Exception when using Ctrl-D in interactive mode

[weavejester]

Expected behavior

Entering Ctrl-D in an interactive nREPL session makes it immediately exit.

Actual behavior

Entering Ctrl-D throws an exception and hangs the process.

Steps to reproduce the problem

$ clj -Sdeps '{:deps {nrepl {:mvn/version "0.4.5"}}}' -m nrepl.cmdline --interactive
nREPL server started on port 54732 on host 0:0:0:0:0:0:0:0 - nrepl://0:0:0:0:0:0:0:0:54732
nREPL 0.4.5
Clojure 1.9.0
Java HotSpot(TM) 64-Bit Server VM 10.0.2+13
user=> ^D
Exception in thread "main" clojure.lang.LispReader$ReaderException: java.lang.RuntimeException: EOF while reading
	at clojure.lang.LispReader.read(LispReader.java:304)
	at clojure.lang.LispReader.read(LispReader.java:206)
	at clojure.lang.LispReader.read(LispReader.java:200)
	at clojure.core$read.invokeStatic(core.clj:3758)
	at clojure.core$read.invokeStatic(core.clj:3733)
	at clojure.core$read.invokeStatic(core.clj:3733)
	at clojure.core$read.invokeStatic(core.clj:3733)
	at clojure.core$read.invoke(core.clj:3733)
	at nrepl.cmdline$run_repl.invokeStatic(cmdline.clj:42)
	at nrepl.cmdline$run_repl.invoke(cmdline.clj:24)
	at nrepl.cmdline$_main.invokeStatic(cmdline.clj:179)
	at nrepl.cmdline$_main.doInvoke(cmdline.clj:138)
	at clojure.lang.RestFn.applyTo(RestFn.java:137)
	at clojure.lang.Var.applyTo(Var.java:702)
	at clojure.core$apply.invokeStatic(core.clj:657)
	at clojure.main$main_opt.invokeStatic(main.clj:317)
	at clojure.main$main_opt.invoke(main.clj:313)
	at clojure.main$main.invokeStatic(main.clj:424)
	at clojure.main$main.doInvoke(main.clj:387)
	at clojure.lang.RestFn.applyTo(RestFn.java:137)
	at clojure.lang.Var.applyTo(Var.java:702)
	at clojure.main.main(main.java:37)
Caused by: java.lang.RuntimeException: EOF while reading
	at clojure.lang.Util.runtimeException(Util.java:221)
	at clojure.lang.LispReader.read(LispReader.java:258)
	... 21 more

[bbatsov]

Yeah, we should fix this.

[mallt]

Changing the cmdline message from

{:op "eval" :code (pr-str (read))}

to

{:op "eval"
 :code (-> (read *in* false (read-string "(System/exit 0)"))
            pr-str)}

seems to do the trick by using the eof-error? and eof-value arguments of the read function.

Would this be an acceptable fix?

[bbatsov]

That seems reasonable. Probably I'd move the read outside of the doseq. You can also check how reply is handing Control+d.

Might be a good idea to also add some special handling of (exit) (as reply does).