sage-download-file: Proper initialization of SSL certificates

[mkoeppe]

(from #29418)

See ticket description of #29418 and the change made in #32527.

When done, we can switch sage-bootstrap-python back to preferring python3 on macOS.

[jhpalmieri]

Edit: hold on, trying again after editing build/bin/sage-system-python.

Is this necessary? I'm not sure how to test, but here's what I did: with #29719 (new flint), I used

$ ./configure --with-python=/usr/bin/python3 --enable-download-from-upstream-url --with-system-flint=no
$ make flint

flint was downloaded properly. Since that worked, I tried a pip package:

$ ./sage -i biopython

That also worked. What should I be testing?

[mkoeppe]

This is affecting upstream URLs that are https. You can test by replacing upstream/mirror_list by something that always fails to force download from the upstream URL.

[jhpalmieri]

I put a print statement in sage-system-python to say what Python it's using (2nd line below). I removed the attrs tarball and modified mirror_list to only include https sites. I see this at the top of the attrs log file:

[attrs-19.3.0] Found local metadata for attrs-19.3.0
[attrs-19.3.0] PYTHON=/usr/bin/python3
[attrs-19.3.0] Attempting to download package attrs-19.3.0.tar.gz from mirrors
[attrs-19.3.0] https://mirror.csclub.uwaterloo.ca/sage/spkg/upstream/attrs/attrs-19.3.0.tar.gz
[attrs-19.3.0] [......................................................................]
[attrs-19.3.0] attrs-19.3.0

[jhpalmieri]

I then modified sage_bootstrap/download/mirror_list.py:

build/sage_bootstrap/download/mirror_list.py

@@ -200 +200 @@
             pass
         for mirror in self.mirrors:
             yield mirror
-        # If all else fails: Try the packages we host ourselves
-        yield 'http://sagepad.org/'
 
     @property
     def fastest(self):

and changed mirror_list to include just a nonsense site. Then

Found local metadata for attrs-19.3.0
PYTHON=/usr/bin/python3
Attempting to download package attrs-19.3.0.tar.gz from mirrors
http://uw.edu/spkg/upstream/attrs/attrs-19.3.0.tar.gz
[xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx]
ERROR [transfer|run:135]: [Errno socket error] [Errno socket error] [Errno 404] Not Found: '//www.washington.edu/spkg/upstream/attrs/attrs-19.3.0.tar.gz'
Attempting to download from https://pypi.io/packages/source/a/attrs/attrs-19.3.0.tar.gz
[......................................................................]
attrs-19.3.0
====================================================

[mkoeppe]

This looks promising... I'm surprised that this seems to be working now. I don't think we changed anything. You don't have SAGE_DOWNLOAD_FILE_OPTIONS set in your global environment by any chance?

[jhpalmieri]

I may be too optimistic, and it may depend, for example, on the version of OS X. Does the version of Python 3 depend on the version of Xcode, or the OS version, or something else? Anyway, this testing was done on Big Sur, although the same version of Python (3.8.2) is present on 10.15.7. The previous problems were reported with Python 3.7, I think.

I don't set any environment variables with names starting "SAGE".

[dimpase]

what is the Python3 involved here?

[dimpase]

You can have Python3 installed in Homebrew, Python3 installed from python.org, and system-provided Python3.

[jhpalmieri]

In my testing, it's the system-provided Python 3, /usr/bin/python3.

[mkoeppe]

Sage development has entered the release candidate phase for 9.3. Setting a new milestone for this ticket based on a cursory review of ticket status, priority, and last modification date.

[tmonteil]

Could you please tell if the proposed branch fixes your issue on MacOS ?

---

New commits:

​f0ded55

#30950 : add a default SSL context for sage_bootstrap/download

[mkoeppe]

Hm... I am having difficulty reproducing the original problem on my current system... this might confirm comment:1, comment:6

[mkoeppe]

Stalled in needs_review or needs_info; likely won't make it into Sage 9.5.