reftable: clarify how empty tables should be written

hanwen · gitster · commit 10f007c37031 · 2020-06-09T13:48:36.000-07:00
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 &lt;hanwen@google.com&gt;
Signed-off-by: Junio C Hamano &lt;gitster@pobox.com&gt;
diff --git 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
 ^^^^^^^^^^^^^
 
