Merge branch 'js/prep-symlink-windows' into js/symlink-windows

* js/prep-symlink-windows:
  trim_last_path_component(): avoid hard-coding the directory separator
  strbuf_readlink(): support link targets that exceed 2*PATH_MAX
  strbuf_readlink(): avoid calling `readlink()` twice in corner-cases
  init: do parse _all_ core.* settings early
  mingw: do resolve symlinks in `getcwd()`
  t7800: work around the MSYS path conversion on Windows
  t6423: introduce Windows-specific handling for symlinking to /dev/null
  t1305: skip symlink tests that do not apply to Windows
  t1006: accommodate for symlink support in MSYS2
  t0600: fix incomplete prerequisite for a test case
  t0301: another fix for Windows compatibility
  t0001: handle `diff --no-index` gracefully
  mingw: special-case `open(symlink, O_CREAT | O_EXCL)`
  apply: symbolic links lack a "trustable executable bit"
  t9700: accommodate for Windows paths

15 files changed, 78 insertions, 41 deletions

diff --git a/apply.c b/apply.c
index c9fb45247d..3de4aa4d2e 100644
--- a/apply.c
+++ b/apply.c
@@ -3818,7 +3818,7 @@ static int check_preimage(struct apply_state *state,
 		if (*ce && !(*ce)->ce_mode)
 			BUG("ce_mode == 0 for path '%s'", old_name);
 
-		if (trust_executable_bit)
+		if (trust_executable_bit || !S_ISREG(st->st_mode))
 			st_mode = ce_mode_from_stat(*ce, st->st_mode);
 		else if (*ce)
 			st_mode = (*ce)->ce_mode;
diff --git a/compat/mingw.c b/compat/mingw.c
index 939f938fe2..cf4f3c92e7 100644
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -629,6 +629,7 @@ int mingw_open (const char *filename, int oflags, ...)
 	int fd, create = (oflags & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL);
 	wchar_t wfilename[MAX_PATH];
 	open_fn_t open_fn;
+	WIN32_FILE_ATTRIBUTE_DATA fdata;
 
 	DECLARE_PROC_ADDR(ntdll.dll, NTSTATUS, NTAPI, RtlGetLastNtStatus, void);
 
@@ -653,6 +654,19 @@ int mingw_open (const char *filename, int oflags, ...)
 	else if (xutftowcs_path(wfilename, filename) < 0)
 		return -1;
 
+	/*
+	 * When `symlink` exists and is a symbolic link pointing to a
+	 * non-existing file, `_wopen(symlink, O_CREAT | O_EXCL)` would
+	 * create that file. Not what we want: Linux would say `EEXIST`
+	 * in that instance, which is therefore what Git expects.
+	 */
+	if (create &&
+	    GetFileAttributesExW(wfilename, GetFileExInfoStandard, &fdata) &&
+	    (fdata.dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT)) {
+		errno = EEXIST;
+		return -1;
+	}
+
 	fd = open_fn(wfilename, oflags, mode);
 
 	/*
@@ -1225,18 +1239,16 @@ char *mingw_getcwd(char *pointer, int len)
 {
 	wchar_t cwd[MAX_PATH], wpointer[MAX_PATH];
 	DWORD ret = GetCurrentDirectoryW(ARRAY_SIZE(cwd), cwd);
+	HANDLE hnd;
 
 	if (!ret || ret >= ARRAY_SIZE(cwd)) {
 		errno = ret ? ENAMETOOLONG : err_win_to_posix(GetLastError());
 		return NULL;
 	}
-	ret = GetLongPathNameW(cwd, wpointer, ARRAY_SIZE(wpointer));
-	if (!ret && GetLastError() == ERROR_ACCESS_DENIED) {
-		HANDLE hnd = CreateFileW(cwd, 0,
-			FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE, NULL,
-			OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, NULL);
-		if (hnd == INVALID_HANDLE_VALUE)
-			return NULL;
+	hnd = CreateFileW(cwd, 0,
+			  FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE, NULL,
+			  OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, NULL);
+	if (hnd != INVALID_HANDLE_VALUE) {
 		ret = GetFinalPathNameByHandleW(hnd, wpointer, ARRAY_SIZE(wpointer), 0);
 		CloseHandle(hnd);
 		if (!ret || ret >= ARRAY_SIZE(wpointer))
@@ -1245,13 +1257,11 @@ char *mingw_getcwd(char *pointer, int len)
 			return NULL;
 		return pointer;
 	}
-	if (!ret || ret >= ARRAY_SIZE(wpointer))
-		return NULL;
-	if (GetFileAttributesW(wpointer) == INVALID_FILE_ATTRIBUTES) {
+	if (GetFileAttributesW(cwd) == INVALID_FILE_ATTRIBUTES) {
 		errno = ENOENT;
 		return NULL;
 	}
-	if (xwcstoutf(pointer, wpointer, len) < 0)
+	if (xwcstoutf(pointer, cwd, len) < 0)
 		return NULL;
 	convert_slashes(pointer);
 	return pointer;
diff --git a/environment.c b/environment.c
index a770b5921d..b65b85a01f 100644
--- a/environment.c
+++ b/environment.c
@@ -324,8 +324,8 @@ next_name:
 	return (current & ~negative) | positive;
 }
 
-static int git_default_core_config(const char *var, const char *value,
-				   const struct config_context *ctx, void *cb)
+int git_default_core_config(const char *var, const char *value,
+			    const struct config_context *ctx, void *cb)
 {
 	/* This needs a better name */
 	if (!strcmp(var, "core.filemode")) {
diff --git a/environment.h b/environment.h
index 51898c99cd..e61f843fdb 100644
--- a/environment.h
+++ b/environment.h
@@ -106,6 +106,8 @@ const char *strip_namespace(const char *namespaced_ref);
 
 int git_default_config(const char *, const char *,
 		       const struct config_context *, void *);
+int git_default_core_config(const char *var, const char *value,
+			    const struct config_context *ctx, void *cb);
 
 /*
  * TODO: All the below state either explicitly or implicitly relies on
diff --git a/lockfile.c b/lockfile.c
index 1d5ed01682..67082a9caa 100644
--- a/lockfile.c
+++ b/lockfile.c
@@ -19,14 +19,14 @@ static void trim_last_path_component(struct strbuf *path)
 	int i = path->len;
 
 	/* back up past trailing slashes, if any */
-	while (i && path->buf[i - 1] == '/')
+	while (i && is_dir_sep(path->buf[i - 1]))
 		i--;
 
 	/*
 	 * then go backwards until a slash, or the beginning of the
 	 * string
 	 */
-	while (i && path->buf[i - 1] != '/')
+	while (i && !is_dir_sep(path->buf[i - 1]))
 		i--;
 
 	strbuf_setlen(path, i);
diff --git a/setup.c b/setup.c
index 3a6a048620..b723f8b339 100644
--- a/setup.c
+++ b/setup.c
@@ -2693,7 +2693,7 @@ int init_db(const char *git_dir, const char *real_git_dir,
 	 * have set up the repository format such that we can evaluate
 	 * includeIf conditions correctly in the case of re-initialization.
 	 */
-	repo_config(the_repository, platform_core_config, NULL);
+	repo_config(the_repository, git_default_core_config, NULL);
 
 	safe_create_dir(the_repository, git_dir, 0);
 
diff --git a/strbuf.c b/strbuf.c
index 6c3851a7f8..ec2b7afbe6 100644
--- a/strbuf.c
+++ b/strbuf.c
@@ -566,7 +566,7 @@ ssize_t strbuf_write(struct strbuf *sb, FILE *f)
 	return sb->len ? fwrite(sb->buf, 1, sb->len, f) : 0;
 }
 
-#define STRBUF_MAXLINK (2*PATH_MAX)
+#define STRBUF_MAXLINK (32767)
 
 int strbuf_readlink(struct strbuf *sb, const char *path, size_t hint)
 {
@@ -578,12 +578,12 @@ int strbuf_readlink(struct strbuf *sb, const char *path, size_t hint)
 	while (hint < STRBUF_MAXLINK) {
 		ssize_t len;
 
-		strbuf_grow(sb, hint);
-		len = readlink(path, sb->buf, hint);
+		strbuf_grow(sb, hint + 1);
+		len = readlink(path, sb->buf, hint + 1);
 		if (len < 0) {
 			if (errno != ERANGE)
 				break;
-		} else if (len < hint) {
+		} else if (len <= hint) {
 			strbuf_setlen(sb, len);
 			return 0;
 		}
diff --git a/t/t0001-init.sh b/t/t0001-init.sh
index 618da080dc..e4d32bb4d2 100755
--- a/t/t0001-init.sh
+++ b/t/t0001-init.sh
@@ -425,7 +425,11 @@ test_expect_success SYMLINKS 're-init to move gitdir symlink' '
 	git init --separate-git-dir ../realgitdir
 	) &&
 	echo "gitdir: $(pwd)/realgitdir" >expected &&
-	test_cmp expected newdir/.git &&
+	case "$GIT_TEST_CMP" in
+	# `git diff --no-index` does not resolve symlinks
+	*--no-index*) cmp expected newdir/.git;;
+	*) test_cmp expected newdir/.git;;
+	esac &&
 	test_cmp expected newdir/here &&
 	test_path_is_dir realgitdir/refs
 '
diff --git a/t/t0301-credential-cache.sh b/t/t0301-credential-cache.sh
index dc30289f75..6f7cfd9e33 100755
--- a/t/t0301-credential-cache.sh
+++ b/t/t0301-credential-cache.sh
@@ -123,7 +123,8 @@ test_expect_success SYMLINKS 'use user socket if user directory is a symlink to
 		rmdir \"\$HOME/dir/\" &&
 		rm \"\$HOME/.git-credential-cache\"
 	" &&
-	mkdir -p -m 700 "$HOME/dir/" &&
+	mkdir -p "$HOME/dir/" &&
+	chmod 700 "$HOME/dir/" &&
 	ln -s "$HOME/dir" "$HOME/.git-credential-cache" &&
 	check approve cache <<-\EOF &&
 	protocol=https
diff --git a/t/t0600-reffiles-backend.sh b/t/t0600-reffiles-backend.sh
index b11126ed47..74bfa2e9ba 100755
--- a/t/t0600-reffiles-backend.sh
+++ b/t/t0600-reffiles-backend.sh
@@ -467,7 +467,7 @@ test_expect_success POSIXPERM 'git reflog expire honors core.sharedRepository' '
 	esac
 '
 
-test_expect_success SYMLINKS 'symref transaction supports symlinks' '
+test_expect_success SYMLINKS,!MINGW 'symref transaction supports symlinks' '
 	test_when_finished "git symbolic-ref -d TEST_SYMREF_HEAD" &&
 	git update-ref refs/heads/new @ &&
 	test_config core.prefersymlinkrefs true &&
diff --git a/t/t1006-cat-file.sh b/t/t1006-cat-file.sh
index 1f61b666a7..0eee3bb878 100755
--- a/t/t1006-cat-file.sh
+++ b/t/t1006-cat-file.sh
@@ -1048,18 +1048,28 @@ test_expect_success 'git cat-file --batch-check --follow-symlinks works for out-
 	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 &&
+	if test_have_prereq MINGW,SYMLINKS
+	then
+		test_write_lines "symlink 2" ..
+	else
+		test_write_lines "symlink 3" ../
+	fi >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 &&
+	if test_have_prereq !MINGW
+	then
+		# The `up-down` and `up-down-trailing` symlinks are normalized
+		# in MSYS in `winsymlinks` mode and are therefore in a
+		# different shape than Git expects them.
+		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
+	fi &&
 	echo HEAD:up-down-file | git cat-file --batch-check --follow-symlinks >actual &&
 	test_cmp found actual &&
 	echo symlink 7 >expect &&
diff --git a/t/t1305-config-include.sh b/t/t1305-config-include.sh
index 8ff2b0c232..6e51f892f3 100755
--- a/t/t1305-config-include.sh
+++ b/t/t1305-config-include.sh
@@ -286,7 +286,7 @@ test_expect_success SYMLINKS 'conditional include, relative path with symlinks'
 	)
 '
 
-test_expect_success SYMLINKS 'conditional include, gitdir matching symlink' '
+test_expect_success SYMLINKS,!MINGW 'conditional include, gitdir matching symlink' '
 	ln -s foo bar &&
 	(
 		cd bar &&
@@ -298,7 +298,7 @@ test_expect_success SYMLINKS 'conditional include, gitdir matching symlink' '
 	)
 '
 
-test_expect_success SYMLINKS 'conditional include, gitdir matching symlink, icase' '
+test_expect_success SYMLINKS,!MINGW 'conditional include, gitdir matching symlink, icase' '
 	(
 		cd bar &&
 		echo "[includeIf \"gitdir/i:BAR/\"]path=bar8" >>.git/config &&
diff --git a/t/t6423-merge-rename-directories.sh b/t/t6423-merge-rename-directories.sh
index 533ac85dc8..53535a8ebf 100755
--- a/t/t6423-merge-rename-directories.sh
+++ b/t/t6423-merge-rename-directories.sh
@@ -5158,13 +5158,18 @@ test_setup_12m () {
 		git switch B &&
 		git rm dir/subdir/file &&
 		mkdir dir &&
-		ln -s /dev/null dir/subdir &&
+		if test_have_prereq MINGW
+		then
+			cmd //c 'mklink dir\subdir NUL'
+		else
+			ln -s /dev/null dir/subdir
+		fi &&
 		git add . &&
 		git commit -m "B"
 	)
 }
 
-test_expect_success '12m: Change parent of renamed-dir to symlink on other side' '
+test_expect_success SYMLINKS '12m: Change parent of renamed-dir to symlink on other side' '
 	test_setup_12m &&
 	(
 		cd 12m &&
diff --git a/t/t7800-difftool.sh b/t/t7800-difftool.sh
index 9b74db5563..bf0f67378d 100755
--- a/t/t7800-difftool.sh
+++ b/t/t7800-difftool.sh
@@ -752,11 +752,11 @@ test_expect_success SYMLINKS 'difftool --dir-diff handles modified symlinks' '
 		c
 	EOF
 	git difftool --symlinks --dir-diff --extcmd ls >output &&
-	grep -v ^/ output >actual &&
+	grep -v ":\$" output >actual &&
 	test_cmp expect actual &&
 
 	git difftool --no-symlinks --dir-diff --extcmd ls >output &&
-	grep -v ^/ output >actual &&
+	grep -v ":\$" output >actual &&
 	test_cmp expect actual &&
 
 	# The left side contains symlink "c" that points to "b"
@@ -786,11 +786,11 @@ test_expect_success SYMLINKS 'difftool --dir-diff handles modified symlinks' '
 
 	EOF
 	git difftool --symlinks --dir-diff --extcmd ls >output &&
-	grep -v ^/ output >actual &&
+	grep -v ":\$" output >actual &&
 	test_cmp expect actual &&
 
 	git difftool --no-symlinks --dir-diff --extcmd ls >output &&
-	grep -v ^/ output >actual &&
+	grep -v ":\$" output >actual &&
 	test_cmp expect actual
 '
 
diff --git a/t/t9700/test.pl b/t/t9700/test.pl
index 58a9b328d5..570b0c5680 100755
--- a/t/t9700/test.pl
+++ b/t/t9700/test.pl
@@ -117,7 +117,12 @@ close TEMPFILE;
 unlink $tmpfile;
 
 # paths
-is($r->repo_path, $abs_repo_dir . "/.git", "repo_path");
+my $abs_git_dir = $abs_repo_dir . "/.git";
+if ($^O eq 'msys' or $^O eq 'cygwin') {
+  $abs_git_dir = `cygpath -am "$abs_repo_dir/.git"`;
+  $abs_git_dir =~ s/\r?\n?$//;
+}
+is($r->repo_path, $abs_git_dir, "repo_path");
 is($r->wc_path, $abs_repo_dir . "/", "wc_path");
 is($r->wc_subdir, "", "wc_subdir initial");
 $r->wc_chdir("directory1");
@@ -127,7 +132,7 @@ is($r->config("test.string"), "value", "config after wc_chdir");
 # Object generation in sub directory
 chdir("directory2");
 my $r2 = Git->repository();
-is($r2->repo_path, $abs_repo_dir . "/.git", "repo_path (2)");
+is($r2->repo_path, $abs_git_dir, "repo_path (2)");
 is($r2->wc_path, $abs_repo_dir . "/", "wc_path (2)");
 is($r2->wc_subdir, "directory2/", "wc_subdir initial (2)");