bpo-38693: Use f-strings instead of str.format() within importlib #17058
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This is a small performance improvement, especially for one or two hot places such as _handle_fromlist() that are called a lot and the .format() method was being used just to join two strings with a dot. Otherwise it is merely a readability improvement. This could be backported to 3.8 as it changes no functionality. I kept `_ERR_MSG` as an attribute in `importlib._bootstrap` and `imp` as I wasn't sure if there were other things in the world that might refer to those. They're private and could go away in 3.9 but should not within 3.8 just in case.
It belongs with a later _ERR_MSG cleanup.
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I think this is generally a good idea, and all of the changes look correct.
However, I'm not sure I'd remove the use of _ERR_MSG, since it is used outside of this file. Either that, or remove it in Lib/imp.py, too (the only other place it's used).
I'm also not sure what value is added by _ERR_MSG_PREFIX. It doesn't seem to be used anywhere. I'd just roll it into _ERR_MSG, if it's being kept.
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When you're done making the requested changes, leave the comment: |
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@gpshead, please take a look at the review comments. Thanks! |
jaraco
added
needs backport to 3.9
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This missed the boat for inclusion in Python 3.9 which accepts security fixes only as of today. |
gpshead
removed
needs backport to 3.10
I left PTAL |
Lib/importlib/_bootstrap.py
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| @@ -1156,8 +1154,7 @@ def _find_and_load(name, import_): | |||
| _lock_unlock_module(name) | |||
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| if module is None: | |||
| message = ('import of {} halted; ' | |||
| 'None in sys.modules'.format(name)) | |||
| message = (f'import of {name} halted; None in sys.modules') | |||
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The parens here can be deleted; it looks like they were previously used for the multi-line string.
* main: bpo-35540 dataclasses.asdict now supports defaultdict fields (pythongh-32056) pythonGH-91052: Add C API for watching dictionaries (pythonGH-31787) bpo-38693: Use f-strings instead of str.format() within importlib (python#17058)
…thon#17058) This is a small performance improvement, especially for one or two hot places such as _handle_fromlist() that are called a lot and the .format() method was being used just to join two strings with a dot. Otherwise it is merely a readability improvement. We keep `_ERR_MSG` and `_ERR_MSG_PREFIX` as those may be used elsewhere for canonical looking error messages.
This is a small performance improvement, especially for one or two hot
places such as
_handle_fromlist()that are called a lot and thestr.format()method was being used just to join two strings with a'.'.Otherwise it is merely a readability improvement.
This could be backported to 3.8 as it does not change any logic.
I kept
_ERR_MSGas an attribute inimportlib._bootstrapandimpas I wasn't sure if there were other things in the world that might
refer to those. They're private and could go away in 3.9 but should
not within 3.8 just in case.
https://bugs.python.org/issue38693