svn commit: r1654937 - /subversion/trunk/subversion/libsvn_fs_fs/structure

[st...@apache.org]

Author: stefan2
Date: Tue Jan 27 01:49:12 2015
New Revision: 1654937

URL: http://svn.apache.org/r1654937
Log:
Update the FSFS structure description.  No functional change.

* subversion/libsvn_fs_fs/structure
  (Revision file format): Document that older releases don't implement the
                          full spec and be explicit about the limitations.

Modified:
    subversion/trunk/subversion/libsvn_fs_fs/structure

Modified: subversion/trunk/subversion/libsvn_fs_fs/structure
URL: http://svn.apache.org/viewvc/subversion/trunk/subversion/libsvn_fs_fs/structure?rev=1654937&r1=1654936&r2=1654937&view=diff
==============================================================================
--- subversion/trunk/subversion/libsvn_fs_fs/structure (original)
+++ subversion/trunk/subversion/libsvn_fs_fs/structure Tue Jan 27 01:49:12 2015
@@ -560,8 +560,7 @@ defined:
   props     "<rev> <item_index> <length> <size> <digest>" for props rep
             <rev> and <item_index> give location of rep
             <length> gives length of rep, sans header and trailer
-            <size> gives size of expanded rep; for props only, it may be 0
-             if equal to the length
+            <size> gives size of expanded rep (*)
             <digest> gives hex MD5 digest of expanded rep
             ### in formats >=4, also present:
             <sha1-digest> gives hex SHA1 digest of expanded rep
@@ -573,6 +572,15 @@ defined:
              which have svn:mergeinfo.
   minfo-here Exists if this node itself has svn:mergeinfo.
 
+(*) Earlier versions of this document would state that <size> may be 0
+    if the actual value matches <length>.  This is only true for property
+    and directory representations and should be avoided in general.  File
+    representations may not be handled correctly by SVN before 1.7.20,
+    1.8.12 and 1.9.0, if they have 0 <size> fields for non-empty contents.
+    Releases 1.8.0 through 1.8.11 may have falsely created instances of
+    that (see issue #4554).  Finally, 0 <size> fields are NEVER legal for
+    DELTA representations.
+
 The predecessor of a node-rev crosses both soft and true copies;
 together with the count field, it allows efficient determination of
 the base for skip-deltas.  The first node-rev of a node contains no