86 lines
2 KiB
Markdown
86 lines
2 KiB
Markdown
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## Credit
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Credit goes to `tazjin@` for this idea :)
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## Background
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Using `git` revisions to pin versions is nice, but git SHAs aren't very
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human-friendly:
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- They're difficult to type.
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- They're difficult to say in conversation.
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- They're difficult to compare. e.g. Which is newer? `2911fcd` or `db6ac90`?
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## Solution
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Let's assign monotonically increasing natural numbers to each of
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our repo's mainline commits and create `git` refs so we can use references like
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`r/123` instead of `2911fcd`.
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- They're easy to type: `r/123`
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- They're easy to say in conversion: "Check-out rev one-twenty-three."
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- They're easy to compare: `r/123` is an earlier version than `r/147`.
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## Backfilling
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Let's start-off by assigning "revision numbers" as refs for each of the mainline
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commits:
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```shell
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for commit in $(git rev-list --first-parent HEAD); do
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git update-ref "refs/r/$(git rev-list --count --first-parent $commit)" $commit
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done
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```
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We can verify with:
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```shell
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λ git log --first-parent --oneline
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```
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If everything looks good, we can publish the refs to the remote:
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```shell
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λ git push origin 'refs/r/*:refs/r/*'
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```
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## Staying Current
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In order to make sure that any newly merged commits have an associated revision
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number as a ref, add something like the following to your CI system to run on
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the builds of your repo's mainline branch:
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```shell
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λ git push origin "HEAD:refs/r/$(git rev-list --count --first-parent HEAD)"
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```
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## Summary
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To verify that the remote now has the expected refs, we can use:
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```shell
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λ git ls-remote origin | less # grep for refs/r
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```
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If that looks good, you should now be able to *manually* fetch the refs with:
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```shell
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λ git fetch origin 'refs/r/*:refs/r/*'
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```
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Or you can use `git config` to automate this:
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```shell
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λ git config --add remote.origin.fetch '+refs/r/*:refs/r/*'
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λ git fetch origin
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```
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Now you can run fun commands like:
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```shell
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λ git show r/1234
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λ git diff r/123{4,8} # see changes from 1234 -> 1238
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```
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Thanks for reading!
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