repeair search warnings when a lcoal definition shadows external

When using `scribble +m` to render an installed document separately,
the entries loaded by `+m` get replaced by the new rendering. The
precence of the `+m` entries, however, could make Scribble think that
searched-for bindings were not found, because they're seen both as
external and as internal.

Author: mflatt

scribble-lib/scribble/base-render.rkt

@@ -403,18 +403,22 @@
         (hash-map ht (lambda (k v) k))))
 
     (define/public (get-external ri)
-      (hash-map (resolve-info-undef ri) (lambda (k v) k)))
+      (for/list ([(k v) (in-hash (resolve-info-undef ri))]
+                 #:unless (eq? v 'local))
+        k))
 
     (define/public (get-undefined ri)
       (for/list ([(k v) (in-hash (resolve-info-undef ri))]
                  #:unless (or (eq? v 'found)
+                              (eq? v 'local)
                               (and v
                                    ;; v is a search key; see if any key in the set was resolved:
                                    (or
                                     (not (car v)) ; search key where failure was an option
                                     (let ([ht (hash-ref (resolve-info-searches ri) v)])
                                       (for/or ([k2 (in-hash-keys ht)])
-                                        (eq? 'found (hash-ref (resolve-info-undef ri) k2 #f))))))))
+                                        (memq (hash-ref (resolve-info-undef ri) k2 #f)
+                                              '(found local))))))))
         k))
 
     (define/public (transfer-info ci src-ci)

scribble-lib/scribble/core.rkt

@@ -52,8 +52,17 @@
 
 (define (resolve-get/ext-id* part ri key search-key)
   (define-values (v ext-id) (resolve-get/where part ri key))
-  (when ext-id
-    (hash-set! (resolve-info-undef ri) (tag-key key ri) (if v 'found search-key)))
+  (when (or ext-id
+            ;; if `v`, make sure it's counted as found; this can happen if external saved
+            ;; information has the key originally, but then it's defined locally, such
+            ;; as when rendering an installed document with `scribble +m ...`
+            (and search-key
+                 v))
+    (hash-set! (resolve-info-undef ri) (tag-key key ri) (if v
+                                                            (if ext-id
+                                                                'found
+                                                                'local)
+                                                            search-key)))
   (values v ext-id))
 
 (define (resolve-get part ri key)