convert: allow svn trunk/branches/tags detection to be skipped

- eluding convert.svn.branches defaults to "branches"
- convert.svn.branches= disables branches detection
- convert.svn.branches=/ is equivalent to former convert.svn.branches=

hgext/convert/__init__.py

@@ -95,7 +95,8 b' def convert(ui, src, dest=None, revmapfi'
     "svn://repo/path/tags" exists, it is looked for tags referencing
     converted branches. Default "trunk", "branches" and "tags" values
     can be overriden with following options. Set them to paths
-    relative to the source URL.
+    relative to the source URL, or leave them blank to disable
+    autodetection.
 
     --config convert.svn.branches=branches    (directory name)
         specify the directory containing branches

hgext/convert/subversion.py

@@ -236,6 +236,8 b' class svn_source(converter_source):'
 
         def getcfgpath(name, rev):
             cfgpath = self.ui.config('convert', 'svn.' + name)
+            if cfgpath is not None and cfgpath.strip() == '':
+                return None
             path = (cfgpath or name).strip('/')
             if not self.exists(path, rev):
                 if cfgpath:
@@ -342,6 +344,9 b' class svn_source(converter_source):'
 
     def gettags(self):
         tags = {}
+        if self.tags is None:
+            return tags
+            
         start = self.revnum(self.head)
         try:
             for entry in get_log(self.url, [self.tags], 0, start):

tests/test-convert.out

@@ -84,7 +84,8 b' Convert a foreign SCM repository to a Me'
     "svn://repo/path/tags" exists, it is looked for tags referencing
     converted branches. Default "trunk", "branches" and "tags" values
     can be overriden with following options. Set them to paths
-    relative to the source URL.
+    relative to the source URL, or leave them blank to disable
+    autodetection.
 
     --config convert.svn.branches=branches    (directory name)
         specify the directory containing branches