Custom Query (1030 matches)

Hi,

This is a very minor bug, but we ran into it in the context of a much larger system and it took awhile to figure out what was going on. This is on CCL 1.11-dev-r16394M-trunk on a Linux 2.6.32-431.el6.x86_64 system.

Setup: Create a file and several levels of symlinks to it. The following will work for this in bash:

    echo "Hello World" > 0
    for ((i=0;i < 30;i=i+1)) do ln -s $i $((i+1)) ; done

Once we get past enough symlinks, we find that CCL reports that the files do not exist:

   > (probe-file "8")
   #P"/home/users/jared/ccl-symlinks/0"
   ...
   > (probe-file "20")
   #P"/home/users/jared/ccl-symlinks/0"
   > (probe-file "21")
   NIL    ;; Bug?  Expected #P"/home/users/jared/ccl-symlinks/0"
   > (probe-file "22")
   NIL    ;; Bug?  Expected #P"/home/users/jared/ccl-symlinks/0"

We also run into problems when trying to open these files. For instance:

    (defun my-read (filename)
      (with-open-file (stream filename :direction :input)
        (read-line stream)))

    > (my-read "8")
    "Hello World"
    NIL
    > (my-read "20")
    "Hello World"
    NIL
    (my-read "21")  ;; Bug?  The file does exist...
    > Error: No such file or directory : "21"
    > While executing: CCL::MAKE-FILE-STREAM, in process listener(1).
    > Type :POP to abort, :R for a list of available restarts.
    > Type :? for other options.

From poking around, it seems like this may be due to the way that #_REALPATH is used in the implementation of %REALPATH, which is used by PROBE-FILE. It looks like the C realpath() function can return many kinds of error conditions, such as ELOOP, which don't necessarily mean that the file doesn't exist, but that the implementation of probe-file essentially just checks its return value without paying attention to the ERRNO.

FWIW, it seems that SBCL can PROBE-FILE all of these files without a problem, but it too fails to open files from "9" and above. Fortunately it provides a good error message instead of saying that the file does not exist:

    error opening #P"/home/users/jared/ccl-symlinks/9":
      Too many levels of symbolic links

Anyway this is all minor, but it would be nice if probe-file would either report that the file does indeed exist or give a "too many symlinks" error, and similarly it would be nice if opening the file either worked or produced a "too many symlinks" error instead of saying the file doesn't exist.

Thanks!

Jared

Welcome to Clozure Common Lisp Version 1.2-r8591:8592MS  (DarwinPPC32)!
? (define-method-combination standard+ ()
         ((around (:around))
          (before (:before))
          (primary () :required t)
          (after (:after)))
   (:arguments &optional args)

   (flet ((call-methods (methods)
            (mapcar #'(lambda (method)
                        `(call-method ,method))
                    methods)))
     (let ((form (if (or before after (rest primary))
                     `(multiple-value-prog1
                        (progn ,@(call-methods before)
                               (call-method ,(first primary)
                                            ,(rest primary)))
                        ,@(call-methods (reverse after)))
                     `(call-method ,(first primary)))))
        `(progn (print ,args)
       ,(if around
           `(call-method ,(first around)
                         (,@(rest around)
                          (make-method ,form)))
           form)))))
;Compiler warnings :
;   Unused lexical variable &OPTIONAL, in an anonymous lambda form
STANDARD+
? 

QRES-GDS> (lisp-implementation-version) "Version 1.2-r9777-working-0711 (LinuxX8664)" QRES-GDS> (defgeneric test-or (a)

(:method ((a sequence))

(reduce #'plus a :key #'identity)))

#<STANDARD-GENERIC-FUNCTION TEST-OR #x30006EF2F15F> QRES-GDS> (defgeneric test-or (a)

(:method ((a sequence))

(reduce #'or a :key #'identity)))

;Compiler warnings : ; In (TEST-OR (SEQUENCE)) inside an anonymous lambda form: FUNCTION can't be used to reference lexically visible macro OR. ; Evaluation aborted.

;;; the slime backtrace buffer contained:

Lambda list of method #<STANDARD-METHOD TEST-OR (SEQUENCE)> is incompatible with that of the generic function TEST-OR. Method's lambda-list : (A) Generic-function's : (A)

[Condition of type SIMPLE-ERROR]

Restarts:

0: [CONTINUE] Remove 0 methods from the generic-function and change its lambda list. 1: [ABORT] Return to SLIME's top level.

Backtrace:

0: (CCL::CHECK-DEFMETHOD-CONGRUENCY #<STANDARD-GENERIC-FUNCTION TEST-OR #x30006EF2F15F> #<STANDARD-METHOD TEST-OR (SEQUENCE)>) 1: (CCL::%ADD-STANDARD-METHOD-TO-STANDARD-GF #<STANDARD-GENERIC-FUNCTION TEST-OR #x30006EF2F15F> #<STANDARD-METHOD TEST-OR (SEQUENCE)>) 2: (CCL::ENSURE-METHOD TEST-OR (#<BUILT-IN-CLASS SEQUENCE>) :FUNCTION #<CCL:METHOD-FUNCTION TEST-OR (SEQUENCE)> :QUALIFIERS NIL :LAMBDA-LIST (A)) 3: (#<Anonymous Function #x30006F896E3F>) 4: (SWANK::EVAL-REGION "(defgeneric test-or (a)

(:method ((a sequence))

(reduce #'or a :key #'identity)))

")

5: ((:INTERNAL SWANK::REPL-EVAL))

...