New submission from Géry <[email protected]>:
The Python library documentation of the `urllib.parse.urlunparse
<https://docs.python.org/3/library/urllib.parse.html#urllib.parse.urlunparse>`_
and `urllib.parse.urlunsplit
<https://docs.python.org/3/library/urllib.parse.html#urllib.parse.urlunsplit>`_
functions states:
This may result in a slightly different, but equivalent URL, if the URL
that was parsed originally had unnecessary delimiters (for example, a ? with an
empty query; the RFC states that these are equivalent).
So with the <http://example.com/?> URI::
>>> import urllib.parse
>>> urllib.parse.urlunparse(urllib.parse.urlparse("http://example.com/?";))
'http://example.com/'
>>> urllib.parse.urlunsplit(urllib.parse.urlsplit("http://example.com/?";))
'http://example.com/'
But `RFC 3986 <https://tools.ietf.org/html/rfc3986?#section-6.2.3>`_ states the
exact opposite:
Normalization should not remove delimiters when their associated component
is empty unless licensed to do so by the scheme specification. For example,
the URI "http://example.com/?"; cannot be assumed to be equivalent to any of the
examples above. Likewise, the presence or absence of delimiters within a
userinfo subcomponent is usually significant to its interpretation. The
fragment component is not subject to any scheme-based normalization; thus, two
URIs that differ only by the suffix "#" are considered different regardless of
the scheme.
So maybe `urllib.parse.urlunparse` ∘ `urllib.parse.urlparse` and
`urllib.parse.urlunsplit` ∘ `urllib.parse.urlsplit` are not supposed to be used
for `syntax-based normalization
<https://tools.ietf.org/html/rfc3986?#section-6>`_ of URIs. But still, both
`urllib.parse.urlparse` or `urllib.parse.urlsplit` lose the "delimiter + empty
component" information of the URI string, so they report false equivalent URIs::
>>> import urllib.parse
>>> urllib.parse.urlparse("http://example.com/?";) ==
urllib.parse.urlparse("http://example.com/";)
True
>>> urllib.parse.urlsplit("http://example.com/?";) ==
urllib.parse.urlsplit("http://example.com/";)
True
P.-S. — Is there a syntax-based normalization function of URIs in the Python
library?
----------
components: Library (Lib)
messages: 350663
nosy: Jeremy.Hylton, maggyero, orsenthil
priority: normal
severity: normal
status: open
title: urllib.parse functions reporting false equivalent URIs
type: behavior
versions: Python 3.7
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Python tracker <[email protected]>
<https://bugs.python.org/issue37969>
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