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Author bignose
Recipients bignose
Date 2016-08-16.04:35:18
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Marked as misclassified Yes
Message-id <>
When using a format specifier with leading zero, the format spec mini-language (as documented at>) says:

> '=' […] becomes the default when ‘0’ immediately precedes the field width.

When the ‘=’ option is only implied, the error message “ValueError: '=' alignment not allowed in string format specifier” becomes surprising and incomprehensible to someone who does not know that implied behaviour.

In issue 15560, Terry Reedy says:

> If the spec string is still available, it could be searched and the message adjusted if '=' is not present.  That proposal should be a new issue if someone wants to push it.

This issue raises that proposal.

The error message should be changed so that:

* It makes sense whether or not the ‘=’ option is explicit in the format specifier.


* Different messages are produced when the ‘=’ option is explicit versus when it is implicit.

I think the former option is better, but either will satisfy this request.
Date User Action Args
2016-08-16 04:35:19bignosesetrecipients: + bignose
2016-08-16 04:35:18bignosesetmessageid: <>
2016-08-16 04:35:18bignoselinkissue27772 messages
2016-08-16 04:35:18bignosecreate