Clojure

defprotocol: invalid method overload syntax getting accepted

Details

  • Type: Defect Defect
  • Status: Closed Closed
  • Priority: Minor Minor
  • Resolution: Completed
  • Affects Version/s: Release 1.5
  • Fix Version/s: Release 1.6
  • Component/s: None
  • Patch:
    Code and Test
  • Approval:
    Ok

Description

The compiler accepts this erroneous form:

user=> (defprotocol Bar (m [this]) (m [this arg]))
Bar

Analysis: defprotocol silently assoc's the last list of signatures found for any particular method name, without checking whether the method name was given earlier.

Patch: clj-1056-2.diff

Approach: Modify defprotocol to check whether each method name has already been encountered earlier, and throw an exception if so. The patch also updates the error message for the case of a protocol function with no args specified.

Behavior with patch clj-1056-2.txt:

user=> (defprotocol Bar (m [this]) (m [this arg]))
IllegalArgumentException Function m in protocol Bar was redefined. Specify all arities in single definition.
user=> (defprotocol Foo (m []))
IllegalArgumentException Definition of function m in protocol Foo must take at least one arg.

Screened by: Stuart Halloway

  1. clj-1056-1.txt
    10/Sep/13 11:24 PM
    3 kB
    Andy Fingerhut
  2. clj-1056-2.diff
    22/Oct/13 9:14 AM
    3 kB
    Alex Miller
  3. clj-1056-2.txt
    18/Oct/13 11:08 AM
    3 kB
    Alex Miller

Activity

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Alex Miller added a comment -

Updated patch to improve error messages and to switch from CompilerException (which is not used outside the Compiler) back to IllegalArgumentException.

I think it would be a good idea to have a general Exception that could carry file/line/col info that could be used by Compiler but also other errors (the EdnReader and LispReader both have their own variants). But I think that should be a separate enhancement, which I have filed as CLJ-1280.

Show
Alex Miller added a comment - Updated patch to improve error messages and to switch from CompilerException (which is not used outside the Compiler) back to IllegalArgumentException. I think it would be a good idea to have a general Exception that could carry file/line/col info that could be used by Compiler but also other errors (the EdnReader and LispReader both have their own variants). But I think that should be a separate enhancement, which I have filed as CLJ-1280.
Hide
Andy Fingerhut added a comment -

Patch clj-1056-1.txt changes defprotocol to throw an exception if the same method name appears more than once.

Without this patch, the last set of signatures for a method name "wins", silently overriding any earlier ones.

Show
Andy Fingerhut added a comment - Patch clj-1056-1.txt changes defprotocol to throw an exception if the same method name appears more than once. Without this patch, the last set of signatures for a method name "wins", silently overriding any earlier ones.
Hide
Alex Miller added a comment -

Moving back to Triaged as Rich has not vetted.

Show
Alex Miller added a comment - Moving back to Triaged as Rich has not vetted.
Hide
Timothy Baldridge added a comment -

Can not reproduce the fist error:

user=> (defprotocol Foo (f ([this]) ([this arg])))
CompilerException java.lang.IllegalArgumentException: Parameter declaration missing, compiling:(NO_SOURCE_PATH:5:1)

But the 2nd one I can reproduce:

user=> (defprotocol Bar (m [this]) (m [this arg]))
Bar
user=> Bar
{:on-interface user.Bar, :on user.Bar, :sigs {:m {:doc nil, :arglists ([this arg]), :name m}}, :var #'user/Bar, :method-map {:m :m}, :method-builders {#'user/m #<user$eval71$fn_72 user$eval71$fn_72@1a2b53fb>}}
user=>

Notice that :arglists only has one entry

Vetting

Show
Timothy Baldridge added a comment - Can not reproduce the fist error: user=> (defprotocol Foo (f ([this]) ([this arg]))) CompilerException java.lang.IllegalArgumentException: Parameter declaration missing, compiling:(NO_SOURCE_PATH:5:1) But the 2nd one I can reproduce: user=> (defprotocol Bar (m [this]) (m [this arg])) Bar user=> Bar {:on-interface user.Bar, :on user.Bar, :sigs {:m {:doc nil, :arglists ([this arg]), :name m}}, :var #'user/Bar, :method-map {:m :m}, :method-builders {#'user/m #<user$eval71$fn_72 user$eval71$fn_72@1a2b53fb>}} user=> Notice that :arglists only has one entry Vetting

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Dates

  • Created:
    Updated:
    Resolved: