We have occasionally seen bugs that affect Git running only against an
HTTP/2 web server, not an HTTP one. For instance, b66c77a64e (http:
match headers case-insensitively when redacting, 2021-09-22). But since
we have no test coverage using HTTP/2, we only uncover these bugs in the
wild.
That commit gives a recipe for converting our Apache setup to support
HTTP/2, but:
- it's not necessarily portable
- we don't want to just test HTTP/2; we really want to do a variety of
basic tests for _both_ protocols
This patch handles both problems by running a duplicate of t5551
(labeled as t5559 here) with an alternate-universe setup that enables
HTTP/2. So we'll continue to run t5551 as before, but run the same
battery of tests again with HTTP/2. If HTTP/2 isn't supported on a given
platform, then t5559 should bail during the webserver setup, and
gracefully skip all tests (unless GIT_TEST_HTTPD has been changed from
"auto" to "yes", where the point is to complain when webserver setup
fails).
In theory other http-related test scripts could benefit from the same
duplication, but doing t5551 should give us a reasonable check of basic
functionality, and would have caught both bugs we've seen in the wild
with HTTP/2.
A few notes on the implementation:
- a script enables the server side config by calling enable_http2
before starting the webserver. This avoids even trying to load any
HTTP/2 config for t5551 (which is what lets it keep working with
regular HTTP even on systems that don't support it). This also sets
a prereq which can be used by individual tests.
- As discussed in b66c77a64e, the http2 module isn't compatible with
the "prefork" mpm, so we need to pick something else. I chose
"event" here, which works on my Debian system, but it's possible
there are platforms which would prefer something else. We can adjust
that later if somebody finds such a platform.
- The test "large fetch-pack requests can be sent using chunked
encoding" makes sure we use a chunked transfer-encoding by looking
for that header in the trace. But since HTTP/2 has its own streaming
mechanisms, we won't find such a header. We could skip the test
entirely by marking it with !HTTP2. But there's some value in making
sure that the fetch itself succeeded. So instead, we'll confirm that
either we're using HTTP2 _or_ we saw the expected chunked header.
- the redaction tests fail under HTTP/2 with recent versions of curl.
This is a bug! I've marked them with !HTTP2 here to skip them under
t5559 for the moment. Using test_expect_failure would be more
appropriate, but would require a bunch of boilerplate. Since we'll
be fixing them momentarily, let's just skip them for now to keep the
test suite bisectable, and we can re-enable them in the commit that
fixes the bug.
- one alternative layout would be to push most of t5551 into a
lib-t5551.sh script, then source it from both t5551 and t5559.
Keeping t5551 intact seemed a little simpler, as its one less level
of indirection for people fixing bugs/regressions in the non-HTTP/2
tests.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
Git - fast, scalable, distributed revision control system
Git is a fast, scalable, distributed revision control system with an
unusually rich command set that provides both high-level operations
and full access to internals.
Git is an Open Source project covered by the GNU General Public
License version 2 (some parts of it are under different licenses,
compatible with the GPLv2). It was originally written by Linus
Torvalds with help of a group of hackers around the net.
Please read the file INSTALL for installation instructions.
Many Git online resources are accessible from https://git-scm.com/
including full documentation and Git related tools.
See Documentation/gittutorial.txt to get started, then see
Documentation/giteveryday.txt for a useful minimum set of commands, and
Documentation/git-<commandname>.txt for documentation of each command.
If git has been correctly installed, then the tutorial can also be
read with man gittutorial or git help tutorial, and the
documentation of each command with man git-<commandname> or git help <commandname>.
CVS users may also want to read Documentation/gitcvs-migration.txt
(man gitcvs-migration or git help cvs-migration if git is
installed).
Those wishing to help with error message, usage and informational message
string translations (localization l10) should see po/README.md
(a po file is a Portable Object file that holds the translations).
Issues which are security relevant should be disclosed privately to
the Git Security mailing list git-security@googlegroups.com.
The maintainer frequently sends the "What's cooking" reports that
list the current status of various development topics to the mailing
list. The discussion following them give a good reference for
project status, development direction and remaining tasks.
The name "git" was given by Linus Torvalds when he wrote the very
first version. He described the tool as "the stupid content tracker"
and the name as (depending on your mood):
random three-letter combination that is pronounceable, and not
actually used by any common UNIX command. The fact that it is a
mispronunciation of "get" may or may not be relevant.
stupid. contemptible and despicable. simple. Take your pick from the
dictionary of slang.
"global information tracker": you're in a good mood, and it actually
works for you. Angels sing, and a light suddenly fills the room.
"goddamn idiotic truckload of sh*t": when it breaks
73c49a4474
