Error while compiling urllib3 dependency

[ghost]

$ python --version
Python version: 3.6.4

$ voc --version
voc 0.1.5

:buildPythonDebug
Compiling app_packages/urllib3/filepost.py ...
Traceback (most recent call last):
Compiling app_packages/urllib3/__init__.py ...
  File "/usr/lib/python3.6/site-packages/voc-0.1.5-py3.6.egg/voc/python/ast.py", line 160, in visit
Compiling app_packages/urllib3/poolmanager.py ...
    super().visit(node)
Compiling app_packages/urllib3/connection.py ...
  File "/usr/lib/python3.6/ast.py", line 253, in visit
Compiling app_packages/urllib3/response.py ...
    return visitor(node)

  File "/usr/lib/python3.6/site-packages/voc-0.1.5-py3.6.egg/voc/python/ast.py", line 49, in dec
Problem occurred in urllib3/response.py
    fn(self, node, *args, **kwargs)
Node: ExceptHandler(type=Attribute(value=Name(id='zlib', ctx=Load(), lineno=46, col_offset=15), attr='error', ctx=Load(), lineno=46, col_offset=15), name=None, body=[
  File "/usr/lib/python3.6/site-packages/voc-0.1.5-py3.6.egg/voc/python/ast.py", line 2310, in visit_ExceptHandler
    Assign(targets=[
    exception = self.full_classref(node.type.id, default_prefix='org.python.exceptions')
        Attribute(value=Name(id='self', ctx=Load(), lineno=47, col_offset=12), attr='_first_try', ctx=Store(), lineno=47, col_offset=12),
AttributeError: 'Attribute' object has no attribute 'id'
      ], value=NameConstant(value=False, lineno=47, col_offset=30), lineno=47, col_offset=12),
    Assign(targets=[
        Attribute(value=Name(id='self', ctx=Load(), lineno=48, col_offset=12), attr='_obj', ctx=Store(), lineno=48, col_offset=12),
      ], value=Call(func=Attribute(value=Name(id='zlib', ctx=Load(), lineno=48, col_offset=24), attr='decompressobj', ctx=Load(), lineno=48, col_offset=24), args=[
        UnaryOp(op=USub(), operand=Attribute(value=Name(id='zlib', ctx=Load(), lineno=48, col_offset=44), attr='MAX_WBITS', ctx=Load(), lineno=48, col_offset=44), lineno=48, col_offset=43),
      ], keywords=[], lineno=48, col_offset=24), lineno=48, col_offset=12),
    Try(body=[
        Return(value=Call(func=Attribute(value=Name(id='self', ctx=Load(), lineno=50, col_offset=23), attr='decompress', ctx=Load(), lineno=50, col_offset=23), args=[
            Attribute(value=Name(id='self', ctx=Load(), lineno=50, col_offset=39), attr='_data', ctx=Load(), lineno=50, col_offset=39),
          ], keywords=[], lineno=50, col_offset=23), lineno=50, col_offset=16),
      ], handlers=[], orelse=[], finalbody=[
        Assign(targets=[
            Attribute(value=Name(id='self', ctx=Load(), lineno=52, col_offset=16), attr='_data', ctx=Store(), lineno=52, col_offset=16),
          ], value=NameConstant(value=None, lineno=52, col_offset=29), lineno=52, col_offset=16),
      ], lineno=49, col_offset=12),
  ], lineno=46, col_offset=8)
:buildPythonDebug FAILED

[eliasdorneles]

Yeah, this is a known bug.

This is a pretty interesting issue, I've tried tackling it before but ended up not going too deep.
Basically, the main thing here is that Python accepts any expression as an exception type to be caught by the except clause.

The current implementation of the except clause handler in VOC doesn't yet support any Python expressions (urllib3.response is doing zlib.error).

I believe the way to fix this is to have two different ways of handling exceptions, depending on what's coming after the except: if it's one of the exceptions from the stdlib, then we can use the current approach (which is nice because it will register the proper exception type in the JVM bytecode exception table).
If it's not, then we need to do a block that catch all possible exceptions, dynamically type-check to see if it matches the type specified by the expression and then decide to handle it (i.e. run code inside of the except block) or to re-raise it if types do not match.

[uranusjr]

Semi-related question, would zlib.error end up inside JVM’s exception table after compilation? Can it? Because that way we can get its class ref here (is this possible?) and use it instead.

[eliasdorneles]

I don't think so, I think the zlib.error case would be handled by generic expression handler, probably with org.python.exceptions.Exception in the JVM table. The compilation should probably only make those kinds of assumptions for exceptions/classes that are declared in the VOC codebase. Le 26 janv. 2018 7:18 PM, "Tzu-ping Chung" <notifications@github.com> a écrit : Semi-related question, would zlib.error end up inside JVM’s exception table after compilation? Can it? Because that way we can get its class ref here (is this possible?) and use it instead. — You are receiving this because you commented. Reply to this email directly, view it on GitHub <#726 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AACSveiRM_dAI6kWtqvqZ4JlEt2zZv2Iks5tOhbmgaJpZM4RuoGC> .