Bug: --update-baseline does not remove duplicated entries

[djmetzle]

We have been experiencing trouble with the most recent versions of psalm.

We're currently running on 5.7.7, but we walked back recent upgrades, and it appears that 5.2 does not have the problem, but our upgrade to 5.6 seems to bring back the problem. This may also be related to the addition of UnusedBaselineEntry, which we've recently enabled. Version 5.5 seems to be the relevant release that changed this behavior for us.

Also, removing the occurrence attribute also may have exposed the problem.
It appears that the ErrorBaseline code:

psalm/src/Psalm/ErrorBaseline.php

Lines 140 to 147 in 9cf4f60

	public static function update(
	FileProvider $fileProvider,
	string $baselineFile,
	array $issues,
	bool $include_php_versions
	): array {
	$existingIssues = self::read($fileProvider, $baselineFile);
	$newIssues = self::countIssueTypesByFile($issues);

as well as the test cases, are concerned still with absolute number of occurrences. This could be confusing the issue.

We have a test case created that seems to reproduce the problem we are seeing:
iFixit@477e0a2

Notice that in our example/testcase we are avoiding encoding the occurrences field in the example baseline XML:
https://github.com/iFixit/psalm/blob/477e0a26bb8dff7772f055da83343909af686679/tests/ErrorBaselineTest.php#L498
but that the remain test cases are still using occurrences.

Specifically, if we have duplicated <code> blocks in our baseline, fixing only one of them does not correctly remove the second instance from the baseline as expected.

Please advise.

CC @jarstelfox @ardelato @sctice-ifixit

[psalm-github-bot]

Hey @djmetzle, can you reproduce the issue on https://psalm.dev ?

[djmetzle]

@psalm-github-bot
This issue deals with baseline handling, and is most likely not reproducible in the online checker.