Re: [PATCH v5 2/8] config: add new way to pass config via `--config-env`

From: Junio C Hamano <gitster@pobox.com>
Date: Dec 23, 2020, 21:35 UTC
Message-ID: <xmqq5z4s6w8w.fsf@gitster.c.googlers.com>
In-Reply-To: <56c9221c4cc8c3e52823938938e3f65a3433f9bf.1608104755.git.ps@pks.im>

Patrick Steinhardt <ps@pks.im> writes:

> +--config-env=<name>=<envvar>::
> +	Like `-c <name>=<var>` except the value is the name of an
> +	environment variable from which to retrieve the value. Unlike

Let's avoid overusing the word "value", as it can refer to <name>=<envvar> as the whole (which is the value given to --config-env), or <envvar> itself (which may appear to the value given to <name>), or the value in the environment veraible.

	Like `-c <name>=<value>`, give configuration variable
	'<name>' a value, where <envvar> is the name of an
	environment variable from which to retrieve the
	value.

or something along that line.

> +	`-c` there is no shortcut for directly setting the value to an
> +	empty string, instead the environment variable itself must be
> +	set to the empty strin. Errors if the `<envvar>` does not exist

	set to the empty string.  It is an error if the ...

> +	in the environment. `<envvar>` may not contain an equals sign
> +	to avoid ambiguity with `<name>`s which contain one.

	which may contain one.

Show 10 quoted lines

> +	This is useful for cases where you want to pass transitory
> +	configuration options to git, but are doing so on OS's where
> +	other processes might be able to read your cmdline
> +	(e.g. `/proc/self/cmdline`), but not your environ
> +	(e.g. `/proc/self/environ`). That behavior is the default on
> +	Linux, but may not be on your system.
> +
> +	Note that this might add security for variables such as
> +	`http.extraHeader` where the sensitive information is part of
> +	the value, but not e.g. `url.<base.insteadOf` where the

"url.<base>.insteadOf"

> +	sensitive information can be part of the key.

When writing multi-paragraph description, the second and later paragraphs need to be dedented and the paragraph breaks are denoted not by a blank line but by a line with only a single '+' on it.

I didn't look at the implementation or tests, as I think it hasn't changed since the last round, and the last round was looked at by Peff already.

Thanks.