Handle mandatory fields name translated and not translated in SCH_COMPONENT::GetFieldText.

Fixes #9520
https://gitlab.com/kicad/code/kicad/issues/9520

eeschema/sch_component.cpp

@@ -922,6 +922,11 @@ wxString SCH_COMPONENT::GetFieldText( const wxString& aFieldName, SCH_EDIT_FRAME
     {
         if( aFieldName == m_Fields[ii].GetName() )
             return m_Fields[ii].GetText();
+
+        if( ii < MANDATORY_FIELDS && aFieldName == TEMPLATE_FIELDNAME::GetCanonicalFieldName( ii ) )
+        {
+            return m_Fields[ii].GetText();
+        }
     }
 
     return wxEmptyString;

eeschema/template_fieldnames.cpp

@@ -31,6 +31,36 @@
 using namespace TFIELD_T;
 
 
+const wxString TEMPLATE_FIELDNAME::GetCanonicalFieldName( int aFieldNdx )
+{
+    // Fixed values for the first few default fields used by EESCHEMA
+    // (mandatory fields)
+    switch( aFieldNdx )
+    {
+    case  REFERENCE:
+        return wxT( "Reference" );   // The component reference, R1, C1, etc.
+
+    case  VALUE:
+        return wxT( "Value" );       // The component value + name
+
+    case  FOOTPRINT:
+        return wxT( "Footprint" );     // The footprint for use with Pcbnew
+
+    case  DATASHEET:
+        return wxT( "Datasheet" );   // Link to a datasheet for component
+
+    default:
+        break;
+    }
+
+    // Other fields are use fields, give a default name:
+    wxString fieldName = wxT( "Field" );
+    fieldName << aFieldNdx;
+    return fieldName;
+}
+
+
+
 const wxString TEMPLATE_FIELDNAME::GetDefaultFieldName( int aFieldNdx )
 {
     static void* locale = nullptr;
@@ -52,6 +82,8 @@ const wxString TEMPLATE_FIELDNAME::GetDefaultFieldName( int aFieldNdx )
         locale = Pgm().GetLocale();
     }
 
+    // Fixed values for the first few default fields used by EESCHEMA
+
     // Fixed values for the first few default fields used by EESCHEMA
     // (mandatory fields)
     switch( aFieldNdx )
@@ -78,6 +110,7 @@ const wxString TEMPLATE_FIELDNAME::GetDefaultFieldName( int aFieldNdx )
     return fieldName;
 }
 
+
 void TEMPLATE_FIELDNAME::Format( OUTPUTFORMATTER* out, int nestLevel ) const
 {
     out->Print( nestLevel, "(field (name %s)",  out->Quotew( m_Name ).c_str() );

eeschema/template_fieldnames.h

@@ -122,6 +122,14 @@ struct TEMPLATE_FIELDNAME
      * @param aFieldNdx The field number index, > 0
      */
     static const wxString GetDefaultFieldName( int aFieldNdx );
+
+    /**
+     * returns a not translated default symbol field name for field \a aFieldNdx
+     * for all components.
+     * These fieldnames are not modifiable, but template fieldnames are.
+     * @param aFieldNdx The field number index, > 0
+     */
+    static const wxString GetCanonicalFieldName( int aFieldNdx );
 };
 
 typedef std::vector< TEMPLATE_FIELDNAME > TEMPLATE_FIELDNAMES;