DMTF Redfish fails with 2.32 request module

[piyushtyagi379]

The DMTF redfish is failing with the latest Request module the issue is not seen with requests-2.31.0.

The issue is in file requests/sessions.py, self.prepare_request(req) function where by encoding "%" url converts to "%25" while preparing request url.

Debug -

/usr/local/lib/python3.12/site-packages/requests/sessions.py(564)request()
-> method=method.upper(),
(Pdb) url
'https://[FE80::5200:E6FF:FEB0:457E%eth0]/redfish/v1'

/usr/local/lib/python3.12/site-packages/requests/sessions.py(575)request()
-> prep = self.prepare_request(req)
(Pdb) prep.url
'https://[fe80::5200:e6ff:feb0:457e%25eth0]/redfish/v1'

[Tom-1508]

Hi @piyushtyagi379 , I spent some time reproducing this locally and wanted to share what I found.

I can reproduce the %eth0 → %25eth0 transformation during Session.prepare_request() consistently, including on requests==2.31.0 when paired with urllib3==1.26.x. In other words, the percent-encoding of the IPv6 zone index does not appear to be new to 2.32 alone.

From what I can tell, this aligns with RFC 6874, which requires the % in an IPv6 zone identifier to be percent-encoded when used inside a URL (i.e. %25eth0). However, this behavior seems to break interoperability with some Redfish implementations, which expect the unencoded form.

At this point, this looks less like a simple regression and more like a spec-compliance vs real-world compatibility issue. I’m happy to dig further (e.g., trace exactly where the encoding decision is made, or explore whether an opt-out / documented workaround would make sense) if that would be useful.

Please let me know how you’d like to proceed.

[piyushtyagi379]

Hi @Tom-1508, With urllib3==2.6.x and requests==2.31.0, the issue is resolve but after upgrading requests to 2.32 this issue appear with same urllib3 version.