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[CLJS-1237] ns-unmap doesn't work on refers from cljs.core Created: 01/May/15  Updated: 27/Jun/17

Status: Open
Project: ClojureScript
Component/s: None
Affects Version/s: 1.7.145
Fix Version/s: 1.9.671

Type: Defect Priority: Minor
Reporter: Chouser Assignee: Unassigned
Resolution: Unresolved Votes: 0
Labels: ns-unmap

Attachments: Text File 0001-CLJS-1237-ns-unmap-adds-to-namespace-s-excludes.patch     Text File 0002-CLJS-1237-ns-unmap-adds-to-namespace-s-excludes.patch    
Patch: Code

 Description   

In ClojureScript, using ns-unmap on a symbol from cljs.core doesn't exclude it from the current namespace. Note that both a function and a macro still exist, even after unmapping:

To quit, type: :cljs/quit  
cljs.user=> (ns-unmap 'cljs.user 'when) ;; macro
true  
cljs.user=> (ns-unmap 'cljs.user 'not)  ;; function
true  
cljs.user=> (when 1 2)  
2  
cljs.user=> (not false)  
true  

This differs from the behavior of Clojure's ns-unmap. Note the appropriate errors when attempting to use unmapped symbols:

Clojure 1.7.0-beta1
user=> (ns-unmap 'user 'when) ;; macro
nil
user=> (ns-unmap 'user 'not)  ;; function
nil
user=> (when 1 2)
CompilerException java.lang.RuntimeException: Unable to resolve symbol: when in this context, compiling:(NO_SOURCE_PATH:11:1) 
user=> (not false)
CompilerException java.lang.RuntimeException: Unable to resolve symbol: not in this context, compiling:(NO_SOURCE_PATH:12:1) 

Somehow ClojureScript's ns-unmap needs to add the symbol to the current namespace's :excludes set. Note that the def special form does this already (after it displays a warning).

We have two solutions. 0001 extends the ns form's :merge behavior to support :excludes, and then uses this in ns-unmap. If the enhancement to ns isn't wanted, patch 0002 changes ns-unmap to update :excludes directly.



 Comments   
Comment by David Nolen [ 05/May/15 7:23 AM ]

The second patch is preferred. However it seems the second patch is too permissive. The :excludes logic should only be applied if the symbol identifies a core macro or fn.

Comment by Chouser [ 05/May/15 3:46 PM ]

The ns form's own :refer-clojure :exclude accepts arbitrary symbols and adds them to the namespace's :excludes set, which seems like the same permissiveness problem. Do you want a patch that addresses the permissiveness of both ns and ns-unmap in this ticket, or should such a patch go in a new ticket?

Comment by David Nolen [ 05/May/15 4:08 PM ]

New ticket to fix the bug that :exclude doesn't check the symbol list for cljs.core declared vars, and an updated patch here please.

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