| Message ID | 20201015184703.5015-1-git@adamspiers.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v1] hook: add sample template for push-to-checkout | expand |
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.
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
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
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