Merge lp:~jelmer/bzr/2.2-feature-flags into lp:bzr/2.2

[Jelmer Vernooij]

Add basic support for feature flags.

Add basic support for feature flags to the 2.2 release series.

This does the bare minimum to:
 * ignore optional feature flags
 * raise an appropriate error (non-confusing) for any other feature flags

[Jelmer Vernooij (jelmer)]

Marking as approved, simply upmerging from 2.1.

[Jelmer Vernooij (jelmer)]

sent to pqm by email

[Jelmer Vernooij (jelmer)]

sent to pqm by email

=== modified file 'NEWS'
--- NEWS	2011-09-02 18:47:36 +0000
+++ NEWS	2012-03-28 00:19:19 +0000
@@ -115,6 +115,10 @@
 Improvements
 ************
 
+ * When opening formats with feature flags, optional features are
+   ignored and an improved error is printed for non-optional features.
+   (Jelmer Vernooij)
+
 Documentation
 *************
 
 
=== modified file 'bzrlib/branch.py'
--- bzrlib/branch.py	2010-08-13 07:32:06 +0000
+++ bzrlib/branch.py	2012-03-28 00:19:19 +0000
@@ -1549,7 +1549,8 @@
         """Return the format for the branch object in a_bzrdir."""
         try:
             transport = a_bzrdir.get_branch_transport(None, name=name)
-            format_string = transport.get_bytes("format")
+            format_string = bzrdir.extract_format_string(
+                transport.get_bytes("format"))
             format = klass._formats[format_string]
             if isinstance(format, MetaDirBranchFormatFactory):
                 return format()
 
=== modified file 'bzrlib/bzrdir.py'
--- bzrlib/bzrdir.py	2010-11-26 18:13:30 +0000
+++ bzrlib/bzrdir.py	2012-03-28 00:19:19 +0000
@@ -86,8 +86,34 @@
     registry,
     symbol_versioning,
     )
-    
-    
+
+
+def extract_format_string(text):
+    """Read a format string from a file.
+
+    The first line is returned. The other lines can contain
+    optional features. An exception is raised when a
+    required feature is present.
+    """
+    lines = text.splitlines(True)
+    try:
+        firstline = lines.pop(0)
+    except IndexError:
+        raise errors.UnknownFormatError(format=text, kind='')
+    for lineno, line in enumerate(lines):
+        try:
+            (necessity, feature) = line.split(" ", 1)
+        except ValueError:
+            raise errors.ParseFormatError(lineno=lineno+2,
+                line=line, text=text)
+        else:
+            if necessity == "optional":
+                mutter("Ignoring optional feature %s", feature)
+            else:
+                raise errors.MissingFeature(feature)
+    return firstline
+
+
 class ControlComponent(object):
     """Abstract base class for control directory components.
     
@@ -1959,6 +1985,8 @@
             format_string = transport.get_bytes(".bzr/branch-format")
         except errors.NoSuchFile:
             raise errors.NotBranchError(path=transport.base)
+        format_string = extract_format_string(format_string)
+
         try:
             return klass._formats[format_string]
         except KeyError:
 
=== modified file 'bzrlib/errors.py'
--- bzrlib/errors.py	2011-01-19 22:26:11 +0000
+++ bzrlib/errors.py	2012-03-28 00:19:19 +0000
@@ -3194,3 +3194,22 @@
     def __init__(self, branch_url):
         self.branch_url = branch_url
 
+
+class MissingFeature(BzrError):
+
+    _fmt = ("Missing feature %(feature)s not provided by this "
+            "version of Bazaar or any plugin.")
+
+    def __init__(self, feature):
+        self.feature = feature
+
+
+class ParseFormatError(BzrError):
+
+    _fmt = "Parse error on line %(lineno)d of format name: %(line)s"
+
+    def __init__(self, lineno, line, text):
+        BzrError.__init__(self)
+        self.lineno = lineno
+        self.line = line
+        self.text = text
 
=== modified file 'bzrlib/repository.py'
--- bzrlib/repository.py	2010-12-02 09:23:10 +0000
+++ bzrlib/repository.py	2012-03-28 00:19:19 +0000
@@ -3108,6 +3108,7 @@
         try:
             transport = a_bzrdir.get_repository_transport(None)
             format_string = transport.get_bytes("format")
+            format_string = bzrdir.extract_format_string(format_string)
             return format_registry.get(format_string)
         except errors.NoSuchFile:
             raise errors.NoRepositoryPresent(a_bzrdir)
 
=== modified file 'bzrlib/tests/test_bzrdir.py'
--- bzrlib/tests/test_bzrdir.py	2010-08-13 07:43:51 +0000
+++ bzrlib/tests/test_bzrdir.py	2012-03-28 00:19:19 +0000
@@ -1411,3 +1411,24 @@
         param_repr = param_reprs[0]
         self.assertStartsWith(param_repr, '<RepoInitHookParams for ')
 
+
+class ExtractFormatStringTests(TestCase):
+
+    def test_normal(self):
+        self.assertEquals("Bazaar-NG branch, format 0.0.4\n",
+            bzrdir.extract_format_string("Bazaar-NG branch, format 0.0.4\n"))
+
+    def test_with_optional_feature(self):
+        self.assertEquals("Bazaar-NG branch, format 0.0.4\n",
+            bzrdir.extract_format_string("Bazaar-NG branch, format 0.0.4\n"
+                                         "optional feature foo\n"))
+
+    def test_with_required_feature(self):
+        self.assertRaises(errors.MissingFeature,
+            bzrdir.extract_format_string, "Bazaar-NG branch, format 0.0.4\n"
+                                          "required feature foo\n")
+
+    def test_with_invalid_line(self):
+        self.assertRaises(errors.ParseFormatError,
+            bzrdir.extract_format_string, "Bazaar-NG branch, format 0.0.4\n"
+                                          "requiredfoo\n")
 
=== modified file 'bzrlib/workingtree.py'
--- bzrlib/workingtree.py	2010-08-17 02:28:46 +0000
+++ bzrlib/workingtree.py	2012-03-28 00:19:19 +0000
@@ -2811,6 +2811,7 @@
         try:
             transport = a_bzrdir.get_workingtree_transport(None)
             format_string = transport.get_bytes("format")
+            format_string = bzrdir.extract_format_string(format_string)
             return klass._formats[format_string]
         except errors.NoSuchFile:
             raise errors.NoWorkingTree(base=transport.base)