[PATCH 0/1] MR9414: Draft: shlwapi: Handling of "C:\...xx" in PathCanonicalize[AW].

[Thomas Csovcsity (＠thc13)]

## Description

This is intended to solve https://bugs.winehq.org/show_bug.cgi?id=58129

Add tests for verification, which pass on my locale win10 machine.

##Todo
 - [] Removed UNC path check which seems okay, but i am not sure why it was introduced. git blame did not help me, therefore any hints or examples to test are welcome.

[PATCH 1/1] shlwapi: Handling of "C:\...xx" in PathCanonicalize[AW].

[Thomas Csovcsity]

From: Thomas Csovcsity

---
 dlls/kernelbase/path.c    | 54 ++++++++++++++++-----------------------
 dlls/shlwapi/tests/path.c | 45 ++++++++++++++++++++++++++++++++
 2 files changed, 67 insertions(+), 32 deletions(-)

diff --git a/dlls/kernelbase/path.c b/dlls/kernelbase/path.c
index ece259ebe7b..8bb1ca1be90 100644
--- a/dlls/kernelbase/path.c
+++ b/dlls/kernelbase/path.c
@@ -1313,44 +1313,21 @@ BOOL WINAPI PathCanonicalizeW(WCHAR *buffer, const WCHAR *path)
     /* Canonicalize the rest of the path */
     while (*src)
     {
-        if (*src == '.')
+        if (*src == '\')
         {
-            if (src[1] == '\' && (src == path || src[-1] == '\' || src[-1] == ':'))
+            if ((dst > buffer + 2) && dst[-2] == '\' && dst[-1] == '.')
             {
-                src += 2; /* Skip .\ */
+                dst -= 1; /* Skip .\ */
+                src++;
             }
-            else if (src[1] == '.' && dst != buffer && dst[-1] == '\')
+            else if ((dst > buffer + 4) && dst[-3] == '\' && dst[-2] == '.' && dst[-1] == '.')
             {
-                /* .. backs up a directory, over the root if it has no \ following X:.
-                 * .. is ignored if it would remove a UNC server name or initial \
-                 */
-                if (dst != buffer)
+                /* .. backs up a directory */
+                dst -= 4;
+                while (dst > buffer && *dst != '\')
                 {
-                    *dst = '\0'; /* Allow PathIsUNCServerShareA test on lpszBuf */
-                    if (dst > buffer + 1 && dst[-1] == '\' && (dst[-2] != '\' || dst > buffer + 2))
-                    {
-                        if (dst[-2] == ':' && (dst > buffer + 3 || dst[-3] == ':'))
-                        {
-                            dst -= 2;
-                            while (dst > buffer && *dst != '\')
-                                dst--;
-                            if (*dst == '\')
-                                dst++; /* Reset to last '' */
-                            else
-                                dst = buffer; /* Start path again from new root */
-                        }
-                        else if (dst[-2] != ':' && !PathIsUNCServerShareW(buffer))
-                            dst -= 2;
-                    }
-                    while (dst > buffer && *dst != '\')
-                        dst--;
-                    if (dst == buffer)
-                    {
-                        *dst++ = '\';
-                        src++;
-                    }
+                    dst--;
                 }
-                src += 2; /* Skip .. in src path */
             }
             else
                 *dst++ = *src++;
@@ -1359,6 +1336,19 @@ BOOL WINAPI PathCanonicalizeW(WCHAR *buffer, const WCHAR *path)
             *dst++ = *src++;
     }

+    /* Remove trailing .. and back up if possible and keep X: */
+    if ((dst > buffer + 4) && dst[-3] == '\' && dst[-2] == '.' && dst[-1] == '.' )
+    {
+        dst -= 4;
+        if (*dst != ':')
+        {
+            while (dst > buffer && *dst != '\')
+                dst--;
+        }
+        else
+            dst++;
+    }
+
     /* Append \ to naked drive specs */
     if (dst - buffer == 2 && dst[-1] == ':')
         *dst++ = '\';
diff --git a/dlls/shlwapi/tests/path.c b/dlls/shlwapi/tests/path.c
index fb8d3f1b9c1..07353b48b73 100644
--- a/dlls/shlwapi/tests/path.c
+++ b/dlls/shlwapi/tests/path.c
@@ -700,6 +700,15 @@ static void test_PathCombineA(void)
     ok(!lstrcmpA(str, "C:\"), "Expected C:\, got %s\n", str);
     ok(GetLastError() == 0xdeadbeef, "Expected 0xdeadbeef, got %ld\n", GetLastError());

+    /* try ...xx as file */
+    /* try forward slashes */
+    SetLastError(0xdeadbeef);
+    lstrcpyA(dest, "control");
+    str = PathCombineA(dest, "C:\", "...xx");
+    ok(str == dest, "Expected str == dest, got %p\n", str);
+    ok(!lstrcmpA(str, "C:\...xx"), "Expected C:\...xx, got %s\n", str);
+    ok(GetLastError() == 0xdeadbeef, "Expected 0xdeadbeef, got %ld\n", GetLastError());
+
     /* try relative paths */
     /* try forward slashes */
     SetLastError(0xdeadbeef);
@@ -1076,6 +1085,42 @@ static void test_PathCanonicalizeA(void)
         "Expected 0xdeadbeef or ERROR_FILENAME_EXCED_RANGE, got %ld\n", GetLastError());
     }
     ok(lstrlenA(too_long) == LONG_LEN - 1, "Expected length LONG_LEN - 1, got %i\n", lstrlenA(too_long));
+
+    /* try C:.. */
+    memset(dest, 0, LONG_LEN + MAX_PATH);
+    lstrcpyA(dest, "test");
+    SetLastError(0xdeadbeef);
+    res = PathCanonicalizeA(dest, "C:\..");
+    ok(res, "Expected success\n");
+    ok(GetLastError() == 0xdeadbeef, "Expected 0xdeadbeef, got %ld\n", GetLastError());
+    ok(!lstrcmpA(dest, "C:\"), "C:\, got %s\n", dest);
+
+    /* try C:...x */
+    memset(dest, 0, LONG_LEN + MAX_PATH);
+    lstrcpyA(dest, "test");
+    SetLastError(0xdeadbeef);
+    res = PathCanonicalizeA(dest, "C:\...x");
+    ok(res, "Expected success\n");
+    ok(GetLastError() == 0xdeadbeef, "Expected 0xdeadbeef, got %ld\n", GetLastError());
+    ok(!lstrcmpA(dest, "C:\...x"), "C:\...x, got %s\n", dest);
+
+    /* try C:\test...x */
+    memset(dest, 0, LONG_LEN + MAX_PATH);
+    lstrcpyA(dest, "test");
+    SetLastError(0xdeadbeef);
+    res = PathCanonicalizeA(dest, "C:\test\...x");
+    ok(res, "Expected success\n");
+    ok(GetLastError() == 0xdeadbeef, "Expected 0xdeadbeef, got %ld\n", GetLastError());
+    ok(!lstrcmpA(dest, "C:\test\...x"), "C:\test\...x, got %s\n", dest);
+
+    /* try C:\test...\x */
+    memset(dest, 0, LONG_LEN + MAX_PATH);
+    lstrcpyA(dest, "test");
+    SetLastError(0xdeadbeef);
+    res = PathCanonicalizeA(dest, "C:\test\...\x");
+    ok(res, "Expected success\n");
+    ok(GetLastError() == 0xdeadbeef, "Expected 0xdeadbeef, got %ld\n", GetLastError());
+    ok(!lstrcmpA(dest, "C:\test\...\x"), "C:\test\...\x, got %s\n", dest);
 }

static void test_PathFindExtensionA(void)

[Elizabeth Figura (＠zfigura)]

For simple tests like that you can add to the file_tests[] array in test_UrlCanonicalizeA() and the TEST_COMBINE[] array.

[Thomas Csovcsity (＠thc13)]

On Tue Nov 11 13:38:17 2025 +0000, Elizabeth Figura wrote:
> For simple tests like that you can add to the file_tests[] array in
> test_UrlCanonicalizeA() and the TEST_COMBINE[] array.

Sorry i do not get it. I modified [PathCanonicalizeW from dlls/kernelbase/path.c](https://gitlab.winehq.org/wine/wine/-/merge_requests/9414/diffs?commit_id=f3...). It seems you refer to UrlCanonicalizeW, which does not call PathCanonicalizeW. That is why i am not sure of the deleted UNC part in the old code. Maybe i missed something. I would appreciate a detailed hint to understand it.