svn commit: r1081645 - /subversion/trunk/notes/api-errata/1.7/ra001.txt

[da...@apache.org]

Author: danielsh
Date: Tue Mar 15 02:34:21 2011
New Revision: 1081645

URL: http://svn.apache.org/viewvc?rev=1081645&view=rev
Log:
Add an errata concerning ra_serf's editor API violations, per
issues #2932 and #3831.

Comments, rewrites, etc welcome.

* notes/api-errata/1.7/ra001.txt: New.

Added:
    subversion/trunk/notes/api-errata/1.7/ra001.txt   (with props)

Added: subversion/trunk/notes/api-errata/1.7/ra001.txt
URL: http://svn.apache.org/viewvc/subversion/trunk/notes/api-errata/1.7/ra001.txt?rev=1081645&view=auto
==============================================================================
--- subversion/trunk/notes/api-errata/1.7/ra001.txt (added)
+++ subversion/trunk/notes/api-errata/1.7/ra001.txt Tue Mar 15 02:34:21 2011
@@ -0,0 +1,47 @@
+API ERRATA -- $Id$
+
+Root Cause of Errata: 
+ Library(s) Affected: libsvn_ra, RA servers (svnserve, mod_dav_svn)
+Function(s) Affected: svn_delta_editor_t
+     New Behavior in: 1.7 (default), 1.4 (client optional)
+      Related Issues: #2932, #3628
+
+
+== Details of Previous Behavior ==
+
+The ra_neon (formerly, ra_dav) drives delta editors (svn_delta_editor_t) in
+accordance with the constraints of that API [1].
+
+[1] ../../../subversion/include/svn_delta.h:svn_delta_editor_t 
+[1] http://subversion.apache.org/docs/api/latest/structsvn__delta__editor__t.html#_details
+
+
+== Details of New Behavior ==
+
+The ra_serf client-side HTTP/DAV layer (introduced in Subversion 1.4, and
+made the default DAV layer in Subversion 1.7) does not respect all the
+ordering constraints of the delta editor API: it may open two sibling
+directores at the same time, which the delta editor API does not permit.
+
+
+== Rationale for Change ==
+
+The ra_serf layer operates on sibling directores simultaneously in order to
+improve overall speed by using the HTTP protocol more efficiently: for
+example, by sending more requests without having to wait for the server's
+responses in all cases.  
+
+### other reasons? caching? httpv2?
+
+
+== Impact on API Users ==
+
+Server-side editor implementors cannot both depend upon being driven in
+the documented directory-depth-first order and support ra_serf clients.
+Server-side editors that will only be accessed over ra_neon/ra_svn/ra_local,
+or that do not depend upon the depth-first restriction, are not affected.
+
+Editors shipped with Subversion itself are not affected.
+
+It is expected that this issue will be revisited as part of the "Editor v2"
+effort (see issue #3628).

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