Patchwork [6,of,8] help: internals topic for wire protocol

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Submitter Yuya Nishihara
Date Sept. 5, 2016, 8:07 p.m.
Message ID <>
Download mbox | patch
Permalink /patch/16557/
State Not Applicable
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Yuya Nishihara - Sept. 5, 2016, 8:07 p.m.
# HG changeset patch
# User Gregory Szorc <>
# Date 1471920399 25200
#      Mon Aug 22 19:46:39 2016 -0700
# Node ID a1092e2d70a30004ce2814351da317d463396e45
# Parent  33461139c31ca59ad98e5aabc4ee39716758846f
help: internals topic for wire protocol

The Mercurial wire protocol is under-documented. This includes a lack
of source docstrings and comments as well as pages on the official

This patch adds the beginnings of "internals" documentation on the
wire protocol.

The documentation should have nearly complete coverage on the
lower-level parts of the protocol, such as the different transport
mechanims, how commands and arguments are sent, capabilities, and,
of course, the commands themselves.

As part of writing this documentation, I discovered a number of
deficiencies in the protocol and bugs in the implementation. I've
started sending patches for some of the issues. I hope to send a lot

This patch starts with the scaffolding for a new internals page.


diff --git a/contrib/wix/help.wxs b/contrib/wix/help.wxs
--- a/contrib/wix/help.wxs
+++ b/contrib/wix/help.wxs
@@ -42,6 +42,7 @@ 
             <File Id="internals.changegroups.txt" Name="changegroups.txt" />
             <File Id="internals.requirements.txt" Name="requirements.txt" />
             <File Id="internals.revlogs.txt"      Name="revlogs.txt" />
+            <File Id="internals.wireprotocol.txt" Name="wireprotocol.txt" />
diff --git a/mercurial/ b/mercurial/
--- a/mercurial/
+++ b/mercurial/
@@ -192,6 +192,8 @@ 
      loaddoc('requirements', subdir='internals')),
     (['revlogs'], _('Revision Logs'),
      loaddoc('revlogs', subdir='internals')),
+    (['wireprotocol'], _('Wire Protocol'),
+     loaddoc('wireprotocol', subdir='internals')),
 def internalshelp(ui):
diff --git a/mercurial/help/internals/wireprotocol.txt b/mercurial/help/internals/wireprotocol.txt
new file mode 100644
--- /dev/null
+++ b/mercurial/help/internals/wireprotocol.txt
@@ -0,0 +1,11 @@ 
+The Mercurial wire protocol is a request-response based protocol
+with multiple wire representations.
+Each request is modeled as a command name, a dictionary of arguments, and
+optional raw input. Command arguments and their types are intrinsic
+properties of commands. So is the response type of the command. This means
+clients can't always send arbitrary arguments to servers and servers can't
+return multiple response types.
+The protocol is synchronous and does not support multiplexing (concurrent
diff --git a/tests/test-help.t b/tests/test-help.t
--- a/tests/test-help.t
+++ b/tests/test-help.t
@@ -933,6 +933,7 @@ 
        changegroups  Changegroups
        requirements  Repository Requirements
        revlogs       Revision Logs
+       wireprotocol  Wire Protocol
 sub-topics can be accessed
@@ -2895,6 +2896,13 @@ 
   Revision Logs
+  <tr><td>
+  <a href="/help/internals.wireprotocol">
+  wireprotocol
+  </a>
+  </td><td>
+  Wire Protocol
+  </td></tr>