mq: cleanup status if applied mq is stripped (issue1881)

stripping of applied mq patches leads to wrong state recorded in status
file. find all mq patches that will be affected and clean up status file
before strip.

hgext/mq.py

@@ -2418,6 +2418,18 b' def strip(ui, repo, rev, **opts):'
     elif rev not in (cl.ancestor(p[0], rev), cl.ancestor(p[1], rev)):
         update = False
 
+    q = repo.mq
+    if q.applied:
+        if rev == cl.ancestor(repo.lookup('qtip'), rev):
+            q.applied_dirty = True
+            start = 0
+            end = len(q.applied)
+            applied_list = [i.node for i in q.applied]
+            if rev in applied_list:
+                start = applied_list.index(rev)
+            del q.applied[start:end]
+            q.save_dirty()
+
     repo.mq.strip(repo, rev, backup=backup, update=update, force=opts['force'])
     return 0
 

tests/test-mq-strip

@@ -53,3 +53,19 b' hg parents'
 hg strip 4 2>&1 | hidebackup
 echo % after strip of merge parent
 hg parents
+
+#strip of applied mq should cleanup status file
+hg up -C 3
+echo fooagain >> bar
+hg ci -mf
+hg qimport -r tip:2
+echo % applied patches before strip
+hg qapplied
+echo % stripping revision in queue
+hg strip 3 | hidebackup
+echo % applied patches after stripping rev in queue
+hg qapplied
+echo % stripping ancestor of queue
+hg strip 1 | hidebackup
+echo % applied patches after stripping ancestor of queue
+hg qapplied

tests/test-mq-strip.out

@@ -165,3 +165,17 b' user: test'
 date:        Thu Jan 01 00:00:00 1970 +0000
 summary:     b
 
+1 files updated, 0 files merged, 0 files removed, 0 files unresolved
+% applied patches before strip
+2.diff
+3.diff
+4.diff
+% stripping revision in queue
+1 files updated, 0 files merged, 0 files removed, 0 files unresolved
+saved backup bundle to 
+% applied patches after stripping rev in queue
+2.diff
+% stripping ancestor of queue
+1 files updated, 0 files merged, 0 files removed, 0 files unresolved
+saved backup bundle to 
+% applied patches after stripping ancestor of queue

tests/test-mq.out

@@ -400,15 +400,13 b' 2 bar qtip tip'
 popping bar
 now at: foo
 changeset:   0:cb9a9f314b8b
-mq status file refers to unknown node
 tag:         tip
 user:        test
 date:        Thu Jan 01 00:00:00 1970 +0000
 summary:     a
 
-mq status file refers to unknown node
 default                        0:cb9a9f314b8b
-abort: trying to pop unknown node
+no patches applied
 new file
 
 diff --git a/new b/new