Make it so that DrRacket deletes .zo files when the corresponding source file isn't present anymore

(when in the DrRAcket-compiles-my-zo-files mode)

collects/compiler/cm.rkt

@@ -540,7 +540,8 @@
     (lambda (src)
       (parameterize ([current-load/use-compiled
                       (make-compilation-manager-load/use-compiled-handler/table
-                       cache)])
+                       cache
+                       #f)])
         (compile-root (car (use-compiled-file-paths))
                       (path->complete-path src)
                       cache
@@ -548,10 +549,10 @@
                       #f)
         (void)))))
 
-(define (make-compilation-manager-load/use-compiled-handler)
-  (make-compilation-manager-load/use-compiled-handler/table (make-hash)))
+(define (make-compilation-manager-load/use-compiled-handler [delete-zos-when-rkt-file-does-not-exist? #f])
+  (make-compilation-manager-load/use-compiled-handler/table (make-hash) delete-zos-when-rkt-file-does-not-exist?))
 
-(define (make-compilation-manager-load/use-compiled-handler/table cache)
+(define (make-compilation-manager-load/use-compiled-handler/table cache delete-zos-when-rkt-file-does-not-exist?)
   (let ([orig-eval (current-eval)]
         [orig-load (current-load)]
         [orig-registry (namespace-module-registry (current-namespace))]
@@ -564,7 +565,13 @@
                       (let ([p2 (rkt->ss path)])
                         (and (not (eq? path p2))
                              (file-exists? p2)))))
-             (trace-printf "skipping:  ~a file does not exist" path)]
+             (trace-printf "skipping:  ~a file does not exist" path)
+             (when delete-zos-when-rkt-file-does-not-exist?
+               (unless (null? modes)
+                 (define to-delete (path-add-suffix (get-compilation-path (car modes) path) #".zo")) 
+                 (when (file-exists? to-delete)
+                   (trace-printf "deleting:  ~s" to-delete)
+                 (delete-file to-delete))))]
             [(or (null? (use-compiled-file-paths))
                  (not (equal? (car modes)
                               (car (use-compiled-file-paths)))))

collects/drracket/private/module-language.rkt

@@ -247,7 +247,7 @@
                    (cons (build-path "compiled" "drracket" "errortrace")
                          (use-compiled-file-paths)))]))
              
-             (current-load/use-compiled (make-compilation-manager-load/use-compiled-handler))
+             (current-load/use-compiled (make-compilation-manager-load/use-compiled-handler #t))
              (let* ([cd (find-system-path 'collects-dir)]
                     [no-dirs (list (CACHE-DIR) 
                                    (if (relative-path? cd)

collects/scribblings/raco/make.scrbl

@@ -117,7 +117,8 @@ and files as @exec{raco make}, so the two tools can be used together.
 implements the compilation and dependency management used by
 @exec{raco make} and @exec{raco setup}.}
 
-@defproc[(make-compilation-manager-load/use-compiled-handler)
+@defproc[(make-compilation-manager-load/use-compiled-handler 
+          [delete-zos-when-rkt-file-does-not-exist? any/c #f])
          (path? (or/c symbol? false/c) . -> . any)]{
 
 Returns a procedure suitable as a value for the
@@ -200,6 +201,10 @@ If @racket[use-compiled-file-paths] contains an empty list when
 @racket[make-compilation-manager-load/use-compiled-handler] is called,
 then @racket[exn:fail:contract] exception is raised.
 
+If the @racket[delete-zos-when-rkt-file-does-not-exist?] argument is a true
+value, then the returned handler will delete @filepath{.zo} files
+when there is no corresponding original source file.
+
 @emph{Do not} install the result of
 @racket[make-compilation-manager-load/use-compiled-handler] when the
 current namespace contains already-loaded versions of modules that may