Add fdb_to_revinfo compatibility with 5-tuple Val

Currently, a 5-tuple `Val` parameter crashes fdb_to_revinfo with a
function_clause error.

This adds a compatible function clause, and also a catchall clause to
log an error and throw an informative exception.

2 files changed, 62 insertions, 1 deletions

diff --git a/src/fabric/src/fabric2_fdb.erl b/src/fabric/src/fabric2_fdb.erl
index e51b8de5d..c18122533 100644
--- a/src/fabric/src/fabric2_fdb.erl
+++ b/src/fabric/src/fabric2_fdb.erl
@@ -38,6 +38,8 @@
     incr_stat/3,
     incr_stat/4,
 
+    fdb_to_revinfo/2,
+
     get_all_revs/2,
     get_winning_revs/3,
     get_winning_revs_future/3,
@@ -1253,6 +1255,21 @@ fdb_to_revinfo(Key, {?CURR_REV_FORMAT, _, _, _, _, _} = Val) ->
         rev_size => RevSize
     };
 
+fdb_to_revinfo(Key, {?CURR_REV_FORMAT, _, _, _, _} = Val) ->
+    {?DB_REVS, _DocId, NotDeleted, RevPos, Rev} = Key,
+    {_RevFormat, Sequence, RevSize, RevPath, AttHash} = Val,
+    #{
+        winner => true,
+        exists => true,
+        deleted => not NotDeleted,
+        rev_id => {RevPos, Rev},
+        rev_path => tuple_to_list(RevPath),
+        sequence => Sequence,
+        branch_count => undefined,
+        att_hash => AttHash,
+        rev_size => RevSize
+    };
+
 fdb_to_revinfo(Key, {?CURR_REV_FORMAT, _, _, _} = Val)  ->
     {?DB_REVS, _DocId, NotDeleted, RevPos, Rev} = Key,
     {_RevFormat, RevPath, AttHash, RevSize} = Val,
@@ -1282,7 +1299,14 @@ fdb_to_revinfo(Key, {1, Seq, BCount, RPath, AttHash}) ->
 
 fdb_to_revinfo(Key, {1, RPath, AttHash}) ->
     Val = {?CURR_REV_FORMAT, RPath, AttHash, 0},
-    fdb_to_revinfo(Key, Val).
+    fdb_to_revinfo(Key, Val);
+
+fdb_to_revinfo(Key, Val) ->
+    couch_log:error(
+        "~p:fdb_to_revinfo unsupported val format "
+        "rev_format=~p key_size=~p val_size=~p",
+        [?MODULE, element(1, Val), tuple_size(Key), tuple_size(Val)]),
+    throw({unsupported_data_format, fdb_to_revinfo_val}).
 
 
 doc_to_fdb(Db, #doc{} = Doc) ->
diff --git a/src/fabric/test/fabric2_db_misc_tests.erl b/src/fabric/test/fabric2_db_misc_tests.erl
index 42a63e2f9..7c88b4ac4 100644
--- a/src/fabric/test/fabric2_db_misc_tests.erl
+++ b/src/fabric/test/fabric2_db_misc_tests.erl
@@ -333,3 +333,40 @@ db_version_bump({DbName, _, _}) ->
 
     % Check that db handle in the cache got the new metadata version
     ?assertMatch(#{db_version := NewDbVersion}, Db2).
+
+
+fdb_to_revinfo_test_() ->
+    {
+        "Test fdb_to_revinfo compatibility",
+        {
+            setup,
+            fun() -> ok end,
+            fun(_) -> ok end,
+            with([
+                ?TDEF(fdb_to_revinfo)
+            ])
+        }
+    }.
+
+
+fdb_to_revinfo(_) ->
+    Sequence = {versionstamp, 10873034897377, 0, 0},
+    Rev = <<60,84,174,140,210,120,192,18,100,148,9,181,129,165,248,92>>,
+    Key = {20, <<"d491280e-feab-42ce-909e-a7287d7b078-bluemix">>, true, 1, Rev},
+    FiveTupleVal = {2, Sequence, 1, {}, <<>>},
+    Expect = #{
+        att_hash => <<>>,
+        branch_count => undefined,
+        deleted => false,
+        exists => true,
+        rev_id =>
+            {1, <<60,84,174,140,210,120,192,18,100,148,9,181,129,165,248,92>>},
+        rev_path => [],
+        rev_size => 1,
+        sequence => Sequence,
+        winner => true
+    },
+    ?assertEqual(Expect, fabric2_fdb:fdb_to_revinfo(Key, FiveTupleVal)),
+    ?assertThrow({unsupported_data_format, fdb_to_revinfo_val},
+        fabric2_fdb:fdb_to_revinfo({bad}, {input})),
+    ok.