http: attempt updating base URL only if no error

http.c supports HTTP redirects of the form

  http://foo/info/refs?service=git-upload-pack
  -> http://anything
  -> http://bar/info/refs?service=git-upload-pack

(that is to say, as long as the Git part of the path and the query
string is preserved in the final redirect destination, the intermediate
steps can have any URL). However, if one of the intermediate steps
results in an HTTP exception, a confusing "unable to update url base
from redirection" message is printed instead of a Curl error message
with the HTTP exception code.

This was introduced by 2 commits. Commit c93c92f ("http: update base
URLs when we see redirects", 2013-09-28) introduced a best-effort
optimization that required checking if only the "base" part of the URL
differed between the initial request and the final redirect destination,
but it performed the check before any HTTP status checking was done. If
something went wrong, the normal code path was still followed, so this
did not cause any confusing error messages until commit 6628eb4 ("http:
always update the base URL for redirects", 2016-12-06), which taught
http to die if the non-"base" part of the URL differed.

Therefore, teach http to check the HTTP status before attempting to
check if only the "base" part of the URL differed. This commit teaches
http_request_reauth to return early without updating options->base_url
upon an error; the only invoker of this function that passes a non-NULL
"options" is remote-curl.c (through "http_get_strbuf"), which only uses
options->base_url for an informational message in the situations that
this commit cares about (that is, when the return value is not HTTP_OK).

The included test checks that the redirect scheme at the beginning of
this commit message works, and that returning a 502 in the middle of the
redirect scheme produces the correct result. Note that this is different
from the test in commit 6628eb4 ("http: always update the base URL for
redirects", 2016-12-06) in that this commit tests that a Git-shaped URL
(http://.../info/refs?service=git-upload-pack) works, whereas commit
6628eb4 tests that a non-Git-shaped URL
(http://.../info/refs/foo?service=git-upload-pack) does not work (even
though Git is processing that URL) and is an error that is fatal, not
silently swallowed.

Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
Acked-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/http.c b/http.c
index 90a1c0f1131c4a5fcbc50d6cc81c1be9cef3cd71..1df186894d2a8b1ae17792cac72c524aa823443a 100644 (file)
--- a/http.c
+++ b/http.c
@@ -1727,6 +1727,9 @@ static int http_request_reauth(const char *url,
 {
        int ret = http_request(url, result, target, options);
 
+       if (ret != HTTP_OK && ret != HTTP_REAUTH)
+               return ret;
+
        if (options && options->effective_url && options->base_url) {
                if (update_url_from_redirect(options->base_url,
                                             url, options->effective_url)) {

diff --git a/t/lib-httpd/apache.conf b/t/lib-httpd/apache.conf
index 69174c6e3110d5e214c048aceccf07232b813ce7..0642ae7e6ef0fbbd9e7eacdebd061d258c8b4222 100644 (file)
--- a/t/lib-httpd/apache.conf
+++ b/t/lib-httpd/apache.conf
@@ -133,6 +133,15 @@ RewriteRule ^/ftp-redir/(.*)$ ftp://localhost:1000/$1 [R=302]
 RewriteRule ^/loop-redir/x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-x-(.*) /$1 [R=302]
 RewriteRule ^/loop-redir/(.*)$ /loop-redir/x-$1 [R=302]
 
+# redir-to/502/x?y -> really-redir-to?path=502/x&qs=y which returns 502
+# redir-to/x?y -> really-redir-to?path=x&qs=y -> x?y
+RewriteCond %{QUERY_STRING} ^(.*)$
+RewriteRule ^/redir-to/(.*)$ /really-redir-to?path=$1&qs=%1 [R=302]
+RewriteCond %{QUERY_STRING} ^path=502/(.*)&qs=(.*)$
+RewriteRule ^/really-redir-to$ - [R=502,L]
+RewriteCond %{QUERY_STRING} ^path=(.*)&qs=(.*)$
+RewriteRule ^/really-redir-to$ /%1?%2 [R=302]
+
 # The first rule issues a client-side redirect to something
 # that _doesn't_ look like a git repo. The second rule is a
 # server-side rewrite, so that it turns out the odd-looking

diff --git a/t/t5550-http-fetch-dumb.sh b/t/t5550-http-fetch-dumb.sh
index aeb3a63f7c07caa3f53ff4da5096dc51493dd4e3..2d3b1e9f937219b84069d9d0b1ce17129e87d110 100755 (executable)
--- a/t/t5550-http-fetch-dumb.sh
+++ b/t/t5550-http-fetch-dumb.sh
@@ -378,5 +378,14 @@ test_expect_success 'http-alternates triggers not-from-user protocol check' '
                clone $HTTPD_URL/dumb/evil.git evil-user
 '
 
+test_expect_success 'can redirect through non-"info/refs?service=git-upload-pack" URL' '
+       git clone "$HTTPD_URL/redir-to/dumb/repo.git"
+'
+
+test_expect_success 'print HTTP error when any intermediate redirect throws error' '
+       test_must_fail git clone "$HTTPD_URL/redir-to/502" 2> stderr &&
+       test_i18ngrep "unable to access.*/redir-to/502" stderr
+'
+
 stop_httpd
 test_done