Fix broken pre-17.4 appup

Upgrade instructions have been added for each 17.X release without
adjusting the instructions for preceeding releases: the instructions
have only been sufficient to upgrading one release at a time: 17.0 to
17.1, 17.1 to 17.2, etc.

Conficting load order requirements make smooth upgrade from an
arbitrarily old release impossible. In this case, 17.3 looks to be as
far back as we can go, so require restart from 17.[0-2] or older.

Update the app suite to deal with binary regexps in appup, and to match
version numbers harder.

1 files changed, 37 insertions, 14 deletions

diff --git a/lib/diameter/test/diameter_app_SUITE.erl b/lib/diameter/test/diameter_app_SUITE.erl
index 6975e83830..84f8a66a8a 100644
--- a/lib/diameter/test/diameter_app_SUITE.erl
+++ b/lib/diameter/test/diameter_app_SUITE.erl
@@ -249,11 +249,10 @@ release() ->
     end.
 
 unversion(App) ->
-    T = lists:dropwhile(fun is_vsn_ch/1, lists:reverse(App)),
-    lists:reverse(case T of [$-|TT] -> TT; _ -> T end).
-
-is_vsn_ch(C) ->
-    $0 =< C andalso C =< $9 orelse $. == C.
+    {Name, [$-|Vsn]} = lists:splitwith(fun(C) -> C /= $- end, App),
+    true = is_app(Name), %% assert
+    Vsn = vsn_str(Vsn),  %%
+    Name.
 
 app('$M_EXPR') -> %% could be anything but assume it's ok
     "erts";
@@ -322,11 +321,11 @@ acc_rel(Dir, Rel, {Vsn, _}, Acc) ->
 
 %% Write a rel file and return its name.
 write_rel(Dir, [Erts | Apps], Vsn) ->
-    true = is_vsn(Vsn),
-    Name = "diameter_test_" ++ Vsn,
+    VS = vsn_str(Vsn),
+    Name = "diameter_test_" ++ VS,
     ok = write_file(filename:join([Dir, Name ++ ".rel"]),
                     {release,
-                     {"diameter " ++ Vsn ++ " test release", Vsn},
+                     {"diameter " ++ VS ++ " test release", VS},
                      Erts,
                      Apps}),
     Name.
@@ -341,10 +340,34 @@ fetch(Key, List) ->
 write_file(Path, T) ->
     file:write_file(Path, io_lib:format("~p.", [T])).
 
-%% Is a version string of the expected form? Return the argument
-%% itself for 'false' for a useful badmatch.
+%% Is a version string of the expected form?
 is_vsn(V) ->
-    is_list(V)
-        andalso length(V) == string:span(V, "0123456789.")
-        andalso V == string:join(string:tokens(V, [$.]), ".")  %% no ".."
-        orelse {error, V}.
+    V = vsn_str(V),
+    true.
+
+%% Turn a from/to version in appup to a version string after ensuring
+%% that it's valid version number of regexp. In the regexp case, the
+%% regexp itself becomes the version string since there's no
+%% requirement that a version in appup be anything but a string. The
+%% restrictions placed on string-valued version numbers (that they be
+%% '.'-separated integers) are our own.
+
+vsn_str(S)
+  when is_list(S) ->
+    {_, match}   = {S, match(S, "^(0|[1-9][0-9]*)(\\.(0|[1-9][0-9]*))*$")},
+    {_, nomatch} = {S, match(S, "\\.0\\.0$")},
+    S;
+
+vsn_str(B)
+  when is_binary(B) ->
+    {ok, _} = re:compile(B),
+    binary_to_list(B).
+
+match(S, RE) ->
+    re:run(S, RE, [{capture, none}]).
+
+%% Is an application name of the expected form?
+is_app(S)
+  when is_list(S) ->
+    {_, match} = {S, match(S, "^([a-z]([a-z_]*|[a-zA-Z]*))$")},
+    true.