Overhaul file locking system.

See bug report for details.

Fixes https://gitlab.com/kicad/code/kicad/issues/8919

common/confirm.cpp

@@ -151,6 +151,19 @@ long KIDIALOG::getStyle( KD_TYPE aType )
 }
 
 
+bool OverrideLock( wxWindow* aParent, const wxString& aMessage  )
+{
+    wxRichMessageDialog dlg( aParent, aMessage, _( "File Open Error" ),
+                             wxYES_NO | wxICON_ERROR | wxCENTER );
+
+    // Note: must use the "no" label to get the correct positioning/spacing for a (potentially)
+    // destructive action
+    dlg.SetYesNoLabels( _( "OK" ), _( "Open Anyway" ) );
+
+    return dlg.ShowModal() == wxID_NO;
+}
+
+
 int UnsavedChangesDialog( wxWindow* parent, const wxString& aMessage, bool* aApplyToAll )
 {
     static bool s_apply_to_all = false;

common/eda_draw_frame.cpp

@@ -205,7 +205,7 @@ bool EDA_DRAW_FRAME::LockFile( const wxString& aFileName )
 {
     m_file_checker = ::LockFile( aFileName );
 
-    return bool( m_file_checker );
+    return m_file_checker && !m_file_checker->IsAnotherRunning();
 }
 
 

eeschema/files-io.cpp

@@ -120,9 +120,12 @@ bool SCH_EDIT_FRAME::OpenProjectFiles( const std::vector<wxString>& aFileSet, in
 
     if( !LockFile( fullFileName ) )
     {
-        msg.Printf( _( "Schematic file '%s' is already open." ), fullFileName );
+        msg.Printf( _( "Schematic file '%s' is already open.\n\n"
-        DisplayError( this, msg );
+                       "Interleaved saves may produce very unexpected results.\n" ),
-        return false;
+                    fullFileName );
+
+        if( !OverrideLock( this, msg ) )
+            return false;
     }
 
     if( !AskToSaveChanges() )
@@ -1131,9 +1134,13 @@ bool SCH_EDIT_FRAME::importFile( const wxString& aFileName, int aFileType )
 
         if( !LockFile( aFileName ) )
         {
-            wxString msg = wxString::Format( _( "Schematic '%s' is already open." ), aFileName );
+            wxString msg;
-            DisplayError( this, msg );
+            msg.Printf( _( "Schematic file '%s' is already open.\n\n"
-            return false;
+                           "Interleaved saves may produce very unexpected results.\n" ),
+                        aFileName );
+
+            if( !OverrideLock( this, msg ) )
+                return false;
         }
 
         try

include/confirm.h

@@ -82,6 +82,13 @@ protected:
 };
 
 
+/**
+ * Display a dialog indicating the file is already open, with an option to reset the lock.
+ * @return true if the lock was reset.
+ */
+bool OverrideLock( wxWindow* aParent, const wxString& aMessage  );
+
+
 /**
  * Display a dialog with Save, Cancel and Discard Changes buttons.
  *

pcbnew/files.cpp

@@ -564,6 +564,7 @@ bool PCB_EDIT_FRAME::OpenProjectFiles( const std::vector<wxString>& aFileSet, in
     }
 
     wxString fullFileName( aFileSet[0] );
+    wxString msg;
 
     if( Kiface().IsSingle() )
     {
@@ -575,11 +576,14 @@ bool PCB_EDIT_FRAME::OpenProjectFiles( const std::vector<wxString>& aFileSet, in
 
     std::unique_ptr<wxSingleInstanceChecker> lockFile = ::LockFile( fullFileName );
 
-    if( !lockFile )
+    if( !lockFile || lockFile->IsAnotherRunning() )
     {
-        wxString msg = wxString::Format( _( "PCB '%s' is already open." ), fullFileName );
+        msg.Printf( _( "PCB file '%s' is already open.\n\n"
-        DisplayError( this, msg );
+                       "Interleaved saves may produce very unexpected results.\n" ),
-        return false;
+                    fullFileName );
+
+        if( !OverrideLock( this, msg ) )
+            return false;
     }
 
     if( IsContentModified() )
@@ -603,9 +607,9 @@ bool PCB_EDIT_FRAME::OpenProjectFiles( const std::vector<wxString>& aFileSet, in
     if( is_new && !( aCtl & KICTL_CREATE ) )
     {
         // notify user that fullFileName does not exist, ask if user wants to create it.
-        wxString ask = wxString::Format( _( "PCB '%s' does not exist. Do you wish to create it?" ),
+        msg.Printf( _( "PCB '%s' does not exist. Do you wish to create it?" ), fullFileName );
-                                         fullFileName );
+
-        if( !IsOK( this, ask ) )
+        if( !IsOK( this, msg ) )
             return false;
     }
 
@@ -662,7 +666,6 @@ bool PCB_EDIT_FRAME::OpenProjectFiles( const std::vector<wxString>& aFileSet, in
     {
         BOARD*           loadedBoard = nullptr;   // it will be set to non-NULL if loaded OK
         PLUGIN::RELEASER pi( IO_MGR::PluginFind( pluginType ) );
-        wxString         msg;
 
         LAYER_REMAPPABLE_PLUGIN* layerRemappablePlugin =
             dynamic_cast< LAYER_REMAPPABLE_PLUGIN* >( (PLUGIN*) pi );