package manager: adjust parsing of file:// URLs

For some reason, I previously made the package manager parse file URLs
by stripping away "file://" and treating the rest directly as a
path. Maybe it was to support relative paths, or maybe it was to
implicitly disallow query and fragment parts of the URL, but it seems
like a terrible idea; I've switched to `string->url` plus `url->path`.

As a result, parsing now implicitly allows and ignores query and
fragment parts of a "file://" URL. That's intended as a feature,
allowing extra information to be attached to a path in, for example,
a catalog.

pkgs/racket-pkgs/racket-doc/pkg/scribblings/pkg.scrbl

@@ -127,6 +127,7 @@ The valid archive formats
 are (currently) @filepath{.zip}, @filepath{.tar}, @filepath{.tgz}, 
 @filepath{.tar.gz}, and
 @filepath{.plt}.
+Any query or fragments parts of a @litchar{file://} URL are ignored.
 
 For example, @filepath{~/tic-tac-toe.zip} is an archive package
 source, and its @tech{checksum} would be inside
@@ -147,12 +148,16 @@ package name is the filename without its suffix.
 
 @history[#:changed "6.0.1.12"
          @elem{Changed treatment of an archive that contains all
-               content within a top-level directory.}]}
+               content within a top-level directory.}
+         #:changed "6.1.1.5"
+         @elem{Changed @litchar{file://} parsing to accept a general
+               URL and ignore any query or fragment.}]}
 
 @; ----------------------------------------
 @item{a local directory (as a plain path or @litchar{file://} URL)
 --- The name of the package is the name of the
 directory. The @tech{checksum} is not present.
+Any query or fragments parts of a @litchar{file://} URL are ignored.
 
 For example,
 @filepath{~/tic-tac-toe/} is a directory package source.
@@ -162,7 +167,11 @@ to a directory only when it does not have a file-archive suffix, does
 not match the grammar of a package name, and either starts with starts 
 with @litchar{file://} or does not start
 with alphabetic characters followed by @litchar{://}. The inferred
-package name is the directory name.}
+package name is the directory name.
+
+@history[#:changed "6.1.1.5"
+         @elem{Changed @litchar{file://} parsing to accept a general
+               URL and ignore any query or fragment.}]}
 
 @item{a remote URL naming an archive --- This type follows the same
 rules as a local file path, but the archive and @tech{checksum} files are

pkgs/racket-pkgs/racket-test/tests/pkg/tests-name.rkt

@@ -147,10 +147,12 @@
   (check-equal-values? (parse "racket/fish/x" 'github #rx"two") (values #f 'github #f))
   (check-equal-values? (parse "fish" 'github #rx"two") (values #f 'github #f))
 
-  (check-equal-values? (parse "file://fish.plt" #f) (values "fish" 'file #t))
+  (check-equal-values? (parse "file://fish.plt" #f) (values #f 'dir #t)) ; missing root means an empty path
   (check-equal-values? (parse "file:///root/fish.plt" #f) (values "fish" 'file #t))
-  (check-equal-values? (parse "file://fish" #f) (values "fish" 'dir #t))
+  (check-equal-values? (parse "file://fish" #f) (values #f 'dir #t)) ; missing root means an empty path
   (check-equal-values? (parse "file:///root/fish" #f) (values "fish" 'dir #t))
+  (check-equal-values? (parse "file:///root/fish.zip?ignored=yes#alsoIgnored" #f) (values "fish" 'file #t))
+  (check-equal-values? (parse "file:///root/fish?ignored=yes#alsoIgnored" #f) (values "fish" 'dir #t))
 
   (check-equal-values? (parse "random://racket-lang.org/fish.plt" #f #rx"scheme") (values #f #f #f))
 

racket/collects/pkg/name.rkt

@@ -256,8 +256,10 @@
     (values (validate-name name complain-name #f)
             (or type (and name-type)))]
    [(and (not type)
-         (regexp-match #rx"^file://(.*)$" s))
+         (regexp-match #rx"^file://" s))
-    => (lambda (m) (parse-path (cadr m)))]
+    => (lambda (m)
+         ;; Note that we're ignoring a query & fragment, if any:
+         (parse-path (url->path (string->url s))))]
    [(and (not type)
          (regexp-match? #rx"^[a-zA-Z]*://" s))
     (complain "unrecognized URL scheme")

racket/collects/pkg/private/stage.rkt

@@ -535,8 +535,8 @@
                       #f ; no git-dir
                       #f ; no clean?
                       given-checksum ; if a checksum is provided, just use it
-                      (directory->module-paths pkg pkg-name metadata-ns)
+                      (directory->module-paths pkg-path pkg-name metadata-ns)
-                      (directory->additional-installs pkg pkg-name metadata-ns))]
+                      (directory->additional-installs pkg-path pkg-name metadata-ns))]
        [else
         (define pkg-dir
           (if in-place?