--- a/mercurial/cmdutil.py	Mon Jul 08 15:01:18 2019 -0700
+++ b/mercurial/cmdutil.py	Tue Jul 09 12:58:29 2019 +0300
@@ -3297,6 +3297,14 @@
         if s._clearable and s.isunfinished(repo):
             util.unlink(repo.vfs.join(s._fname))
 
+def getunfinishedstate(repo):
+    ''' Checks for unfinished operations and returns statecheck object
+        for it'''
+    for state in statemod._unfinishedstates:
+        if state.isunfinished(repo):
+            return state
+    return None
+
 def howtocontinue(repo):
     '''Check for an unfinished operation and return the command to finish
     it.

--- a/mercurial/commands.py	Mon Jul 08 15:01:18 2019 -0700
+++ b/mercurial/commands.py	Tue Jul 09 12:58:29 2019 +0300
@@ -3952,6 +3952,10 @@
     if abort and repo.dirstate.p2() == nullid:
         cmdutil.wrongtooltocontinue(repo, _('merge'))
     if abort:
+        state = cmdutil.getunfinishedstate(repo)
+        if state and state._opname != 'merge':
+            raise error.Abort(_('cannot abort merge with %s in progress') %
+                                (state._opname), hint=state.hint())
         if node:
             raise error.Abort(_("cannot specify a node with --abort"))
         if opts.get('rev'):

--- a/relnotes/next	Mon Jul 08 15:01:18 2019 -0700
+++ b/relnotes/next	Tue Jul 09 12:58:29 2019 +0300
@@ -81,6 +81,10 @@
 
  * `cmdutil.checkunfinished()` now includes detection for merge too.
 
+ * merge abort has been disallowed in case an operation of higher
+   precedence is in progress to avoid cases of partial abort of
+   operations.
+
  * We used to automatically attempt to make extensions compatible with
    Python 3 (by translating their source code while loading it). We no
    longer do that.

--- a/tests/test-shelve2.t	Mon Jul 08 15:01:18 2019 -0700
+++ b/tests/test-shelve2.t	Tue Jul 09 12:58:29 2019 +0300
@@ -847,3 +847,38 @@
 #endif
 
   $ cd ..
+
+Block merge abort when unshelve in progress(issue6160)
+------------------------------------------------------
+
+  $ hg init a
+  $ cd a
+  $ echo foo > a ; hg commit -qAm "initial commit"
+  $ echo bar > a
+  $ hg shelve
+  shelved as default
+  1 files updated, 0 files merged, 0 files removed, 0 files unresolved
+  $ echo foobar > a
+  $ hg unshelve
+  unshelving change 'default'
+  temporarily committing pending changes (restore with 'hg unshelve --abort')
+  rebasing shelved changes
+  merging a
+  warning: conflicts while merging a! (edit, then use 'hg resolve --mark')
+  unresolved conflicts (see 'hg resolve', then 'hg unshelve --continue')
+  [1]
+
+  $ hg log --template '{desc|firstline}  {author}  {date|isodate} \n' -r .
+  pending changes temporary commit  shelve@localhost  1970-01-01 00:00 +0000 
+  $ hg merge --abort
+  abort: cannot abort merge with unshelve in progress
+  (use 'hg unshelve --continue' or 'hg unshelve --abort')
+  [255]
+
+  $ hg unshelve --abort
+  unshelve of 'default' aborted
+
+  $ hg log -G --template '{desc|firstline}  {author}  {date|isodate} \n' -r .
+  @  initial commit  test  1970-01-01 00:00 +0000
+  
+  $ cd ..