Re: [PATCH 1/9] fetch: optionally allow disabling FETCH_HEAD update

From: Jonathan Nieder <jrnieder@gmail.com>
To: Junio C Hamano <gitster@pobox.com>
Cc: Emily Shaffer <emilyshaffer@google.com>,
	Junio C Hamano via GitGitGadget <gitgitgadget@gmail.com>,
	git@vger.kernel.org, sandals@crustytoothpaste.net,
	steadmon@google.com, peff@peff.net, congdanhqx@gmail.com,
	phillip.wood123@gmail.com, sluongng@gmail.com,
	jonathantanmy@google.com,
	Derrick Stolee <derrickstolee@github.com>
Subject: Re: [PATCH 1/9] fetch: optionally allow disabling FETCH_HEAD update
Date: Wed, 12 Aug 2020 18:45:32 -0700	[thread overview]
Message-ID: <20200813014532.GC104953@google.com> (raw)
In-Reply-To: <xmqqo8nf4dkb.fsf@gitster.c.googlers.com>

Junio C Hamano wrote:

> As the feature itself is primarily designed for scripts that want to
> always disable writing of FETCH_HEAD, I can certainly understand a
> short-term/sighted view of not wanting to add configuration, though.

Yes, I think that since this feature is primarily designed for
scripts, an option is more likely to be useful for them than a config
setting.  An option kicks in when the calling script requests it; a
config setting can kick in even when they didn't intend to request it.

My opinion would change if we think that we're going to flip the
default to --no-write-fetch-head some day, in which case a config
setting would be a good way to request a preview of the future.  But I
don't believe anyone's brought that up as a direction we want to
pursue.

[...]
>>            If someone specifies both, then they probably want to say
>> "show me what I would write to FETCH_HEAD but don't actually do that" -
>> which isn't info that we print anyways, right now.
>
> Do you mean "don't actually write but show it to standard output
> instead" or something?

My take is that the behavior that the patch implements for --dry-run
--write-fetch-head is correct and what a user would want: it acts *as
though* you passed --write-fetch-head (including producing the same
console output), without producing mutations that the user might
regret (such as updating FETCH_HEAD).

Thanks and hope that helps,
Jonathan