Clojure exceptions are really just Java exceptions under the hood. However, at times clojure shows them formatted as a map
data structure. For instance, that's what you get if you inspect them in the REBL. This is because clojure implements the Datafy protocol for Throwable
objects, delegating to clojure.core/Throwable->map.
This gist is a reminder of how to interpret that data assuming familiary with Java printed stack traces.
| {:cause ; <- Exception message form the root (innermost) exception in the exception chain | |
| "rootcause" | |
| :data ; <- ex-data from the root (innermost) exception in the exception chain | |
| {:data-from :a} | |
| :trace ; <- stack trace of the root (innermost) exception in the exceptions chain | |
| [[playground$a invokeStatic "playground.clj" 99] ; <- stack-frame that threw the exception is the first (topmost) | |
| [playground$a invoke "playground.clj" 22] | |
| [playground$b invokeStatic "NO_SOURCE_FILE" 102] | |
| [playground$b invoke "NO_SOURCE_FILE" 101] | |
| [playground$bar invokeStatic "NO_SOURCE_FILE" 105] | |
| [playground$bar invoke "NO_SOURCE_FILE" 104] | |
| [playground$foo invokeStatic "NO_SOURCE_FILE" 109] | |
| [playground$foo invoke "NO_SOURCE_FILE" 108] | |
| [playground$fn__24983 invokeStatic "playground.clj" 112] | |
| [playground$fn__24983 invoke "playground.clj" 112] | |
| [clojure.lang.AFn applyToHelper "AFn.java" 152] | |
| [clojure.lang.AFn applyTo "AFn.java" 144] | |
| [clojure.lang.Compiler$InvokeExpr eval "Compiler.java" 3702] | |
| [clojure.lang.Compiler$DefExpr eval "Compiler.java" 457] | |
| [clojure.lang.Compiler eval "Compiler.java" 7182] | |
| [clojure.lang.Compiler eval "Compiler.java" 7132] | |
| [clojure.core$eval invokeStatic "core.clj" 3214] | |
| [clojure.core.server$prepl$fn__8941 invoke "server.clj" 232] | |
| [clojure.core.server$prepl invokeStatic "server.clj" 228] | |
| [clojure.core.server$prepl doInvoke "server.clj" 191] | |
| [clojure.lang.RestFn invoke "RestFn.java" 425] | |
| [cognitect.rebl$repl invokeStatic "rebl.clj" 122] | |
| [cognitect.rebl$repl invoke "rebl.clj" 96] | |
| [cognitect.rebl$_main invokeStatic "rebl.clj" 125] | |
| [cognitect.rebl$_main invoke "rebl.clj" 124] | |
| [clojure.lang.AFn applyToHelper "AFn.java" 152] | |
| [clojure.lang.AFn applyTo "AFn.java" 144] | |
| [clojure.lang.Var applyTo "Var.java" 705] | |
| [clojure.core$apply invokeStatic "core.clj" 665] | |
| [clojure.main$main_opt invokeStatic "main.clj" 514] | |
| [clojure.main$main_opt invoke "main.clj" 510] | |
| [clojure.main$main invokeStatic "main.clj" 664] | |
| [clojure.main$main doInvoke "main.clj" 616] | |
| [clojure.lang.RestFn applyTo "RestFn.java" 137] | |
| [clojure.lang.Var applyTo "Var.java" 705] | |
| [clojure.main main "main.java" 40]] ; <- stack-frame of the beggining of the thread call stack is the last (bottom) | |
| :via ; <- for each exception in the chain: | |
| [{:type clojure.lang.ExceptionInfo, ; <- It's class | |
| :message "wrapping", ; <- It's message | |
| :data {:data-from :bar}, ; <- It's ex-data | |
| :at [playground$bar invokeStatic "NO_SOURCE_FILE" 106]} ; <- Stack frame that threw the exception (i.e. the topmost stack frame) | |
| {:type clojure.lang.ExceptionInfo, | |
| :message "rootcause", | |
| :data {:data-from :a}, | |
| :at [playground$a invokeStatic "playground.clj" 99]}] | |
| } |
| clojure.lang.ExceptionInfo: wrapping {:data-from :bar} | |
| at playground$bar.invokeStatic(NO_SOURCE_FILE:106) | |
| at playground$bar.invoke(NO_SOURCE_FILE:104) | |
| at playground$foo.invokeStatic(NO_SOURCE_FILE:109) | |
| at playground$foo.invoke(NO_SOURCE_FILE:108) | |
| at playground$fn__24983.invokeStatic(playground.clj:112) | |
| at playground$fn__24983.invoke(playground.clj:112) | |
| at clojure.lang.AFn.applyToHelper(AFn.java:152) | |
| at clojure.lang.AFn.applyTo(AFn.java:144) | |
| at clojure.lang.Compiler$InvokeExpr.eval(Compiler.java:3702) | |
| at clojure.lang.Compiler$DefExpr.eval(Compiler.java:457) | |
| at clojure.lang.Compiler.eval(Compiler.java:7182) | |
| at clojure.lang.Compiler.eval(Compiler.java:7132) | |
| at clojure.core$eval.invokeStatic(core.clj:3214) | |
| at clojure.core.server$prepl$fn__8941.invoke(server.clj:232) | |
| at clojure.core.server$prepl.invokeStatic(server.clj:228) | |
| at clojure.core.server$prepl.doInvoke(server.clj:191) | |
| at clojure.lang.RestFn.invoke(RestFn.java:425) | |
| at cognitect.rebl$repl.invokeStatic(rebl.clj:122) | |
| at cognitect.rebl$repl.invoke(rebl.clj:96) | |
| at cognitect.rebl$_main.invokeStatic(rebl.clj:125) | |
| at cognitect.rebl$_main.invoke(rebl.clj:124) | |
| at clojure.lang.AFn.applyToHelper(AFn.java:152) | |
| at clojure.lang.AFn.applyTo(AFn.java:144) | |
| at clojure.lang.Var.applyTo(Var.java:705) | |
| at clojure.core$apply.invokeStatic(core.clj:665) | |
| at clojure.main$main_opt.invokeStatic(main.clj:514) | |
| at clojure.main$main_opt.invoke(main.clj:510) | |
| at clojure.main$main.invokeStatic(main.clj:664) | |
| at clojure.main$main.doInvoke(main.clj:616) | |
| at clojure.lang.RestFn.applyTo(RestFn.java:137) | |
| at clojure.lang.Var.applyTo(Var.java:705) | |
| at clojure.main.main(main.java:40) | |
| Caused by: clojure.lang.ExceptionInfo: rootcause {:data-from :a} | |
| at playground$a.invokeStatic(playground.clj:99) | |
| at playground$a.invoke(playground.clj:22) | |
| at playground$b.invokeStatic(NO_SOURCE_FILE:102) | |
| at playground$b.invoke(NO_SOURCE_FILE:101) | |
| at playground$bar.invokeStatic(NO_SOURCE_FILE:105) | |
| ... 31 more |
| (defn a [] | |
| (throw (ex-info "rootcause" {:data-from :a}))) | |
| (defn b [] | |
| (a)) | |
| (defn bar [] | |
| (try (b) | |
| (catch Exception b (throw (ex-info "wrapping" {:data-from :bar} b))))) | |
| (defn foo [] | |
| (bar)) | |
| (def e (try (foo) (catch Exception e e))) |