, &flag); + strbuf_release(&buf); if (!(flag & REF_ISSYMREF)) return; + dst_name = strip_namespace(dst_name); + if (!dst_name) { + rp_error("refusing update to broken symref '%s'", cmd->ref_name); + cmd->skip_update = 1; + cmd->error_string = "broken symref"; + return; + } + if ((item = string_list_lookup(list, dst_name)) == NULL) return; diff --git a/upload-pack.c b/upload-pack.c index ce5cbbea6b..267e5b1d82 100644 --- a/upload-pack.c +++ b/upload-pack.c @@ -641,16 +641,17 @@ static int send_ref(const char *refname, const unsigned char *sha1, int flag, vo " side-band-64k ofs-delta shallow no-progress" " include-tag multi_ack_detailed"; struct object *o = parse_object(sha1); + const char *refname_nons = strip_namespace(refname); if (!o) die("git upload-pack: cannot find object %s:", sha1_to_hex(sha1)); if (capabilities) - packet_write(1, "%s %s%c%s%s\n", sha1_to_hex(sha1), refname, + packet_write(1, "%s %s%c%s%s\n", sha1_to_hex(sha1), refname_nons, 0, capabilities, stateless_rpc ? " no-done" : ""); else - packet_write(1, "%s %s\n", sha1_to_hex(sha1), refname); + packet_write(1, "%s %s\n", sha1_to_hex(sha1), refname_nons); capabilities = NULL; if (!(o->flags & OUR_REF)) { o->flags |= OUR_REF; @@ -659,7 +660,7 @@ static int send_ref(const char *refname, const unsigned char *sha1, int flag, vo if (o->type == OBJ_TAG) { o = deref_tag(o, refname, 0); if (o) - packet_write(1, "%s %s^{}\n", sha1_to_hex(o->sha1), refname); + packet_write(1, "%s %s^{}\n", sha1_to_hex(o->sha1), refname_nons); } return 0; } @@ -680,12 +681,12 @@ static void upload_pack(void) { if (advertise_refs || !stateless_rpc) { reset_timeout(); - head_ref(send_ref, NULL); - for_each_ref(send_ref, NULL); + head_ref_namespaced(send_ref, NULL); + for_each_namespaced_ref(send_ref, NULL); packet_flush(1); } else { - head_ref(mark_our_ref, NULL); - for_each_ref(mark_our_ref, NULL); + head_ref_namespaced(mark_our_ref, NULL); + for_each_namespaced_ref(mark_our_ref, NULL); } if (advertise_refs) return; From d49483f0ca1be0994c4f20fe1804d36a28013676 Mon Sep 17 00:00:00 2001 From: Josh Triplett Date: Fri, 8 Jul 2011 16:14:10 -0700 Subject: [PATCH 4/5] ref namespaces: documentation Document the namespace mechanism in a new gitnamespaces(7) page. Reference it from receive-pack and upload-pack. Document the new --namespace option and GIT_NAMESPACE environment variable in git(1), and reference gitnamespaces(7). Add a sample Apache configuration to http-backend(1) to support namespaced repositories, and reference gitnamespaces(7). Signed-off-by: Josh Triplett Signed-off-by: Jamey Sharp Signed-off-by: Junio C Hamano --- Documentation/Makefile | 2 +- Documentation/git-http-backend.txt | 8 +++ Documentation/git-receive-pack.txt | 2 +- Documentation/git-upload-pack.txt | 4 ++ Documentation/git.txt | 13 ++++- Documentation/gitnamespaces.txt | 75 ++++++++++++++++++++++++++ contrib/completion/git-completion.bash | 2 +- 7 files changed, 101 insertions(+), 5 deletions(-) create mode 100644 Documentation/gitnamespaces.txt diff --git a/Documentation/Makefile b/Documentation/Makefile index 36989b7f65..2004fbe630 100644 --- a/Documentation/Makefile +++ b/Documentation/Makefile @@ -6,7 +6,7 @@ MAN5_TXT=gitattributes.txt gitignore.txt gitmodules.txt githooks.txt \ gitrepository-layout.txt MAN7_TXT=gitcli.txt gittutorial.txt gittutorial-2.txt \ gitcvs-migration.txt gitcore-tutorial.txt gitglossary.txt \ - gitdiffcore.txt gitrevisions.txt gitworkflows.txt + gitdiffcore.txt gitnamespaces.txt gitrevisions.txt gitworkflows.txt MAN_TXT = $(MAN1_TXT) $(MAN5_TXT) $(MAN7_TXT) MAN_XML=$(patsubst %.txt,%.xml,$(MAN_TXT)) diff --git a/Documentation/git-http-backend.txt b/Documentation/git-http-backend.txt index 277d9e141b..f4e0741c11 100644 --- a/Documentation/git-http-backend.txt +++ b/Documentation/git-http-backend.txt @@ -119,6 +119,14 @@ ScriptAliasMatch \ ScriptAlias /git/ /var/www/cgi-bin/gitweb.cgi/ ---------------------------------------------------------------- ++ +To serve multiple repositories from different linkgit:gitnamespaces[7] in a +single repository: ++ +---------------------------------------------------------------- +SetEnvIf Request_URI "^/git/([^/]*)" GIT_NAMESPACE=$1 +ScriptAliasMatch ^/git/[^/]*(.*) /usr/libexec/git-core/git-http-backend/storage.git$1 +---------------------------------------------------------------- Accelerated static Apache 2.x:: Similar to the above, but Apache can be used to return static diff --git a/Documentation/git-receive-pack.txt b/Documentation/git-receive-pack.txt index f34e0ae1bd..3534ba01c4 100644 --- a/Documentation/git-receive-pack.txt +++ b/Documentation/git-receive-pack.txt @@ -149,7 +149,7 @@ if the repository is packed and is served via a dumb transport. SEE ALSO -------- -linkgit:git-send-pack[1] +linkgit:git-send-pack[1], linkgit:gitnamespaces[7] GIT --- diff --git a/Documentation/git-upload-pack.txt b/Documentation/git-upload-pack.txt index 4c0ca9ded2..61a9a04a8d 100644 --- a/Documentation/git-upload-pack.txt +++ b/Documentation/git-upload-pack.txt @@ -33,6 +33,10 @@ OPTIONS :: The repository to sync from. +SEE ALSO +-------- +linkgit:gitnamespaces[7] + GIT --- Part of the linkgit:git[1] suite diff --git a/Documentation/git.txt b/Documentation/git.txt index 19d4deff70..1fe4341791 100644 --- a/Documentation/git.txt +++ b/Documentation/git.txt @@ -10,8 +10,8 @@ SYNOPSIS -------- [verse] 'git' [--version] [--exec-path[=]] [--html-path] [--man-path] [--info-path] - [-p|--paginate|--no-pager] [--no-replace-objects] - [--bare] [--git-dir=] [--work-tree=] + [-p|--paginate|--no-pager] [--no-replace-objects] [--bare] + [--git-dir=] [--work-tree=] [--namespace=] [-c =] [--help] [] @@ -323,6 +323,11 @@ help ...`. variable (see core.worktree in linkgit:git-config[1] for a more detailed discussion). +--namespace=:: + Set the git namespace. See linkgit:gitnamespaces[7] for more + details. Equivalent to setting the `GIT_NAMESPACE` environment + variable. + --bare:: Treat the repository as a bare repository. If GIT_DIR environment is not set, it is set to the current working @@ -587,6 +592,10 @@ git so take care if using Cogito etc. This can also be controlled by the '--work-tree' command line option and the core.worktree configuration variable. +'GIT_NAMESPACE':: + Set the git namespace; see linkgit:gitnamespaces[7] for details. + The '--namespace' command-line option also sets this value. + 'GIT_CEILING_DIRECTORIES':: This should be a colon-separated list of absolute paths. If set, it is a list of directories that git should not chdir diff --git a/Documentation/gitnamespaces.txt b/Documentation/gitnamespaces.txt new file mode 100644 index 0000000000..ed8924e856 --- /dev/null +++ b/Documentation/gitnamespaces.txt @@ -0,0 +1,75 @@ +gitnamespaces(7) +================ + +NAME +---- +gitnamespaces - Git namespaces + +DESCRIPTION +----------- + +Git supports dividing the refs of a single repository into multiple +namespaces, each of which has its own branches, tags, and HEAD. Git can +expose each namespace as an independent repository to pull from and push +to, while sharing the object store, and exposing all the refs to +operations such as linkgit:git-gc[1]. + +Storing multiple repositories as namespaces of a single repository +avoids storing duplicate copies of the same objects, such as when +storing multiple branches of the same source. The alternates mechanism +provides similar support for avoiding duplicates, but alternates do not +prevent duplication between new objects added to the repositories +without ongoing maintenance, while namespaces do. + +To specify a namespace, set the `GIT_NAMESPACE` environment variable to +the namespace. For each ref namespace, git stores the corresponding +refs in a directory under `refs/namespaces/`. For example, +`GIT_NAMESPACE=foo` will store refs under `refs/namespaces/foo/`. You +can also specify namespaces via the `--namespace` option to +linkgit:git[1]. + +Note that namespaces which include a `/` will expand to a hierarchy of +namespaces; for example, `GIT_NAMESPACE=foo/bar` will store refs under +`refs/namespaces/foo/refs/namespaces/bar/`. This makes paths in +`GIT_NAMESPACE` behave hierarchically, so that cloning with +`GIT_NAMESPACE=foo/bar` produces the same result as cloning with +`GIT_NAMESPACE=foo` and cloning from that repo with `GIT_NAMESPACE=bar`. It +also avoids ambiguity with strange namespace paths such as `foo/refs/heads/`, +which could otherwise generate directory/file conflicts within the `refs` +directory. + +linkgit:git-upload-pack[1] and linkgit:git-receive-pack[1] rewrite the +names of refs as specified by `GIT_NAMESPACE`. git-upload-pack and +git-receive-pack will ignore all references outside the specified +namespace. + +The smart HTTP server, linkgit:git-http-backend[1], will pass +GIT_NAMESPACE through to the backend programs; see +linkgit:git-http-backend[1] for sample configuration to expose +repository namespaces as repositories. + +For a simple local test, you can use linkgit:git-remote-ext[1]: + +---------- +git clone ext::'git --namespace=foo %s /tmp/prefixed.git' +---------- + +SECURITY +-------- + +Anyone with access to any namespace within a repository can potentially +access objects from any other namespace stored in the same repository. +You can't directly say "give me object ABCD" if you don't have a ref to +it, but you can do some other sneaky things like: + +. Claiming to push ABCD, at which point the server will optimize out the + need for you to actually send it. Now you have a ref to ABCD and can + fetch it (claiming not to have it, of course). + +. Requesting other refs, claiming that you have ABCD, at which point the + server may generate deltas against ABCD. + +None of this causes a problem if you only host public repositories, or +if everyone who may read one namespace may also read everything in every +other namespace (for instance, if everyone in an organization has read +permission to every repository). diff --git a/contrib/completion/git-completion.bash b/contrib/completion/git-completion.bash index 32eb9cb4ff..9b426ff76c 100755 --- a/contrib/completion/git-completion.bash +++ b/contrib/completion/git-completion.bash @@ -1468,7 +1468,7 @@ _git_help () __gitcomp "$__git_all_commands $(__git_aliases) attributes cli core-tutorial cvs-migration diffcore gitk glossary hooks ignore modules - repository-layout tutorial tutorial-2 + namespaces repository-layout tutorial tutorial-2 workflows " } From bf7930caa0da2fbd6def59a54608ac494c272197 Mon Sep 17 00:00:00 2001 From: Josh Triplett Date: Thu, 21 Jul 2011 13:10:54 -0700 Subject: [PATCH 5/5] ref namespaces: tests Test pushing, pulling, and mirroring of repositories with ref namespaces. Signed-off-by: Josh Triplett Signed-off-by: Jamey Sharp Signed-off-by: Junio C Hamano --- t/t5509-fetch-push-namespaces.sh | 85 ++++++++++++++++++++++++++++++++ 1 file changed, 85 insertions(+) create mode 100755 t/t5509-fetch-push-namespaces.sh diff --git a/t/t5509-fetch-push-namespaces.sh b/t/t5509-fetch-push-namespaces.sh new file mode 100755 index 0000000000..cc0b31f6b0 --- /dev/null +++ b/t/t5509-fetch-push-namespaces.sh @@ -0,0 +1,85 @@ +#!/bin/sh + +test_description='fetch/push involving ref namespaces' +. ./test-lib.sh + +test_expect_success setup ' + test_tick && + git init original && + ( + cd original && + echo 0 >count && + git add count && + test_commit 0 && + echo 1 >count && + git add count && + test_commit 1 && + git remote add pushee-namespaced "ext::git --namespace=namespace %s ../pushee" && + git remote add pushee-unnamespaced ../pushee + ) && + commit0=$(cd original && git rev-parse HEAD^) && + commit1=$(cd original && git rev-parse HEAD) && + git init pushee && + git init puller +' + +test_expect_success 'pushing into a repository using a ref namespace' ' + ( + cd original && + git push pushee-namespaced master && + git ls-remote pushee-namespaced >actual && + printf "$commit1\trefs/heads/master\n" >expected && + test_cmp expected actual && + git push pushee-namespaced --tags && + git ls-remote pushee-namespaced >actual && + printf "$commit0\trefs/tags/0\n" >>expected && + printf "$commit1\trefs/tags/1\n" >>expected && + test_cmp expected actual && + # Verify that the GIT_NAMESPACE environment variable works as well + GIT_NAMESPACE=namespace git ls-remote "ext::git %s ../pushee" >actual && + test_cmp expected actual && + # Verify that --namespace overrides GIT_NAMESPACE + GIT_NAMESPACE=garbage git ls-remote pushee-namespaced >actual && + test_cmp expected actual && + # Try a namespace with no content + git ls-remote "ext::git --namespace=garbage %s ../pushee" >actual && + test_cmp /dev/null actual && + git ls-remote pushee-unnamespaced >actual && + sed -e "s|refs/|refs/namespaces/namespace/refs/|" expected >expected.unnamespaced && + test_cmp expected.unnamespaced actual + ) +' + +test_expect_success 'pulling from a repository using a ref namespace' ' + ( + cd puller && + git remote add -f pushee-namespaced "ext::git --namespace=namespace %s ../pushee" && + git for-each-ref refs/ >actual && + printf "$commit1 commit\trefs/remotes/pushee-namespaced/master\n" >expected && + printf "$commit0 commit\trefs/tags/0\n" >>expected && + printf "$commit1 commit\trefs/tags/1\n" >>expected && + test_cmp expected actual + ) +' + +# This test with clone --mirror checks for possible regressions in clone +# or the machinery underneath it. It ensures that no future change +# causes clone to ignore refs in refs/namespaces/*. In particular, it +# protects against a regression caused by any future change to the refs +# machinery that might cause it to ignore refs outside of refs/heads/* +# or refs/tags/*. More generally, this test also checks the high-level +# functionality of using clone --mirror to back up a set of repos hosted +# in the namespaces of a single repo. +test_expect_success 'mirroring a repository using a ref namespace' ' + git clone --mirror pushee mirror && + ( + cd mirror && + git for-each-ref refs/ >actual && + printf "$commit1 commit\trefs/namespaces/namespace/refs/heads/master\n" >expected && + printf "$commit0 commit\trefs/namespaces/namespace/refs/tags/0\n" >>expected && + printf "$commit1 commit\trefs/namespaces/namespace/refs/tags/1\n" >>expected && + test_cmp expected actual + ) +' + +test_done