Feat: Pin external references on a release

[sudo-bmitch]

This pins references to external specs (distribution and runtime) to their latest release on a release of this project.

See the discussion on #1207 for more context.

[tianon]

How do we make sure the latest releases include whatever our links are referring to and that we're not implicitly relying on unreleased content?

(Also, if you want to avoid the GitHub API and thus avoid their API limits as well, you might like git ls-remote)

[sudo-bmitch]

How do we make sure the latest releases include whatever our links are referring to and that we're not implicitly relying on unreleased content?

That's why we have a 2/3rds super majority voting on the release. 😄

(Also, if you want to avoid the GitHub API and thus avoid their API limits as well, you might like git ls-remote)

Wouldn't that require a clone of the other repository first? Granted that the maintainer doing the release probably has those, but everyone would have a potentially different directory structure and remote names.

If we were to make a lot of requests, this could also inject a token in the curl, but I figured we could roll the dice with only 2 requests. If it fails, the maintainer doing the release can sort it out since this isn't an automated workflow.

[tianon]

That's why we have a 2/3rds super majority voting on the release. 😄

Ah right, because we'll review the commit that updates all the references, which is a natural place to review that they're accurate with the surrounding text. That tracks; thanks for helping me through that. 😄

Wouldn't that require a clone of the other repository first?

Nope, that's the beauty of git ls-remote! I'll use a container to illustrate more dramatically (so it's really clear I can't possibly have a pre-existing repository or even a local .git):

$ docker run --rm buildpack-deps:scm sh -euc '
git ls-remote https://github.com/opencontainers/runtime-spec.git refs/tags/v[0-9]* \
| cut -d/ -f3 \
| cut -d^ -f1 \
| grep -vF -- - \
| sort -uV \
| tail -1
'
v1.2.0

[tianon]

In the spirit of your existing script (since sort -V is a GNU-ism), here's a version that only relies on git and jq instead:

$ docker run --rm buildpack-deps:scm git ls-remote https://github.com/opencontainers/runtime-spec.git 'refs/tags/v[0-9]*' | jq -rnR '[ inputs | split("/")[2] | split("^")[0] | select(contains("-") | not) ] | unique_by(ltrimstr("v") | split(".") | map(tonumber? // .))[-1]'
v1.2.0

Split with whitespace (and comments) so it's easier to read/follow:

$ docker run --rm buildpack-deps:scm git ls-remote https://github.com/opencontainers/runtime-spec.git 'refs/tags/v[0-9]*' \
	| jq -rnR '
		[
			inputs
			| split("/")[2] # "commit-hash\trefs/tags/xxx^{}" -> "xxx^{}"
			| split("^")[0] # "xxx^{}" -> "xxx"
			| select(contains("-") | not) # ignore pre-releases
		]
		| unique_by(ltrimstr("v") | split(".") | map(tonumber? // .)) # very very rough version sorting (and dedupe)
		| .[-1] # we only care about "latest" (the last entry)
	'
v1.2.0

[tianon]

You're going to change the list of commands, but in general, the command built-in is pretty well behaved so this can be somewhat simpler/cleaner too:

Suggested change

	if [ ! -x "$(command -v curl )" ] || [ ! -x "$(command -v jq )" ] || [ ! -x "$(command -v find )" ] || [ ! -x "$(command -v sed )" ]; then
	if ! command -v curl > /dev/null || ! command -v jq > /dev/null || ! command -v find > /dev/null || ! command -v sed > /dev/null; then

or even:

Suggested change

	if [ ! -x "$(command -v curl )" ] || [ ! -x "$(command -v jq )" ] || [ ! -x "$(command -v find )" ] || [ ! -x "$(command -v sed )" ]; then
	if ! { command -v curl && command -v jq && command -v find && command -v sed; } > /dev/null; then

[sudo-bmitch]

@tianon is now the forever-maintainer of that jq command. I disavow all responsibility. 😂

$ docker run --rm buildpack-deps:scm git ls-remote https://github.com/opencontainers/runtime-spec.git 'refs/tags/v[0-9]*' \
	| jq -rnR '
		[
			inputs
			| split("/")[2] # "commit-hash\trefs/tags/xxx^{}" -> "xxx^{}"
			| split("^")[0] # "xxx^{}" -> "xxx"
			| select(contains("-") | not) # ignore pre-releases
		]
		| unique_by(ltrimstr("v") | split(".") | map(tonumber? // .)) # very very rough version sorting (and dedupe)
		| .[-1] # we only care about "latest" (the last entry)
	'
v1.2.0