racket/port: possible repair for `read-bytes-evt'

Also restore and add some tests.

Merge to v5.3
(cherry picked from commit 70ef4e6e57)

Conflicts:
	collects/racket/port.rkt

collects/mzlib/port.rkt

@@ -962,6 +962,7 @@
   ;; go is the main reading function, either called directly for
   ;; a poll, or called in a thread for a non-poll read
   (define (go nack ch poll?)
+    ;; FIXME - what if the input port is closed?
     (let try-again ([pos 0] [bstr orig-bstr] [progress-evt #f])
       (let* ([progress-evt 
               ;; if no progress event is given, get one to ensure that
@@ -1004,10 +1005,11 @@
                                       (channel-put-evt ch result))
                                     input-port)
                 result]
-               [(and (eof-object? eof)
+
+               [(and (eof-object? v)
                      (zero? pos)
                      (not (sync/timeout 0 progress-evt)))
-                ;; Must be a true end-of-file
+                ;; Must be a true end-of-file, since commit failed
                 (let ([result (combo bstr eof)])
                   (if poll? result (channel-put ch result)))]
                [poll? #f]

collects/tests/racket/portlib.rktl

@@ -286,7 +286,7 @@
     (go-stream #t #t #t #t)))
 
 ;; make-input-port/read-to-peek
-(define (make-list-port . l)
+(define (make-list-port #:eof-as-special? [eof-as-special? #f] . l)
   (make-input-port/read-to-peek 
    'list-port
    (lambda (bytes)
@@ -301,6 +301,10 @@
        (bytes-set! bytes 0 (char->integer (car l)))
        (set! l (cdr l))
        1]
+      [(and (not eof-as-special?)
+            (eof-object? (car l)))
+       (set! l (cdr l))
+       eof]
       [else
        (let ([v (car l)])
 	 (set! l (cdr l))
@@ -345,11 +349,23 @@
   (test 'lo read p)
   (test eof read p)
   (test eof read p))
+(let ([p (make-list-port #:eof-as-special? #t #\h #\e #\l eof #\l #\o)])
+  (test 'hel read p)
+  (test eof read p)
+  (test 'lo read p)
+  (test eof read p)
+  (test eof read p))
 (let ([p (make-list-port #\h #\e #\l #\u7238 #\l #\o)])
   (test 'hel read p)
   (test #\u7238 read p)
   (test 'lo read p))
 
+(let ([p (make-list-port 65 eof 66 67)])
+  (test 65 peek-byte p 0)
+  (test eof peek-byte p 1)
+  (test #t port-commit-peeked 2 (port-progress-evt p) always-evt p)
+  (test 66 peek-byte p 0))
+
 ;; Check that make-input-port/read-to-peek isn't trying
 ;; to use chars when it should use bytes:
 (let-values ([(pipe-r pipe-w) (make-pipe)])
@@ -964,13 +980,13 @@
         (define-values (i o) (tcp-connect "localhost" PORT))
         (write-bytes s o)
         (close-output-port o)
-        (test s read-bytes M i)))
+        (test s read-bytes M i)
+        (close-input-port i)))
 
     (sync server)
     (tcp-close listener))
 
   (let ([integer->byte (lambda (s) (bitwise-and s #xFF))])
-    #;
     (check-can-reuse read-bytes-evt read-bytes write-bytes integer->byte list->bytes bytes?)
     ;; the following should work because we use the same evt only after
     ;; success or to start at the same point in the input stream:
@@ -979,7 +995,6 @@
                        (wrap-evt (read-bytes!-evt bstr in)
                                  (lambda (v) (if (eof-object? v) v bstr))))
                      read-bytes write-bytes integer->byte list->bytes bytes?))
-  #;
   (check-can-reuse read-string-evt read-string write-string integer->char list->string string?))
 
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