fix(git/cache): getCachedBehindBaseResult returns true when branch is not modified

[Gabriel-Ladzaretti]

Changes

In isBranchModified

renovate/lib/util/git/index.ts

Lines 591 to 593 in 6246a61

	export async function isBranchModified(branchName: string): Promise<boolean> {
	if (!branchExists(branchName)) {
	logger.debug(

we cache branch data regardless of repositoryCache -

renovate/lib/util/git/index.ts

Lines 643 to 647 in 6246a61

	setCachedModifiedResult(
	branchName,
	config.branchCommits[branchName],
	false
	);

and

renovate/lib/util/git/index.ts

Line 655 in 6246a61

setCachedModifiedResult(branchName, config.branchCommits[branchName], true);

therefore, if we later query getCachedBehindBaseResult it might return true regardless if the branch have been modified or not.

this is because cacheBranch is defined, but cachedBranch.parentSha is not.
if which case the return statement will always be true.

renovate/lib/util/git/behind-base-branch-cache.ts

Lines 15 to 20 in 6246a61

	if (!cachedBranch) {
	return null;
	}
	return currentBaseBranchSha !== cachedBranch.parentSha;
	}

This in turn effects isBehindBase
due to:

renovate/lib/util/git/index.ts

Lines 559 to 566 in 6246a61

	export async function isBranchBehindBase(branchName: string): Promise<boolean> {
	const { currentBranchSha } = config;
	let isBehind = getCachedBehindBaseResult(branchName, currentBranchSha);
	if (isBehind !== null) {
	return isBehind;
	}

Context

closes #16751

Documentation (please check one with an [x])

• I have updated the documentation, or
• No documentation update is required

How I've tested my work (please tick one)

I have verified these changes via:

• Code inspection only, or
• Newly added/modified unit tests, or
• No unit tests but ran on a real repository, or
• Both unit tests + ran on a real repository

[Gabriel-Ladzaretti]

dont merge it yet, there is some git/index failing test, i want test it some further
coverage related, but it is a bit strage nonetheless

[rarkins]

[Gabriel-Ladzaretti]

git.getBranchParentSha was always returning null, which supposed to be a parent sha in one of the tests which caused coverage issues, as we handle this exact case and we end up with branch is not being covered.

im just using HEAD's sha instead.

[renovate-release]

🎉 This PR is included in version 32.127.5 🎉

The release is available on:

• GitHub release
• 32.127.5

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