hg: avoid auto sharing when the clone destination is remote stable

hg: avoid auto sharing when the clone destination is remote

Before this patch, when auto sharing is enabled, 'hg.clone()' tries to
create local clone regardless of locality of the clone destination on
the host, and causes failure.

To avoid auto sharing when the clone destination is remote, this patch
adds examination of 'islocal(dest)' before auto sharing in
'hg.clone()'.

'islocal(dest)' is examined after 'sharepool', because:

  - the former is more expensive than the latter
  - without enabling share extension, the later is always negative

--- a/mercurial/hg.py	Wed Aug 12 12:26:39 2015 -0400
+++ b/mercurial/hg.py	Thu Aug 13 15:07:07 2015 +0900
@@ -404,7 +404,7 @@
     shareopts = shareopts or {}
     sharepool = shareopts.get('pool')
     sharenamemode = shareopts.get('mode')
-    if sharepool:
+    if sharepool and islocal(dest):
         sharepath = None
         if sharenamemode == 'identity':
             # Resolve the name from the initial changeset in the remote

--- a/tests/test-clone.t	Wed Aug 12 12:26:39 2015 -0400
+++ b/tests/test-clone.t	Thu Aug 13 15:07:07 2015 +0900
@@ -1013,3 +1013,15 @@
   adding remote bookmark bookA
 
   $ ls share-1anowc
+
+Test that auto sharing doesn't cause failure of "hg clone local remote"
+
+  $ cd $TESTTMP
+  $ hg -R a id -r 0
+  acb14030fe0a
+  $ hg id -R remote -r 0
+  abort: there is no Mercurial repository here (.hg not found)
+  [255]
+  $ hg --config share.pool=share -q clone -e "python \"$TESTDIR/dummyssh\"" a ssh://user@dummy/remote
+  $ hg -R remote id -r 0
+  acb14030fe0a