Merge lp:~jelmer/brz/prober-features into lp:brz

[Jelmer Vernooij]

Add an optional priority method for probers.

Add an optional priority method for probers.

This allows decreasing the priority of certain kinds of probers that we only
want to run as a last resort - e.g. probing for Monotone or CVS.

Use this to replace the previous register_server_prober() method, which
essentially helped provide two priorities.

[Jelmer Vernooij (jelmer)]

review: Approve

=== modified file 'breezy/bzr/__init__.py'
--- breezy/bzr/__init__.py	2018-11-19 22:05:30 +0000
+++ breezy/bzr/__init__.py	2019-11-06 01:42:18 +0000
@@ -32,6 +32,10 @@
     """The known .bzr formats."""
 
     @classmethod
+    def priority(klass, transport):
+        return 10
+
+    @classmethod
     def probe_transport(klass, transport):
         """Return the .bzrdir style format present in a directory."""
         try:
@@ -69,6 +73,10 @@
     """Prober for remote servers that provide a Bazaar smart server."""
 
     @classmethod
+    def priority(klass, transport):
+        return -10
+
+    @classmethod
     def probe_transport(klass, transport):
         """Return a RemoteBzrDirFormat object if it looks possible."""
         try:
@@ -99,7 +107,7 @@
         return [RemoteBzrDirFormat()]
 
 
-controldir.ControlDirFormat.register_server_prober(RemoteBzrProber)
+controldir.ControlDirFormat.register_prober(RemoteBzrProber)
 
 # Register bzr formats
 BzrProber.formats.register_lazy(

=== modified file 'breezy/controldir.py'
--- breezy/controldir.py	2019-06-27 00:17:42 +0000
+++ breezy/controldir.py	2019-11-06 01:42:18 +0000
@@ -1028,12 +1028,6 @@
     _default_format = None
     """The default format used for new control directories."""
 
-    _server_probers = []
-    """The registered server format probers, e.g. RemoteBzrProber.
-
-    This is a list of Prober-derived classes.
-    """
-
     _probers = []
     """The registered format probers, e.g. BzrProber.
 
@@ -1124,24 +1118,13 @@
         """
         klass._probers.remove(prober)
 
-    @classmethod
-    def register_server_prober(klass, prober):
-        """Register a control format prober for client-server environments.
-
-        These probers will be used before ones registered with
-        register_prober.  This gives implementations that decide to the
-        chance to grab it before anything looks at the contents of the format
-        file.
-        """
-        klass._server_probers.append(prober)
-
     def __str__(self):
         # Trim the newline
         return self.get_format_description().rstrip()
 
     @classmethod
     def all_probers(klass):
-        return klass._server_probers + klass._probers
+        return klass._probers
 
     @classmethod
     def known_formats(klass):
@@ -1156,7 +1139,9 @@
     def find_format(klass, transport, probers=None):
         """Return the format present at transport."""
         if probers is None:
-            probers = klass.all_probers()
+            probers = sorted(
+                klass.all_probers(),
+                key=lambda prober: prober.priority(transport))
         for prober_kls in probers:
             prober = prober_kls()
             try:
@@ -1276,8 +1261,8 @@
     probers that detect .bzr/ directories and Bazaar smart servers,
     respectively.
 
-    Probers should be registered using the register_server_prober or
-    register_prober methods on ControlDirFormat.
+    Probers should be registered using the register_prober methods on
+    ControlDirFormat.
     """
 
     def probe_transport(self, transport):
@@ -1301,6 +1286,21 @@
         """
         raise NotImplementedError(klass.known_formats)
 
+    @classmethod
+    def priority(klass, transport):
+        """Priority of this prober.
+
+        A lower value means the prober gets checked first.
+
+        Other conventions:
+
+        -10: This is a "server" prober
+        0: No priority set
+        10: This is a regular file-based prober
+        100: This is a prober for an unsupported format
+        """
+        return 0
+
 
 class ControlDirFormatInfo(object):
 

=== modified file 'breezy/git/__init__.py'
--- breezy/git/__init__.py	2019-11-02 23:19:18 +0000
+++ breezy/git/__init__.py	2019-11-06 01:42:18 +0000
@@ -104,6 +104,10 @@
 
 class LocalGitProber(Prober):
 
+    @classmethod
+    def priority(klass, transport):
+        return 10
+
     def probe_transport(self, transport):
         try:
             external_url = transport.external_url()
@@ -150,6 +154,14 @@
 
 class RemoteGitProber(Prober):
 
+    @classmethod
+    def priority(klass, transport):
+        # This is a surprisingly good heuristic to determine whether this
+        # prober is more likely to succeed than the Bazaar one.
+        if 'git' in transport.base:
+            return -15
+        return -10
+
     def probe_http_transport(self, transport):
         # This function intentionally doesn't use any of the support code under
         # breezy.git, since it's called for every repository that's
@@ -221,7 +233,7 @@
 
 
 ControlDirFormat.register_prober(LocalGitProber)
-ControlDirFormat._server_probers.append(RemoteGitProber)
+ControlDirFormat.register_prober(RemoteGitProber)
 
 register_transport_proto(
     'git://', help="Access using the Git smart server protocol.")

=== modified file 'breezy/plugins/cvs/__init__.py'
--- breezy/plugins/cvs/__init__.py	2018-11-11 04:08:32 +0000
+++ breezy/plugins/cvs/__init__.py	2019-11-06 01:42:18 +0000
@@ -67,6 +67,10 @@
 class CVSProber(controldir.Prober):
 
     @classmethod
+    def priority(klass, transport):
+        return 100
+
+    @classmethod
     def probe_transport(klass, transport):
         # little ugly, but works
         # try a manual probe first, its a little faster perhaps ?

=== modified file 'breezy/plugins/darcs/__init__.py'
--- breezy/plugins/darcs/__init__.py	2019-10-13 16:49:05 +0000
+++ breezy/plugins/darcs/__init__.py	2019-11-06 01:42:18 +0000
@@ -74,6 +74,10 @@
 class DarcsProber(controldir.Prober):
 
     @classmethod
+    def priority(klass, transport):
+        return 100
+
+    @classmethod
     def probe_transport(klass, transport):
         if transport.has('_darcs'):
             return DarcsDirFormat()

=== modified file 'breezy/plugins/mtn/__init__.py'
--- breezy/plugins/mtn/__init__.py	2018-11-11 04:08:32 +0000
+++ breezy/plugins/mtn/__init__.py	2019-11-06 01:42:18 +0000
@@ -67,6 +67,10 @@
 class MonotoneProber(controldir.Prober):
 
     @classmethod
+    def priority(klass, transport):
+        return 100
+
+    @classmethod
     def probe_transport(klass, transport):
         """Our format is present if the transport has a '_MTN/' subdir."""
         if transport.has('_MTN'):

=== modified file 'breezy/tests/test_controldir.py'
--- breezy/tests/test_controldir.py	2019-06-03 21:45:21 +0000
+++ breezy/tests/test_controldir.py	2019-11-06 01:42:18 +0000
@@ -104,6 +104,10 @@
         super(TestProber, self).setUp()
         self.prober = self.prober_cls()
 
+    def test_priority(self):
+        transport = self.get_transport(".")
+        self.assertIsInstance(self.prober.priority(transport), int)
+
     def test_probe_transport_empty(self):
         transport = self.get_transport(".")
         self.assertRaises(errors.NotBranchError,

=== modified file 'breezy/tests/test_remote.py'
--- breezy/tests/test_remote.py	2019-06-01 02:04:54 +0000
+++ breezy/tests/test_remote.py	2019-11-06 01:42:18 +0000
@@ -133,8 +133,7 @@
     def test_find_correct_format(self):
         """Should open a RemoteBzrDir over a RemoteTransport"""
         fmt = BzrDirFormat.find_format(self.transport)
-        self.assertTrue(RemoteBzrProber
-                        in controldir.ControlDirFormat._server_probers)
+        self.assertIn(RemoteBzrProber, controldir.ControlDirFormat._probers)
         self.assertIsInstance(fmt, RemoteBzrDirFormat)
 
     def test_open_detected_smart_format(self):

=== modified file 'doc/en/release-notes/brz-3.1.txt'
--- doc/en/release-notes/brz-3.1.txt	2019-11-02 23:19:18 +0000
+++ doc/en/release-notes/brz-3.1.txt	2019-11-06 01:42:18 +0000
@@ -128,6 +128,11 @@
 * New ``Tree.get_nested_tree`` method for retrieving a nested tree.
   (Jelmer Vernooij)
 
+* The ``ControlDirFormat.register_server_prober`` method has been removed.
+  Instead, probers can now have a ``priority`` method to influence
+  when they are run. (Jelmer Vernooij)
+
+
 Internals
 *********