Re: [PATCH 6/8] ssh: 'auto' variant to select between 'ssh' and 'simple'
From: Junio C Hamano <hidden>
Date: 2017-11-21 01:48:45
Jonathan Nieder [off-list ref] writes:
Android's "repo" tool is a tool for managing a large codebase consisting of multiple smaller repositories, similar to Git's submodule feature. Starting with Git 94b8ae5a (ssh: introduce a 'simple' ssh variant, 2017-10-16), users noticed that it stopped handling the port in ssh:// URLs. ... Reported-by: William Yan <redacted> Improved-by: Jonathan Tan [off-list ref] Signed-off-by: Jonathan Nieder <redacted> ---
Not a big issue, but the above made me wonder, due to lack of any signed-off-by before improved-by, what "base" was improved by JTan. If you were writing a change before formally passing it around with your sign-off and somebody had a valuable input to improve it, it seems that people say helped-by around here.
ssh.variant:: - Depending on the value of the environment variables `GIT_SSH` or - `GIT_SSH_COMMAND`, or the config setting `core.sshCommand`, Git - auto-detects whether to adjust its command-line parameters for use - with ssh (OpenSSH), plink or tortoiseplink, as opposed to the default - (simple). + By default, Git determines the command line arguments to use + based on the basename of the configured SSH command (configured + using the environment variable `GIT_SSH` or `GIT_SSH_COMMAND` or + the config setting `core.sshCommand`). If the basename is + unrecognized, Git will attempt to detect support of OpenSSH + options by first invoking the configured SSH command with the + `-G` (print configuration) option and will subsequently use + OpenSSH options (if that is successful) or no options besides + the host and remote command (if it fails). + -The config variable `ssh.variant` can be set to override this auto-detection; -valid values are `ssh`, `simple`, `plink`, `putty` or `tortoiseplink`. Any -other value will be treated as normal ssh. This setting can be overridden via -the environment variable `GIT_SSH_VARIANT`. +The config variable `ssh.variant` can be set to override this detection. +Valid values are `ssh` (to use OpenSSH options), `plink`, `putty`, +`tortoiseplink`, `simple` (no options except the host and remote command). +The default auto-detection can be explicitly requested using the value +`auto`. Any other value is treated as `ssh`. This setting can also be +overridden via the environment variable `GIT_SSH_VARIANT`. +
Cleanly written and easily read. Good.
quoted hunk
@@ -982,6 +985,21 @@ static void fill_ssh_args(struct child_process *conn, const char *ssh_host, variant = determine_ssh_variant(ssh, 0); } + if (variant == VARIANT_AUTO) { + struct child_process detect = CHILD_PROCESS_INIT; + + detect.use_shell = conn->use_shell; + detect.no_stdin = detect.no_stdout = detect.no_stderr = 1; + + argv_array_push(&detect.args, ssh); + argv_array_push(&detect.args, "-G"); + push_ssh_options(&detect.args, &detect.env_array, + VARIANT_SSH, port, flags); + argv_array_push(&detect.args, ssh_host); + + variant = run_command(&detect) ? VARIANT_SIMPLE : VARIANT_SSH; + }
I briefly wondered if it safe to simply append "-G" in both cases, i.e. where "ssh" came from GIT_SSH and it came from GIT_SSH_COMMAND, but in the real invocation we see in the post-context of this hunk, we'd push options the same way regardless, so it should be fine.
argv_array_push(&conn->args, ssh); push_ssh_options(&conn->args, &conn->env_array, variant, port, flags); argv_array_push(&conn->args, ssh_host);
+test_expect_success 'OpenSSH-like uplink is treated as ssh' ' + write_script "$TRASH_DIRECTORY/uplink" <<-EOF && + if test "\$1" = "-G" + then + exit 0 + fi && + exec "\$TRASH_DIRECTORY/ssh$X" "\$@" + EOF
OK.
+ test_when_finished "rm -f \"\$TRASH_DIRECTORY/uplink\"" && + GIT_SSH="$TRASH_DIRECTORY/uplink" && + test_when_finished "GIT_SSH=\"\$TRASH_DIRECTORY/ssh\$X\"" && + git clone "[myhost:123]:src" ssh-bracket-clone-sshlike-uplink && + expect_ssh "-p 123" myhost src +' + test_expect_success 'plink is treated specially (as putty)' ' copy_ssh_wrapper_as "$TRASH_DIRECTORY/plink" && git clone "[myhost:123]:src" ssh-bracket-clone-plink-0 &&
Thanks.