git node v8 backport aborts on merge conflict

[hashseed]

git node v8 backport attempts at some point to do a git apply -3, which fails often. The -3 doesn't help since Node's copy of V8 doesn't have a git history.

How about not aborting, but wait for the user to fix the conflicts and git add the fixes and then continue?

[targos]

+1000 if you know how to do that! I was not able to get conflict markers with git apply when I developed the command.

[joyeecheung]

I think the thing necessary to implement is more like to have a way to persist the state and then be able to restart from here once the user fixes the conflict?

node-core-utils/lib/update-v8/backport.js

Line 12 in 092cbe5

const todo = [common.getCurrentV8Version(), generatePatch(), applyPatch()];

git node land is able to do that by persisting states to .ncu/land and always reading this file to understand the previous state so that users can git node land --continue all the way down while fixing errors

node-core-utils/lib/session.js

Lines 19 to 21 in 092cbe5

	get session() {
	return readJson(this.sessionPath);
	}

[targos]

The real problem is that there is no conflict to fix. The patch fails and that's all. No files are modified

[joyeecheung]

@targos One way to tackle that is to use git apply --reject, and prompt the user to use wiggle on the .rej files (which applies wherever possible and generates the conflict marker wherever impossible), though that cannot guarantee to work either (I guess it's better than outright failure?) Then when the conflicts are fixed, read some persisted state from disk to bake the commit message and so on.

[hashseed]

I made an attempt to solve this: use patch -p1 --merge --no-backup-if-mismatch so that we get conflict markers in the files, and then prompt the user to continue once conflicts are resolved.