Fix flaky ./pants idea-plugin when using Python 3 by properly using ConsoleTask interface

[Eric-Arellano]

Problem

The Idea plugin integration tests would frequently flake with Python 3.

This appears to be because the task is a ConsoleTask, but it overrides execute() when it is instead expected to override console_output(). With this override, we would no longer call self._outstream.flush(), so the tests would sometimes complain that there was no entry in the --output-file, as the change would not always be persisted. It makes sense that this did not start flaking until Python 3, because IO streams changed their behavior in Python 3.

Refer to ConsoleTask for everything we need to do to properly output to the console and files:

pants/src/python/pants/task/console_task.py

Lines 52 to 62 in e620a9e

	def execute(self):
	with self._guard_sigpipe():
	try:
	targets = self.context.targets()
	for value in self.console_output(targets) or tuple():
	self._outstream.write(value.encode('utf-8'))
	self._outstream.write(self._console_separator.encode('utf-8'))
	finally:
	self._outstream.flush()
	if self.get_options().output_file:
	self._outstream.close()

Will close #7150.

Solution

No longer override execute() and instead move the logic into console_output().

Result

The tests no longer flake.

This was confirmed locally by creating the script untilfail:

#!/bin/bash

while $@; do :; done

Then running ./untilfail ./pants clean-all test.pytest tests/python/pants_test/backend/project_info/tasks:idea_plugin_integration -- -k test_idea_plugin_single_target for 10 minutes on both macOS and Ubuntu without fail.

[stuhood]

Nice find!