From b91173f76ef3b69c727ed643d439a62935e22a2f Mon Sep 17 00:00:00 2001
From: Vadim Zeitlin <vadim@wxwidgets.org>
Date: Wed, 23 Mar 2022 13:43:44 +0100
Subject: [PATCH] Fix comparing wxDataFormat with wxDF_INVALID in wxGTK

Define wxDataFormat::operator==(wxDataFormatId) instead of relying on
the implicit conversion from wxDataFormatId to wxDataFormat, as this
can't be done when the format ID is wxDF_INVALID because creating
wxDataFormat results in an assert failure in this case, while comparing
with wxDF_INVALID is clearly a perfectly valid operation.

Add a unit test checking for this.

Closes #22213.
---
 include/wx/gtk/dataform.h | 9 +++++----
 tests/misc/guifuncs.cpp   | 7 +++++++
 2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/include/wx/gtk/dataform.h b/include/wx/gtk/dataform.h
index ae5a2c232b..e248653eea 100644
--- a/include/wx/gtk/dataform.h
+++ b/include/wx/gtk/dataform.h
@@ -33,10 +33,11 @@ public:
     wxDataFormat& operator=(NativeFormat format)
         { SetId(format); return *this; }
 
-    // comparison (note that we rely on implicit conversions for comparison
-    // with wxDataFormatId, but have to provide them explicitly for comparison
-    // with NativeFormat to avoid ambiguity between comparing from it to
-    // wxDataFormat or vice versa)
+    // comparison
+    bool operator==(wxDataFormatId type) const
+        { return m_type == type; }
+    bool operator!=(wxDataFormatId type) const
+        { return m_type != type; }
     bool operator==(NativeFormat format) const
         { return m_format == (NativeFormat)format; }
     bool operator!=(NativeFormat format) const
diff --git a/tests/misc/guifuncs.cpp b/tests/misc/guifuncs.cpp
index 1461a03147..857cbdaab1 100644
--- a/tests/misc/guifuncs.cpp
+++ b/tests/misc/guifuncs.cpp
@@ -70,6 +70,13 @@ TEST_CASE("GUI::URLDataObject", "[guifuncs]")
     CHECK( wxTheClipboard->SetData(dobj) );
     wxTheClipboard->Flush();
 }
+
+TEST_CASE("GUI::DataFormatCompare", "[guifuncs][dataformat]")
+{
+    const wxDataFormat df(wxDF_TEXT);
+    CHECK( df == wxDF_TEXT );
+    CHECK( df != wxDF_INVALID );
+}
 #endif // wxUSE_DATAOBJ
 
 TEST_CASE("GUI::ParseFileDialogFilter", "[guifuncs]")