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https://issues.apache.org/jira/browse/BEAM-7746?focusedWorklogId=369304&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-369304
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ASF GitHub Bot logged work on BEAM-7746:
----------------------------------------
Author: ASF GitHub Bot
Created on: 09/Jan/20 19:52
Start Date: 09/Jan/20 19:52
Worklog Time Spent: 10m
Work Description: chadrik commented on pull request #10367: [BEAM-7746]
Add python type hints (part 2)
URL: https://github.com/apache/beam/pull/10367#discussion_r364930741
##########
File path: sdks/python/apache_beam/runners/common.py
##########
@@ -437,13 +439,15 @@ def invoke_start_bundle(self):
# type: () -> None
"""Invokes the DoFn.start_bundle() method.
"""
+ assert self.output_processor is not None
Review comment:
I have not done performance testing on this. Is there a way that we can
invoke the perf suite on Jenkins from github?
The underlying issue in this case is that it's possible to instantiate a
`DoFnInvoker` without an `output_processor` and that's considered ok as long as
you don't call any of the methods that use the `output_processor`. If you do,
then it would raise an exception. The asserts obviously also raise an
exception, but it serves as a way to communicate to mypy that you're aware of
it, and it can adjust its type analysis within that scope.
**Solutions**
Easy: Judiciously add `type: ignore` comments. I say "judiciously" because
ignoring an error does not change the type analysis, so similar errors can pop
up nearby in the same scope. In this particular case the methods are brief, so
a `type: ignore` comment would suffice.
Not Easy: Rework the code so there's a subclass of `DoFnInvoker` that
always has a non-optional `output_processor`, and only this class possesses
these "safe if you're careful" methods, which would, under that design, always
be safe.
The easy solution is fine for this particular case (we're aware there could
be an error, but we accept it), but it's not a general solution to this
problem. Choosing the right solution for each case takes some consideration.
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Issue Time Tracking
-------------------
Worklog Id: (was: 369304)
Time Spent: 42h 50m (was: 42h 40m)
> Add type hints to python code
> -----------------------------
>
> Key: BEAM-7746
> URL: https://issues.apache.org/jira/browse/BEAM-7746
> Project: Beam
> Issue Type: New Feature
> Components: sdk-py-core
> Reporter: Chad Dombrova
> Assignee: Chad Dombrova
> Priority: Major
> Time Spent: 42h 50m
> Remaining Estimate: 0h
>
> As a developer of the beam source code, I would like the code to use pep484
> type hints so that I can clearly see what types are required, get completion
> in my IDE, and enforce code correctness via a static analyzer like mypy.
> This may be considered a precursor to BEAM-7060
> Work has been started here: [https://github.com/apache/beam/pull/9056]
>
>
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