transport-helper: report errors properly

If a push fails because the remote-helper died (with fast-export),
the user may not see any error message. We do correctly die with a
failed exit code, as we notice that the helper has died while
reading back the ref status from the helper. However, we don't print
any message. This is OK if the helper itself printed a useful error
message, but we cannot count on that; let's let the user know that
the helper failed.

In the long run, it may make more sense to propagate the error back
up to push, so that it can present the usual status table and give a
nicer message. But this is a much simpler fix that can help
immediately.

While we're adding tests, let's also confirm that the remote-helper
dying is also detected when importing refs. We currently do so
robustly when the helper uses the "done" feature (and that is what
we test).  We cannot do so reliably when the helper does not use the
"done" feature, but it is not even worth testing; the right solution
is for the helper to start using "done".

Suggested-by: Jeff King <peff@peff.net>
Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: Jeff King <peff@peff.net>
Acked-by: Sverre Rabbelier <srabbelier@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
transport-helper: mention helper name when it dies

When we try to read from a remote-helper and get EOF or an
error, we print a message indicating that the helper died.
However, users may not know that a remote helper was in use
(e.g., when using git-over-http), or even what a remote
helper is.

Let's print the name of the helper (e.g., "git-remote-https");
this makes it more obvious what the program is for, and
provides a useful token for reporting bugs or searching for
more information (e.g., in manpages).

Signed-off-by: Jeff King <peff@peff.net>
Acked-by: Sverre Rabbelier <srabbelier@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
transport-helper: improve push messages

If there's already a remote-helper tracking ref, we can fetch the SHA-1
to report proper push messages (as opposed to always reporting
[new branch]).

The remote-helper currently can specify the old SHA-1 to avoid this
problem, but there's no point in forcing all remote-helpers to be aware
of git commit ids; they should be able to be agnostic of them.

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
transport-helper: clarify *:* refspec

The *:* refspec doesn't work, and never has, clarify the code and
documentation to reflect that. This in effect reverts commit 9e7673e
(gitremote-helpers(1): clarify refspec behaviour).

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
transport-helper: update refspec documentation

The refspec capability is not only used by 'import', also by
'export', and it's recommended in both.

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
transport-helper: clarify pushing without refspecs

This has never worked, since it's inception the code simply skips all
the refs, essentially telling fast-export to do nothing.

Let's at least tell the user what's going on.

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
transport-helper: warn when refspec is not used

For the modes that need it. In the future we should probably error out,
instead of providing half-assed support.

The reason we want to do this is because if it's not present, the remote
helper might be updating refs/heads/*, or refs/remotes/origin/*,
directly, and in the process fetch will get confused trying to update
refs that are already updated, or older than what they should be. We
shouldn't be messing with the rest of git.

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
transport-helper: trivial code shuffle

Just shuffle the die() part to make it more explicit, and cleanup the
code-style.

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
transport-helper: update remote helper namespace

When pushing, the remote namespace is updated correctly
(e.g. refs/origin/master), but not the remote helper's
(e.g. refs/testgit/origin/master), which currently is only
updated while fetching.

Since the remote namespace is used to tell fast-export which commits
to avoid (because they were already imported/exported), it makes
sense to have them in sync so they don't get generated twice. If the
remote helper was implemented properly, they would be ignored, if
not, they probably would end up repeated.

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
t5801: "VAR=VAL shell_func args" is forbidden

It is not a portable expectation that a single-shot environment
variable assignment works when calling a shell function, not a
command.

Set and export the variable before calling "test_must_fail git push"
instead.  This change would not hurt because this is the last
command in the subprocess and the environment will not seep through
to later tests without using a single-shot assignment.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
git-remote-testgit: avoid process substitution

The implementation of bash on Windows does not offer process substitution.

Signed-off-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
git-remote-testgit: further remove some bashisms

Signed-off-by: Johannes Sixt <j6t@kdbg.org>
git-remote-testgit: build it to run under $SHELL_PATH

Just like all the other shell scripts, replace the shebang line to
make sure it runs under the shell the user specified.

As this no longer depends on bashisms, t5801 does not have to say
bash must be available somewhere on the system.

Signed-off-by: Junio C Hamano <gitster@pobox.com>
Merge branch 'js/transport-helper-error-reporting-fix' into fc/makefile

* js/transport-helper-error-reporting-fix:
  git-remote-testgit: build it to run under $SHELL_PATH
  git-remote-testgit: further remove some bashisms
  git-remote-testgit: avoid process substitution
  t5801: "VAR=VAL shell_func args" is forbidden
  transport-helper: update remote helper namespace
  transport-helper: trivial code shuffle
  transport-helper: warn when refspec is not used
  transport-helper: clarify pushing without refspecs
  transport-helper: update refspec documentation
  transport-helper: clarify *:* refspec
  transport-helper: improve push messages
  transport-helper: mention helper name when it dies
  transport-helper: report errors properly

Conflicts:
	t/t5801-remote-helpers.sh
build: generate and clean test scripts

Commit 416fda6 (build: do not install git-remote-testpy) made it so
git-remote-testpy is not only not installed, but also not generated
by default.  From a fresh checkout, "make --test=5800 test" would
have failed.

This was not found primarily because "make clean" failed to remove
git-remote-testpy, which is another bug in the same commit.

Fix the former by having 'all' target depend on $(NO_INSTALL) and
the latter by removing $(NO_INSTALL) in the 'clean' target.

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
build: do not install git-remote-testgit

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Makefile: use $^ to avoid listing prerequisites on the command line

There's no need to list again the prerequisites.

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>