Bug report #6243: QgsProject.read() should open a project file in "append" mode - QGIS Application - QGIS Issue Tracking

Bug report #6243

QgsProject.read() should open a project file in "append" mode

Added by luca76 - about 12 years ago. Updated over 8 years ago.

Status:	Closed
Priority:	Normal
Assignee:	-
Category:	Project Loading/Saving
Affected QGIS version:	master	Regression?:	No
Operating System:		Easy fix?:	No
Pull Request or Patch supplied:	No	Resolution:	invalid
Crashes QGIS or corrupts data:	No	Copied to github as #:	15550

Description

QgsProject API Documentation states:

bool read (QFileInfo const &file)
read project file

bool read ()
presuming that the caller has already reset the map canvas, map registry, and legend

the first read (QFileInfo const &file) sets the project filename and calls the second read (). As you read, it says: "presuming that the caller has already reset the map canvas, map registry, and legend", so I wanted to use it to append my QGIS project file to current.

But it doesn't happen: current maplayers are cleared and substituted to the layers of the project file, althrough I still see the old project title in the window titlebar.

Here's how you can reproduce it:

write a plugin with this code: QgsProject.instance().read ( new QFileInfo ( "<path of a qgis file>" ) );
open a different qgis project file
launch the plugin
all layers are substituted.

History

#1 Updated by Paolo Cavallini about 12 years ago

Target version changed from Version 1.8.0 to Version 2.0.0

#2 Updated by Sandro Santilli about 12 years ago

I'm also looking for a way to "append" layers to an existing project. Ideally all under a group named after the file.

#3 Updated by Sandro Santilli about 12 years ago

The code is intentionally clearing all stuff, surely for project properties but don't know if for anything else too (assets referenced by layers?):

  // before we start loading everything, let's clear out the current set of
  // properties first so that we don't have the properties from the previous
  // project still hanging around

  imp_->clear();
  mEmbeddedLayers.clear();