bug#29609: 27.0.50; Format number as hexadecimal with hash-flag

[Gustaf Waldemarson]

Hello,

I recently noticed that the `format` function behaves incorrectly when
formatting numbers as hexadecimal together with the hash-flag. E.g.,
following this recipe yields:

1. M-x ielm
2. Evaluate: (format "%#08x" #x10) -> "00000x10"

Typically Bash, C and other formatting implementations typically formats
this as "0x00000010", and I think Emacs should do the same in this case.

This seems to be present in a few different versions of Emacs, I've
tried it on 24.5.1 and 27.0.50 and they both behave the same.

Regards,
Gustaf


In GNU Emacs 27.0.50 (build 1, x86_64-pc-linux-gnu, GTK+ Version 3.22.11)
 of 2017-11-29 built on ShadowX
Repository revision: 95369ac346d75a7b75bc2c5adf632cc4faa1241a
Windowing system distributor 'The X.Org Foundation', version 11.0.11903000
System Description:    Ubuntu 17.04

Recent messages:
scroll-down-command: Beginning of buffer
Mark set (rectangle mode)
When done with a buffer, type C-x #
Configuring package message...done
Configuring package git-commit...done
Configuring package magit...done [2 times]
When done with a buffer, type C-x # [2 times]
Making completion list... [2 times]
delete-backward-char: Text is read-only
Making completion list...

Configured using:
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