Do not cache Python Script and ZODB Component source code in linecache.cache

to avoid concurrency and transactional issues.

Considering that linecache is used by traceback and pdb, this should not be an
issue from a performance point of view anyway.

product/ERP5Type/dynamic/component_package.py

@@ -339,13 +339,4 @@ class ComponentDynamicPackage(ModuleType):
       # the meantime
       del sys.modules[module_name]
 
-      # Delete linecache data to get updated source code (__file__ attribute
-      # (<ComponentID>) is used as linecache key)
-      import linecache
-      try:
-        del linecache.cache[getattr(package, name).__file__]
-      # __file__ may not be defined
-      except (AttributeError, KeyError):
-        pass
-
       delattr(package, name)

product/ERP5Type/patches/PythonScript.py

@@ -14,22 +14,6 @@ from Products.PythonScripts.PythonScript import PythonScript
 from OFS.misc_ import p_
 from App.ImageFile import ImageFile
 
-PythonScript_write = PythonScript.write
-def write(self, text):
-  """
-  Change the Python Script and purge linecache cache entry (meaningful for any
-  module relying on linecache, such as traceback and pdb)
-  """
-  PythonScript_write(self, text)
-
-  import linecache
-  try:
-    del linecache.cache[self.get_filepath()]
-  except KeyError:
-    pass
-
-PythonScript.write = write
-
 def haveProxyRole(self):
   """if a script has proxy role, return True"""
   return bool(self._proxy_roles)

product/ERP5Type/patches/python.py

@@ -100,48 +100,29 @@ if 1:
 from docutils import utils
 utils.relative_path = lambda source, target: os.path.abspath(target)
 
-# Patch of linecache module (used in traceback and pdb module) to display ZODB
-# Components source code properly without requiring to create a temporary file
-# on the filesystem
 import linecache
 
 linecache_getlines = linecache.getlines
 def getlines(filename, module_globals=None):
   """
-  The filename is always '<string>' for any code executed by exec(). ZODB
-  Component modules always set __file__ attribute to <erp5.component...> and
-  'Script (Python)' for Zope Python Scripts.
-
-  The original getlines() will be called which look into the cache and if not
-  available, call updatecache.
-  """
-  if ((filename == '<string>' or filename == 'Script (Python)')
-      and module_globals and '__file__' in module_globals):
-    filename = module_globals['__file__']
-
-  return linecache_getlines(filename, module_globals)
-
-linecache.getlines = getlines
-
-linecache_updatecache = linecache.updatecache
-def updatecache(filename, module_globals=None):
-  """
-  Original updatecache requires a filename which doesn't match <.*>, which is
-  strange considering that it then looks whether the module has been loaded
-  through PEP 302 Loader, but it is perhaps to be more generic. Anyhow, <> is
-  really needed to differenciate files on the filesystem to the ones only in
-  memory...
-
-  Also, get source code of Zope Python Script and store it in the linecache
-  cache as well (using __file__ module attribute equals to: 'Script
-  (Python):ABSOLUTE_URL'). See PythonScript.py patch as well to remove cache
-  entry when a PythonScript is modified.
+  Patch of linecache module (used in traceback and pdb module) to display ZODB
+  Components and Python Script source code properly without requiring to
+  create a temporary file on the filesystem
+
+  The filename is always '<string>' for any code executed by exec() (ZODB
+  Components) and '(FILENAME)?Script \(Python\)' for Zope Python Scripts.
+
+  linecache.cache filled by linecache.updatecache() called by the original
+  linecache.getlines() is bypassed for ZODB Components and Python Script to
+  avoid getting inconsistent source code. Having no cache could be an issue if
+  performances would be required here but as linecache module is only called
+  by traceback and pdb modules not used often, this should not be an issue.
   """
   if filename and module_globals:
     data = None
 
     # Get source code of ZODB Components (following PEP 302)
-    if filename[0] == '<' and filename[-1] == '>' and '__loader__' in module_globals:
+    if filename == '<string>' and '__loader__' in module_globals:
       name = module_globals.get('__name__')
       loader = module_globals['__loader__']
       get_source = getattr(loader, 'get_source', None)
@@ -150,20 +131,15 @@ def updatecache(filename, module_globals=None):
           data = get_source(name)
         except (ImportError, AttributeError):
           pass
-        else:
-          if data is None:
-            return []
 
     # Get source code of Zope Python Script
-    elif filename.startswith('Script (Python)') and 'script' in module_globals:
+    elif 'Script (Python)' in filename and 'script' in module_globals:
       data = module_globals['script'].body()
 
     if data is not None:
-      data_len = len(data)
       data = [line + '\n' for line in data.splitlines()]
-      linecache.cache[filename] = (data_len, None, data, filename)
       return data
 
-  return linecache_updatecache(filename, module_globals)
+  return linecache_getlines(filename, module_globals)
 
-linecache.updatecache = updatecache
+linecache.getlines = getlines