[PATCH] contrib/hooks: avoid requiring root access in usage instructions

[PATCH] contrib/hooks: avoid requiring root access in usage instructions

[Jonathan Nieder]

Comments in hooks/post-receive-email suggest:

 For example, on debian the hook is stored in
 /usr/share/git-core/contrib/hooks/post-receive-email:

  chmod a+x post-receive-email
  cd /path/to/your/repository.git
  ln -sf /usr/share/git-core/contrib/hooks/post-receive-email hooks/post-receive

Doing that means changing permissions on a file provided by a package,
which is problematic in a number of ways: the permissions would be
likely to change back in later upgrades, and changing them requires
root access.  Copying the script into each repo that uses it is not
much better, since each copy would be maintained separately and not
benefit from bugfixes in the master copy.

Better to ship the hook with executable permission and remove the
chmod line so enabling the hook becomes a one-step process: just
symlink it into place.

Likewise for the pre-auto-gc-battery hook.

Reported-by: Olivier Berger <olivier.berger@it-sudparis.eu>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
From <http://bugs.debian.org/687391>.

Thoughts?
Jonathan

 contrib/hooks/post-receive-email  | 1 -
 contrib/hooks/pre-auto-gc-battery | 1 -
 2 files changed, 2 deletions(-)
 mode change 100644 => 100755 contrib/hooks/pre-auto-gc-battery

diff --git a/contrib/hooks/post-receive-email b/contrib/hooks/post-receive-email
index 8ca6607a..359f1ad2 100755
--- a/contrib/hooks/post-receive-email
+++ b/contrib/hooks/post-receive-email
@@ -13,7 +13,6 @@
 # For example, on debian the hook is stored in
 # /usr/share/git-core/contrib/hooks/post-receive-email:
 #
-#  chmod a+x post-receive-email
 #  cd /path/to/your/repository.git
 #  ln -sf /usr/share/git-core/contrib/hooks/post-receive-email hooks/post-receive
 #
diff --git a/contrib/hooks/pre-auto-gc-battery b/contrib/hooks/pre-auto-gc-battery
old mode 100644
new mode 100755
index 1f914c94..9d0c2d19
--- a/contrib/hooks/pre-auto-gc-battery
+++ b/contrib/hooks/pre-auto-gc-battery
@@ -13,7 +13,6 @@
 # For example, if the hook is stored in
 # /usr/share/git-core/contrib/hooks/pre-auto-gc-battery:
 #
-# chmod a+x pre-auto-gc-battery
 # cd /path/to/your/repository.git
 # ln -sf /usr/share/git-core/contrib/hooks/pre-auto-gc-battery \
 #	hooks/pre-auto-gc
-- 
1.8.0.rc2

Re: [PATCH] contrib/hooks: avoid requiring root access in usage instructions

[Junio C Hamano]

Jonathan Nieder <jrnieder@gmail.com> writes:

> Comments in hooks/post-receive-email suggest:
>
>  For example, on debian the hook is stored in
>  /usr/share/git-core/contrib/hooks/post-receive-email:
>
>   chmod a+x post-receive-email
>   cd /path/to/your/repository.git
>   ln -sf /usr/share/git-core/contrib/hooks/post-receive-email hooks/post-receive
>
> Doing that means changing permissions on a file provided by a package,
> which is problematic in a number of ways: the permissions would be
> likely to change back in later upgrades, and changing them requires
> root access.  Copying the script into each repo that uses it is not
> much better, since each copy would be maintained separately and not
> benefit from bugfixes in the master copy.
>
> Better to ship the hook with executable permission and remove the
> chmod line so enabling the hook becomes a one-step process: just
> symlink it into place.
>
> Likewise for the pre-auto-gc-battery hook.
>
> Reported-by: Olivier Berger <olivier.berger@it-sudparis.eu>
> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
> ---
> From <http://bugs.debian.org/687391>.
>
> Thoughts?

We already encourage casting-in-stone a particular version of the
sample hook when a new repository is created by copying them from
the template directory.  This prevents from surprising users when an
updated version of Git changes the behaviour of these samples.  Even
if you think bugs in older ones may be corrected in newer ones,
silently updating the hook the user chose to use by inspecting one
particular version is not something we would want to do lightly. A
buggy devil you know is better than a devil that suddenly changes
its behaviour depending on when your sysadmin updates the version of
Git without your knowing.

I personally think the same applies to these contrib/ hooks, and I
would think it is simpler and more consistent to correct the
instruction in these files to tell users to copy them.

Adding +x bits to these files is a good idea but that is orthogonal
to copying vs symlinking, I think.

> Jonathan
>
>  contrib/hooks/post-receive-email  | 1 -
>  contrib/hooks/pre-auto-gc-battery | 1 -
>  2 files changed, 2 deletions(-)
>  mode change 100644 => 100755 contrib/hooks/pre-auto-gc-battery
>
> diff --git a/contrib/hooks/post-receive-email b/contrib/hooks/post-receive-email
> index 8ca6607a..359f1ad2 100755
> --- a/contrib/hooks/post-receive-email
> +++ b/contrib/hooks/post-receive-email
> @@ -13,7 +13,6 @@
>  # For example, on debian the hook is stored in
>  # /usr/share/git-core/contrib/hooks/post-receive-email:
>  #
> -#  chmod a+x post-receive-email
>  #  cd /path/to/your/repository.git
>  #  ln -sf /usr/share/git-core/contrib/hooks/post-receive-email hooks/post-receive
>  #
> diff --git a/contrib/hooks/pre-auto-gc-battery b/contrib/hooks/pre-auto-gc-battery
> old mode 100644
> new mode 100755
> index 1f914c94..9d0c2d19
> --- a/contrib/hooks/pre-auto-gc-battery
> +++ b/contrib/hooks/pre-auto-gc-battery
> @@ -13,7 +13,6 @@
>  # For example, if the hook is stored in
>  # /usr/share/git-core/contrib/hooks/pre-auto-gc-battery:
>  #
> -# chmod a+x pre-auto-gc-battery
>  # cd /path/to/your/repository.git
>  # ln -sf /usr/share/git-core/contrib/hooks/pre-auto-gc-battery \
>  #	hooks/pre-auto-gc

Re: [PATCH] contrib/hooks: avoid requiring root access in usage instructions

[Jonathan Nieder]

Junio C Hamano wrote:

> We already encourage casting-in-stone a particular version of the
> sample hook when a new repository is created by copying them from
> the template directory.  This prevents from surprising users when an
> updated version of Git changes the behaviour of these samples.  Even
> if you think bugs in older ones may be corrected in newer ones,
> silently updating the hook the user chose to use by inspecting one
> particular version is not something we would want to do lightly.

For context, the sample hooks you are talking about are the *.sample
files from the templates/ directory.  Except for post-update.sample,
most are not very useful out of the box, and they are very much
intended as examples to start people's thinking, as opposed to
something one-size-fits-all.

By contrast, the post-receive-email script from contrib is a complete
program with a well-defined behavior and configuration that have
stayed consistent while the details of its implementation improved.
It can be used by symlinking into place, but maybe a better set of
instructions would say

	# This script takes no arguments and expects the same input format
	# as git's post-receive hook, so if this script is at
	# /usr/share/git-core/contrib/hooks/post-receive-email (as it is
	# on Debian and Fedora), you can do
	#
	#  cd /path/to/your/repository.git
	#  echo '#!/bin/sh' >hooks/post-receive
	#  echo 'exec /usr/share/git-core/contrib/hooks/post-receive-email' \
	#	>>hooks/post-receive
	#  chmod +x hooks/post-receive

That would make it more obvious what I can do next if my post-receive
input should be passed both to post-receive-email and some other tool
(perhaps in a pipeline using "tee").

Hmm?
Jonathan