diff options
Diffstat (limited to 'lib/stdlib')
| -rw-r--r-- | lib/stdlib/doc/src/gen_statem.xml | 18 | ||||
| -rw-r--r-- | lib/stdlib/src/gen_statem.erl | 13 |
2 files changed, 20 insertions, 11 deletions
diff --git a/lib/stdlib/doc/src/gen_statem.xml b/lib/stdlib/doc/src/gen_statem.xml index c57a31fa21..ed44eef912 100644 --- a/lib/stdlib/doc/src/gen_statem.xml +++ b/lib/stdlib/doc/src/gen_statem.xml @@ -1262,9 +1262,9 @@ handle_event(_, _, State, Data) -> <v> Vsn = term()</v> <v>OldState = NewState = term()</v> <v>Extra = term()</v> - <v>Result = {NewCallbackMode,NewState,NewData} | Reason</v> + <v>Result = {CallbackMode,NewState,NewData} | Reason</v> <v> - NewCallbackMode = + CallbackMode = <seealso marker="#type-callback_mode">callback_mode()</seealso> </v> <v> @@ -1321,11 +1321,19 @@ handle_event(_, _, State, Data) -> <p> If successful, the function must return the updated internal state in an - <c>{NewCallbackMode,NewState,NewData}</c> tuple. + <c>{CallbackMode,NewState,NewData}</c> tuple. </p> <p> - If the function returns <c>Reason</c>, the ongoing - upgrade fails and rolls back to the old release.</p> + If the function returns a failure <c>Reason</c>, the ongoing + upgrade fails and rolls back to the old release. + Note that <c>Reason</c> can not be a 3-tuple since that + will be regarded as a + <c>{CallbackMode,NewState,NewData}</c> tuple, + and that a tuple matching <c>{ok,_}</c> + is an invalid failure <c>Reason</c>. + It is recommended to use an atom as <c>Reason</c> since + it will be wrapped in an <c>{error,Reason}</c> tuple. + </p> <p> This function can use <seealso marker="erts:erlang#throw/1"><c>erlang:throw/1</c></seealso> diff --git a/lib/stdlib/src/gen_statem.erl b/lib/stdlib/src/gen_statem.erl index 23bddafeed..c02e6a1a19 100644 --- a/lib/stdlib/src/gen_statem.erl +++ b/lib/stdlib/src/gen_statem.erl @@ -219,9 +219,10 @@ OldState :: state(), OldData :: data(), Extra :: term()) -> - {NewCallbackMode :: callback_mode(), + {CallbackMode :: callback_mode(), NewState :: state(), - NewData :: data()}. + NewData :: data()} | + (Reason :: term()). %% Format the callback module state in some sensible that is %% often condensed way. For StatusOption =:= 'normal' the perferred @@ -630,11 +631,11 @@ system_code_change( Result -> Result end of - {NewCallbackMode,NewState,NewData} -> - callback_mode(NewCallbackMode) orelse - error({callback_mode,NewCallbackMode}), + {CallbackMode,NewState,NewData} -> + callback_mode(CallbackMode) orelse + error({callback_mode,CallbackMode}), {ok, - S#{callback_mode := NewCallbackMode, + S#{callback_mode := CallbackMode, state := NewState, data := NewData}}; {ok,_} = Error -> |