Disable path validation, add warning

src/cascadia/TerminalConnection/ConptyConnection.cpp

@@ -300,8 +300,20 @@ namespace winrt::Microsoft::Terminal::TerminalConnection::implementation
         // EXIT POINT
         const auto hr = wil::ResultFromCaughtException();
 
-        winrt::hstring failureText{ fmt::format(std::wstring_view{ RS_(L"ProcessFailedToLaunch") }, gsl::narrow_cast<unsigned long>(hr), _commandline) };
+        winrt::hstring failureText{ fmt::format(std::wstring_view{ RS_(L"ProcessFailedToLaunch") },
+                                                gsl::narrow_cast<unsigned long>(hr),
+                                                _commandline) };
         _TerminalOutputHandlers(failureText);
+
+        // If the path was invalid, let's present an informative message to the user
+        if (hr == HRESULT_FROM_WIN32(ERROR_DIRECTORY))
+        {
+            winrt::hstring badPathText{ fmt::format(std::wstring_view{ RS_(L"BadPathText") },
+                                                    _startingDirectory) };
+            _TerminalOutputHandlers(L"\r\n");
+            _TerminalOutputHandlers(badPathText);
+        }
+
         _transitionToState(ConnectionState::Failed);
 
         // Tear down any state we may have accumulated.

src/cascadia/TerminalConnection/Resources/en-US/Resources.resw

@@ -212,4 +212,8 @@
     <comment>The first argument {0...} is the hexadecimal error code. The second argument {1} is the user-specified path to a program.
       If this string is broken to multiple lines, it will not be displayed properly.</comment>
   </data>
-</root>
+  <data name="BadPathText" xml:space="preserve">
+    <value>Could not access starting directory "{0}"</value>
+    <comment>The first argument {0} is a path to a directory on the filesystem, as provided by the user.</comment>
+  </data>
+</root>

src/cascadia/TerminalSettingsModel/Profile.cpp

@@ -413,21 +413,17 @@ std::wstring Profile::EvaluateStartingDirectory(const std::wstring& directory)
     std::unique_ptr<wchar_t[]> evaluatedPath = std::make_unique<wchar_t[]>(numCharsInput);
     THROW_LAST_ERROR_IF(0 == ExpandEnvironmentStrings(directory.c_str(), evaluatedPath.get(), numCharsInput));
 
-    // Validate that the resulting path is legitimate
-    const DWORD dwFileAttributes = GetFileAttributes(evaluatedPath.get());
-    if ((dwFileAttributes != INVALID_FILE_ATTRIBUTES) && (WI_IsFlagSet(dwFileAttributes, FILE_ATTRIBUTE_DIRECTORY)))
-    {
-        return std::wstring(evaluatedPath.get(), numCharsInput);
-    }
-    else
-    {
-        // In the event where the user supplied a path that can't be resolved, use a reasonable default (in this case, %userprofile%)
-        const DWORD numCharsDefault = ExpandEnvironmentStrings(DEFAULT_STARTING_DIRECTORY.c_str(), nullptr, 0);
-        std::unique_ptr<wchar_t[]> defaultPath = std::make_unique<wchar_t[]>(numCharsDefault);
-        THROW_LAST_ERROR_IF(0 == ExpandEnvironmentStrings(DEFAULT_STARTING_DIRECTORY.c_str(), defaultPath.get(), numCharsDefault));
-
-        return std::wstring(defaultPath.get(), numCharsDefault);
-    }
+    // Prior to GH#9541, we'd validate that the user's startingDirectory existed
+    // here. If it was invalid, we'd gracefully fall back to %USERPROFILE%.
+    //
+    // However, that could cause hangs when combined with WSL. When the WSL
+    // filesystem is slow to respond, we'll end up waiting indefinitely for
+    // their filesystem driver to respond. This can result in the whole terminal
+    // becoming unresponsive.
+    //
+    // If the path is eventually invalid, we'll display warning in the
+    // ConptyConnection when the process fails to launch.
+    return std::wstring(evaluatedPath.get(), numCharsInput);
 }
 
 // Function Description: