From 3b1b4a0d26fe1d80e9f44826add0f8cb9dd87305 Mon Sep 17 00:00:00 2001
From: Matthew Flatt <mflatt@racket-lang.org>
Date: Tue, 19 Apr 2016 05:42:07 -0600
Subject: [PATCH] string->url: always mark as absolute when a host is present

Fixes a failure in the web server tests caused by d23b296627.

Formerly, `(string->url "http://racket-lang.org")`, with no trailing
slash, would produce a `url` structure with `path-absolute?` as #f.
That doesn't exactly make sense, because a URL with a host must always
have an absolute path component. Claiming a relative path component
interacts badly with extending a URL with a path later. (Although
`combine-url/relative` compenstate, a similar function in the web
server doesn't.) The revised `url->string` always sets `path-absolute?`
to #t when a host is present, and whether the path is empty or contains
an empty string still records whether a trailing "/" was present.

The `url->string` function, meanwhile, now needs to use whether the
path is empty to determine whether a "/" should be added after
the host name, not whether `path-absolute?` is true.
---
 racket/collects/net/url-string.rkt | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/racket/collects/net/url-string.rkt b/racket/collects/net/url-string.rkt
index 68f893f761..af7c5daff7 100644
--- a/racket/collects/net/url-string.rkt
+++ b/racket/collects/net/url-string.rkt
@@ -242,6 +242,10 @@
               [port     (and port (string->number port))]
               [abs?     (or (equal? "file" scheme)
                             (regexp-match? #rx"^/" path))]
+              [use-abs? (or abs?
+                            ;; If an authority part is provided, the (empty) path must be
+                            ;; absolute, even if it isn't written with a "/":
+                            (and (or host user port) #t))]
               [path     (if win-file?
                             (url-path win-file-url)
                             (separate-path-strings path))]
@@ -252,7 +256,7 @@
                                      " host provided with non-absolute path (i.e., missing a slash)\n"
                                      "  in: ~e")
                       str))
-         (make-url scheme user host port abs? path query fragment))))
+         (make-url scheme user host port use-abs? path query fragment))))
    (cdr (regexp-match url-regexp str))))
 
 (define (uri-decode/maybe f) (friendly-decode/maybe f uri-decode))
@@ -287,7 +291,7 @@
 (define (combine-path-strings absolute? path/params)
   (cond [(null? path/params) null]
         [else (let ([p (add-between (map join-params path/params) "/")])
-                (if absolute? (cons "/" p) p))]))
+                (if (and absolute? (pair? p)) (cons "/" p) p))]))
 
 (define (join-params s)
   (if (null? (path/param-param s))