feat[next-dace]: Less Verbose Warnings

[philip-paul-mueller]

This PR wraps all warnings such that they are only shown if we are not in debug mode, i.e. __debug__ is True.
However, it only targets the warnings in the transformations and not the one in DaCe.

[philip-paul-mueller]

An alternative would we to simply disable all warnings, but I am not sure if this is a good idea?

It is possible to filter out warnings, however, the documentation warns that this feature should not be used in a multi threaded way, which we do.
There is a work around but it is only available since Python 3.14.

[edopao]

If this is really unexpected, we could also throw an exception.

[philip-paul-mueller]

It is more a super serious performance warning but (should) not affect correctness.
I think I will not handle it in a special way.

[egparedes]

I think the PR can be simplified. Also, IIUC, this PR will only silence our own gt4py warnings, but not DaCe warnings, right? Shouldn't we also silence DaCe warnings with a warning filter or DaCe does not create warnings?

P.S. As warnings filter for DaCe I mean something like:

import sys

if not sys.warnoptions:
    import warning
    warnings.filterwarnings(
        action="ignore",
        module="^dace(\..*)?"   # Regex pattern matching 'dace' or any submodule
    )

[egparedes]

The check for __debug__ should be done only once at import time. I also think this can be simplified much further (and also maybe renamed to avoid misunderstandings, although it is not critical):

Suggested change

	@functools.wraps(warnings.warn)
	def warn(
	message: str,
	category: type[Warning] | None = None,
	stacklevel: int = 1,
	source: Any | None = None,
	) -> None:
	"""Wrapper around `warnings.warn()` function that is only enabled in debug mode."""
	if __debug__:
	# NOTE: The `skip_file_prefixes` argument was introduced in Python 3.12 and is
	# ignored.
	warnings.warn(
	message=message,
	category=category,
	stacklevel=(stacklevel + 1),
	source=source,
	)
	if __debug__:
	from warnings import warn as debug_warn
	else:
	@functools.wraps(warnings.warn)
	def debug_warn(*args, **kwargs): -> None:
	pass

Finally, I think this is not the right place for this definition. Consider moving it to something like gt4py.next.utils.

[egparedes]

Actually, I've just realized that this redefinition might not be even needed. We could just use the standard warnings.warn function and install a filter for gt4py-produced warnings if __debug__ is false, in the same way I proposed for DaCe.

[philip-paul-mueller]

The problem is that we have multiple workers and as I understand the documentation doing this is only safe for Python >=3.14, otherwise we would have a data race.

Thus for Pythoon older than 3.14 we would need to inject the filter before we start the workers and maintain the filter (assuming that we use a context) until we are done.
We would thus not only silence the DaCe warnings but pretty much everything.

[egparedes]

The way I understand the documentation is that using context handlers is not thread safe, but I'm proposing to add a global filter at import time for warnings coming from gt4py and dace modules. I don't see why this would be a problem.

For more explicit user control, we could also add a config option/env var GT4PY_SKIP_WARNINGS=0/1 which can be explicitly enabled by the user and otherwise default to filter warnings if not in debug mode. Something conceptually like: skip_warnings = bool(os.env.get(GT4PY_SKIP_WARNINGS, not __debug__))

[philip-paul-mueller]

That is possible I agree, you just have to make sure that this filter is installed before you start the threads and that you never get rid of the filter.

Do you have an idea where, i.e. which file, we should install this filter?
Directly inside the config.py or is there a better location?

[egparedes]

I'm fine adding this to config.py as a quick workaround for now. It can be cleaned up later in the PR with the new config system.

Some good suggestions from Enrique need to be addressed.

[egparedes]

Shouldn't the condition be a more specific?

Suggested change

	assert not gtx_config.SKIP_WARNINGS, "Tests do not run in debug mode."
	assert not gtx_config.SKIP_WARNINGS or not __debug__ , "Tests do not run in debug mode."

[edopao]

Suggested change

	action="ignore", module="^gt4py.next.program_processors.runners.dace(\..+)?"
	action="ignore", module="^gt4py.next.program_processors.runners.dace.transformations(\..+)?"