gh-100107: Make Py launcher ignore app aliases that launch Microsoft Store

PC/launcher2.c

@@ -571,6 +571,21 @@ findArgv0End(const wchar_t *buffer, int bufferLength)
 /******************************************************************************\
  ***                          COMMAND-LINE PARSING                          ***
 \******************************************************************************/
+// Adapted from https://stackoverflow.com/a/65583702
+typedef struct AppExecLinkFile { // For tag IO_REPARSE_TAG_APPEXECLINK
+    DWORD reparseTag;
+    WORD reparseDataLength;
+    WORD reserved;
+    ULONG version;
+    wchar_t stringList[MAX_PATH * 4];  // Multistring (Consecutive UTF-16 strings each ending with a NUL)
+    /* There are normally 4 strings here. Ex:
+        Package ID:  L"Microsoft.DesktopAppInstaller_8wekyb3d8bbwe"
+        Entry Point: L"Microsoft.DesktopAppInstaller_8wekyb3d8bbwe!PythonRedirector"
+        Executable:  L"C:\Program Files\WindowsApps\Microsoft.DesktopAppInstaller_1.17.106910_x64__8wekyb3d8bbwe\AppInstallerPythonRedirector.exe"
+        Applic. Type: L"0"   // Integer as ASCII. "0" = Desktop bridge application; Else sandboxed UWP application
+    */
+} AppExecLinkFile;
+
 
 
 int
@@ -826,6 +841,72 @@ searchPath(SearchInfo *search, const wchar_t *shebang, int shebangLength)
         return RC_BAD_VIRTUAL_PATH;
     }
 
+    // Make sure we didn't find a reparse point that will open the Microsoft Store
+    // If we did, pretend there was no shebang and let normal handling take over
+    WIN32_FIND_DATAW findData;
+    HANDLE hFind = FindFirstFileW(buffer, &findData);
+    if (!hFind) {
+        if (GetLastError() == ERROR_FILE_NOT_FOUND) {
+            debug(L"# %s on disappeared\n", buffer);
+            // The file found on PATH disappeared. Alias probably disabled by user while trying to run, let normal handling take over
+            RC_NO_SHEBANG;
+        }
+
+        // Other errors should cause us to break
+        winerror(0, L"Failed to find %s on PATH\n", filename);
+        return RC_BAD_VIRTUAL_PATH;
+    }
+
+    if (findData.dwFileAttributes & FILE_ATTRIBUTE_REPARSE_POINT &&
+        findData.dwReserved0 & IO_REPARSE_TAG_APPEXECLINK) {
+        const size_t bufSize = sizeof(AppExecLinkFile);
+        wchar_t appExecLinkBuf[sizeof(AppExecLinkFile)];
+
+        HANDLE hReparsePoint = CreateFileW(buffer, 0, FILE_SHARE_READ, NULL, OPEN_EXISTING, FILE_FLAG_OPEN_REPARSE_POINT, NULL);
+        if (!hReparsePoint) {
+            if (GetLastError() == ERROR_FILE_NOT_FOUND) {
+                debug(L"# %s on disappeared\n", buffer);
+                // The file found on PATH disappeared. Alias probably disabled by user while trying to run, let normal handling take over
+                RC_NO_SHEBANG;
+            }
+
+            // Other errors should cause us to break
+            winerror(0, L"Failed to find %s on PATH\n", filename);
+            return RC_BAD_VIRTUAL_PATH;
+        }
+
+        if (!DeviceIoControl(hReparsePoint, FSCTL_GET_REPARSE_POINT, NULL, 0, appExecLinkBuf, bufSize, NULL, NULL)) {
+            if (GetLastError() == ERROR_FILE_NOT_FOUND) {
+                debug(L"# %s on disappeared\n", buffer);
+                // The file found on PATH disappeared. Alias probably disabled by user while trying to run, let normal handling take over
+                RC_NO_SHEBANG;
+            }
+
+            // Other errors should cause us to break
+            winerror(0, L"Failed to find %s on PATH\n", filename);
+            return RC_BAD_VIRTUAL_PATH;
+        }
+
+        CloseHandle(hReparsePoint);
+
+        AppExecLinkFile* appExecLinkFilePtr;
+
+        appExecLinkFilePtr = (AppExecLinkFile*)&appExecLinkBuf;
+
+        wchar_t redirectorPackageId[] = L"Microsoft.DesktopAppInstaller";
+        int redirectorStrLen = wcsnlen_s(redirectorPackageId, 29);
+
+        wchar_t partialId[30];
+        wcsncpy_s(partialId, redirectorStrLen + 1, appExecLinkFilePtr->stringList, redirectorStrLen);
+
+        if (0 == wcsncmp(partialId, &redirectorPackageId, redirectorStrLen)) {
+            debug(L"# ignoring redirector that would launch store\n");
+            return RC_NO_SHEBANG;
+        }
+    }
+
+    FindClose(hFind);
+
     // Check that we aren't going to call ourselves again
     // If we are, pretend there was no shebang and let normal handling take over
     if (GetModuleFileNameW(NULL, filename, MAXLEN) &&