raco setup: skip creation of redundant untethered executables

When tethering is configured for an installation layer, skip creating
untethered executables.

pkgs/racket-doc/help/installer.rkt

@@ -1,6 +1,9 @@
 #lang scheme/base
 (require launcher
-         setup/dirs)
+         setup/dirs
+         setup/variant
+         racket/file
+         racket/path)
 
 ;; Builds different kinds of executables for different platforms.
 ;; The `plt-help' executable is for backward compatibility.
@@ -10,27 +13,22 @@
 (provide installer)
 
 (define (installer path coll user? no-main?)
+  (cond
+    [user?
+     (if (find-addon-tethered-console-bin-dir)
+         (do-installer path coll #t #t)
+         (do-installer path coll #t #f))]
+    [else
      (unless no-main?
-    (do-installer path coll user? #f)
+       (if (find-config-tethered-console-bin-dir)
-    (when (and (not user?)
+           (do-installer path coll #f #t)
-               (find-config-tethered-console-bin-dir))
+           (do-installer path coll #f #f)))]))
-      (do-installer path coll #f #t)))
-  (when (find-addon-tethered-console-bin-dir)
-    (do-installer path coll #t #t)))
 
 (define (do-installer path collection user? tethered?)
   (for ([mr? (case (system-type)
                [(macosx)  '(#t #f)]
                [(windows) '(#t)]
-               [else      '(#f)])]
+               [else      '(#f)])])
-        #:when (or (not tethered?)
-                   (if mr?
-                       (if user?
-                           (find-addon-tethered-gui-bin-dir)
-                           (find-config-tethered-gui-bin-dir))
-                       (if user?
-                           (find-addon-tethered-console-bin-dir)
-                           (find-config-tethered-console-bin-dir)))))
     (define-values (variants mk-launcher mk-path extras)
       (if mr?
         (values available-mred-variants
@@ -42,14 +40,33 @@
                 make-mzscheme-launcher
                 mzscheme-program-launcher-path
                 '())))
-    (for ([variant (remove* '(script-3m script-cgc) (variants))])
+    (for ([variant (filter (lambda (x) (not (script-variant? x))) (variants))])
       (parameterize ([current-launcher-variant variant])
+        (define exe-path
+          (mk-path (if mr? "Racket Documentation" "plt-help") #:user? user? #:tethered? tethered?))
+        (unless (exists-in-another-layer? exe-path user? tethered? #:gui? mr?)
           (mk-launcher #:tether-mode (and tethered? (if user? 'addon 'config))
                        (append
                         '("-l-" "help/help"))
-                     (mk-path (if mr? "Racket Documentation" "plt-help") #:user? user? #:tethered? tethered?)
+                       (prep-dir exe-path)
                        `([exe-name . ,(if mr? "Racket Documentation" "plt-help")]
                          [relative? . ,(not user?)]
                          [install-mode . ,(if user? 'user 'main)]
                          [start-menu? . ,(not user?)]
-                       ,@extras))))))
+                         ,@extras)))))))
+
+(define (exists-in-another-layer? exe-name user? tethered? #:gui? gui?)
+  ;; for an untethered main installation, check whether the
+  ;; executable exists already in an earlier layer
+  (and (not user?)
+       (not tethered?)
+       (let-values ([(base name dir?) (split-path exe-name)])
+         (for/or ([dir (in-list (if gui?
+                                    (get-gui-bin-extra-search-dirs)
+                                    (get-console-bin-extra-search-dirs)))])
+           (file-or-directory-type (build-path dir name) #f)))))
+
+(define (prep-dir p)
+  (define dir (path-only p))
+  (make-directory* dir)
+  p)

pkgs/racket-doc/scribblings/raco/setup.scrbl

@@ -2577,13 +2577,13 @@ layer:
  @item{An @defterm{installation} layer with tethering is like a one
        without tethering (see @secref["layered-install"]), but where
        the layer's @filepath{@nonterm{layer-dir}/etc/config.rktd} file
-       htat maps @racket['config-tethered-console-bin-dir] to
+       that maps @racket['config-tethered-console-bin-dir] to
        @nonterm{tethered-bin-dir} and
        @racket['config-tethered-gui-bin-dir] to
-       @nonterm{tethered-gui-bin-dir}. The @racket['bin-dir]
+       @nonterm{tethered-gui-bin-dir}. The @racket['bin-dir] and
-       configuration can point to a directory that is ignored, since
+       @racket['gui-bin-dir] configurations can point to the same
-       the executables there will not be tethered. Initialize the
+       directories, but executables are not specifically created there by
-       tethered layer with
+       @exec{raco setup}. Initialize the tethered layer with
 
        @commandline{racket -G @nonterm{layer-dir}/etc -l- raco setup}}
 

racket/collects/setup/setup-core.rkt

@@ -1554,6 +1554,9 @@
                (define skip-non-addon? (and (cc-main? cc)
                                             (avoid-main-installation)))
                (define skip-untethered-main? (and (cc-main? cc)
+                                                  (or
+                                                   ;; Don't create untethered if we're creating tethered
+                                                   config-p
                                                    ;; If the executable already exists in a search
                                                    ;; directory other than the one for `p`, no need
                                                    ;; to write `p` after all
@@ -1565,20 +1568,19 @@
                                                      (define-values (base name dir?) (split-path p))
                                                      (define p2 (build-path dir name))
                                                      (or (file-exists? p2)
-                                                        (directory-exists? p2)))))
+                                                         (directory-exists? p2))))))
                (unless skip-non-addon?
+                 (prep-dir receipt-path)
                  (unless skip-untethered-main?
-                   (prep-dir p)
+                   (prep-dir p))
-                   (prep-dir receipt-path))
                  (when config-p
                    (prep-dir config-p)))
                (when addon-p
                  (prep-dir addon-p))
-               (unless skip-untethered-main?
                (hash-set! created-launchers
                           (record-launcher receipt-path mzln kind (current-launcher-variant) 
                                            (cc-collection cc) (cc-path cc))
-                            #t))
+                          #t)
                (define (create p user? tethered?)
                  (define aux
                    (append