When new components are registered, re-scan the Python directory for

new .pth files (which may have just been installed).

Add _xpcom.GetSpecialDirectory() to make this work.

Not part of the build.

extensions/python/xpcom/server/loader.py

@@ -110,6 +110,7 @@ class PythonComponentLoader:
 
     def autoRegisterComponents (self, when, directory):
         directory_path = directory.path
+        self.num_modules_this_register = 0
         if xpcom.verbose:
             print "Auto-registering all Python components in", directory_path
 
@@ -149,6 +150,24 @@ class PythonComponentLoader:
         if not loader_mgr.hasFileChanged(componentFile, None, modtime):
             return 1
 
+        if self.num_modules_this_register == 0:
+            # New conponents may have just installed new Python
+            # modules into the main python directory (including new .pth files)
+            # So we ask Python to re-process our site directory.
+            # Note that the pyloader does the equivalent when loading.
+            try:
+                from xpcom import _xpcom
+                import site
+                NS_XPCOM_CURRENT_PROCESS_DIR="XCurProcD"
+                dirname = _xpcom.GetSpecialDirectory(NS_XPCOM_CURRENT_PROCESS_DIR)
+                dirname.append("python")
+                site.addsitedir(dirname.path)
+            except:
+                print "PyXPCOM loader failed to process site directory before component registration"
+                traceback.print_exc()
+
+        self.num_modules_this_register += 1
+
         # auto-register via the module.
         m = self._getCOMModuleForLocation(componentFile)
         m.registerSelf(components.manager, componentFile, None, self._reg_component_type_)

extensions/python/xpcom/src/xpcom.cpp

@@ -374,6 +374,19 @@ PyXPCOMMethod_GetProxyForObject(PyObject *self, PyObject *args)
 	return result;
 }
 
+PyObject *PyGetSpecialDirectory(PyObject *self, PyObject *args)
+{
+	char *dirname;
+	if (!PyArg_ParseTuple(args, "s:GetSpecialDirectory", &dirname))
+		return NULL;
+	nsIFile *file = NULL;
+	nsresult r = NS_GetSpecialDirectory(dirname, &file);
+	if ( NS_FAILED(r) )
+		return PyXPCOM_BuildPyException(r);
+	// returned object swallows our reference.
+	return Py_nsISupports::PyObjectFromInterface(file, NS_GET_IID(nsIFile), PR_FALSE);
+}
+
 PyObject *AllocateBuffer(PyObject *self, PyObject *args)
 {
 	int bufSize;
@@ -419,6 +432,7 @@ static struct PyMethodDef xpcom_methods[]=
 	{"_GetGatewayCount", PyXPCOMMethod_GetGatewayCount, 1},
 	{"getProxyForObject", PyXPCOMMethod_GetProxyForObject, 1},
 	{"GetProxyForObject", PyXPCOMMethod_GetProxyForObject, 1},
+	{"GetSpecialDirectory", PyGetSpecialDirectory, 1},
 	{"AllocateBuffer", AllocateBuffer, 1},
 	{"LogWarning", LogWarning, 1},
 	{"LogError", LogError, 1},