Author bignose
Recipients bignose
Date 2016-08-16.04:35:18
SpamBayes Score -1.0
Marked as misclassified Yes
Message-id <1471322118.97.0.225723730885.issue27772@psf.upfronthosting.co.za>
In-reply-to
Content
When using a format specifier with leading zero, the format spec mini-language (as documented at https://docs.python.org/3/library/string.html#format-specification-mini-language>) 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.

Or:

* 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.
History
Date User Action Args
2016-08-16 04:35:19bignosesetrecipients: + bignose
2016-08-16 04:35:18bignosesetmessageid: <1471322118.97.0.225723730885.issue27772@psf.upfronthosting.co.za>
2016-08-16 04:35:18bignoselinkissue27772 messages
2016-08-16 04:35:18bignosecreate