* [PATCH v1] hook: add sample template for push-to-checkout
@ 2020-10-15 18:47 Adam Spiers
2020-10-15 20:43 ` Junio C Hamano
0 siblings, 1 reply; 3+ messages in thread
From: Adam Spiers @ 2020-10-15 18:47 UTC (permalink / raw)
To: git list
The template is a more-or-less exact translation to shell of the C
code for the default behaviour for git's push-to-checkout hook defined
in the push_to_deploy() function in builtin/receive-pack.c, to serve
as a convenient starting point for modification.
It also contains relevant text extracted from the git-config(1) and
githooks(5) man pages.
Signed-off-by: Adam Spiers <git@adamspiers.org>
---
templates/hooks--push-to-checkout.sample | 74 ++++++++++++++++++++++++
1 file changed, 74 insertions(+)
create mode 100755 templates/hooks--push-to-checkout.sample
diff --git a/templates/hooks--push-to-checkout.sample b/templates/hooks--push-to-checkout.sample
new file mode 100755
index 0000000000..2c6e06f8f1
--- /dev/null
+++ b/templates/hooks--push-to-checkout.sample
@@ -0,0 +1,74 @@
+#!/bin/bash
+
+# An example hook script to update a checked-out tree on a git push.
+#
+# This hook is invoked by git-receive-pack(1) when it reacts to git
+# push and updates reference(s) in its repository, and when the push
+# tries to update the branch that is currently checked out and the
+# receive.denyCurrentBranch configuration variable is set to
+# updateInstead.
+#
+# By default, such a push is refused if the working tree and the index
+# of the remote repository has any difference from the currently
+# checked out commit; when both the working tree and the index match
+# the current commit, they are updated to match the newly pushed tip
+# of the branch. This hook is to be used to override the default
+# behaviour; however the code below reimplements the default behaviour
+# as a starting point for convenient modification.
+#
+# The hook receives the commit with which the tip of the current
+# branch is going to be updated:
+commit="$1"
+#echo "push-to-checkout $commit"
+
+# It can exit with a non-zero status to refuse the push (when it does
+# so, it must not modify the index or the working tree).
+die () {
+ echo >&2 "$*"
+ exit 1
+}
+
+# Or it can make any necessary changes to the working tree and to the
+# index to bring them to the desired state when the tip of the current
+# branch is updated to the new commit, and exit with a zero status.
+#
+# For example, the hook can simply run git read-tree -u -m HEAD "$1"
+# in order to emulate git fetch that is run in the reverse direction
+# with git push, as the two-tree form of git read-tree -u -m is
+# essentially the same as git switch or git checkout that switches
+# branches while keeping the local changes in the working tree that do
+# not interfere with the difference between the branches.
+
+# The below is a more-or-less exact translation to shell of the C code
+# for the default behaviour for git's push-to-checkout hook defined in
+# the push_to_deploy() function in builtin/receive-pack.c.
+#
+# Note that the hook will be executed from the repository directory,
+# not from the working tree, so if you want to perform operations on
+# the working tree, you will have to adapt your code accordingly, e.g.
+# by adding "cd .." or using relative paths.
+
+if ! git update-index -q --ignore-submodules --refresh; then
+ die "Up-to-date check failed"
+fi
+
+if ! git diff-files --quiet --ignore-submodules --; then
+ die "Working directory has unstaged changes"
+fi
+
+# This is a rough translation of:
+#
+# head_has_history() ? "HEAD" : EMPTY_TREE_SHA1_HEX
+if git cat-file -t HEAD >&/dev/null; then
+ head=HEAD
+else
+ head=4b825dc642cb6eb9a060e54bf8d69288fbee4904
+fi
+
+if ! git diff-index --quiet --cached --ignore-submodules $head --; then
+ die "Working directory has staged changes"
+fi
+
+if ! git read-tree -u -m $commit; then
+ die "Could not update working tree to new HEAD"
+fi
--
2.26.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH v1] hook: add sample template for push-to-checkout
2020-10-15 18:47 [PATCH v1] hook: add sample template for push-to-checkout Adam Spiers
@ 2020-10-15 20:43 ` Junio C Hamano
2020-10-15 22:54 ` [PATCH v2] " Adam Spiers
0 siblings, 1 reply; 3+ messages in thread
From: Junio C Hamano @ 2020-10-15 20:43 UTC (permalink / raw)
To: Adam Spiers; +Cc: git list
Adam Spiers <git@adamspiers.org> writes:
> The template is a more-or-less exact translation to shell of the C
> code for the default behaviour for git's push-to-checkout hook defined
> in the push_to_deploy() function in builtin/receive-pack.c, to serve
> as a convenient starting point for modification.
>
> It also contains relevant text extracted from the git-config(1) and
> githooks(5) man pages.
>
> Signed-off-by: Adam Spiers <git@adamspiers.org>
> ---
> templates/hooks--push-to-checkout.sample | 74 ++++++++++++++++++++++++
> 1 file changed, 74 insertions(+)
> create mode 100755 templates/hooks--push-to-checkout.sample
>
> diff --git a/templates/hooks--push-to-checkout.sample b/templates/hooks--push-to-checkout.sample
> new file mode 100755
> index 0000000000..2c6e06f8f1
> --- /dev/null
> +++ b/templates/hooks--push-to-checkout.sample
> @@ -0,0 +1,74 @@
> +#!/bin/bash
If we want to make this part of the sample hooks shown to everybody,
we should stick to /bin/sh if we could. Do you have to rely on any
bash-ism that are not found in other shells to write this script, or
is this just shows your inertia that you always work with bash?
> +# The hook receives the commit with which the tip of the current
> +# branch is going to be updated:
> +commit="$1"
Strictly speaking, a parameter on the right hand side of an
assignment does not have to get dquoted to protect it from getting
munged at $IFS, so this can be
commit=$1
but it gives us an important clue. If $1 is worth protecting from
getting munged at $IFS, then we should assume later use of $commit
must be careful the same way.
> +#echo "push-to-checkout $commit"
Leftover debugging statement to be removed (instead of commented
out).
> +# It can exit with a non-zero status to refuse the push (when it does
> +# so, it must not modify the index or the working tree).
> +die () {
> + echo >&2 "$*"
> + exit 1
> +}
Style (Documentation/CodingGudielines). One level of indent is a
single tab byte in our codebase.
> +if ! git update-index -q --ignore-submodules --refresh; then
Style (Documentation/CodingGudielines).
> + die "Up-to-date check failed"
This is "failed to refresh" (in other words, not being up-to-date is
OK and that is not what we are checking), but the patch is meant as
a faithful translation of the original, so it is OK here.
> +fi
> +
> +if ! git diff-files --quiet --ignore-submodules --; then
> + die "Working directory has unstaged changes"
> +fi
> +
> +# This is a rough translation of:
> +#
> +# head_has_history() ? "HEAD" : EMPTY_TREE_SHA1_HEX
> +if git cat-file -t HEAD >&/dev/null; then
Is ">&/dev/null" portable? I'd rather see it written like
git cat-file -t HEAD >/dev/null 2>&1
to be portable.
cf. https://pubs.opengroup.org/onlinepubs/9699919799/utilities/V3_chap02.html#tag_18_07
But there is a better way to spell it (see below).
> + head=HEAD
> +else
> + head=4b825dc642cb6eb9a060e54bf8d69288fbee4904
This hardcodes the object name from SHA-1 world, and will break
after the user migrates to SHA-256.
> +fi
Here is probably a better version.
if git cat-file -e HEAD
then
head=HEAD
else
head=$(git hash-object -t tree --stdin </dev/null)
fi
> +
> +if ! git diff-index --quiet --cached --ignore-submodules $head --; then
> + die "Working directory has staged changes"
> +fi
> +
> +if ! git read-tree -u -m $commit; then
You forgot "" around $commit here. Here, an $IFS byte in $commit will
get the command line munged. I.e.
if ! git read-tree -u -m "$commit"
then
...
> + die "Could not update working tree to new HEAD"
> +fi
Thanks.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH v2] hook: add sample template for push-to-checkout
2020-10-15 20:43 ` Junio C Hamano
@ 2020-10-15 22:54 ` Adam Spiers
0 siblings, 0 replies; 3+ messages in thread
From: Adam Spiers @ 2020-10-15 22:54 UTC (permalink / raw)
To: Junio C Hamano; +Cc: git list
On Thu, Oct 15, 2020 at 01:43:28PM -0700, Junio C Hamano wrote:
>Adam Spiers <git@adamspiers.org> writes:
>
>>The template is a more-or-less exact translation to shell of the C
>>code for the default behaviour for git's push-to-checkout hook defined
>>in the push_to_deploy() function in builtin/receive-pack.c, to serve
>>as a convenient starting point for modification.
>>
>>It also contains relevant text extracted from the git-config(1) and
>>githooks(5) man pages.
>>
>>Signed-off-by: Adam Spiers <git@adamspiers.org>
>>---
>> templates/hooks--push-to-checkout.sample | 74 ++++++++++++++++++++++++
>> 1 file changed, 74 insertions(+)
>> create mode 100755 templates/hooks--push-to-checkout.sample
>>
>>diff --git a/templates/hooks--push-to-checkout.sample b/templates/hooks--push-to-checkout.sample
>>new file mode 100755
>>index 0000000000..2c6e06f8f1
>>--- /dev/null
>>+++ b/templates/hooks--push-to-checkout.sample
>>@@ -0,0 +1,74 @@
>>+#!/bin/bash
>
>If we want to make this part of the sample hooks shown to everybody,
>we should stick to /bin/sh if we could. Do you have to rely on any
>bash-ism that are not found in other shells to write this script, or
>is this just shows your inertia that you always work with bash?
I usually work with bash and zsh, and just forgot to convert it in
this case.
>>+# The hook receives the commit with which the tip of the current
>>+# branch is going to be updated:
>>+commit="$1"
>
>Strictly speaking, a parameter on the right hand side of an
>assignment does not have to get dquoted to protect it from getting
>munged at $IFS, so this can be
>
> commit=$1
Ah, interesting thanks - not sure why it's taken me 25 years to
discover that.
-- >8 --
Subject: [PATCH v2] hook: add sample template for push-to-checkout
The template is a more-or-less exact translation to shell of the C
code for the default behaviour for git's push-to-checkout hook defined
in the push_to_deploy() function in builtin/receive-pack.c, to serve
as a convenient starting point for modification.
It also contains relevant text extracted from the git-config(1) and
githooks(5) man pages.
Signed-off-by: Adam Spiers <git@adamspiers.org>
---
templates/hooks--push-to-checkout.sample | 78 ++++++++++++++++++++++++
1 file changed, 78 insertions(+)
create mode 100755 templates/hooks--push-to-checkout.sample
diff --git a/templates/hooks--push-to-checkout.sample b/templates/hooks--push-to-checkout.sample
new file mode 100755
index 0000000000..af5a0c0018
--- /dev/null
+++ b/templates/hooks--push-to-checkout.sample
@@ -0,0 +1,78 @@
+#!/bin/sh
+
+# An example hook script to update a checked-out tree on a git push.
+#
+# This hook is invoked by git-receive-pack(1) when it reacts to git
+# push and updates reference(s) in its repository, and when the push
+# tries to update the branch that is currently checked out and the
+# receive.denyCurrentBranch configuration variable is set to
+# updateInstead.
+#
+# By default, such a push is refused if the working tree and the index
+# of the remote repository has any difference from the currently
+# checked out commit; when both the working tree and the index match
+# the current commit, they are updated to match the newly pushed tip
+# of the branch. This hook is to be used to override the default
+# behaviour; however the code below reimplements the default behaviour
+# as a starting point for convenient modification.
+#
+# The hook receives the commit with which the tip of the current
+# branch is going to be updated:
+commit=$1
+
+# It can exit with a non-zero status to refuse the push (when it does
+# so, it must not modify the index or the working tree).
+die () {
+ echo >&2 "$*"
+ exit 1
+}
+
+# Or it can make any necessary changes to the working tree and to the
+# index to bring them to the desired state when the tip of the current
+# branch is updated to the new commit, and exit with a zero status.
+#
+# For example, the hook can simply run git read-tree -u -m HEAD "$1"
+# in order to emulate git fetch that is run in the reverse direction
+# with git push, as the two-tree form of git read-tree -u -m is
+# essentially the same as git switch or git checkout that switches
+# branches while keeping the local changes in the working tree that do
+# not interfere with the difference between the branches.
+
+# The below is a more-or-less exact translation to shell of the C code
+# for the default behaviour for git's push-to-checkout hook defined in
+# the push_to_deploy() function in builtin/receive-pack.c.
+#
+# Note that the hook will be executed from the repository directory,
+# not from the working tree, so if you want to perform operations on
+# the working tree, you will have to adapt your code accordingly, e.g.
+# by adding "cd .." or using relative paths.
+
+if ! git update-index -q --ignore-submodules --refresh
+then
+ die "Up-to-date check failed"
+fi
+
+if ! git diff-files --quiet --ignore-submodules --
+then
+ die "Working directory has unstaged changes"
+fi
+
+# This is a rough translation of:
+#
+# head_has_history() ? "HEAD" : EMPTY_TREE_SHA1_HEX
+if git cat-file -e HEAD 2>/dev/null
+then
+ head=HEAD
+else
+ head=$(git hash-object -t tree --stdin </dev/null)
+fi
+
+if ! git diff-index --quiet --cached --ignore-submodules $head --
+then
+ die "Working directory has staged changes"
+fi
+
+if ! git read-tree -u -m "$commit"
+then
+ die "Could not update working tree to new HEAD"
+fi
--
2.28.0
^ permalink raw reply related [flat|nested] 3+ messages in thread
end of thread, other threads:[~2020-10-15 22:54 UTC | newest]
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2020-10-15 18:47 [PATCH v1] hook: add sample template for push-to-checkout Adam Spiers
2020-10-15 20:43 ` Junio C Hamano
2020-10-15 22:54 ` [PATCH v2] " Adam Spiers
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