From 79f06970a89d4e9414a217093fe1f8ce23efe24d Mon Sep 17 00:00:00 2001
From: Vadim Zeitlin <vadim@wxwidgets.org>
Date: Thu, 28 Nov 2024 00:13:04 +0100
Subject: [PATCH] Make wxTextCtrl::SetLabel() consistently do nothing
 everywhere

Previously it did the same thing as SetValue() in wxMSW but didn't do
anything in wxGTK (and probably other ports), which made it easy to
write code that only worked under Windows but mysteriously didn't show
any text under Linux.

Change it to not do anything anywhere and add an assert to help
detecting wrong uses of this function.

Also add a unit test checking this behaviour.

See #24982.
---
 docs/changes.txt         |  4 ++++
 include/wx/textctrl.h    |  4 ++++
 interface/wx/window.h    |  7 +++++++
 src/common/textcmn.cpp   |  5 +++++
 tests/controls/label.cpp | 12 ++++++++++++
 5 files changed, 32 insertions(+)

diff --git a/docs/changes.txt b/docs/changes.txt
index cf98b6a78f..21dc79d48d 100644
--- a/docs/changes.txt
+++ b/docs/changes.txt
@@ -113,6 +113,10 @@ Changes in behaviour not resulting in compilation errors
   but may require removing any compensation for not doing this before that may
   be present in the application code.
 
+- Calling wxTextCtrl::SetLabel() now consistently does nothing and asserts
+  under all platforms instead of behaving as SetValue() under MSW and doing
+  nothing elsewhere.
+
 
 Changes in behaviour which may result in build errors
 -----------------------------------------------------
diff --git a/include/wx/textctrl.h b/include/wx/textctrl.h
index 19f89bb36a..a719a53f6c 100644
--- a/include/wx/textctrl.h
+++ b/include/wx/textctrl.h
@@ -913,6 +913,10 @@ public:
         return GetCompositeControlsDefaultAttributes(variant);
     }
 
+    // Setting label for text control doesn't work portably, use SetValue() or
+    // ChangeValue() instead.
+    virtual void SetLabel(const wxString& label) override;
+
     virtual const wxTextEntry* WXGetTextEntry() const override { return this; }
 
 #if wxUSE_SPELLCHECK
diff --git a/interface/wx/window.h b/interface/wx/window.h
index 332db03416..d175cfb581 100644
--- a/interface/wx/window.h
+++ b/interface/wx/window.h
@@ -3399,6 +3399,13 @@ public:
     /**
         Sets the window's label.
 
+        Please note that not all windows have labels and this function may do
+        nothing in this case. And some other derived windows use different
+        functions for changing the text shown in them, e.g. wxTextCtrl uses
+        wxTextCtrl::SetValue() or wxTextCtrl::ChangeValue() and trying to use
+        SetLabel() on it will assert to help to detect possibly erroneous calls
+        to SetLabel().
+
         @param label
             The window label.
 
diff --git a/src/common/textcmn.cpp b/src/common/textcmn.cpp
index d31f761f9d..e7d6a30dbf 100644
--- a/src/common/textcmn.cpp
+++ b/src/common/textcmn.cpp
@@ -931,6 +931,11 @@ bool wxTextCtrlBase::SetDefaultStyle(const wxTextAttr& style)
     return true;
 }
 
+void wxTextCtrlBase::SetLabel(const wxString& WXUNUSED(label))
+{
+    wxFAIL_MSG("Use SetValue() or ChangeValue() instead.");
+}
+
 wxString wxTextAreaBase::GetRTFValue() const
 {
     wxFAIL_MSG("Not implemented for the current platform.");
diff --git a/tests/controls/label.cpp b/tests/controls/label.cpp
index ec72d1a3b7..c242f8f793 100644
--- a/tests/controls/label.cpp
+++ b/tests/controls/label.cpp
@@ -20,6 +20,7 @@
 #include "wx/checkbox.h"
 #include "wx/control.h"
 #include "wx/stattext.h"
+#include "wx/textctrl.h"
 
 #include "wx/generic/stattextg.h"
 
@@ -118,6 +119,17 @@ TEST_CASE("wxControl::Label", "[wxControl][label]")
             cb(new wxCheckBox(wxTheApp->GetTopWindow(), wxID_ANY, ORIGINAL_LABEL));
         DoTestLabel(cb.get());
     }
+
+    SECTION("wxTextCtrl")
+    {
+        const std::unique_ptr<wxTextCtrl>
+            tc(new wxTextCtrl(wxTheApp->GetTopWindow(), wxID_ANY, ORIGINAL_LABEL));
+
+        // Setting the label of a wxTextCtrl should _not_ work, it has value
+        // and not a label.
+        WX_ASSERT_FAILS_WITH_ASSERT( tc->SetLabel("something else") );
+        CHECK( tc->GetValue() == ORIGINAL_LABEL );
+    }
 }
 
 TEST_CASE("wxControl::RemoveMnemonics", "[wxControl][label][mnemonics]")