hgweb: send proper error messages to the client

Fixes a bug in protocol which caused an exception during exception handling in
some cases on Windows. Also makes sure the server error message is correctly
propagated to the client, instead of being thrown away.

mercurial/hgweb/common.py

@@ -31,8 +31,8 b' def _statusmessage(code):'
     responses = BaseHTTPRequestHandler.responses
     return responses.get(code, ('Error', 'Unknown error'))[0]
 
-def statusmessage(code):
-    return '%d %s' % (code, _statusmessage(code))
+def statusmessage(code, message=None):
+    return '%d %s' % (code, message or _statusmessage(code))
 
 def get_mtime(repo_path):
     store_path = os.path.join(repo_path, ".hg")

mercurial/hgweb/protocol.py

@@ -181,18 +181,19 b' def unbundle(repo, req):'
         except ValueError, inst:
             raise ErrorResponse(HTTP_OK, inst)
         except (OSError, IOError), inst:
-            filename = getattr(inst, 'filename', '')
-            # Don't send our filesystem layout to the client
-            if filename.startswith(repo.root):
-                filename = filename[len(repo.root)+1:]
-            else:
-                filename = ''
             error = getattr(inst, 'strerror', 'Unknown error')
             if inst.errno == errno.ENOENT:
                 code = HTTP_NOT_FOUND
             else:
                 code = HTTP_SERVER_ERROR
-            raise ErrorResponse(code, '%s: %s' % (error, filename))
+            filename = getattr(inst, 'filename', '')
+            # Don't send our filesystem layout to the client
+            if filename and filename.startswith(repo.root):
+                filename = filename[len(repo.root)+1:]
+                text = '%s: %s' % (error, filename)
+            else:
+                text = error.replace(repo.root + os.path.sep, '')
+            raise ErrorResponse(code, text)
     finally:
         fp.close()
         os.unlink(tempname)

mercurial/hgweb/request.py

@@ -77,7 +77,7 b' class wsgirequest(object):'
 
             if isinstance(status, ErrorResponse):
                 self.header(status.headers)
-                status = statusmessage(status.code)
+                status = statusmessage(status.code, status.message)
             elif status == 200:
                 status = '200 Script output follows'
             elif isinstance(status, int):