From f66fff1ca92722365649859833c8fce3273e866c Mon Sep 17 00:00:00 2001
From: Matthew Flatt <mflatt@racket-lang.org>
Date: Sun, 24 May 2020 11:05:53 -0600
Subject: [PATCH] setup/xref: fix `load-collections-xref` for multple uses

When the result of `load-collections-xref` is used in multiple
document renderings (e.g., multiple calls to `render`), then an
intenal cache behaved the wrong way. Fixing the problem required an
extension to `scribble/xref`.
---
 pkgs/racket-doc/info.rkt                     |  2 +-
 pkgs/racket-doc/scribblings/raco/setup.scrbl | 13 ++++----
 pkgs/racket-index/setup/xref.rkt             | 32 ++++++++++++--------
 3 files changed, 27 insertions(+), 20 deletions(-)

diff --git a/pkgs/racket-doc/info.rkt b/pkgs/racket-doc/info.rkt
index 8a9b51e731..ba36f0e1bd 100644
--- a/pkgs/racket-doc/info.rkt
+++ b/pkgs/racket-doc/info.rkt
@@ -6,7 +6,7 @@
                ["base" #:version "6.5.0.2"]
                "net-lib"
                "sandbox-lib"
-               ["scribble-lib" #:version "1.14"]
+               ["scribble-lib" #:version "1.34"]
                "racket-index"))
 (define build-deps '("rackunit-doc"
                      "compatibility"
diff --git a/pkgs/racket-doc/scribblings/raco/setup.scrbl b/pkgs/racket-doc/scribblings/raco/setup.scrbl
index 6222d9fd11..aabf3b3a74 100644
--- a/pkgs/racket-doc/scribblings/raco/setup.scrbl
+++ b/pkgs/racket-doc/scribblings/raco/setup.scrbl
@@ -2157,11 +2157,10 @@ Returns @racket[#t] if cross-installation mode has been detected,
 @defproc[(load-collections-xref [on-load (-> any/c) (lambda () (void))])
          xref?]{
 
-Like @racket[load-xref], but automatically find all cross-reference files for
-manuals that have been installed with @exec{raco setup}.
-
-A cached copy of cross-reference information can be used, in which
-case @racket[on-load] is @emph{not} called.}
+Either creates and caches or returns a cached cross-reference record
+created with @racket[make-collections-xref]. The @racket[on-load]
+function is called only when a previously cached record is not
+returned.}
 
 
 @defproc[(make-collections-xref [#:no-user? no-user? any/c #f]
@@ -2171,7 +2170,9 @@ case @racket[on-load] is @emph{not} called.}
                                 [#:register-shutdown! register-shutdown! ((-> any) . -> . any) void])
          xref?]{
 
-Like @racket[load-collections-xref], but takes advantage of a
+Like @racket[load-xref], but automatically finds all cross-reference
+files for manuals that have been installed with @exec{raco setup}.
+The resulting cross-reference record takes advantage of a
 cross-reference database @racket[db-path], when support is available,
 to delay the loading of cross-reference details until needed.
 
diff --git a/pkgs/racket-index/setup/xref.rkt b/pkgs/racket-index/setup/xref.rkt
index d2a8fe9f04..e30501432a 100644
--- a/pkgs/racket-index/setup/xref.rkt
+++ b/pkgs/racket-index/setup/xref.rkt
@@ -103,20 +103,25 @@
                                 (close p))))
                         (when main-db (close main-db))
                         (when user-db (close user-db))))
-  (define done-ht (make-hash)) ; tracks already-loaded documents
-  (define forced-all? #f)
-  (define (force-all)
+  (define done-hts (make-hasheq)) ; tracks already-loaded documents per ci
+  (define (get-done-ht use-id)
+    (or (hash-ref done-hts use-id #f)
+        (let ([ht (make-hash)])
+          (hash-set! done-hts use-id ht)
+          ht)))
+  (define forced-all?s (make-hasheq)) ; per ci: whether forced all
+  (define (force-all use-id)
     ;; force all documents
-    (define thunks (get-reader-thunks no-user? no-main? quiet-fail? done-ht))
-    (set! forced-all? #t)
+    (define thunks (get-reader-thunks no-user? no-main? quiet-fail? (get-done-ht use-id)))
+    (hash-set! forced-all?s use-id #t)
     (lambda () 
       ;; return a procedure so we can produce a list of results:
       (lambda () 
         (for/list ([thunk (in-list thunks)])
           (thunk)))))
-  (lambda (key)
+  (lambda (key use-id)
     (cond
-     [forced-all? #f]
+     [(hash-ref forced-all?s use-id #f) #f]
      [key
       (define (try p)
         (and p
@@ -140,11 +145,11 @@
       (define dest (or (try main-db) (try user-db)))
       (and dest
            (if (eq? dest #t)
-               (force-all)
-               ((dest->source done-ht quiet-fail?) dest)))]
+               (force-all use-id)
+               ((dest->source (get-done-ht use-id) quiet-fail?) dest)))]
      [else
-      (unless forced-all?
-        (force-all))])))
+      (unless (hash-ref forced-all?s use-id #f)
+        (force-all use-id))])))
 
 (define (get-reader-thunks no-user? no-main? quiet-fail? done-ht)
   (map (dest->source done-ht quiet-fail?)
@@ -165,8 +170,9 @@
                                #:register-shutdown! [register-shutdown! void])
   (if (doc-db-available?)
       (load-xref null
-                 #:demand-source (make-key->source db-path no-user? no-main? quiet-fail?
-                                                   register-shutdown!))
+                 #:demand-source-for-use
+                 (make-key->source db-path no-user? no-main? quiet-fail?
+                                   register-shutdown!))
       (load-xref (get-reader-thunks no-user? no-main? quiet-fail? (make-hash)))))