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diff mercurial/wireprotov2peer.py @ 37725:3ea8323d6f95

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wireprotov2: change command response protocol to include a leading map The error handling mechanism for the new wire protocol isn't very well-defined. This commit takes us a step in the right direction by introducing a leading CBOR map for command responses. This map will contain an overall result of the command. Currently, the map indicates whether the command was overall successful or if an error occurred. And if an error occurred, that error is present in the map. There is still a dedicated error frame. My intent is to use that for protocol-level errors and for errors that are encountered after the initial response frame has been sent. This will be clarified in a later commit. Differential Revision: https://phab.mercurial-scm.org/D3385
author Gregory Szorc <gregory.szorc@gmail.com>
date Sat, 14 Apr 2018 15:19:36 -0700
parents 89a16704114c
children 1467b6c27ff9
line wrap: on
line diff
--- a/mercurial/wireprotov2peer.py	Sat Apr 14 14:37:23 2018 -0700
+++ b/mercurial/wireprotov2peer.py	Sat Apr 14 15:19:36 2018 -0700
@@ -18,6 +18,21 @@
     wireprotoframing,
 )
 
+def formatrichmessage(atoms):
+    """Format an encoded message from the framing protocol."""
+
+    chunks = []
+
+    for atom in atoms:
+        msg = _(atom[b'msg'])
+
+        if b'args' in atom:
+            msg = msg % atom[b'args']
+
+        chunks.append(msg)
+
+    return b''.join(chunks)
+
 class commandresponse(object):
     """Represents the response to a command request."""
 
@@ -128,9 +143,20 @@
                 # decoded value. Otherwise resolve to the rich response object.
                 decoder = COMMAND_DECODERS.get(response.command)
 
-                result = decoder(response) if decoder else response
+                # TODO consider always resolving the overall status map.
+                if decoder:
+                    objs = response.cborobjects()
+
+                    overall = next(objs)
 
-                self._futures[frame.requestid].set_result(result)
+                    if overall['status'] == 'ok':
+                        self._futures[frame.requestid].set_result(decoder(objs))
+                    else:
+                        e = error.RepoError(
+                            formatrichmessage(overall['error']['message']))
+                        self._futures[frame.requestid].set_exception(e)
+                else:
+                    self._futures[frame.requestid].set_result(response)
 
                 del self._requests[frame.requestid]
                 del self._futures[frame.requestid]
@@ -139,31 +165,31 @@
             raise error.ProgrammingError(
                 'unhandled action from clientreactor: %s' % action)
 
-def decodebranchmap(resp):
+def decodebranchmap(objs):
     # Response should be a single CBOR map of branch name to array of nodes.
-    bm = next(resp.cborobjects())
+    bm = next(objs)
 
     return {encoding.tolocal(k): v for k, v in bm.items()}
 
-def decodeheads(resp):
+def decodeheads(objs):
     # Array of node bytestrings.
-    return next(resp.cborobjects())
+    return next(objs)
 
-def decodeknown(resp):
+def decodeknown(objs):
     # Bytestring where each byte is a 0 or 1.
-    raw = next(resp.cborobjects())
+    raw = next(objs)
 
     return [True if c == '1' else False for c in raw]
 
-def decodelistkeys(resp):
+def decodelistkeys(objs):
     # Map with bytestring keys and values.
-    return next(resp.cborobjects())
+    return next(objs)
 
-def decodelookup(resp):
-    return next(resp.cborobjects())
+def decodelookup(objs):
+    return next(objs)
 
-def decodepushkey(resp):
-    return next(resp.cborobjects())
+def decodepushkey(objs):
+    return next(objs)
 
 COMMAND_DECODERS = {
     'branchmap': decodebranchmap,