export async function shouldUpdateLanguageServer()

in src/goLanguageServer.ts [1062:1128]
43 lines of code
19 McCabe index (conditional complexity)

export async function shouldUpdateLanguageServer(
	tool: Tool,
	cfg: LanguageServerConfig,
	mustCheck?: boolean
): Promise<semver.SemVer> {
	// Only support updating gopls for now.
	if (tool.name !== 'gopls' || (!mustCheck && (cfg.checkForUpdates === 'off' || IsInCloudIDE))) {
		return null;
	}
	if (!cfg.enabled) {
		return null;
	}

	// If the Go version is too old, don't update.
	const goVersion = await getGoVersion();
	if (!goVersion || (tool.minimumGoVersion && goVersion.lt(tool.minimumGoVersion.format()))) {
		return null;
	}

	// First, run the "gopls version" command and parse its results.
	// TODO(rstambler): Confirm that the gopls binary's modtime matches the
	// modtime in the config. Update it if needed.
	const usersVersion = await getLocalGoplsVersion(cfg);

	// We might have a developer version. Don't make the user update.
	if (usersVersion === '(devel)') {
		return null;
	}

	// Get the latest gopls version. If it is for nightly, using the prereleased version is ok.
	let latestVersion =
		cfg.checkForUpdates === 'local' ? tool.latestVersion : await latestToolVersion(tool, isInPreviewMode());

	// If we failed to get the gopls version, pick the one we know to be latest at the time of this extension's last update
	if (!latestVersion) {
		latestVersion = tool.latestVersion;
	}

	// If "gopls" is so old that it doesn't have the "gopls version" command,
	// or its version doesn't match our expectations, usersVersion will be empty or invalid.
	// Suggest the latestVersion.
	if (!usersVersion || !semver.valid(usersVersion)) {
		return latestVersion;
	}

	// The user may have downloaded golang.org/x/tools/gopls@master,
	// which means that they have a pseudoversion.
	const usersTime = parseTimestampFromPseudoversion(usersVersion);
	// If the user has a pseudoversion, get the timestamp for the latest gopls version and compare.
	if (usersTime) {
		let latestTime = cfg.checkForUpdates
			? await getTimestampForVersion(tool, latestVersion)
			: tool.latestVersionTimestamp;
		if (!latestTime) {
			latestTime = tool.latestVersionTimestamp;
		}
		return usersTime.isBefore(latestTime) ? latestVersion : null;
	}

	// If the user's version does not contain a timestamp,
	// default to a semver comparison of the two versions.
	const usersVersionSemver = semver.parse(usersVersion, {
		includePrerelease: true,
		loose: true
	});
	return semver.lt(usersVersionSemver, latestVersion) ? latestVersion : null;
}