lein-figwheel expects files with .js extension inside its source directories to be foreign libraries. And foreign libraries must declare a namespace. In fact, lein-figwheel assumes it, and if it
doesn't find it and can't map the file back to a source .cljs file, it bombs out with a NullPointerException when trying to check for its existance.
This might happen when you put your externs file(s) inside the source directories (this is our case, e.g. https://github.com/magnetcoop/hydrogen-ce/blob/master/src/hyd/client/externs.js)
While lein-figwheel doesn't by default try to process such files on its own, when using Duct server.figwheel it tells lein-figwheel to proccess all files inside the configured source directories (see
https://github.com/duct-framework/server.figwheel/blob/master/src/duct/server/figwheel.clj#L54-L55).
Clearly lein-figwheel should be more robust and handle that situation in a more graceful way[1]. But on the other hand Duct server.figwheel shouldn't be telling lein-figwheel to
process absolutely all files in source directories (but probably just those having .cljs/cljc extension and those declared as foreign libraries).
[1] We have opened a pull request in lein-figwheel regarding this behaviour, see bhauman/lein-figwheel#739
lein-figwheel expects files with .js extension inside its source directories to be foreign libraries. And foreign libraries must declare a namespace. In fact, lein-figwheel assumes it, and if it
doesn't find it and can't map the file back to a source .cljs file, it bombs out with a NullPointerException when trying to check for its existance.
This might happen when you put your externs file(s) inside the source directories (this is our case, e.g. https://github.com/magnetcoop/hydrogen-ce/blob/master/src/hyd/client/externs.js)
While lein-figwheel doesn't by default try to process such files on its own, when using Duct server.figwheel it tells lein-figwheel to proccess all files inside the configured source directories (see
https://github.com/duct-framework/server.figwheel/blob/master/src/duct/server/figwheel.clj#L54-L55).
Clearly lein-figwheel should be more robust and handle that situation in a more graceful way[1]. But on the other hand Duct server.figwheel shouldn't be telling lein-figwheel to
process absolutely all files in source directories (but probably just those having .cljs/cljc extension and those declared as foreign libraries).
[1] We have opened a pull request in lein-figwheel regarding this behaviour, see bhauman/lein-figwheel#739