When reannotating keep existing prefix in most cases.

(Execption is reannotating entire schematic, in which case we reset
all of them.)

Fixes https://gitlab.com/kicad/code/kicad/issues/11379

eeschema/annotate.cpp

@@ -63,20 +63,20 @@ void SCH_EDIT_FRAME::mapExistingAnnotation( std::map<wxString, wxString>& aMap )
 void SCH_EDIT_FRAME::DeleteAnnotation( ANNOTATE_SCOPE_T aAnnotateScope, bool* aAppendUndo )
 {
     auto clearSymbolAnnotation =
-        [&]( EDA_ITEM* aItem, SCH_SCREEN* aScreen, SCH_SHEET_PATH* aSheet )
+        [&]( EDA_ITEM* aItem, SCH_SCREEN* aScreen, SCH_SHEET_PATH* aSheet, bool aResetPrefixes )
         {
             SCH_SYMBOL* symbol = static_cast<SCH_SYMBOL*>( aItem );
 
             SaveCopyInUndoList( aScreen, symbol, UNDO_REDO::CHANGED, *aAppendUndo );
             *aAppendUndo = true;
-            symbol->ClearAnnotation( aSheet );
+            symbol->ClearAnnotation( aSheet, aResetPrefixes );
         };
 
     auto clearSheetAnnotation =
-            [&]( SCH_SCREEN* aScreen, SCH_SHEET_PATH* aSheet )
+            [&]( SCH_SCREEN* aScreen, SCH_SHEET_PATH* aSheet, bool aResetPrefixes )
             {
                 for( SCH_ITEM* item : aScreen->Items().OfType( SCH_SYMBOL_T ) )
-                    clearSymbolAnnotation( item, aScreen, aSheet );
+                    clearSymbolAnnotation( item, aScreen, aSheet, aResetPrefixes );
             };
 
     SCH_SCREEN* screen = GetScreen();
@@ -87,13 +87,15 @@ void SCH_EDIT_FRAME::DeleteAnnotation( ANNOTATE_SCOPE_T aAnnotateScope, bool* aA
     case ANNOTATE_ALL:
     {
         for( const SCH_SHEET_PATH& sheet : Schematic().GetSheets() )
-            clearSheetAnnotation( sheet.LastScreen(), nullptr );
+            clearSheetAnnotation( sheet.LastScreen(), nullptr, true );
 
         break;
     }
     case ANNOTATE_CURRENT_SHEET:
     {
-        clearSheetAnnotation( screen, &currentSheet );
+        // One could make an argument that this should clear prefixes.  I have no idea what
+        // the right answer is.
+        clearSheetAnnotation( screen, &currentSheet, false );
         break;
     }
 
@@ -105,7 +107,11 @@ void SCH_EDIT_FRAME::DeleteAnnotation( ANNOTATE_SCOPE_T aAnnotateScope, bool* aA
         for( EDA_ITEM* item : selection.Items() )
         {
             if( item->Type() == SCH_SYMBOL_T )
-                clearSymbolAnnotation( item, screen, &currentSheet );
+            {
+                // One could make an argument that this should clear prefixes.  I have no idea
+                // what the right answer is.
+                clearSymbolAnnotation( item, screen, &currentSheet, false );
+            }
         }
         break;
     }

eeschema/sch_screen.cpp

@@ -988,14 +988,14 @@ size_t SCH_SCREEN::CountConnectedItems( const VECTOR2I& aPos, bool aTestJunction
 }
 
 
-void SCH_SCREEN::ClearAnnotation( SCH_SHEET_PATH* aSheetPath )
+void SCH_SCREEN::ClearAnnotation( SCH_SHEET_PATH* aSheetPath, bool aResetPrefix )
 {
 
     for( SCH_ITEM* item : Items().OfType( SCH_SYMBOL_T ) )
     {
         SCH_SYMBOL* symbol = static_cast<SCH_SYMBOL*>( item );
 
-        symbol->ClearAnnotation( aSheetPath );
+        symbol->ClearAnnotation( aSheetPath, aResetPrefix );
     }
 }
 
@@ -1301,7 +1301,7 @@ void SCH_SCREENS::ClearAnnotationOfNewSheetPaths( SCH_SHEET_LIST& aInitialSheetP
             // Otherwise ClearAnnotation do nothing, because the F1 field is used as
             // reference default value and takes the latest displayed value
             curr_screen->EnsureAlternateReferencesExist();
-            curr_screen->ClearAnnotation( &sheetpath );
+            curr_screen->ClearAnnotation( &sheetpath, false );
         }
     }
 }

eeschema/sch_screen.h

@@ -379,8 +379,10 @@ public:
      *
      * @param[in] aSheetPath The sheet path of the symbol annotation to clear.  If NULL then
      *                       the entire hierarchy is cleared.
+     * @param[in] aResetPrefix The annotation prefix ('R', 'U', etc.) should be reset to the
+     *                         symbol library prefix.
      */
-    void ClearAnnotation( SCH_SHEET_PATH* aSheetPath );
+    void ClearAnnotation( SCH_SHEET_PATH* aSheetPath, bool aResetPrefix );
 
     /**
      * For screens shared by many sheetpaths (complex hierarchies):

eeschema/sch_symbol.cpp

@@ -1067,7 +1067,7 @@ bool SCH_SYMBOL::ResolveTextVar( wxString* token, int aDepth ) const
 }
 
 
-void SCH_SYMBOL::ClearAnnotation( const SCH_SHEET_PATH* aSheetPath )
+void SCH_SYMBOL::ClearAnnotation( const SCH_SHEET_PATH* aSheetPath, bool aResetPrefix )
 {
     // Build a reference with no annotation, i.e. a reference ending with a single '?'
     wxString defRef = UTIL::GetRefDesUnannotated( m_prefix );
@@ -1079,13 +1079,23 @@ void SCH_SYMBOL::ClearAnnotation( const SCH_SHEET_PATH* aSheetPath )
         for( SYMBOL_INSTANCE_REFERENCE& instance : m_instanceReferences )
         {
             if( instance.m_Path == path )
-                instance.m_Reference = defRef;
+            {
+                if( instance.m_Reference.IsEmpty() || aResetPrefix )
+                    instance.m_Reference = UTIL::GetRefDesUnannotated( m_prefix );
+                else
+                    instance.m_Reference = UTIL::GetRefDesUnannotated( instance.m_Reference );
+            }
         }
     }
     else
     {
         for( SYMBOL_INSTANCE_REFERENCE& instance : m_instanceReferences )
-            instance.m_Reference = defRef;
+        {
+            if( instance.m_Reference.IsEmpty() || aResetPrefix)
+                instance.m_Reference = UTIL::GetRefDesUnannotated( m_prefix );
+            else
+                instance.m_Reference = UTIL::GetRefDesUnannotated( instance.m_Reference );
+        }
     }
 
     for( std::unique_ptr<SCH_PIN>& pin : m_pins )
@@ -1095,7 +1105,12 @@ void SCH_SYMBOL::ClearAnnotation( const SCH_SHEET_PATH* aSheetPath )
     // When a clear annotation is made, the calling function must call a
     // UpdateAllScreenReferences for the active sheet.
     // But this call cannot made here.
-    m_fields[REFERENCE_FIELD].SetText( defRef ); //for drawing.
+    wxString currentReference = m_fields[REFERENCE_FIELD].GetText();
+
+    if( currentReference.IsEmpty() || aResetPrefix )
+        m_fields[REFERENCE_FIELD].SetText( UTIL::GetRefDesUnannotated( m_prefix ) );
+    else
+        m_fields[REFERENCE_FIELD].SetText( UTIL::GetRefDesUnannotated( currentReference ) );
 }
 
 

eeschema/sch_symbol.h

@@ -296,8 +296,10 @@ public:
      *
      * @param aSheetPath is the hierarchical path of the symbol to clear or remove all
      *                   annotations for this symbol if NULL.
+     * @param[in] aResetPrefix The annotation prefix ('R', 'U', etc.) should be reset to the
+     *                         symbol library prefix.
      */
-    void ClearAnnotation( const SCH_SHEET_PATH* aSheetPath );
+    void ClearAnnotation( const SCH_SHEET_PATH* aSheetPath, bool aResetPrefix );
 
     /**
      * Add an instance to the alternate references list (m_instanceReferences), if this entry

eeschema/tools/sch_edit_tool.cpp

@@ -1493,7 +1493,7 @@ int SCH_EDIT_TOOL::Properties( const TOOL_EVENT& aEvent )
             // Clear annotation of g_CurrentSheet itself, because its sheetpath is not a new
             // path, but symbols managed by its sheet path must have their annotation cleared
             // because they are new:
-            sheet->GetScreen()->ClearAnnotation( &m_frame->GetCurrentSheet() );
+            sheet->GetScreen()->ClearAnnotation( &m_frame->GetCurrentSheet(), false );
         }
 
         if( doRefresh )

eeschema/tools/sch_editor_control.cpp

@@ -1493,7 +1493,7 @@ void SCH_EDITOR_CONTROL::updatePastedSymbol( SCH_SYMBOL* aSymbol, SCH_SCREEN* aP
     if( aForceKeepAnnotations && !reference.IsEmpty() )
         aSymbol->SetRef( &aPastePath, reference );
     else
-        aSymbol->ClearAnnotation( &aPastePath );
+        aSymbol->ClearAnnotation( &aPastePath, false );
 
     // We might clear annotations but always leave the original unit number, value and footprint
     // from the paste