Unbalanced parens cause NullPointerException

[yayitswei]

Sometimes unbalanced parens cause the "lein-cljsbuild auto" process to crash with an NPE, and I have to restart the process.

(on $body :click :#a nil
    (fn [e]
      (log "test";;)
      )
    )

yields

wei:papyrus wei$ lein cljsbuild auto main-prod template-prod
Compiling ClojureScript.
Compiling "../app/assets/javascripts/bin/template.js" from ["src/cljs-template"]...
* Notification delivered.
Compiling "../app/assets/javascripts/bin/template.js" failed.
Exception in thread "main" java.lang.NullPointerException
    at java.util.regex.Matcher.getTextLength(Matcher.java:1140)
    at java.util.regex.Matcher.reset(Matcher.java:291)
    at java.util.regex.Matcher.<init>(Matcher.java:211)
    at java.util.regex.Pattern.matcher(Pattern.java:888)
    at clj_stacktrace.utils$re_gsub.invoke(utils.clj:6)
    at clj_stacktrace.core$clojure_ns.invoke(core.clj:14)
    at clj_stacktrace.core$parse_trace_elem.invoke(core.clj:68)
    at clojure.core$map$fn__4087.invoke(core.clj:2434)
    at clojure.lang.LazySeq.sval(LazySeq.java:42)
    at clojure.lang.LazySeq.seq(LazySeq.java:60)
    at clojure.lang.Cons.next(Cons.java:39)
    at clojure.lang.RT.next(RT.java:587)
    at clojure.core$next.invoke(core.clj:64)
    at clojure.core$reduce1.invoke(core.clj:880)
    at clojure.core$reverse.invoke(core.clj:888)

[emezeske]

Hmm, lein-cljsbuild definitely catches all compiler errors, so those shouldn't cause the auto process to stop. I guess what's happening here (from the stack trace) is that clj-stacktrace (which lein-cljsbuild uses to pretty-print stack traces, with color, etc) is crashing when lein-cljsbuild tries to print the unmatched-parens exception. Bleh!

I checked to see if clj-stacktrace has a newer version out, but the latest that I see is 0.2.5, which is what lein-cljsbuild depends on right now.

I don't see any open bug reports for clj-stacktrace that seem related to this problem. Maybe you could open one?

If I have some time later this week, I can get the exact contents of the exception that clj-stacktrace is crashing while trying to print, which might be helpful to debug clj-stacktrace.

[yayitswei]

Thanks for the quick response and good catch.