SYMBOL_LIB_TABLE and PANEL_SYM_LIB_TABLE: fix some issues:

- Ensure a change in plugin type is detected
- do not force automatic plugin type selection for *.lib files that need
an access to these libraries: they can be not always available.

eeschema/dialogs/panel_sym_lib_table.cpp

@@ -3,7 +3,7 @@
  *
  * Copyright (C) 2017 Wayne Stambaugh <stambaughw@gmail.com>
  * Copyright (C) 2021 CERN
- * Copyright (C) 2017-2022 KiCad Developers, see AUTHORS.txt for contributors.
+ * Copyright (C) 2017-2023 KiCad Developers, see AUTHORS.txt for contributors.
  *
  * This program is free software: you can redistribute it and/or modify it
  * under the terms of the GNU General Public License as published by the
@@ -328,6 +328,23 @@ PANEL_SYM_LIB_TABLE::~PANEL_SYM_LIB_TABLE()
 }
 
 
+bool PANEL_SYM_LIB_TABLE::allowAutomaticPluginTypeSelection( wxString& aLibraryPath )
+{
+    // When the plugin type depends only of the file extension, return true.
+    // if it needs to read the actual file (taht can be not available), return false
+
+    wxFileName fn( aLibraryPath );
+    wxString   ext = fn.GetExt().Lower();
+
+    // Currently, only the extension .lib is common to legacy libraries and Cadstar libraries
+    // so return false in this case
+    if( ext == LegacySymbolLibFileExtension )
+        return false;
+
+    return true;
+}
+
+
 bool PANEL_SYM_LIB_TABLE::verifyTables()
 {
     wxString msg;
@@ -389,7 +406,16 @@ bool PANEL_SYM_LIB_TABLE::verifyTables()
             {
                 // set the trimmed values back into the table so they get saved to disk.
                 model->SetValue( r, COL_NICKNAME, nick );
-                model->SetValue( r, COL_URI, uri );
+
+                if( allowAutomaticPluginTypeSelection( uri ) )
+                    model->SetValue( r, COL_URI, uri );
+                else
+                {
+                    wxString ltype  = model->GetValue( r, COL_TYPE );
+                    model->LIB_TABLE_GRID::SetValue( r, COL_URI, uri );
+                    model->SetValue( r, COL_TYPE, ltype );
+                }
+
                 ++r;        // this row was OK.
             }
         }

eeschema/dialogs/panel_sym_lib_table.h

@@ -74,6 +74,14 @@ private:
 
     SYMBOL_LIB_TABLE_GRID* cur_model() const;
 
+    /**
+     * @return true if the plugin type can be selected from the library path only
+     * (i.e. only from its extension)
+     * if the type needs an access to the file itself, return false because
+     * the file can be not (at least temporary) available
+     */
+    bool allowAutomaticPluginTypeSelection( wxString& aLibraryPath );
+
 private:
     // Caller's tables are modified only on OK button and successful verification.
     SYMBOL_LIB_TABLE*           m_globalTable;

eeschema/sch_io_mgr.cpp

@@ -168,6 +168,11 @@ SCH_IO_MGR::SCH_FILE_T SCH_IO_MGR::GuessPluginTypeFromLibPath( const wxString& a
     {
         wxString fullName = ExpandEnvVarSubstitutions( aLibPath, nullptr );
 
+        // Of course the file should exist to be read. If not, use the SCH_LEGACY
+        // format: it is more usual than SCH_CADSTAR_ARCHIVE
+        if( !wxFileExists( fullName ) )
+            return SCH_LEGACY;
+
         for( SCH_FILE_T pluginType : { SCH_LEGACY, SCH_CADSTAR_ARCHIVE } )
         {
             SCH_PLUGIN::SCH_PLUGIN_RELEASER pi( SCH_IO_MGR::FindPlugin( pluginType ) );
@@ -179,16 +184,13 @@ SCH_IO_MGR::SCH_FILE_T SCH_IO_MGR::GuessPluginTypeFromLibPath( const wxString& a
             }
         }
 
+        // If not found, use the SCH_LEGACY.
+        return SCH_LEGACY;
     }
 
     for( SCH_IO_MGR::SCH_FILE_T piType : SCH_IO_MGR::SCH_FILE_T_vector )
     {
-
-        if( ext == LegacySymbolLibFileExtension )
-        {
-            break;
-        }
-        else if( SCH_IO_MGR::GetLibraryFileExtension( piType ).Lower() == fn.GetExt().Lower() )
+        if( SCH_IO_MGR::GetLibraryFileExtension( piType ).Lower() == ext )
         {
             ret = piType;
             break;

eeschema/symbol_lib_table.cpp

@@ -3,7 +3,7 @@
  *
  * Copyright (C) 2016 Wayne Stambaugh <stambaughw@gmail.com>
  * Copyright (C) 2022 CERN
- * Copyright (C) 2016-2022 KiCad Developers, see AUTHORS.txt for contributors.
+ * Copyright (C) 2016-2023 KiCad Developers, see AUTHORS.txt for contributors.
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
@@ -680,6 +680,26 @@ bool SYMBOL_LIB_TABLE::LoadGlobalTable( SYMBOL_LIB_TABLE& aTable )
 }
 
 
+bool SYMBOL_LIB_TABLE::operator==( const SYMBOL_LIB_TABLE& aOther ) const
+{
+    if( m_rows.size() != aOther.m_rows.size() )
+        return false;
+
+    unsigned i;
+
+    for( i = 0; i < m_rows.size(); ++i )
+    {
+        const SYMBOL_LIB_TABLE_ROW& curr = static_cast<const SYMBOL_LIB_TABLE_ROW&>( m_rows[i] );
+        const SYMBOL_LIB_TABLE_ROW& curr_other = static_cast<const SYMBOL_LIB_TABLE_ROW&>( aOther.m_rows[i] );
+
+        if( curr != curr_other )
+            return false;
+    }
+
+    return true;
+}
+
+
 wxString SYMBOL_LIB_TABLE::GetGlobalTableFileName()
 {
     wxFileName fn;

eeschema/symbol_lib_table.h

@@ -2,7 +2,7 @@
  * This program source code file is part of KiCad, a free EDA CAD application.
  *
  * Copyright (C) 2016 Wayne Stambaugh <stambaughw@gmail.com>
- * Copyright (C) 2016-2021 KiCad Developers, see change_log.txt for contributors.
+ * Copyright (C) 2016-2023 KiCad Developers, see AUTHORS.txt for contributors.
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
@@ -308,6 +308,15 @@ public:
 
     static const wxString& GetSymbolLibTableFileName();
 
+   /**
+     * Compares this table against another.
+     * This compares the row *contents* against each other.
+     */
+    bool operator==( const SYMBOL_LIB_TABLE& aOther ) const;
+
+    bool operator!=( const SYMBOL_LIB_TABLE& aOther ) const { return !( *this == aOther ); }
+
+
 private:
     friend class SYMBOL_LIB_TABLE_GRID;
     friend class PANEL_SYM_LIB_TABLE;