tests/test-debugextensions.t

sslutil: print a warning when using TLS 1.0 on legacy Python

Mercurial now requires TLS 1.1+ when TLS 1.1+ is supported by the
client. Since we made the decision to require TLS 1.1+ when running
with modern Python versions, it makes sense to do something for
legacy Python versions that only support TLS 1.0.

Feature parity would be to prevent TLS 1.0 connections out of the
box and require a config option to enable them. However, this is
extremely user hostile since Mercurial wouldn't talk to https://
by default in these installations! I can easily see how someone
would do something foolish like use "--insecure" instead - and
that would be worse than allowing TLS 1.0!

This patch takes the compromise position of printing a warning when
performing TLS 1.0 connections when running on old Python
versions. While this warning is no more annoying than the
CA certificate / fingerprint warnings in Mercurial 3.8, we provide
a config option to disable the warning because to many people
upgrading Python to make the warning go away is not an available
recourse (unlike pinning fingerprints is for the CA warning).

The warning appears as optional output in a lot of tests.

  $ hg debugextensions

  $ debugpath=`pwd`/extwithoutinfos.py

  $ cat > extwithoutinfos.py <<EOF
  > EOF

  $ cat >> $HGRCPATH <<EOF
  > [extensions]
  > color=
  > histedit=
  > patchbomb=
  > rebase=
  > mq=
  > ext1 = $debugpath
  > EOF

  $ hg debugextensions
  color
  ext1 (untested!)
  histedit
  mq
  patchbomb
  rebase

  $ hg debugextensions -v
  color
    location: */hgext/color.py* (glob)
    tested with: internal
  ext1
    location: */extwithoutinfos.py* (glob)
  histedit
    location: */hgext/histedit.py* (glob)
    tested with: internal
  mq
    location: */hgext/mq.py* (glob)
    tested with: internal
  patchbomb
    location: */hgext/patchbomb.py* (glob)
    tested with: internal
  rebase
    location: */hgext/rebase.py* (glob)
    tested with: internal

  $ hg debugextensions -Tjson | sed 's|\\\\|/|g'
  [
   {
    "buglink": "",
    "name": "color",
    "source": "*/hgext/color.py*", (glob)
    "testedwith": "internal"
   },
   {
    "buglink": "",
    "name": "ext1",
    "source": "*/extwithoutinfos.py*", (glob)
    "testedwith": ""
   },
   {
    "buglink": "",
    "name": "histedit",
    "source": "*/hgext/histedit.py*", (glob)
    "testedwith": "internal"
   },
   {
    "buglink": "",
    "name": "mq",
    "source": "*/hgext/mq.py*", (glob)
    "testedwith": "internal"
   },
   {
    "buglink": "",
    "name": "patchbomb",
    "source": "*/hgext/patchbomb.py*", (glob)
    "testedwith": "internal"
   },
   {
    "buglink": "",
    "name": "rebase",
    "source": "*/hgext/rebase.py*", (glob)
    "testedwith": "internal"
   }
  ]