How to read clojure stack trace?

Question

I tried some clojure tutorial. I copied dependencies part to my project.clj. And I made a mistake. Instead of "1.6.0" version of clojure I put "1.7.0". You can see all 'dependencies' here:

:dependencies [[org.clojure/clojure "1.7.0"]
                 [org.clojure/core.async "0.1.346.0-17112a-alpha"]

                 [compojure "1.3.1"]

                 [ring/ring-core "1.3.2" :exclusions [javax.servlet/servlet-api]]
                 [ring/ring-servlet "1.3.2" :exclusions [javax.servlet/servlet-api]]
                 [ring/ring-defaults "0.1.2" :exclusions [javax.servlet/servlet-api]]

                 [cc.qbits/jet "0.5.4"]]

With this mistake I got this after 'lein run':

Exception in thread "main" clojure.lang.ArityException: Wrong number of args (2) passed to: StringReader, compiling:(abnf.clj:189:28)
    at clojure.lang.Compiler$InvokeExpr.eval(Compiler.java:3628)
    at clojure.lang.Compiler$InvokeExpr.eval(Compiler.java:3622)
    at clojure.lang.Compiler$DefExpr.eval(Compiler.java:439)
    at clojure.lang.Compiler.eval(Compiler.java:6787)
    at clojure.lang.Compiler.load(Compiler.java:7227)
    at clojure.lang.RT.loadResourceScript(RT.java:371)
    at clojure.lang.RT.loadResourceScript(RT.java:362)
    at clojure.lang.RT.load(RT.java:446)
    at clojure.lang.RT.load(RT.java:412)
    at clojure.core$load$fn__5448.invoke(core.clj:5866)
    at clojure.core$load.doInvoke(core.clj:5865)
    at clojure.lang.RestFn.invoke(RestFn.java:408)
    at clojure.core$load_one.invoke(core.clj:5671)
    at clojure.core$load_lib$fn__5397.invoke(core.clj:5711)
    at clojure.core$load_lib.doInvoke(core.clj:5710)
    at clojure.lang.RestFn.applyTo(RestFn.java:142)
    at clojure.core$apply.invoke(core.clj:632)
    at clojure.core$load_libs.doInvoke(core.clj:5749)
    at clojure.lang.RestFn.applyTo(RestFn.java:137)
    at clojure.core$apply.invoke(core.clj:632)
    at clojure.core$require.doInvoke(core.clj:5832)
    at clojure.lang.RestFn.invoke(RestFn.java:805)
    at instaparse.core$eval9510$loading__5340__auto____9511.invoke(core.clj:1)
    at instaparse.core$eval9510.invoke(core.clj:1)
    at clojure.lang.Compiler.eval(Compiler.java:6782)
    at clojure.lang.Compiler.eval(Compiler.java:6771)
    at clojure.lang.Compiler.load(Compiler.java:7227)
    at clojure.lang.RT.loadResourceScript(RT.java:371)
    at clojure.lang.RT.loadResourceScript(RT.java:362)
    at clojure.lang.RT.load(RT.java:446)
    at clojure.lang.RT.load(RT.java:412)
    at clojure.core$load$fn__5448.invoke(core.clj:5866)
    at clojure.core$load.doInvoke(core.clj:5865)
    at clojure.lang.RestFn.invoke(RestFn.java:408)
    at clojure.core$load_one.invoke(core.clj:5671)
    at clojure.core$load_lib$fn__5397.invoke(core.clj:5711)
    at clojure.core$load_lib.doInvoke(core.clj:5710)
    at clojure.lang.RestFn.applyTo(RestFn.java:142)
    at clojure.core$apply.invoke(core.clj:632)
    at clojure.core$load_libs.doInvoke(core.clj:5749)
    at clojure.lang.RestFn.applyTo(RestFn.java:137)
    at clojure.core$apply.invoke(core.clj:632)
    at clojure.core$require.doInvoke(core.clj:5832)
    at clojure.lang.RestFn.invoke(RestFn.java:436)
    at clout.core$eval9504$loading__5340__auto____9505.invoke(core.clj:1)
    at clout.core$eval9504.invoke(core.clj:1)
    at clojure.lang.Compiler.eval(Compiler.java:6782)
    at clojure.lang.Compiler.eval(Compiler.java:6771)
    at clojure.lang.Compiler.load(Compiler.java:7227)
    at clojure.lang.RT.loadResourceScript(RT.java:371)
    at clojure.lang.RT.loadResourceScript(RT.java:362)
    at clojure.lang.RT.load(RT.java:446)
    at clojure.lang.RT.load(RT.java:412)
    at clojure.core$load$fn__5448.invoke(core.clj:5866)
    at clojure.core$load.doInvoke(core.clj:5865)
    at clojure.lang.RestFn.invoke(RestFn.java:408)
    at clojure.core$load_one.invoke(core.clj:5671)
    at clojure.core$load_lib$fn__5397.invoke(core.clj:5711)
    at clojure.core$load_lib.doInvoke(core.clj:5710)
    at clojure.lang.RestFn.applyTo(RestFn.java:142)
    at clojure.core$apply.invoke(core.clj:632)
    at clojure.core$load_libs.doInvoke(core.clj:5749)
    at clojure.lang.RestFn.applyTo(RestFn.java:137)
    at clojure.core$apply.invoke(core.clj:632)
    at clojure.core$require.doInvoke(core.clj:5832)
    at clojure.lang.RestFn.invoke(RestFn.java:482)
    at compojure.core$eval9322$loading__5340__auto____9323.invoke(core.clj:1)
    at compojure.core$eval9322.invoke(core.clj:1)
    at clojure.lang.Compiler.eval(Compiler.java:6782)
    at clojure.lang.Compiler.eval(Compiler.java:6771)
    at clojure.lang.Compiler.load(Compiler.java:7227)
    at clojure.lang.RT.loadResourceScript(RT.java:371)
    at clojure.lang.RT.loadResourceScript(RT.java:362)
    at clojure.lang.RT.load(RT.java:446)
    at clojure.lang.RT.load(RT.java:412)
    at clojure.core$load$fn__5448.invoke(core.clj:5866)
    at clojure.core$load.doInvoke(core.clj:5865)
    at clojure.lang.RestFn.invoke(RestFn.java:408)
    at clojure.core$load_one.invoke(core.clj:5671)
    at clojure.core$load_lib$fn__5397.invoke(core.clj:5711)
    at clojure.core$load_lib.doInvoke(core.clj:5710)
    at clojure.lang.RestFn.applyTo(RestFn.java:142)
    at clojure.core$apply.invoke(core.clj:632)
    at clojure.core$load_libs.doInvoke(core.clj:5749)
    at clojure.lang.RestFn.applyTo(RestFn.java:137)
    at clojure.core$apply.invoke(core.clj:632)
    at clojure.core$require.doInvoke(core.clj:5832)
    at clojure.lang.RestFn.invoke(RestFn.java:512)
    at server.core$eval20$loading__5340__auto____21.invoke(core.clj:1)
    at server.core$eval20.invoke(core.clj:1)
    at clojure.lang.Compiler.eval(Compiler.java:6782)
    at clojure.lang.Compiler.eval(Compiler.java:6771)
    at clojure.lang.Compiler.load(Compiler.java:7227)
    at clojure.lang.RT.loadResourceScript(RT.java:371)
    at clojure.lang.RT.loadResourceScript(RT.java:362)
    at clojure.lang.RT.load(RT.java:446)
    at clojure.lang.RT.load(RT.java:412)
    at clojure.core$load$fn__5448.invoke(core.clj:5866)
    at clojure.core$load.doInvoke(core.clj:5865)
    at clojure.lang.RestFn.invoke(RestFn.java:408)
    at clojure.core$load_one.invoke(core.clj:5671)
    at clojure.core$load_lib$fn__5397.invoke(core.clj:5711)
    at clojure.core$load_lib.doInvoke(core.clj:5710)
    at clojure.lang.RestFn.applyTo(RestFn.java:142)
    at clojure.core$apply.invoke(core.clj:632)
    at clojure.core$load_libs.doInvoke(core.clj:5749)
    at clojure.lang.RestFn.applyTo(RestFn.java:137)
    at clojure.core$apply.invoke(core.clj:632)
    at clojure.core$require.doInvoke(core.clj:5832)
    at clojure.lang.RestFn.invoke(RestFn.java:408)
    at user$eval5$fn__7.invoke(form-init2532813080817058510.clj:1)
    at user$eval5.invoke(form-init2532813080817058510.clj:1)
    at clojure.lang.Compiler.eval(Compiler.java:6782)
    at clojure.lang.Compiler.eval(Compiler.java:6772)
    at clojure.lang.Compiler.load(Compiler.java:7227)
    at clojure.lang.Compiler.loadFile(Compiler.java:7165)
    at clojure.main$load_script.invoke(main.clj:275)
    at clojure.main$init_opt.invoke(main.clj:280)
    at clojure.main$initialize.invoke(main.clj:308)
    at clojure.main$null_opt.invoke(main.clj:343)
    at clojure.main$main.doInvoke(main.clj:421)
    at clojure.lang.RestFn.invoke(RestFn.java:421)
    at clojure.lang.Var.invoke(Var.java:383)
    at clojure.lang.AFn.applyToHelper(AFn.java:156)
    at clojure.lang.Var.applyTo(Var.java:700)
    at clojure.main.main(main.java:37)
Caused by: clojure.lang.ArityException: Wrong number of args (2) passed to: StringReader
    at clojure.lang.AFn.throwArity(AFn.java:429)
    at clojure.lang.AFn.invoke(AFn.java:36)
    at instaparse.cfg$eval10231$safe_read_string__10232.invoke(cfg.clj:163)
    at instaparse.cfg$process_string.invoke(cfg.clj:180)
    at instaparse.cfg$build_rule.invoke(cfg.clj:217)
    at clojure.core$map$fn__4553.invoke(core.clj:2622)
    at clojure.lang.LazySeq.sval(LazySeq.java:40)
    at clojure.lang.LazySeq.seq(LazySeq.java:49)
    at clojure.lang.RT.seq(RT.java:507)
    at clojure.core$seq__4128.invoke(core.clj:137)
    at clojure.core$apply.invoke(core.clj:630)
    at instaparse.cfg$build_rule.invoke(cfg.clj:215)
    at clojure.core$map$fn__4553.invoke(core.clj:2622)
    at clojure.lang.LazySeq.sval(LazySeq.java:40)
    at clojure.lang.LazySeq.seq(LazySeq.java:49)
    at clojure.lang.RT.seq(RT.java:507)
    at clojure.core$seq__4128.invoke(core.clj:137)
    at clojure.core$apply.invoke(core.clj:630)
    at instaparse.cfg$build_rule.invoke(cfg.clj:211)
    at instaparse.cfg$build_rule.invoke(cfg.clj:214)
    at clojure.core$map$fn__4553.invoke(core.clj:2622)
    at clojure.lang.LazySeq.sval(LazySeq.java:40)
    at clojure.lang.LazySeq.seq(LazySeq.java:49)
    at clojure.lang.RT.seq(RT.java:507)
    at clojure.core$seq__4128.invoke(core.clj:137)
    at clojure.core$apply.invoke(core.clj:630)
    at instaparse.cfg$build_rule.invoke(cfg.clj:215)
    at clojure.core$map$fn__4553.invoke(core.clj:2622)
    at clojure.lang.LazySeq.sval(LazySeq.java:40)
    at clojure.lang.LazySeq.seq(LazySeq.java:49)
    at clojure.lang.RT.seq(RT.java:507)
    at clojure.core$seq__4128.invoke(core.clj:137)
    at clojure.core$apply.invoke(core.clj:630)
    at instaparse.cfg$build_rule.invoke(cfg.clj:211)
    at instaparse.cfg$build_rule.invoke(cfg.clj:207)
    at clojure.core$map$fn__4553.invoke(core.clj:2622)
    at clojure.lang.LazySeq.sval(LazySeq.java:40)
    at clojure.lang.LazySeq.seq(LazySeq.java:49)
    at clojure.lang.RT.seq(RT.java:507)
    at clojure.core$seq__4128.invoke(core.clj:137)
    at clojure.core.protocols$seq_reduce.invoke(protocols.clj:30)
    at clojure.core.protocols$fn__6506.invoke(protocols.clj:101)
    at clojure.core.protocols$fn__6452$G__6447__6465.invoke(protocols.clj:13)
    at clojure.core$reduce.invoke(core.clj:6519)
    at clojure.core$into.invoke(core.clj:6600)
    at instaparse.cfg$ebnf.invoke(cfg.clj:277)
    at clojure.lang.AFn.applyToHelper(AFn.java:154)
    at clojure.lang.AFn.applyTo(AFn.java:144)
    at clojure.lang.Compiler$InvokeExpr.eval(Compiler.java:3623)
    ... 125 more

So It took some time to realize that I have wrong clojure version. And for this mistake was absolutly not clear from stack trace that I got.

Does anybody can help explain me what does this stack traces actually tells? How I should understand that clojure version is not good? BTW Why it is not good version?

Cynthea

Answer 1

That stacktrace is unfortunate. It doesn't help much in understanding what's happening. The most we can say without digging too deep is "something is wrong while compiling instaparse". You don't have to know what instaparse is, but it's used by compojure.

The thing is: the clojure version is not wrong. It's just that compojure 1.3.1 is not compatible with clojure 1.7.0. Clojure 1.7.0 is the last stable version. You can use 1.6.0 or 1.7.0. It's just that if you are going to use clojure 1.7.0, then the compojure version is wrong (of course you didn't have to know that). Try with [compojure "1.3.4"] on clojure 1.7.0, everything should be fine.

From Clojure Stack Traces for the Uninitiated I'll take some guidance when facing with a clojure stacktrace:

1. Find the ultimate cause: Find the last line that starts with "Caused by". That's where the exception originated.
2. Look for your namespace (and I'll add, if there's any, look for a namespace different than "clojure"): In this case, it will make us to say "oh, something is wrong with instaparse!".
3. Break out your decoder ring (or find the $ sign): Here we have a bit of knowledge on how clojure compiles our code. One important thing to know is that every function is compiled into a separate class, and many times we can identify the function by what's following the $ sign. In this case, from instaparse.cfg$process_string.invoke(cfg.clj:180) we can assume the issue is in the line 180 of cfg.clj in instaparse, where the process_string* function is defined.

* most probably it's process-string because of name munging, but that's another story.

Carton