remote-bzr: fix for disappeared revisions

It's possible that the previous tip goes away, we should not assume it's
always present. Fortunately we are only using it to calculate the
progress to display to the user, so only that needs to be fixed.

Also, add a test that triggers this issue.

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

contrib/remote-helpers/git-remote-bzr

@@ -282,9 +282,13 @@ def export_branch(repo, name):
 
     branch.lock_read()
     revs = branch.iter_merge_sorted_revisions(None, tip, 'exclude', 'forward')
-    tip_revno = branch.revision_id_to_revno(tip)
-    last_revno, _ = branch.last_revision_info()
-    total = last_revno - tip_revno
+    try:
+        tip_revno = branch.revision_id_to_revno(tip)
+        last_revno, _ = branch.last_revision_info()
+        total = last_revno - tip_revno
+    except bzrlib.errors.NoSuchRevision:
+        tip_revno = 0
+        total = 0
 
     for revid, _, seq, _ in revs:
 
@@ -353,7 +357,10 @@ def export_branch(repo, name):
 
         progress = (revno - tip_revno)
         if (progress % 100 == 0):
-            print "progress revision %d '%s' (%d/%d)" % (revno, name, progress, total)
+            if total:
+                print "progress revision %d '%s' (%d/%d)" % (revno, name, progress, total)
+            else:
+                print "progress revision %d '%s' (%d)" % (revno, name, progress)
 
     branch.unlock()
 

contrib/remote-helpers/test-bzr.sh

@@ -300,4 +300,42 @@ test_expect_success 'proper bzr repo' '
   test_cmp ../expected actual
 '
 
+test_expect_success 'strip' '
+  # Do not imitate this style; always chdir inside a subshell instead
+  mkdir -p tmp && cd tmp &&
+  test_when_finished "cd .. && rm -rf tmp" &&
+
+  (
+  bzr init bzrrepo &&
+  cd bzrrepo &&
+
+  echo one >> content &&
+  bzr add content &&
+  bzr commit -m one &&
+
+  echo two >> content &&
+  bzr commit -m two
+  ) &&
+
+  git clone "bzr::$PWD/bzrrepo" gitrepo &&
+
+  (
+  cd bzrrepo &&
+  bzr uncommit --force &&
+
+  echo three >> content &&
+  bzr commit -m three &&
+
+  echo four >> content &&
+  bzr commit -m four &&
+  bzr log --line | sed -e "s/^[0-9]\+: //" > ../expected
+  ) &&
+
+  (cd gitrepo &&
+  git fetch &&
+  git log --format="%an %ad %s" --date=short origin/master > ../actual) &&
+
+  test_cmp expected actual
+'
+
 test_done