read-cache: optionally disallow HFS+ .git variants

The point of disallowing ".git" in the index is that we
would never want to accidentally overwrite files in the
repository directory. But this means we need to respect the
filesystem's idea of when two paths are equal. The prior
commit added a helper to make such a comparison for HFS+;
let's use it in verify_path.

We make this check optional for two reasons:

1. It restricts the set of allowable filenames, which is
unnecessary for people who are not on HFS+. In practice
this probably doesn't matter, though, as the restricted
names are rather obscure and almost certainly would
never come up in practice.

2. It has a minor performance penalty for every path we
insert into the index.

This patch ties the check to the core.protectHFS config
option. Though this is expected to be most useful on OS X,
we allow it to be set everywhere, as HFS+ may be mounted on
other platforms. The variable does default to on for OS X,
though.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Documentation/config.txt b/Documentation/config.txt
index ab26963d61877a2f8e03a3532ace5b31bc68738e..0677bd8df5807ed664262afee0d106b10f524794 100644 (file)
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -234,6 +234,11 @@ core.precomposeunicode::
        When false, file names are handled fully transparent by Git,
        which is backward compatible with older versions of Git.
 
+core.protectHFS::
+       If set to true, do not allow checkout of paths that would
+       be considered equivalent to `.git` on an HFS+ filesystem.
+       Defaults to `true` on Mac OS, and `false` elsewhere.
+
 core.trustctime::
        If false, the ctime differences between the index and the
        working tree are ignored; useful when the inode change time

diff --git a/cache.h b/cache.h
index ce377e1354a4d0fd719b50edb32124110956467f..b600a0c3e497ee457fd0f58e077e9b1534a41a81 100644 (file)
--- a/cache.h
+++ b/cache.h
@@ -584,6 +584,7 @@ extern int fsync_object_files;
 extern int core_preload_index;
 extern int core_apply_sparse_checkout;
 extern int precomposed_unicode;
+extern int protect_hfs;
 
 /*
  * The character that begins a commented line in user-editable file

diff --git a/config.c b/config.c
index e1d66a145b756c49c4e4902200c354499532a428..b519cedc0146121355f1f41bcaec99260bdf7fe4 100644 (file)
--- a/config.c
+++ b/config.c
@@ -881,6 +881,11 @@ static int git_default_core_config(const char *var, const char *value)
                return 0;
        }
 
+       if (!strcmp(var, "core.protecthfs")) {
+               protect_hfs = git_config_bool(var, value);
+               return 0;
+       }
+
        /* Add other config variables here and to Documentation/config.txt. */
        return 0;
 }

diff --git a/config.mak.uname b/config.mak.uname
index 82d549e48ba796469a27ef41ad0c9ad2a8d96cbc..23af148837704e9cf8c5e24e8490e4332f0fdff4 100644 (file)
--- a/config.mak.uname
+++ b/config.mak.uname
@@ -97,6 +97,7 @@ ifeq ($(uname_S),Darwin)
        HAVE_DEV_TTY = YesPlease
        COMPAT_OBJS += compat/precompose_utf8.o
        BASIC_CFLAGS += -DPRECOMPOSE_UNICODE
+       BASIC_CFLAGS += -DPROTECT_HFS_DEFAULT=1
 endif
 ifeq ($(uname_S),SunOS)
        NEEDS_SOCKET = YesPlease

diff --git a/environment.c b/environment.c
index 0a15349cfe38ab76b1d1cc94878cec2a8d754bbd..828b574a290808569298f1930e82df1074e5b1ed 100644 (file)
--- a/environment.c
+++ b/environment.c
@@ -63,6 +63,11 @@ int precomposed_unicode = -1; /* see probe_utf8_pathname_composition() */
 struct startup_info *startup_info;
 unsigned long pack_size_limit_cfg;
 
+#ifndef PROTECT_HFS_DEFAULT
+#define PROTECT_HFS_DEFAULT 0
+#endif
+int protect_hfs = PROTECT_HFS_DEFAULT;
+
 /*
  * The character that begins a commented line in user-editable file
  * that is subject to stripspace.

diff --git a/read-cache.c b/read-cache.c
index 122be494f3886e12316b3f6b3896fa5828b941c1..7f48a08c155f083f0daf333623f1c23f3ed7a254 100644 (file)
--- a/read-cache.c
+++ b/read-cache.c
@@ -14,6 +14,7 @@
 #include "resolve-undo.h"
 #include "strbuf.h"
 #include "varint.h"
+#include "utf8.h"
 
 static struct cache_entry *refresh_cache_entry(struct cache_entry *ce, int really);
 
@@ -786,6 +787,8 @@ int verify_path(const char *path)
                        return 1;
                if (is_dir_sep(c)) {
 inside:
+                       if (protect_hfs && is_hfs_dotgit(path))
+                               return 0;
                        c = *path++;
                        if ((c == '.' && !verify_dotfile(path)) ||
                            is_dir_sep(c) || c == '\0')

diff --git a/t/t1014-read-tree-confusing.sh b/t/t1014-read-tree-confusing.sh
index eff8aedf7a45bfed92e2f72fcc191f3fc10976cb..ec310d59386c1ab8de9e1d4d37aa69093234c9ed 100755 (executable)
--- a/t/t1014-read-tree-confusing.sh
+++ b/t/t1014-read-tree-confusing.sh
@@ -11,23 +11,39 @@ test_expect_success 'create base tree' '
        tree=$(git rev-parse HEAD^{tree})
 '
 
-while read path; do
-       test_expect_success "reject $path at end of path" '
+test_expect_success 'enable core.protectHFS for rejection tests' '
+       git config core.protectHFS true
+'
+
+while read path pretty; do
+       : ${pretty:=$path}
+       test_expect_success "reject $pretty at end of path" '
                printf "100644 blob %s\t%s" "$blob" "$path" >tree &&
                bogus=$(git mktree <tree) &&
                test_must_fail git read-tree $bogus
        '
 
-       test_expect_success "reject $path as subtree" '
+       test_expect_success "reject $pretty as subtree" '
                printf "040000 tree %s\t%s" "$tree" "$path" >tree &&
                bogus=$(git mktree <tree) &&
                test_must_fail git read-tree $bogus
        '
-done <<-\EOF
+done <<-EOF
 .
 ..
 .git
 .GIT
+${u200c}.Git {u200c}.Git
+.gI${u200c}T .gI{u200c}T
+.GiT${u200c} .GiT{u200c}
 EOF
 
+test_expect_success 'utf-8 paths allowed with core.protectHFS off' '
+       test_when_finished "git read-tree HEAD" &&
+       test_config core.protectHFS false &&
+       printf "100644 blob %s\t%s" "$blob" ".gi${u200c}t" >tree &&
+       ok=$(git mktree <tree) &&
+       git read-tree $ok
+'
+
 test_done

diff --git a/t/test-lib.sh b/t/test-lib.sh
index b25249ec4cc2844f5cd7491dd5fcc88c884ff450..d4569f8df0506f15ec4a836e0363df34d9cbd2ba 100644 (file)
--- a/t/test-lib.sh
+++ b/t/test-lib.sh
@@ -154,7 +154,11 @@ _z40=0000000000000000000000000000000000000000
 LF='
 '
 
-export _x05 _x40 _z40 LF
+# UTF-8 ZERO WIDTH NON-JOINER, which HFS+ ignores
+# when case-folding filenames
+u200c=$(printf '\342\200\214')
+
+export _x05 _x40 _z40 LF u200c
 
 # Each test should start with something like this, after copyright notices:
 #