A user of my tracker entered some new information to an
existing item and got this error:

Accessing SNEP74:

Templating Error

exceptions.IndexError: no such station 42

Debugging information follows

   1. While evaluating the standard:'context/history'
expression on line 242
      Current variables:
      templates <roundup.cgi.templating.Templates
instance at 0x5c2a58>
      repeat   
<roundup.cgi.PageTemplates.TALES.SafeMapping instance at
0x103a738>
      false 0
      context   <HTMLItem(0x103a5d0) station 42>
      utils <roundup.cgi.templating.TemplatingUtils
instance at 0x103a670>
      db    <roundup.cgi.templating.HTMLDatabase
instance at 0x103a620>
      nothing   None
      i18n 
<roundup.cgi.TranslationService.NullTranslationService
instance at
0x10338c8>
      true  1
      default  
<roundup.cgi.PageTemplates.TALES.Default instance at
0x55d440>
      request   <roundup.cgi.templating.HTMLRequest
instance at 0x103a238>
      tracker   <roundup.instance.Tracker instance at
0x5b80d0>
      template  <Roundup PageTemplate 'station.item.html'>
      config    <roundup.configuration.CoreConfig
instance at 0x5b86e8>
      options   {'ok_message': [], 'error_message': []}
      loop 
<roundup.cgi.PageTemplates.TALES.SafeMapping instance
at 0x103a738>
      attrs {'tal:condition': 'context/id',
'tal:replace': 'structure
context/history'}
   2. A problem occurred in your template
"station.item.html".

Full traceback:

Traceback (most recent call last):
  File
"/System/Library/Frameworks/Python.framework/Versions/2.3/lib/python2.3/site-
packages/roundup/cgi/client.py", line 686, in renderContext
    result = pt.render(self, None, None, **args)
  File
"/System/Library/Frameworks/Python.framework/Versions/2.3/lib/python2.3/site-
packages/roundup/cgi/templating.py", line 318, in render
    getEngine().getContext(c), output, tal=1,
strictinsert=0)()
  File
"/System/Library/Frameworks/Python.framework/Versions/2.3/lib/python2.3/site-
packages/roundup/cgi/TAL/TALInterpreter.py", line 192,
in __call__
    self.interpret(self.program)
  File
"/System/Library/Frameworks/Python.framework/Versions/2.3/lib/python2.3/site-
packages/roundup/cgi/TAL/TALInterpreter.py", line 236,
in interpret
    handlers[opcode](self, args)
  File
"/System/Library/Frameworks/Python.framework/Versions/2.3/lib/python2.3/site-
packages/roundup/cgi/TAL/TALInterpreter.py", line 666,
in do_useMacro
    self.interpret(macro)
  File
"/System/Library/Frameworks/Python.framework/Versions/2.3/lib/python2.3/site-
packages/roundup/cgi/TAL/TALInterpreter.py", line 236,
in interpret
    handlers[opcode](self, args)
  File
"/System/Library/Frameworks/Python.framework/Versions/2.3/lib/python2.3/site-
packages/roundup/cgi/TAL/TALInterpreter.py", line 411,
in do_optTag_tal
    self.do_optTag(stuff)
  File
"/System/Library/Frameworks/Python.framework/Versions/2.3/lib/python2.3/site-
packages/roundup/cgi/TAL/TALInterpreter.py", line 396,
in do_optTag
    return self.no_tag(start, program)
  File
"/System/Library/Frameworks/Python.framework/Versions/2.3/lib/python2.3/site-
packages/roundup/cgi/TAL/TALInterpreter.py", line 391,
in no_tag
    self.interpret(program)
  File
"/System/Library/Frameworks/Python.framework/Versions/2.3/lib/python2.3/site-
packages/roundup/cgi/TAL/TALInterpreter.py", line 236,
in interpret
    handlers[opcode](self, args)
  File
"/System/Library/Frameworks/Python.framework/Versions/2.3/lib/python2.3/site-
packages/roundup/cgi/TAL/TALInterpreter.py", line 689,
in do_defineSlot
    self.interpret(slot)
  File
"/System/Library/Frameworks/Python.framework/Versions/2.3/lib/python2.3/site-
packages/roundup/cgi/TAL/TALInterpreter.py", line 236,
in interpret
    handlers[opcode](self, args)
  File
"/System/Library/Frameworks/Python.framework/Versions/2.3/lib/python2.3/site-
packages/roundup/cgi/TAL/TALInterpreter.py", line 632,
in do_condition
    self.interpret(block)
  File
"/System/Library/Frameworks/Python.framework/Versions/2.3/lib/python2.3/site-
packages/roundup/cgi/TAL/TALInterpreter.py", line 236,
in interpret
    handlers[opcode](self, args)
  File
"/System/Library/Frameworks/Python.framework/Versions/2.3/lib/python2.3/site-
packages/roundup/cgi/TAL/TALInterpreter.py", line 564,
in do_insertStructure_tal
    structure = self.engine.evaluateStructure(expr)
  File
"/System/Library/Frameworks/Python.framework/Versions/2.3/lib/python2.3/site-
packages/roundup/cgi/PageTemplates/TALES.py", line 227,
in evaluate
    return expression(self)
  File
"/System/Library/Frameworks/Python.framework/Versions/2.3/lib/python2.3/site-
packages/roundup/cgi/PageTemplates/Expressions.py",
line 194, in __call__
    return self._eval(econtext)
  File
"/System/Library/Frameworks/Python.framework/Versions/2.3/lib/python2.3/site-
packages/roundup/cgi/PageTemplates/Expressions.py",
line 189, in _eval
    return render(ob, econtext.vars)
  File
"/System/Library/Frameworks/Python.framework/Versions/2.3/lib/python2.3/site-
packages/roundup/cgi/PageTemplates/Expressions.py",
line 95, in render
    ob = ob()
  File
"/System/Library/Frameworks/Python.framework/Versions/2.3/lib/python2.3/site-
packages/roundup/cgi/templating.py", line 818, in history
    history = self._klass.history(self._nodeid)
  File
"/System/Library/Frameworks/Python.framework/Versions/2.3/lib/python2.3/site-
packages/roundup/backends/back_anydbm.py", line 1353,
in history
    return self.db.getjournal(self.classname, nodeid)
  File
"/System/Library/Frameworks/Python.framework/Versions/2.3/lib/python2.3/site-
packages/roundup/backends/back_anydbm.py", line 536, in
getjournal
    raise IndexError, 'no such %s %s'%(classname, nodeid)
IndexError: no such station 42

It looks like the journal was trashed by whatever the
edit was.
I commented out the history section of the item's page
so people could continue to use the tracker, and
another user entered some information on that item. 
That recreated the history for that item and everything
seems to work again.

I'm running roundup 0.8.1 on Python 2.3 on a Mac with
OS 10.3 with anydbm as the db.

Any clues?

I have no clue and the code has changed a bit since then.
Hopefully the code that allowed this to happen had been 
replaced.

Without the corrupted journal file and a hint of what the last update
was to the issue that caused the problem I can't see solving this.

Closing as out of date. Sorry about that.