How do I get dialyzer to ignore certain unexported functions?

Question

I'm using lager to do my logging; it has a parser transform which converts lager:warn/1, etc. functions into lager:trace... functions.

dialyzer doesn't process the parser transform, so it warns with Call to missing or unexported function lager:warn/1.

How do I tell it that this function does exist, and not to warn about it?

Answer 1

The best way to do it is to have dialyzer look at your compile beam files, as long as the parse transform is applied when the code is compiled and you include lager in your .plt file it will be fine

Answer 2

Stumbled upon a way by checking out what's done in the meck project's Makefile regarding dialyzer. Have a look: Makefile
Key part is this:

| \
    fgrep -v -f ./dialyzer.ignore-warnings

So within that file: dialyzer.ignore-warnings you'll see what to do. In my version I added:

Call to missing or unexported function lager:warning/1
Call to missing or unexported function lager:warning/2
Call to missing or unexported function lager:info/1
Call to missing or unexported function lager:info/2
Call to missing or unexported function lager:error/1
Call to missing or unexported function lager:error/2

And the warnings I was getting went away. I do of course have this entry in my rebar.config:

{erl_opts, [{parse_transform, lager_transform}]}.