MNT use raise from in validation.py #17545
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This is most certainly valuable. We should check where the pattern can be found in our codebase. I assume that we are using the @jnothman I always relied on you on these raising issues. Do you have any opinion? Maybe @thomasjpfan or @NicolasHug? |
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I've been using |
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Awesome. After this PR is merged, I'll create more PR(s) with the other cases. Here's a list of possible cases. Note that it may contain false positives. |
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I would prefer "raise from". I think we haven't used them everywhere because it is a Python 3 feature (and we use to support Python 2). |
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@thomasjpfan Can we move this forward? |
| except TypeError: | ||
| raise TypeError(message) | ||
| except TypeError as type_error: | ||
| raise TypeError(message) from type_error |
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Surely this should just be bare raise?
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don't we still want the message to be passed?
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I'm with @NicolasHug here, the message is valuable.
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I think the argument for keeping the bare raise here, is that the additional message may case too much noise?
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We have the error message in master, I see no reason to remove it now.
I'll merge the PR, @jnothman please feel free to raise any concern if any
| except TypeError: | ||
| raise TypeError(message) | ||
| except TypeError as type_error: | ||
| raise TypeError(message) from type_error |
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I think the argument for keeping the bare raise here, is that the additional message may case too much noise?
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Thanks @cool-RR |
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Sorry for my silence. Raising with the message is appropriate. Sorry for
the noise.
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I recently went over Matplotlib, Pandas and NumPy, fixing a small mistake in the way that Python 3's exception chaining is used. If you're interested, I can do it here too. I've done it on just one file right now.
The mistake is this: In some parts of the code, an exception is being caught and replaced with a more user-friendly error. In these cases the syntax
raise new_error from old_errorneeds to be used.Python 3's exception chaining means it shows not only the traceback of the current exception, but that of the original exception (and possibly more.) This is regardless of
raise from. The usage ofraise fromtells Python to put a more accurate message between the tracebacks. Instead of this:You'll get this:
The first is inaccurate, because it signifies a bug in the exception-handling code itself, which is a separate situation than wrapping an exception.
Let me know what you think!