[Py30a3] xml.parsers.expat recognizes encoding="utf-8" but not encoding="utf8"

[mark-summerfield]

BPO	2278
Nosy	@birkenfeld, @mark-summerfield, @benjaminp

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = <Date 2008-03-17.07:42:41.887>
created_at = <Date 2008-03-12.11:03:55.861>
labels = ['expert-XML', 'type-bug', 'library']
title = '[Py30a3] xml.parsers.expat recognizes encoding="utf-8" but not encoding="utf8"'
updated_at = <Date 2008-03-17.07:42:41.833>
user = 'https://github.com/mark-summerfield'

bugs.python.org fields:

activity = <Date 2008-03-17.07:42:41.833>
actor = 'georg.brandl'
assignee = 'none'
closed = True
closed_date = <Date 2008-03-17.07:42:41.887>
closer = 'georg.brandl'
components = ['Library (Lib)', 'XML']
creation = <Date 2008-03-12.11:03:55.861>
creator = 'mark'
dependencies = []
files = []
hgrepos = []
issue_num = 2278
keywords = []
message_count = 4.0
messages = ['63471', '63516', '63558', '63621']
nosy_count = 3.0
nosy_names = ['georg.brandl', 'mark', 'benjamin.peterson']
pr_nums = []
priority = 'normal'
resolution = 'wont fix'
stage = None
status = 'closed'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue2278'
versions = ['Python 3.0']

[mark-summerfield]

Here is how to reproduce the bug:

from xml.etree.ElementTree import parse
import io
xml1 = """<?xml version="1.0" encoding="utf8"?>
<test>text</test>"""
xml2 = """<?xml version="1.0" encoding="utf-8"?>
<test>text</test>"""
f1 = io.StringIO(xml1)
f2 = io.StringIO(xml2)
tree2 = parse(f2) # this uses "utf-8" and works fine
tree1 = parse(f1)
Traceback (most recent call last):
  File "<pyshell#20>", line 1, in <module>
    tree1 = parse(f1)
  File
"/home/mark/opt/python30a3/lib/python3.0/xml/etree/ElementTree.py", line
823, in parse
    tree.parse(source, parser)
  File
"/home/mark/opt/python30a3/lib/python3.0/xml/etree/ElementTree.py", line
561, in parse
    parser.feed(data)
  File
"/home/mark/opt/python30a3/lib/python3.0/xml/etree/ElementTree.py", line
1201, in feed
    self._parser.Parse(data, 0)
xml.parsers.expat.ExpatError: unknown encoding: line 1, column 30

[benjaminp]

Should the parser recognize "utf8"? I looked at the XML standard [1] and
it referred me to the IANA's charts [2]. It appears the the only correct
way to denote UTF-8 is "UTF-8".

[1] http://www.w3.org/TR/2006/REC-xml11-20060816/#NT-EncodingDecl
[2] http://www.iana.org/assignments/character-sets

[mark-summerfield]

You're right that the parser should not recognise "utf8" since it isn't
correct XML (as per the references you gave).

I made the mistake because I used the etree module and wrote an XML file
with encoding "utf8" which etree accepted. I've now switched to using
"UTF-8".

[birkenfeld]

Okay to close this, then?