Spurious TemplateNotFound errors in App Engine caused by invalid 'rbU' file mode in TemplateLoader.directory

[Erik Swanson <erik.swanson@…>]

In TemplateLoader?.directory, the file mode 'rbU' is specified, which is invalid. ('U' has no effect when a file is opened in binary mode 'b'.)

This is a showstopper In the App Engine environment (I'm using Python 2.7), where attempting to open a file with this mode results in "IOError: invalid mode: rbU" being raised.

This IoError? is then incorrectly handled by TemplateLoader?.load in the 'for loadfunc in search_path:' where there is a blind 'except IOError:' that suppresses it.

The result that 'raise TemplateNotFound?(filename, search_path)' is reached even when the template exists.

[Erik Swanson <erik.swanson@…>]

Use the original file mode 'rU' instead of the invalid 'rbU'.

[hodgestar]

Fix committed to trunk in r1180 (it didn't appear to affect 0.6.x where both the 'r' and 'b' where not present). Thanks for our bug report and patch.

[hodgestar]

It looks like the 'b' was important. Without it the file is automatically decoded under Python 3.2 and reading the file fails if the wrong encoding is guessed. Maybe a better idea is to drop the 'U'? An alternative is to pass the encoding to codecs.open but that is a more invasive change.

[hodgestar]

Invasive patch that opens files loaded via the template loader as unicode. Undecided whether this is a good approach.

[hodgestar]

Moved to milestone 0.9.