reftable: clarify how empty tables should be written

The format allows for some ambiguity, as a lone footer also starts
with a valid file header. However, the current JGit code will barf on
this. This commit codifies this behavior into the standard.

Signed-off-by: Han-Wen Nienhuys <hanwen@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Documentation/technical/reftable.txt b/Documentation/technical/reftable.txt
index d652f42cbbfee3c555863f420ba234f41b2c3aee..103f65b061f4cd0c4c30a3cbb649f1e3cf48b772 100644 (file)
--- a/Documentation/technical/reftable.txt
+++ b/Documentation/technical/reftable.txt
@@ -733,6 +733,12 @@ version)
 
 Once verified, the other fields of the footer can be accessed.
 
+Empty tables
+++++++++++++
+
+A reftable may be empty. In this case, the file starts with a header
+and is immediately followed by a footer.
+
 Binary search
 ^^^^^^^^^^^^^