substitute-binary: Pass `filtered-port' an unbuffered port.

This fixes a bug whereby `read-response' would read more than just the
response, with the extra data going into the port's buffer; the
"bzip2 -dc" process spawned by `filtered-port' would not see the those
buffered data, which are definitely lost, and would bail out with
"bzip2: (stdin) is not a bzip2 file."

* guix/utils.scm (filtered-port): Document that INPUT must be
  unbuffered.
* guix/web.scm (http-fetch): Add `buffered?' parameter.  Call
  `open-socket-for-uri' explicitly, and call `setvbuf' when BUFFERED? is
  false.  Pass the port to `http-get'.  Close it upon 301/302.
* guix/scripts/substitute-binary.scm (fetch): Add `buffered?'
  parameter.  Pass it to `http-fetch'; honor it for `file' URIs.
  (guix-substitute-binary): Call `fetch' with #:buffered? #f for port RAW.
* tests/utils.scm ("filtered-port, file"): Open FILE as unbuffered.

1 files changed, 10 insertions, 11 deletions

diff --git a/tests/utils.scm b/tests/utils.scm
index c2fb274193..e8549204d0 100644
--- a/tests/utils.scm
+++ b/tests/utils.scm
@@ -102,17 +102,16 @@
     list))
 
 (test-assert "filtered-port, file"
-  (let ((file (search-path %load-path "guix.scm")))
-    (call-with-input-file file
-      (lambda (input)
-        (let*-values (((compressed pids1)
-                       (filtered-port `(,%gzip "-c" "--fast") input))
-                      ((decompressed pids2)
-                       (filtered-port `(,%gzip "-d") compressed)))
-          (and (every (compose zero? cdr waitpid)
-                      (append pids1 pids2))
-               (equal? (get-bytevector-all decompressed)
-                       (call-with-input-file file get-bytevector-all))))))))
+  (let* ((file  (search-path %load-path "guix.scm"))
+         (input (open-file file "r0")))
+    (let*-values (((compressed pids1)
+                   (filtered-port `(,%gzip "-c" "--fast") input))
+                  ((decompressed pids2)
+                   (filtered-port `(,%gzip "-d") compressed)))
+      (and (every (compose zero? cdr waitpid)
+                  (append pids1 pids2))
+           (equal? (get-bytevector-all decompressed)
+                   (call-with-input-file file get-bytevector-all))))))
 
 (test-assert "filtered-port, non-file"
   (let ((data (call-with-input-file (search-path %load-path "guix.scm")