It Seems something is causing hg to crash out while trying to create the working directory.

[freemor@freelap iceweasel]$ makepkg -si
==> Making package: iceweasel 1:61.0.2-1.parabola4 (Thu 01 Nov 2018 04:25:20 PM ADT)
==> Checking runtime dependencies...
==> Checking buildtime dependencies...
==> Retrieving sources...
  -> Cloning mozilla-unified hg repo...
applying clone bundle from https://hg.cdn.mozilla.net/mozilla-unified/20ae9023dd79e7108da0e3c909af8d6066b75761.zstd-max.hg
adding changesets
adding manifests                                                                                                                                                                                                  
adding file changes                                                                                                                                                                                               
added 495381 changesets with 2906892 changes to 474472 files (+11 heads)                                                                                                                                          
finished applying clone bundle
searching for changes
adding changesets
adding manifests                                                                                                                                                                                                  
adding file changes
added 128 changesets with 1445 changes to 1361 files (+1 heads)                                                                                                                                                   
new changesets 417d75b25e56:84d3cfc3fbc6
495381 local changesets published
  -> Found iceweasel.desktop
  -> Found iceweasel_61.0-1.branding.tar.xz
  -> Found iceweasel_61.0-1.branding.tar.xz.sig
  -> Found 0001-branding-Fix-for-v60-v61.patch
  -> Found libre.patch
==> Validating source files with sha256sums...
    mozilla-unified ... Skipped
    iceweasel.desktop ... Passed
    iceweasel_61.0-1.branding.tar.xz ... Passed
    iceweasel_61.0-1.branding.tar.xz.sig ... Skipped
    0001-branding-Fix-for-v60-v61.patch ... Passed
    libre.patch ... Passed
==> Verifying source file signatures with gpg...
    iceweasel_61.0-1.branding.tar.xz ... Passed (WARNING: the key has expired.)
==> WARNING: Warnings have occurred while verifying the signatures.
    Please make sure you really trust them.
==> Extracting sources...
  -> Creating working copy of mozilla-unified hg repo...
pulling from /home/freemor/packages/abslibre/libre/iceweasel/mozilla-unified
requesting all changes
adding changesets
adding manifests                                                                                                                                                                                                  
transaction abort!                                                                                                                                                                                                
rollback completed
** unknown exception encountered, please report by visiting
** https://mercurial-scm.org/wiki/BugTracker
** Python 2.7.15 (default, Jun 27 2018, 13:05:28) [GCC 8.1.1 20180531]
** Mercurial Distributed SCM (version 4.7.2)
** Extensions loaded: 
Traceback (most recent call last):
  File "/usr/bin/hg", line 41, in <module>
    dispatch.run()
  File "/usr/lib/python2.7/site-packages/mercurial/dispatch.py", line 90, in run
    status = dispatch(req)
  File "/usr/lib/python2.7/site-packages/mercurial/dispatch.py", line 213, in dispatch
    ret = _runcatch(req) or 0
  File "/usr/lib/python2.7/site-packages/mercurial/dispatch.py", line 354, in _runcatch
    return _callcatch(ui, _runcatchfunc)
  File "/usr/lib/python2.7/site-packages/mercurial/dispatch.py", line 362, in _callcatch
    return scmutil.callcatch(ui, func)
  File "/usr/lib/python2.7/site-packages/mercurial/scmutil.py", line 161, in callcatch
    return func()
  File "/usr/lib/python2.7/site-packages/mercurial/dispatch.py", line 344, in _runcatchfunc
    return _dispatch(req)
  File "/usr/lib/python2.7/site-packages/mercurial/dispatch.py", line 984, in _dispatch
    cmdpats, cmdoptions)
  File "/usr/lib/python2.7/site-packages/mercurial/dispatch.py", line 730, in runcommand
    ret = _runcommand(ui, options, cmd, d)
  File "/usr/lib/python2.7/site-packages/mercurial/dispatch.py", line 992, in _runcommand
    return cmdfunc()
  File "/usr/lib/python2.7/site-packages/mercurial/dispatch.py", line 981, in <lambda>
    d = lambda: util.checksignature(func)(ui, *args, **strcmdopt)
  File "/usr/lib/python2.7/site-packages/mercurial/util.py", line 1528, in check
    return func(*args, **kwargs)
  File "/usr/lib/python2.7/site-packages/mercurial/commands.py", line 4213, in pull
    opargs=pullopargs).cgresult
  File "/usr/lib/python2.7/site-packages/mercurial/exchange.py", line 1489, in pull
    _fullpullbundle2(repo, pullop)
  File "/usr/lib/python2.7/site-packages/mercurial/exchange.py", line 1429, in _fullpullbundle2
    _pullbundle2(pullop)
  File "/usr/lib/python2.7/site-packages/mercurial/exchange.py", line 1672, in _pullbundle2
    bundle2.processbundle(pullop.repo, bundle, op=op)
  File "/usr/lib/python2.7/site-packages/mercurial/bundle2.py", line 460, in processbundle
    processparts(repo, op, unbundler)
  File "/usr/lib/python2.7/site-packages/mercurial/bundle2.py", line 467, in processparts
    _processpart(op, part)
  File "/usr/lib/python2.7/site-packages/mercurial/bundle2.py", line 534, in _processpart
    handler(op, part)
  File "/usr/lib/python2.7/site-packages/mercurial/bundle2.py", line 1805, in handlechangegroup
    expectedtotal=nbchangesets, **extrakwargs)
  File "/usr/lib/python2.7/site-packages/mercurial/bundle2.py", line 470, in _processchangegroup
    ret = cg.apply(op.repo, tr, source, url, **kwargs)
  File "/usr/lib/python2.7/site-packages/mercurial/changegroup.py", line 321, in apply
    self._unpackmanifests(repo, revmap, trp, progress)
  File "/usr/lib/python2.7/site-packages/mercurial/changegroup.py", line 248, in _unpackmanifests
    repo.manifestlog.addgroup(deltas, revmap, trp)
  File "/usr/lib/python2.7/site-packages/mercurial/manifest.py", line 1356, in addgroup
    return self._revlog.addgroup(deltas, linkmapper, transaction)
  File "/usr/lib/python2.7/site-packages/mercurial/revlog.py", line 2678, in addgroup
    deltacomputer=deltacomputer)
  File "/usr/lib/python2.7/site-packages/mercurial/revlog.py", line 2556, in _addrevision
    entry = self._io.packentry(e, self.node, self.version, curr)
  File "/usr/lib/python2.7/site-packages/mercurial/revlog.py", line 834, in packentry
    return indexformatv0_pack(*e2)
struct.error: 'l' format requires -2147483648 <= number <= 2147483647
==> ERROR: Failure while updating working copy of mozilla-unified hg repo
    Aborting...
[freemor@freelap iceweasel]$