archive: abort on empty repository. Fixes #624.

mercurial/commands.py

@@ -142,7 +142,10 b' def archive(ui, repo, dest, **opts):'
     The default is the basename of the archive, with suffixes removed.
     '''
 
-    node = repo.changectx(opts['rev']).node()
+    ctx = repo.changectx(opts['rev'])
+    if not ctx:
+        raise util.Abort(_('repository has no revisions'))
+    node = ctx.node()
     dest = cmdutil.make_filename(repo, dest, node)
     if os.path.realpath(dest) == repo.root:
         raise util.Abort(_('repository root cannot be destination'))

tests/test-archive

@@ -63,3 +63,9 b' hg archive -t zip -r 2 test.zip'
 unzip -t test.zip
 
 hg archive -t tar - | tar tf - | sed "s/$QTIP/TIP/"
+
+echo '% empty repo'
+hg init ../empty
+cd ../empty
+hg archive ../test-empty
+exit 0
  No newline at end of file

tests/test-archive.out

@@ -38,3 +38,5 b' test-TIP/.hg_archival.txt'
 test-TIP/bar
 test-TIP/baz/bletch
 test-TIP/foo
+% empty repo
+abort: repository has no revisions