diff -r 5698c5eee12b -r 1bd33932713d setup.py
--- a/setup.py	Thu Apr 29 22:01:04 2021 +0200
+++ b/setup.py	Tue Jan 31 11:41:59 2023 +0100
@@ -217,9 +217,10 @@
         cmd = self.cmd + args
         returncode, out, err = runcmd(cmd, self.env)
         err = filterhgerr(err)
-        if err or returncode != 0:
+        if err:
             print("stderr from '%s':" % (' '.join(cmd)), file=sys.stderr)
             print(err, file=sys.stderr)
+        if returncode != 0:
             return b''
         return out
 
@@ -333,8 +334,12 @@
     else:  # no tag found
         ltagcmd = ['parents', '--template', '{latesttag}']
         ltag = sysstr(hg.run(ltagcmd))
+        if not ltag:
+            ltag = 'null'
         changessincecmd = ['log', '-T', 'x\n', '-r', "only(.,'%s')" % ltag]
         changessince = len(hg.run(changessincecmd).splitlines())
+        if ltag == 'null':
+            ltag = '0.0'
         version = '%s+hg%s.%s' % (ltag, changessince, hgid)
     if version.endswith('+'):
         version = version[:-1] + 'local' + time.strftime('%Y%m%d')