GC Issue 109: RT.load's "don't load if already loaded" mechanism breaks ":reload-all"

 Reported by scgilardi, Apr 24, 2009

What (small set of) steps will reproduce the problem?

"require" and "use" support a ":reload-all" flag that is intended to  
cause the specified libs to be reloaded along with all libs on which  
they directly or indirectly depend. This is implemented by temporarily  
binding a "loaded-libs" var to the empty set and then loading the  
specified libs.

AOT compilation added another "already loaded" mechanism to  
clojure.lang.RT.load() which is currently not sensitive to a "reload-
all" being in progress and breaks its operation in the following case:

        A, B, and C are libs
        A depends on B. (via :require in its ns form)
        B depends on C. (via :require in its ns form)
        B has been compiled (B.class is on classpath)

        At the repl I "require" A which loads A, B, and C (either from
class files or clj files)
        I modify C.clj
        At the repl I "require" A with the :reload-all flag, intending to  
pick up the changes to C
        C is not reloaded because RT.load() skips loading B: B.class
exists, is already loaded, and B.clj hasn't changed since it was compiled.


What is the expected output? What do you see instead?

I expect :reload-all to be effective. It isn't.

What version are you using?

svn 1354, 1.0.0RC1

Was this discussed on the group? If so, please provide a link to the
discussion:

http://groups.google.com/group/clojure/browse_frm/thread/9bbc290321fd895f/e6a967250021462a#e6a967250021462a

Please provide any additional information below.

I'll upload a patch soon that creates a "*reload-all*" var with a  
root binding of nil and code to bind it to true when the current  
thread has a :reload-all call pending. When *reload-all* is true,  
RT.load() will (re)load all libs from their ".clj" files even if  
they're already loaded.

The fix for this may need to be coordinated with a fix for issue #3.