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[CLJ-1261] Invalid defrecord results in exception attributed to namespace that imports namespace with defrecord Created: 12/Sep/13  Updated: 29/Aug/14  Resolved: 29/Aug/14

Status: Closed
Project: Clojure
Component/s: None
Affects Version/s: Release 1.5
Fix Version/s: Release 1.7

Type: Defect Priority: Minor
Reporter: Howard Lewis Ship Assignee: Unassigned
Resolution: Completed Votes: 0
Labels: defrecord, errormsgs

Attachments: File clj-1261-2.diff     File clj-1261-3.diff     File clj-1261-4.diff     File clj-1261-5.diff    
Patch: Code and Test
Approval: Ok

 Description   

I was introducing a namespace that included a defrecord.

My defrecord was wrong; it used a keyword to define a field, not a symbol. Minimal test case:

% cat src/useclj16/init.clj
(ns useclj16.init)

(defrecord Application [:shutdown-fn])
% cat src/useclj16/app.clj 
(ns useclj16.app
  (:require [useclj16.init :as init]))

However, the exception was perplexing:

% java -cp clojure-1.6.0-master-SNAPSHOT.jar:src clojure.main
user=> (require 'useclj16.app)
ClassCastException clojure.lang.Keyword cannot be cast to clojure.lang.IObj  clojure.core/with-meta (core.clj:214)

user=> (pst *e 100)
ClassCastException clojure.lang.Keyword cannot be cast to clojure.lang.IObj
        clojure.core/with-meta (core.clj:214)
        clojure.core/defrecord/fn--147 (core_deftype.clj:362)
        clojure.core/map/fn--4210 (core.clj:2494)
        clojure.lang.LazySeq.sval (LazySeq.java:42)
        clojure.lang.LazySeq.seq (LazySeq.java:60)
        clojure.lang.RT.seq (RT.java:484)
        clojure.lang.LazilyPersistentVector.create (LazilyPersistentVector.java:31)
        clojure.core/vec (core.clj:354)
        clojure.core/defrecord (core_deftype.clj:362)
        clojure.lang.Var.invoke (Var.java:427)
        clojure.lang.Var.applyTo (Var.java:532)
        clojure.lang.Compiler.macroexpand1 (Compiler.java:6483)
        clojure.lang.Compiler.macroexpand (Compiler.java:6544)
        clojure.lang.Compiler.eval (Compiler.java:6618)
        clojure.lang.Compiler.load (Compiler.java:7079)
        clojure.lang.RT.loadResourceScript (RT.java:370)
        clojure.lang.RT.loadResourceScript (RT.java:361)
        clojure.lang.RT.load (RT.java:440)
        clojure.lang.RT.load (RT.java:411)
        clojure.core/load/fn--5024 (core.clj:5546)
        clojure.core/load (core.clj:5545)
        clojure.core/load-one (core.clj:5352)
        clojure.core/load-lib/fn--4973 (core.clj:5391)
        clojure.core/load-lib (core.clj:5390)
        clojure.core/apply (core.clj:619)
        clojure.core/load-libs (core.clj:5429)
        clojure.core/apply (core.clj:619)
        clojure.core/require (core.clj:5512)
        useclj16.app/eval322/loading--4916--auto----323 (app.clj:1)
        useclj16.app/eval322 (app.clj:1)
        clojure.lang.Compiler.eval (Compiler.java:6634)
        clojure.lang.Compiler.eval (Compiler.java:6623)
        clojure.lang.Compiler.load (Compiler.java:7079)
        clojure.lang.RT.loadResourceScript (RT.java:370)
        clojure.lang.RT.loadResourceScript (RT.java:361)
        clojure.lang.RT.load (RT.java:440)
        clojure.lang.RT.load (RT.java:411)
        clojure.core/load/fn--5024 (core.clj:5546)
        clojure.core/load (core.clj:5545)
        clojure.core/load-one (core.clj:5352)
        clojure.core/load-lib/fn--4973 (core.clj:5391)
        clojure.core/load-lib (core.clj:5390)
        clojure.core/apply (core.clj:619)
        clojure.core/load-libs (core.clj:5429)
        clojure.core/apply (core.clj:619)
        clojure.core/require (core.clj:5512)
        user/eval318 (NO_SOURCE_FILE:1)
        clojure.lang.Compiler.eval (Compiler.java:6634)
        clojure.lang.Compiler.eval (Compiler.java:6597)
        clojure.core/eval (core.clj:2864)
        clojure.main/repl/read-eval-print--6594/fn--6597 (main.clj:260)
        clojure.main/repl/read-eval-print--6594 (main.clj:260)
        clojure.main/repl/fn--6603 (main.clj:278)
        clojure.main/repl (main.clj:278)
        clojure.main/repl-opt (main.clj:344)
        clojure.main/main (main.clj:442)
        clojure.lang.Var.invoke (Var.java:411)
        clojure.lang.Var.applyTo (Var.java:532)
        clojure.main.main (main.java:37)
nil

The error was attributed to app.clj (useclj16.app), a namespace which requires useclj16.init, the namespace containing the defrecord.

No indication that this concerned a defrecord, or even what namespace contained the error, was present in the exception.

Patch: clj-1261-5.diff

Approach: Check explicitly that the fields are all symbols, for both defrecord and deftype, and throw a CompilerException with file, line, and column number if not. Example of exception after patch is applied, in the case give above:

user=> (require 'useclj16.app)
CompilerException java.lang.AssertionError: defrecord and deftype fields must be symbols, useclj16.init.Application had: :shutdown-fn, compiling:(useclj16/init.clj:3:1)

Screened by: Alex Miller



 Comments   
Comment by Alex Miller [ 12/Sep/13 8:58 PM ]

Can you include an example of the defrecord definition just so we're clear what it looks like?

Comment by Alex Miller [ 12/Sep/13 8:59 PM ]

Also, "feedback" is not a useful label. Please use "errormsgs" for stuff like this. See the list of many commonly used labels here: http://dev.clojure.org/display/community/Creating+Tickets

Comment by Howard Lewis Ship [ 13/Sep/13 10:42 AM ]

"Feedback" is my own personal crusade http://tapestryjava.blogspot.com/2013/05/once-more-feedback-please.html

In my case, my invalid code was:

(defrecord Application [:shutdown-fn])

And the mistake was that :shutdown-fn should be a symbol, not a keyword.

Here it is, more completely:

(ns novate.services.initialization
  "Infrastructure for system-as-transient state.")

(defrecord Application [:shutdown-fn])

and

(ns novate.services.activator
  "Responsible for bootstrapping the application by loading certain namespaces and invoking certain functions, guided by data in JAR manifests."
  (:gen-class)
  (:require [clojure.edn :as edn]
            [clojure.java.io :as io]
            [novate.util.logging :as l]
            [novate.services
             [initialization :as init]
             [ordering :as o]])
  (:import [java.io PushbackReader]))

The error was attributed to this file.

Comment by Andy Fingerhut [ 13/Sep/13 11:48 AM ]

Patch clj-1261-v1.txt throws an exception if any fields given to defrecord or deftype are not symbols. They are CompilerExceptions, so include an accurate file, line, and column number.

Comment by Andy Fingerhut [ 13/Sep/13 11:57 AM ]

Updated description to give minimal test case.

Comment by Andy Fingerhut [ 23/Nov/13 1:06 AM ]

Patch clj-1261-2.diff is identical to clj-1261-v1.txt except that it applies cleanly to latest master. The only change was to some lines of context due to recent commits to Clojure.

Comment by Alex Miller [ 18/Apr/14 1:16 PM ]

I think the patch is ok but I have two suggestions in the error message - first, include the record/type ns+name (I think the classname in the patched fn is what you want). Second, I think the wording could be adjusted a bit and the parens should go away - those look like but don't actually have meaning in the original context (since you are filtering out the symbols). Maybe something like:

"defrecord and deftype fields must be symbols, useclj16.init.Application had: :shutdown-fn, :foo-bar"

Comment by Andy Fingerhut [ 30/Apr/14 9:32 AM ]

Patch clj-1261-3.diff attempts to incorporate Alex's suggested error message changes.

There are other errors caught by function validate-fields that could have more details like the namespace and record/type name added to them, but I don't want to go out of scope for the ticket. I can create another patch that does that if there is interest.

Comment by Alex Miller [ 30/Apr/14 2:56 PM ]

Can you update the "after" example in the Approach section of the description to match new?

Comment by Andy Fingerhut [ 01/May/14 4:18 PM ]

Updated example output at end of description to be what is seen after patch clj-1261-3.diff is applied.

Comment by Alex Miller [ 05/May/14 1:56 PM ]

Description looks good, patch looks good. Test?

Comment by Andy Fingerhut [ 05/May/14 2:03 PM ]

I'd be happy to write one, if I had a "similar" one to pattern them on.

By similar, I mean: are there any existing tests that require a namespace that isn't already loaded & compiled when the tests begin running, and catch exceptions thrown during the require?

Comment by Alex Miller [ 05/May/14 3:56 PM ]

I think you should be able to test the right error message here by just invoking the defrecord form.

Otherwise, maybe https://github.com/clojure/clojure/blob/master/test/clojure/test_clojure/ns_libs.clj#L87 ?

Comment by Andy Fingerhut [ 10/May/14 6:43 PM ]

Patch clj-1261-4.diff is identical to clj-1261-3.diff except that it adds a couple of unit tests verifying that an exception of the desired type and with an appropriate message is thrown when keywords are used as defrecord or deftype fields.

Comment by Alex Miller [ 13/May/14 10:41 PM ]

same as -4 but changed final defrecord to deftype in test (seemed like a typo)

Comment by Andy Fingerhut [ 13/May/14 11:40 PM ]

Thanks for the catch on that typo in the tests. You changed it to what I had intended.

Comment by Alex Miller [ 13/May/14 11:54 PM ]

seemed pretty clear

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