* [PATCH] builtin/receive-pack.c: remove redundant 'if'
@ 2022-05-18 20:26 Taylor Blau
2022-05-18 21:16 ` Junio C Hamano
0 siblings, 1 reply; 2+ messages in thread
From: Taylor Blau @ 2022-05-18 20:26 UTC (permalink / raw)
To: git; +Cc: avarab, gitster
In c7c4bdeccf (run-command API: remove "env" member, always use
"env_array", 2021-11-25), there was a push to replace
cld.env = env->v;
with
strvec_pushv(&cld.env_array, env->v);
The conversion in c7c4bdeccf was mostly plug-and-play, with the snag
that some instances of strvec_pushv() became guarded with a NULL check
to ensure that the second argument was non-NULL.
This conversion was slightly over-eager to add a conditional in
builtin/receive-pack.c::unpack(), since we know at the point that we
add the result of `tmp_objdir_env()` into the child process's
environment, that `tmp_objdir` is non-NULL.
This follows from the conditional just before our strvec_pushv() call
(which returns from the function if `tmp_objdir` was NULL), as well as
the call to tmp_objdir_add_as_alternate() just below, which relies on
its argument (`tmp_objdir`) being non-NULL.
In the meantime, this extra conditional isn't hurting anything. But it
is redundant and thus unnecessarily confusing. So let's remove it.
Signed-off-by: Taylor Blau <me@ttaylorr.com>
---
builtin/receive-pack.c | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)
diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index 9aabffa1af..f673e0e76e 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -2214,8 +2214,7 @@ static const char *unpack(int err_fd, struct shallow_info *si)
close(err_fd);
return "unable to create temporary object directory";
}
- if (tmp_objdir)
- strvec_pushv(&child.env_array, tmp_objdir_env(tmp_objdir));
+ strvec_pushv(&child.env_array, tmp_objdir_env(tmp_objdir));
/*
* Normally we just pass the tmp_objdir environment to the child
--
2.36.1.94.gb0d54bedca
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] builtin/receive-pack.c: remove redundant 'if'
2022-05-18 20:26 [PATCH] builtin/receive-pack.c: remove redundant 'if' Taylor Blau
@ 2022-05-18 21:16 ` Junio C Hamano
0 siblings, 0 replies; 2+ messages in thread
From: Junio C Hamano @ 2022-05-18 21:16 UTC (permalink / raw)
To: Taylor Blau; +Cc: git, avarab
Taylor Blau <me@ttaylorr.com> writes:
> The conversion in c7c4bdeccf was mostly plug-and-play, with the snag
> that some instances of strvec_pushv() became guarded with a NULL check
> to ensure that the second argument was non-NULL.
Thanks. I am not sure about the reference to plug-and-play but most
of the changes in the commit were mechanical conversion akin to
@@
struct child_process C;
expression V;
@@
-C.env = V;
+strvec_pushv(&C.env_array, V);
but a few have rewritten them to
@@
-C.env = V;
+if (V) strvec_pushv(&C.env_array, V);
And this hunk is one of them. If we know V is never NULL, the check
becomes redundant, and we can tell tmp_objdir is not NULL at this
point in the control flow. If C.env (or C.env_array) weren't empty
by the time the control reaches at this point, however, this rewrite
changes behaviour X-<.
Another one in connected.c looks like this:
diff --git a/connected.c b/connected.c
index 35bd4a2638..ed3025e7a2 100644
--- a/connected.c
+++ b/connected.c
@@ -109,7 +109,8 @@ int check_connected(oid_iterate_fn fn, void *cb_data,
_("Checking connectivity"));
rev_list.git_cmd = 1;
- rev_list.env = opt->env;
+ if (opt->env)
+ strvec_pushv(&rev_list.env_array, opt->env);
rev_list.in = -1;
rev_list.no_stdout = 1;
if (opt->err_fd)
If opt->env can be NULL, the original code would have just cleared
existing rev_list.env but new code instead keeps whatever is in
rev_list.env, which technically speaking changes the behaviour but
we are saved by the fact that rev_list.env hasn't been touched at
this point in the control flow since it was initialized, which makes
it a correct conversion.
There are few others in editor.c::launch_specified_editor(),
run-command.c::run_command_v_opt_cd_env_tr2() and
run-command.c::run_hook_ve(), but the story is identical in these
places.
> diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
> index 9aabffa1af..f673e0e76e 100644
> --- a/builtin/receive-pack.c
> +++ b/builtin/receive-pack.c
> @@ -2214,8 +2214,7 @@ static const char *unpack(int err_fd, struct shallow_info *si)
> close(err_fd);
> return "unable to create temporary object directory";
> }
> - if (tmp_objdir)
> - strvec_pushv(&child.env_array, tmp_objdir_env(tmp_objdir));
> + strvec_pushv(&child.env_array, tmp_objdir_env(tmp_objdir));
>
> /*
> * Normally we just pass the tmp_objdir environment to the child
So, in short, looks good, well spotted, and will apply.
Thanks.
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