Mercurial repo: lockfile should contain hash and not Mercurial "revision"

[paugier]

When using a Mercurial repository for a dependency, the lockfile currently contains something like:

[[package]]
name = "transonic"
version = "0.5.3"
requires_python = ">= 3.9"
hg = "https://foss.heptapod.net/fluiddyn/transonic"
ref = "default"
revision = "679"
[...]

However, it is wrong to save a Mercurial "revision" (obtained with something like hg log -r default -T "{rev}") because it is only a local identification of a commit (not valid for other clones). Instead PDM should save the hash of the commit (obtained with hg log -r default -T "{node}").

This can lead to some bugs when trying to create an environment from the lockfile:

Retry failed jobs
  ✖ Install transonic 0.5.3 failed

ERRORS:
add transonic failed:
Traceback (most recent call last):
  File 
"/opt/hostedtoolcache/Python/3.10.13/x64/lib/python3.10/concurrent/futures/threa
d.py", line 58, in run
    result = self.fn(*self.args, **self.kwargs)
  File 
"/opt/hostedtoolcache/Python/3.10.13/x64/lib/python3.10/site-packages/pdm/instal
lers/synchronizers.py", line 286, in install_candidate
    self.manager.install(can)
  File 
"/opt/hostedtoolcache/Python/3.10.13/x64/lib/python3.10/site-packages/pdm/instal
lers/manager.py", line 34, in install
    dist_info = installer(str(prepared.build()), self.environment, 
prepared.direct_url())
  File 
"/opt/hostedtoolcache/Python/3.10.13/x64/lib/python3.10/site-packages/pdm/models
/candidates.py", line 403, in build
    self.obtain(allow_all=False)
  File 
"/opt/hostedtoolcache/Python/3.10.13/x64/lib/python3.10/site-packages/pdm/models
/candidates.py", line 458, in obtain
    self._unpack(validate_hashes=not allow_all)
  File 
"/opt/hostedtoolcache/Python/3.10.13/x64/lib/python3.10/site-packages/pdm/models
/candidates.py", line 472, in _unpack
    result = finder.download_and_unpack(
  File 
"/opt/hostedtoolcache/Python/3.10.13/x64/lib/python3.10/site-packages/unearth/fi
nder.py", line 421, in download_and_unpack
    file = unpack_link(
  File 
"/opt/hostedtoolcache/Python/3.10.13/x64/lib/python3.10/site-packages/unearth/pr
eparer.py", line 311, in unpack_link
    backend.fetch(link, location)
  File 
"/opt/hostedtoolcache/Python/3.10.13/x64/lib/python3.10/site-packages/unearth/vc
s/base.py", line 152, in fetch
    return self.fetch_new(location, url, rev, args)
  File 
"/opt/hostedtoolcache/Python/3.10.13/x64/lib/python3.10/site-packages/unearth/vc
s/hg.py", line 35, in fetch_new
    self.run_command(
  File 
"/opt/hostedtoolcache/Python/3.10.13/x64/lib/python3.10/site-packages/unearth/vc
s/base.py", line 78, in run_command
    raise UnpackError(e.output) from None
unearth.errors.UnpackError: abort: unknown revision '679'

[paugier]

A workaround is to manually correct the lockfile with the hash instead of the revision number.

Where is the code that gets this revision number for Mercurial repository? In PDM?

[paugier]

Would it be enough to change ["parents", "--template={rev}"], to ["parents", "--template={node}"], in this line https://github.com/frostming/unearth/blob/main/src/unearth/vcs/hg.py#L49C38-L49C41 ?