Bug report #12340

using --configpath on new empty dir raises Python error + subsequest segfault

Added by Richard Duivenvoorde about 9 years ago. Updated almost 9 years ago.

Status:Closed
Priority:Normal
Assignee:Nathan Woodrow
Category:Expressions
Affected QGIS version:2.8.1 Regression?:No
Operating System: Easy fix?:No
Pull Request or Patch supplied:No Resolution:fixed/implemented
Crashes QGIS or corrupts data:No Copied to github as #:20516

Description

Paolo asked for it on the dev list, I can confirm:

  1. create a new dir:
    mkdir /tmp/t1
  2. start qgis using --configpath
    qgis --configpath /tmp/t1

QGIS will generate the following python error and crash after that:

Couldn't load qgis.user.
Python support will be disabled.

Traceback (most recent call last):
  File "", line 1, in 
  File "/home/richard/apps/qgis/master/debug/share/qgis/python/qgis/utils.py", line 478, in _import
    mod = _builtin_import(name, globals, locals, fromlist, level)
  File "/home/richard/apps/qgis/master/debug/share/qgis/python/qgis/user.py", line 39, in 
    import expressions
  File "/home/richard/apps/qgis/master/debug/share/qgis/python/qgis/utils.py", line 478, in _import
    mod = _builtin_import(name, globals, locals, fromlist, level)
ImportError: No module named expressions

NOTE: starting QGIS again using same dir is now ok...

Associated revisions

Revision 738838ac
Added by Nathan Woodrow almost 9 years ago

Fix #12340 - Reload site to pick up new expressions package

History

#1 Updated by Paolo Cavallini about 9 years ago

Thanks Richard.

#2 Updated by Jürgen Fischer about 9 years ago

  • Assignee set to Nathan Woodrow

expressions/__init__.py is created when it's not available - but the freshly created module can apparently not be initially loaded via "import expressions".

#3 Updated by Jürgen Fischer about 9 years ago

  • Category changed from Browser to Expressions

#4 Updated by Nathan Woodrow almost 9 years ago

  • Status changed from Open to Closed

#5 Updated by Nathan Woodrow almost 9 years ago

  • Resolution set to fixed/implemented

Should hopefully be fixed now. Not sure if doing reload(site) is the best solution but it does work and doesn't seem to mess anything up.

#6 Updated by Richard Duivenvoorde almost 9 years ago

  • Status changed from Closed to Reopened

Reopening this one, because this still occurs with me.

If I surround the import expressions part with a try/catch, and write some warning, then at least I do not have a segfault the first time:


import site                                                                      
reload(site)                                                                     

try:                                                                             
    # try this import, but will fail when this is a fresh configuration directory
    # eg when starting QGIS with: "qgis --configpath /tmp/foo "                  
    import expressions                                                           

    expressions.load = load_user_expressions                                     
    expressions.load(expressionspath)                                            
    expressions.template = """\\"\\"\\"                                             
    Define new functions using @qgsfunction. feature and parent must always be the
    last args. Use args=-1 to pass a list of values as arguments                 
    \\"\\"\\"                                                                       

    from qgis.core import *                                                      
    from qgis.gui import *                                                       

    @qgsfunction(args='auto', group='Custom')                                    
    def func(value1, feature, parent):                                           
        return value1                                                            
    """                                                                          
except:                                                                          
    msgtitle = QCoreApplication.translate("UserExpressions", "User expressions") 
    msg = QCoreApplication.translate("UserExpressions", "Unable to load Expressions... New Settings/Config?")
    QgsMessageLog.logMessage(msg, msgtitle, QgsMessageLog.WARNING)

Let me know if this is fix or need a pull request

#7 Updated by Richard Duivenvoorde almost 9 years ago

@nathan:

is 2112128 the final fix? So we can close this one?

#8 Updated by Nathan Woodrow almost 9 years ago

  • Status changed from Reopened to Closed

Yep. Seems it was close to what you had too. Sorry I didn't even check.

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