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

Question

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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.

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Answer 1

Comment made by: importer

richhickey said: Updating tickets (#8, #19, #30, #31, #126, #17, #42, #47, #50, #61, #64, #69, #71, #77, #79, #84, #87, #89, #96, #99, #103, #107, #112, #113, #114, #115, #118, #119, #121, #122, #124)

Answer 2

Comment made by: importer

richhickey said: Updating tickets (#8, #42, #113, #2, #20, #94, #96, #104, #119, #124, #127, #149, #162)

Answer 3

Comment made by: importer

Converted from http://www.assembla.com/spaces/clojure/tickets/113

Answer 4

Comment made by: hiredman

seems like the code that is emitted in the static init for namespace classes could be emitted into a init_ns() static method and the static init could call init_ns(). then RT.load could call init_ns() to get the behavior of reloading an AOT compiled namespace.

Answer 5

Comment made by: hiredman

looking at the compiler it looks like most of what I mentioned above is already implemented, just need RT to reflectively call load() on the namespace class in the right place

Answer 6

Reference: https://clojure.atlassian.net/browse/CLJ-113 (reported by alex+import)