[Openmcl-devel] An unfortunate interaction between CFFI and open-shared-library
ron at flownet.com
Sun Sep 19 20:31:39 UTC 2010
Today I tried to load CL-MYSQL which I have done a zillion times before. To my dismay, it failed with the following error on the altconsole:
> Error: Error opening shared library "libmysqlclient_r.dylib": dlopen(libmysqlclient_r.dylib, 10): image not found
> While executing: (:INTERNAL GUI::|-[LispApplication sendEvent:]|), in process Initial(0).
This despite the fact that I hadn't changed anything since the last time it worked, except for updating CCL itself.
The cause seems to be a recent change in open-shared-library:
(defun open-shared-library (name &optional (process #+darwin-target :initial
"If the library denoted by name can be loaded by the operating system,
return an object of type SHLIB that describes the library; if the library
is already open, increment a reference count. If the library can't be
loaded, signal a SIMPLE-ERROR which contains an often-cryptic message from
the operating system."
(if (or (eq process :current)
(eq process *current-process*)
(and (eq process :initial)
(eq *current-process* *initial-process*)))
(call-in-process (lambda () (open-shared-library name))
(if (eq process :initial)
It appears that open-shared-library when run on Darwin runs on the main thread rather than the calling thread. But CFFI wraps this call in a handler-case, which it relies on to find the library:
(defun load-foreign-library-path (name path)
"Tries to load PATH using %LOAD-FOREIGN-LIBRARY which should try and
find it using the OS's usual methods. If that fails we try to find it
(%load-foreign-library name path)
(if-let (file (find-file path *foreign-library-directories*))
(%load-foreign-library name (native-namestring file))
(report-simple-error name error)))
(report-simple-error name error)))))
Now that open-shared-library is running in a different thread it is no longer in the dynamic context of the handler-case, so it dies if it can't find the library on the first try.
So... is there a reason that open-shared-library is dispatching to the initial thread? If there isn't, it really shouldn't. And if there is, well, then Houston, we have a problem.
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