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[CLJ-148] Poor reporting of symbol conflicts when using (ns) Created: 10/Jul/09  Updated: 14/Dec/15  Resolved: 14/Dec/15

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

Type: Enhancement Priority: Major
Reporter: Anonymous Assignee: Unassigned
Resolution: Declined Votes: 1
Labels: errormsgs


 Description   

I have a module that includes pprint and my own utils.

When com.howard.lewisship.cascade.dom/write was changed from private to public I get the following error:

java.lang.IllegalStateException: write already refers to: #'clojure.contrib.pprint/write in namespace: com.howardlewisship.cascade.test-views (test_views.clj:0)

(ns com.howardlewisship.cascade.test-views ; line 15
(:use
(clojure.contrib test-is pprint duck-streams)
(app1 views fragments)
(com.howardlewisship.cascade config dom view-manager)
com.howardlewisship.cascade.internal.utils))

That line number is wrong but better yet, identifying the true conflict (com.howard.lewisship.cascade.dom/write) would be even more important.



 Comments   
Comment by Assembla Importer [ 24/Aug/10 3:54 AM ]

Converted from http://www.assembla.com/spaces/clojure/tickets/148

Comment by Assembla Importer [ 24/Aug/10 3:54 AM ]

scgilardi said: It's saying that the symbol com.howardlewisship.cascade.test-views/write already resolves to #���clojure.contrib.pprint/write, so you can't def a new write in com.howardlewisship.cascade.test-views.

What do you propose for an alternate wording of the error message here?

Comment by Jeff Rose [ 12/May/11 9:49 AM ]

I think the issue is that only one side of the conflict is reported in the error, so if you get this kind of error in the middle of a large project it can be hard to figure out which namespace is conflicting. Take a toy example:

user=> (ns foo)
foo=> (def foobar 42)
foo=> (ns bar)
bar=> (def foobar 0)
bar=> (ns problem)
problem=> (refer 'foo)
problem=> (refer 'bar)
java.lang.IllegalStateException: foobar already refers to: #'foo/foobar in namespace: problem (NO_SOURCE_FILE:0)

In this case it would be best if the error said something like:

"Conflict referring to #'bar/foobar in #<Namespace problem> because foobar already refers to: #'foo/foobar."

This way the error message clearly identifies the location of the conflict, and the locations of the two conflicting vars.

Hopefully this helps clarify. I think I see where to fix it in warnOrFailOnReplace on line 88 of src/jvm/clojure/lang/Namespace.java, and this reminds me I need to send in a CA so I can pitch in next time...

Comment by Aaron Bedra [ 28/Jun/11 6:42 PM ]

It looks like the true conflict is in test-views, not in dom. A small example of the line number breakage showing the problem on master (1.3) would be very helpful.

Comment by Alex Miller [ 14/Dec/15 3:10 PM ]

I know this is super old. I'm closing as
1) The example is not clear.
2) It contains multiple issues (error message and line number). 3) The error message seems pretty explicit to me and I find the suggestions in the comments to be more confusing.
4) We've had several line number related fixes that should affect this. If there is still a problem, a fresh ticket with a good reproducible example would be best.

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