Sync with v1.8.5.6

* maint-1.8.5:
  Git 1.8.5.6
  fsck: complain about NTFS ".git" aliases in trees
  read-cache: optionally disallow NTFS .git variants
  path: add is_ntfs_dotgit() helper
  fsck: complain about HFS+ ".git" aliases in trees
  read-cache: optionally disallow HFS+ .git variants
  utf8: add is_hfs_dotgit() helper
  fsck: notice .git case-insensitively
  t1450: refactor ".", "..", and ".git" fsck tests
  verify_dotfile(): reject .git case-insensitively
  read-tree: add tests for confusing paths like ".." and ".git"
  unpack-trees: propagate errors adding entries to the index

Documentation/RelNotes/1.8.5.6.txt

@@ -0,0 +1,34 @@
+Git v1.8.5.6 Release Notes
+==========================
+
+Fixes since v1.8.5.5
+--------------------
+
+ * We used to allow committing a path ".Git/config" with Git that is
+   running on a case sensitive filesystem, but an attempt to check out
+   such a path with Git that runs on a case insensitive filesystem
+   would have clobbered ".git/config", which is definitely not what
+   the user would have expected.  Git now prevents you from tracking
+   a path with ".Git" (in any case combination) as a path component.
+
+ * On Windows, certain path components that are different from ".git"
+   are mapped to ".git", e.g. "git~1/config" is treated as if it were
+   ".git/config".  HFS+ has a similar issue, where certain unicode
+   codepoints are ignored, e.g. ".g\u200cit/config" is treated as if
+   it were ".git/config".  Pathnames with these potential issues are
+   rejected on the affected systems.  Git on systems that are not
+   affected by this issue (e.g. Linux) can also be configured to
+   reject them to ensure cross platform interoperability of the hosted
+   projects.
+
+ * "git fsck" notices a tree object that records such a path that can
+   be confused with ".git", and with receive.fsckObjects configuration
+   set to true, an attempt to "git push" such a tree object will be
+   rejected.  Such a path may not be a problem on a well behaving
+   filesystem but in order to protect those on HFS+ and on case
+   insensitive filesystems, this check is enabled on all platforms.
+
+A big "thanks!" for bringing this issue to us goes to our friends in
+the Mercurial land, namely, Matt Mackall and Augie Fackler.
+
+Also contains typofixes, documentation updates and trivial code clean-ups.

Documentation/config.txt

@@ -234,6 +234,17 @@ 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.protectNTFS::
+	If set to true, do not allow checkout of paths that would
+	cause problems with the NTFS filesystem, e.g. conflict with
+	8.3 "short" names.
+	Defaults to `true` on Windows, 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

Documentation/git.txt

@@ -52,9 +52,10 @@ Documentation for older releases are available here:
   link:RelNotes/1.9.1.txt[1.9.1],
   link:RelNotes/1.9.0.txt[1.9.0].
 
-* link:v1.8.5.5/git.html[documentation for release 1.8.5.5]
+* link:v1.8.5.6/git.html[documentation for release 1.8.5.6]
 
 * release notes for
+  link:RelNotes/1.8.5.6.txt[1.8.5.6],
   link:RelNotes/1.8.5.5.txt[1.8.5.5],
   link:RelNotes/1.8.5.4.txt[1.8.5.4],
   link:RelNotes/1.8.5.3.txt[1.8.5.3],

cache.h

@@ -587,6 +587,8 @@ extern int fsync_object_files;
 extern int core_preload_index;
 extern int core_apply_sparse_checkout;
 extern int precomposed_unicode;
+extern int protect_hfs;
+extern int protect_ntfs;
 
 /*
  * The character that begins a commented line in user-editable file
@@ -782,6 +784,7 @@ int longest_ancestor_length(const char *path, struct string_list *prefixes);
 char *strip_path_suffix(const char *path, const char *suffix);
 int daemon_avoid_alias(const char *path);
 int offset_1st_component(const char *path);
+extern int is_ntfs_dotgit(const char *name);
 
 /* object replacement */
 #define LOOKUP_REPLACE_OBJECT 1

config.c

@@ -885,6 +885,16 @@ 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;
+	}
+
+	if (!strcmp(var, "core.protectntfs")) {
+		protect_ntfs = git_config_bool(var, value);
+		return 0;
+	}
+
 	/* Add other config variables here and to Documentation/config.txt. */
 	return 0;
 }

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
@@ -369,6 +370,7 @@ ifeq ($(uname_S),Windows)
 	EXTLIBS = user32.lib advapi32.lib shell32.lib wininet.lib ws2_32.lib
 	PTHREAD_LIBS =
 	lib =
+	BASIC_CFLAGS += -DPROTECT_NTFS_DEFAULT=1
 ifndef DEBUG
 	BASIC_CFLAGS += -GL -Os -MT
 	BASIC_LDFLAGS += -LTCG
@@ -513,6 +515,7 @@ ifneq (,$(findstring MINGW,$(uname_S)))
 	COMPAT_OBJS += compat/mingw.o compat/winansi.o \
 		compat/win32/pthread.o compat/win32/syslog.o \
 		compat/win32/dirent.o
+	BASIC_CFLAGS += -DPROTECT_NTFS_DEFAULT=1
 	BASIC_LDFLAGS += -Wl,--large-address-aware
 	EXTLIBS += -lws2_32
 	GITLIBS += git.res

environment.c

@@ -64,6 +64,16 @@ 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;
+
+#ifndef PROTECT_NTFS_DEFAULT
+#define PROTECT_NTFS_DEFAULT 0
+#endif
+int protect_ntfs = PROTECT_NTFS_DEFAULT;
+
 /*
  * The character that begins a commented line in user-editable file
  * that is subject to stripspace.

fsck.c

@@ -6,6 +6,7 @@
 #include "commit.h"
 #include "tag.h"
 #include "fsck.h"
+#include "utf8.h"
 
 static int fsck_walk_tree(struct tree *tree, fsck_walk_func walk, void *data)
 {
@@ -175,7 +176,8 @@ static int fsck_tree(struct tree *item, int strict, fsck_error error_func)
 			has_dot = 1;
 		if (!strcmp(name, ".."))
 			has_dotdot = 1;
-		if (!strcmp(name, ".git"))
+		if (!strcasecmp(name, ".git") || is_hfs_dotgit(name) ||
+				is_ntfs_dotgit(name))
 			has_dotgit = 1;
 		has_zero_pad |= *(char *)desc.buffer == '0';
 		update_tree_entry(&desc);

path.c

@@ -830,3 +830,36 @@ int offset_1st_component(const char *path)
 		return 2 + is_dir_sep(path[2]);
 	return is_dir_sep(path[0]);
 }
+
+static int only_spaces_and_periods(const char *path, size_t len, size_t skip)
+{
+	if (len < skip)
+		return 0;
+	len -= skip;
+	path += skip;
+	while (len-- > 0) {
+		char c = *(path++);
+		if (c != ' ' && c != '.')
+			return 0;
+	}
+	return 1;
+}
+
+int is_ntfs_dotgit(const char *name)
+{
+	int len;
+
+	for (len = 0; ; len++)
+		if (!name[len] || name[len] == '\\' || is_dir_sep(name[len])) {
+			if (only_spaces_and_periods(name, len, 4) &&
+					!strncasecmp(name, ".git", 4))
+				return 1;
+			if (only_spaces_and_periods(name, len, 5) &&
+					!strncasecmp(name, "git~1", 5))
+				return 1;
+			if (name[len] != '\\')
+				return 0;
+			name += len + 1;
+			len = -1;
+		}
+}

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,
 					       unsigned int options);
@@ -752,9 +753,10 @@ static int verify_dotfile(const char *rest)
 	 * shares the path end test with the ".." case.
 	 */
 	case 'g':
-		if (rest[1] != 'i')
+	case 'G':
+		if (rest[1] != 'i' && rest[1] != 'I')
 			break;
-		if (rest[2] != 't')
+		if (rest[2] != 't' && rest[2] != 'T')
 			break;
 		rest += 2;
 	/* fallthrough */
@@ -778,6 +780,10 @@ int verify_path(const char *path)
 			return 1;
 		if (is_dir_sep(c)) {
 inside:
+			if (protect_hfs && is_hfs_dotgit(path))
+				return 0;
+			if (protect_ntfs && is_ntfs_dotgit(path))
+				return 0;
 			c = *path++;
 			if ((c == '.' && !verify_dotfile(path)) ||
 			    is_dir_sep(c) || c == '\0')

t/t1014-read-tree-confusing.sh

@@ -0,0 +1,62 @@
+#!/bin/sh
+
+test_description='check that read-tree rejects confusing paths'
+. ./test-lib.sh
+
+test_expect_success 'create base tree' '
+	echo content >file &&
+	git add file &&
+	git commit -m base &&
+	blob=$(git rev-parse HEAD:file) &&
+	tree=$(git rev-parse HEAD^{tree})
+'
+
+test_expect_success 'enable core.protectHFS for rejection tests' '
+	git config core.protectHFS true
+'
+
+test_expect_success 'enable core.protectNTFS for rejection tests' '
+	git config core.protectNTFS true
+'
+
+while read path pretty; do
+	: ${pretty:=$path}
+	case "$path" in
+	*SPACE)
+		path="${path%SPACE} "
+		;;
+	esac
+	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 $pretty as subtree" '
+		printf "040000 tree %s\t%s" "$tree" "$path" >tree &&
+		bogus=$(git mktree <tree) &&
+		test_must_fail git read-tree $bogus
+	'
+done <<-EOF
+.
+..
+.git
+.GIT
+${u200c}.Git {u200c}.Git
+.gI${u200c}T .gI{u200c}T
+.GiT${u200c} .GiT{u200c}
+git~1
+.git.SPACE .git.{space}
+.\\\\.GIT\\\\foobar backslashes
+.git\\\\foobar backslashes2
+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

t/t1450-fsck.sh

@@ -251,35 +251,40 @@ test_expect_success 'fsck notices submodule entry pointing to null sha1' '
 	)
 '
 
-test_expect_success 'fsck notices "." and ".." in trees' '
-	(
-		git init dots &&
-		cd dots &&
-		blob=$(echo foo | git hash-object -w --stdin) &&
-		tab=$(printf "\\t") &&
-		git mktree <<-EOF &&
-		100644 blob $blob$tab.
-		100644 blob $blob$tab..
-		EOF
-		git fsck 2>out &&
-		cat out &&
-		grep "warning.*\\." out
-	)
-'
-
-test_expect_success 'fsck notices ".git" in trees' '
-	(
-		git init dotgit &&
-		cd dotgit &&
-		blob=$(echo foo | git hash-object -w --stdin) &&
-		tab=$(printf "\\t") &&
-		git mktree <<-EOF &&
-		100644 blob $blob$tab.git
-		EOF
-		git fsck 2>out &&
-		cat out &&
-		grep "warning.*\\.git" out
-	)
-'
+while read name path pretty; do
+	while read mode type; do
+		: ${pretty:=$path}
+		test_expect_success "fsck notices $pretty as $type" '
+		(
+			git init $name-$type &&
+			cd $name-$type &&
+			echo content >file &&
+			git add file &&
+			git commit -m base &&
+			blob=$(git rev-parse :file) &&
+			tree=$(git rev-parse HEAD^{tree}) &&
+			value=$(eval "echo \$$type") &&
+			printf "$mode $type %s\t%s" "$value" "$path" >bad &&
+			bad_tree=$(git mktree <bad) &&
+			git fsck 2>out &&
+			cat out &&
+			grep "warning.*tree $bad_tree" out
+		)'
+	done <<-\EOF
+	100644 blob
+	040000 tree
+	EOF
+done <<-EOF
+dot .
+dotdot ..
+dotgit .git
+dotgit-case .GIT
+dotgit-unicode .gI${u200c}T .gI{u200c}T
+dotgit-case2 .Git
+git-tilde1 git~1
+dotgitdot .git.
+dot-backslash-case .\\\\.GIT\\\\foobar
+dotgit-case-backslash .git\\\\foobar
+EOF
 
 test_done

t/test-lib.sh

@@ -158,7 +158,11 @@ _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:
 #