docs/config: mention protocol implications of url.insteadOf

If a URL rewrite switches the protocol to something
nonstandard (like "persistent-https" for "https"), the user
may be bitten by the fact that the default protocol
restrictions are different between the two. Let's drop a
note in insteadOf that points the user in the right
direction.

It would be nice if we could make this work out of the box,
but we can't without knowing the security implications of
the user's rewrite. Only the documentation for a particular
remote helper can advise one way or the other. Since we do
include the persistent-https helper in contrib/ (and since
it was the helper in the real-world case that inspired that
patch), let's also drop a note there.

Suggested-by: Elliott Cable <me@ell.io>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/Documentation/config.txt b/Documentation/config.txt
index 475e874d51550eba26a578c0ce3b17b61384fddc..2c1d7494b92134f8b9cc53f932ef381e882d6808 100644 (file)
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -3208,6 +3208,13 @@ url.<base>.insteadOf::
        the best alternative for the particular user, even for a
        never-before-seen repository on the site.  When more than one
        insteadOf strings match a given URL, the longest match is used.
++
+Note that any protocol restrictions will be applied to the rewritten
+URL. If the rewrite changes the URL to use a custom protocol or remote
+helper, you may need to adjust the `protocol.*.allow` config to permit
+the request.  In particular, protocols you expect to use for submodules
+must be set to `always` rather than the default of `user`. See the
+description of `protocol.allow` above.
 
 url.<base>.pushInsteadOf::
        Any URL that starts with this value will not be pushed to;

diff --git a/contrib/persistent-https/README b/contrib/persistent-https/README
index f784dd2e66b9373285027dc1c47948231b172f46..7c4cd8d257da0d64098f6b31834280e90f6e4f31 100644 (file)
--- a/contrib/persistent-https/README
+++ b/contrib/persistent-https/README
@@ -35,6 +35,16 @@ to use persistent-https:
 [url "persistent-http"]
        insteadof = http
 
+You may also want to allow the use of the persistent-https helper for
+submodule URLs (since any https URLs pointing to submodules will be
+rewritten, and Git's out-of-the-box defaults forbid submodules from
+using unknown remote helpers):
+
+[protocol "persistent-https"]
+       allow = always
+[protocol "persistent-http"]
+       allow = always
+
 
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 # BUILDING FROM SOURCE