Fix sorting problem in QuickFileOpenService

[colin-grant-work]

What it does

There were a couple of problems in the sort function for the file quick pick and in the tests for them:

A positive returns means left after right, so these values are reversed.

theia/examples/api-tests/src/file-search.spec.js

Lines 41 to 42 in be4eba9

	assert.equal(quickFileOpenService['compareItems'](a, b), 1, 'a should be before b');
	assert.equal(quickFileOpenService['compareItems'](b, a), -1, 'a should be before b');

I've replaced the return expectations with actual passes through a sort function so that we're guaranteed to mirror the actual behavior of the function in its intended context of use.

---

To test whether L before R, these should also be reversed (but since the test expectations were reversed, the tests passed)

theia/packages/file-search/src/browser/quick-file-open.ts

Line 272 in be4eba9

const compareByLabel = (l: FileQuickPickItem, r: FileQuickPickItem) => r.label.localeCompare(l.label);

---

Fuzzy scores can be greater than Scores.max (1000), so imperfect matches could get a lead over perfect matches.

theia/packages/file-search/src/browser/quick-file-open.ts

Line 254 in be4eba9

matchScore = (fuzzyMatch.score === Infinity) ? QuickFileOpenService.Scores.max : fuzzyMatch.score;

How to test

1. Mostly see if the tests pass.
2. Create a workspace with files with the filenames used in the new test.
3. Search for the perfect match.
4. Observe that it is ordered above the very good match.

Review checklist

• As an author, I have thoroughly tested my changes and carefully followed the review guidelines

Reminder for reviewers

• As a reviewer, I agree to behave in accordance with the review guidelines

[vince-fugnitto]

@colin-grant-work unfortunately the changes do not work for me, the file-search is broken when I tried in the browser and electron. The following error is reported multiple times:

quick-file-open.ts:247 Uncaught (in promise) TypeError: Cannot read properties of null (reading 'score')
    at score (/home/evinfug/workspaces/theia/examples/electron/lib/packages_file-search_lib_browser_file-search-frontend-module_js.bundle.js:346)
    at Array.compareByLabelScore (/home/evinfug/workspaces/theia/examples/electron/lib/packages_file-search_lib_browser_file-search-frontend-module_js.bundle.js:355)
    at compareWithDiscriminators (/home/evinfug/workspaces/theia/examples/electron/lib/packages_file-search_lib_browser_file-search-frontend-module_js.bundle.js:523)
    at QuickFileOpenService.compareItems (/home/evinfug/workspaces/theia/examples/electron/lib/packages_file-search_lib_browser_file-search-frontend-module_js.bundle.js:361)
    at /home/evinfug/workspaces/theia/examples/electron/lib/packages_file-search_lib_browser_file-search-frontend-module_js.bundle.js:305
    at Array.sort (<anonymous>)
    at handler (/home/evinfug/workspaces/theia/examples/electron/lib/packages_file-search_lib_browser_file-search-frontend-module_js.bundle.js:305)

Steps to Reproduce:

1. start the application with theia as a workspace
2. search for pack
3. the file-search is broken

[colin-grant-work]

3. the file-search is broken

@vince-fugnitto, good catch. The perils of only doing searches that work in a small workspace (and of trusting the declared types...)! I've pushed a commit that handles the null returns from fuzzy, and I also noticed that we were mishandling the file results (not recently opened) separator and fixed that.

[vince-fugnitto]

I confirm that the changes work as expected following the update, and the tests successfully pass 👍
I verified using a large workspace with exact, good and invalid results and it works fine, even with recent results.

[JonasHelming]

Looks good to me, I did a smoke test as well.