git-node: add --backport flag to land

[andrewhughes101]

This commit adds functionality to land that allows you to land backports
with the correct metadata

example: git node land --backport <PR number>

Co-authored-by: @AshCripps ashley.cripps@ibm.com

[codecov]

Codecov Report

Merging #383 into master will increase coverage by 0.28%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #383      +/-   ##
==========================================
+ Coverage   75.66%   75.95%   +0.28%     
==========================================
  Files          21       21              
  Lines        1422     1439      +17     
==========================================
+ Hits         1076     1093      +17     
  Misses        346      346

Impacted Files	Coverage Δ
lib/links.js	89.85% <100%> (+1.33%)	⬆️
lib/metadata_gen.js	100% <100%> (ø)	⬆️

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[sam-github]

@andrewhughes101 I labelled WIP because I think you intend to extend the tests now that the current ones are passing.

[sam-github]

LGTM, but I've never reviewed this code before, someone who actually has should at least have a look. Or... maybe unnecessary, since this is additive? As long as it works for @nodejs/lts, and @BethGriggs approves, perhaps that's enough?

[BethGriggs]

Mostly LGTM. I've pulled down the code and tried pulling in a few backports and it works as expected 😃. The only one I had issues with was nodejs/node#31431 - it states that it cannot detect PR-URL (but the PR-URL is in each of the commits). Is the issue because the tool is looking for "PR-URL:" in the PR body rather than in the individual commit messages?

[AshCripps]

Mostly LGTM. I've pulled down the code and tried pulling in a few backports and it works as expected 😃. The only one I had issues with was nodejs/node#31431 - it states that it cannot detect PR-URL (but the PR-URL is in each of the commits). Is the issue because the tool is looking for "PR-URL:" in the PR body rather than in the individual commit messages?

Yeah the tool itself doesn't have that functionality that we could see at least, it only goes through the data inside the PR message itself

[MylesBorins]

Some of the commits in that PR had corrupt meta data... specifically they had PR-URL: #number-of-pr instead of the actual URL

[andrewhughes101]

I've updated the PR to always place the Backport-PR-URL below the PR-URL in the metadata. I've also created some asciinema of this feature in action

Single commit: https://asciinema.org/a/300758
Multiple commits: https://asciinema.org/a/300808