From f54f99dd8b8ea6dbe47bfbaacbc7b99d2d26bb6e Mon Sep 17 00:00:00 2001
From: Johannes Schindelin <johannes.schindelin@gmx.de>
Date: Fri, 31 Jan 2020 11:49:04 +0100
Subject: [PATCH] mingw: implement a platform-specific `strbuf_realpath()`

There is a Win32 API function to resolve symbolic links, and we can use
that instead of resolving them manually. Even better, this function also
resolves NTFS junction points (which are somewhat similar to bind
mounts).

This fixes https://github.com/git-for-windows/git/issues/2481.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
---
 compat/mingw.c   | 63 ++++++++++++++++++++++++++++++++++++++++++++++++
 compat/mingw.h   |  3 +++
 t/t3700-add.sh   |  2 +-
 t/t5601-clone.sh |  7 ++++++
 4 files changed, 74 insertions(+), 1 deletion(-)

diff --git a/compat/mingw.c b/compat/mingw.c
index 901375d584..c49d7e4d10 100644
--- a/compat/mingw.c
+++ b/compat/mingw.c
@@ -1115,6 +1115,69 @@ struct tm *localtime_r(const time_t *timep, struct tm *result)
 }
 #endif
 
+char *mingw_strbuf_realpath(struct strbuf *resolved, const char *path)
+{
+	wchar_t wpath[MAX_PATH];
+	HANDLE h;
+	DWORD ret;
+	int len;
+	const char *last_component = NULL;
+
+	if (xutftowcs_path(wpath, path) < 0)
+		return NULL;
+
+	h = CreateFileW(wpath, 0,
+			FILE_SHARE_READ | FILE_SHARE_WRITE | FILE_SHARE_DELETE, NULL,
+			OPEN_EXISTING, FILE_FLAG_BACKUP_SEMANTICS, NULL);
+
+	/*
+	 * strbuf_realpath() allows the last path component to not exist. If
+	 * that is the case, now it's time to try without last component.
+	 */
+	if (h == INVALID_HANDLE_VALUE &&
+	    GetLastError() == ERROR_FILE_NOT_FOUND) {
+		/* cut last component off of `wpath` */
+		wchar_t *p = wpath + wcslen(wpath);
+
+		while (p != wpath)
+			if (*(--p) == L'/' || *p == L'\\')
+				break; /* found start of last component */
+
+		if (p != wpath && (last_component = find_last_dir_sep(path))) {
+			last_component++; /* skip directory separator */
+			*p = L'\0';
+			h = CreateFileW(wpath, 0, FILE_SHARE_READ |
+					FILE_SHARE_WRITE | FILE_SHARE_DELETE,
+					NULL, OPEN_EXISTING,
+					FILE_FLAG_BACKUP_SEMANTICS, NULL);
+		}
+	}
+
+	if (h == INVALID_HANDLE_VALUE)
+		return NULL;
+
+	ret = GetFinalPathNameByHandleW(h, wpath, ARRAY_SIZE(wpath), 0);
+	CloseHandle(h);
+	if (!ret || ret >= ARRAY_SIZE(wpath))
+		return NULL;
+
+	len = wcslen(wpath) * 3;
+	strbuf_grow(resolved, len);
+	len = xwcstoutf(resolved->buf, normalize_ntpath(wpath), len);
+	if (len < 0)
+		return NULL;
+	resolved->len = len;
+
+	if (last_component) {
+		/* Use forward-slash, like `normalize_ntpath()` */
+		strbuf_addch(resolved, '/');
+		strbuf_addstr(resolved, last_component);
+	}
+
+	return resolved->buf;
+
+}
+
 char *mingw_getcwd(char *pointer, int len)
 {
 	wchar_t cwd[MAX_PATH], wpointer[MAX_PATH];
diff --git a/compat/mingw.h b/compat/mingw.h
index 209cf7ceba..cadf2c4c69 100644
--- a/compat/mingw.h
+++ b/compat/mingw.h
@@ -452,6 +452,9 @@ static inline void convert_slashes(char *path)
 #define PATH_SEP ';'
 char *mingw_query_user_email(void);
 #define query_user_email mingw_query_user_email
+struct strbuf;
+char *mingw_strbuf_realpath(struct strbuf *resolved, const char *path);
+#define platform_strbuf_realpath mingw_strbuf_realpath
 #if !defined(__MINGW64_VERSION_MAJOR) && (!defined(_MSC_VER) || _MSC_VER < 1800)
 #define PRIuMAX "I64u"
 #define PRId64 "I64d"
diff --git a/t/t3700-add.sh b/t/t3700-add.sh
index c2e4cfe100..648019d38e 100755
--- a/t/t3700-add.sh
+++ b/t/t3700-add.sh
@@ -498,7 +498,7 @@ test_expect_success CASE_INSENSITIVE_FS 'path is case-insensitive' '
 	git add "$downcased"
 '
 
-test_expect_failure MINGW 'can add files via NTFS junctions' '
+test_expect_success MINGW 'can add files via NTFS junctions' '
 	test_when_finished "cmd //c rmdir junction && rm -rf target" &&
 	test_create_repo target &&
 	cmd //c "mklink /j junction target" &&
diff --git a/t/t5601-clone.sh b/t/t5601-clone.sh
index 45f0803ed4..cdf8eb0ab5 100755
--- a/t/t5601-clone.sh
+++ b/t/t5601-clone.sh
@@ -94,6 +94,13 @@ test_expect_success LIBCURL 'clone does not detect username:password when it is
 	! grep "uses plaintext credentials" err
 '
 
+test_expect_success CASE_INSENSITIVE_FS 'core.worktree is not added due to path case' '
+
+	mkdir UPPERCASE &&
+	git clone src "$(pwd)/uppercase" &&
+	test "unset" = "$(git -C UPPERCASE config --default unset core.worktree)"
+'
+
 test_expect_success 'clone from hooks' '
 
 	test_create_repo r0 &&