ZheNing Hu [off-list ref] writes:
The configuration is like this:
trailer.bug.key=BUG:
trailer.bug.ifexists=add
trailer.bug.cmd=echo "123"
And use:
$ git interpret-trailers --trailer="bug:456" --trailer="bug:789"<<-EOF
EOF
BUG: 123
BUG: 123 456
BUG: 123 789
I think that is quite expected. You said the command to run is
'echo 123', and that is not "pick a directory $D on $PATH where
there is an executable '$D/echo 123' exists, and run that". It
runs the given command with the shell, and in general that is
what we want for end-user supplied commands specified in the
configuration file [*1*].
So we form a shell command whose beginning is 'echo 123' and tuck
the argument after that command line, so it is understandable that
"echo 123 456" gets executed for "--trailer=bug:456".
I wasn't following the discussion between you and Christian closely
but I recall seeing him saying that the command is executed one
extra time without any arg before it is run for actual --trailer
requests with the value? I am guessing that is where the first
output "BUG: 123" (without anything else) is coming from.
*1* Imagine .editor set to 'emacs -nw' or 'vim -f'; we do not want
Git to find a directory on $PATH that has an executable whose
name is 'emacs -nw' and run that file (i.e. give 'emacs -nw' as
the first argument to execlp()). Instead, you'd want to behave
as if the user typed "emacs -nw", followed by any arguments we
want to give to it (in .editor's case, the name of the file to
be edited) properly quoted for the shell.
And the way we do so is to form a moral equivalent of
execlp("sh", "-c", "emacs -nw $@", ...);
and put the arguments at the end where I wrote ... (we actually
do so with execvp(), but illustrating with execlp() is easier to
read and write---hence "a moral equivalent of").
Junio C Hamano [off-list ref] 于2021年4月1日周四 上午2:20写道：
ZheNing Hu [off-list ref] writes:
quoted
The configuration is like this:
trailer.bug.key=BUG:
trailer.bug.ifexists=add
trailer.bug.cmd=echo "123"
And use:
$ git interpret-trailers --trailer="bug:456" --trailer="bug:789"<<-EOF
EOF
BUG: 123
BUG: 123 456
BUG: 123 789
I think that is quite expected. You said the command to run is
'echo 123', and that is not "pick a directory $D on $PATH where
there is an executable '$D/echo 123' exists, and run that". It
runs the given command with the shell, and in general that is
what we want for end-user supplied commands specified in the
configuration file [*1*].
I agree that if you want to use execv directly to execute a terminal
command, if arg[0] is something like "emacs -nw", error will be
reported:"No such file or directory". But by wrapping a layer of
"sh" "-c", The program name 'emacs' in 'emacs -nw' can be
found and executed normally.
So we form a shell command whose beginning is 'echo 123' and tuck
the argument after that command line, so it is understandable that
"echo 123 456" gets executed for "--trailer=bug:456".
I wasn't following the discussion between you and Christian closely
but I recall seeing him saying that the command is executed one
extra time without any arg before it is run for actual --trailer
requests with the value? I am guessing that is where the first
output "BUG: 123" (without anything else) is coming from.
Exactly.
Each .command/.cmd willl executes this 'beforeCLI' operation once,
I use ifexists='add' here just for seeing the effect, In general, we will
use ifexists='replace'.
*1* Imagine .editor set to 'emacs -nw' or 'vim -f'; we do not want
Git to find a directory on $PATH that has an executable whose
name is 'emacs -nw' and run that file (i.e. give 'emacs -nw' as
the first argument to execlp()). Instead, you'd want to behave
as if the user typed "emacs -nw", followed by any arguments we
want to give to it (in .editor's case, the name of the file to
be edited) properly quoted for the shell.
And the way we do so is to form a moral equivalent of
execlp("sh", "-c", "emacs -nw $@", ...);
and put the arguments at the end where I wrote ... (we actually
do so with execvp(), but illustrating with execlp() is easier to
read and write---hence "a moral equivalent of").
I can see the benefits of this.