Performance improvement: ``PsiFileValidator#isScannable``

[AB-xdev]

Problem description

The following methods inside PsiFileValidator#isScannable always call PluginConfigurationManager#getCurrent():

checkstyle-idea/src/main/java/org/infernus/idea/checkstyle/checker/PsiFileValidator.java

Lines 37 to 39 in 34562bc

	&& isInSource(psiFile, pluginConfig, overrideConfigLocation)
	&& isValidFileType(psiFile, pluginConfig)
	&& isScannableIfTest(psiFile, pluginConfig)

The call to PluginConfigurationManager#getCurrent() always causes the complete configuration to be populated:

checkstyle-idea/src/main/java/org/infernus/idea/checkstyle/config/PluginConfigurationManager.java

Lines 42 to 46 in 538dc0f

	public PluginConfiguration getCurrent() {
	final PluginConfigurationBuilder defaultConfig = PluginConfigurationBuilder.defaultConfiguration(project);
	return projectConfigurationState()
	.populate(defaultConfig)
	.build();

Currently this only causes a noteworthy performance impact when (bulk) scanning a lot of files, however it's still noteable.

I was not able to find any valid explanation for the current behavior. According to git blame the code was last touched in 2015.

Proposed solution

Hand over the PluginConfiguration instead of the PluginConfigurationManager and only get the configuration once

[AB-xdev]

Note: Similar code is also present in

checkstyle-idea/src/main/java/org/infernus/idea/checkstyle/CheckStyleInspection.java

Line 134 in ce41b4e

.map(checker -> checker.scan(scannableFiles, configurationManager(psiFile.getProject()).getCurrent().isSuppressErrors()))

and

checkstyle-idea/src/main/java/org/infernus/idea/checkstyle/config/ConfigurationLocationSource.java

Lines 35 to 45 in ce41b4e

	PluginConfiguration configuration = configurationManager().getCurrent();
	TreeSet<ConfigurationLocation> moduleActiveConfigurations = moduleConfiguration.getActiveLocationIds().stream()
	.map(id -> configuration.getLocationById(id).orElse(null))
	.filter(Objects::nonNull)
	.collect(Collectors.toCollection(TreeSet::new));
	if (!moduleActiveConfigurations.isEmpty()) {
	return moduleActiveConfigurations;
	}
	}
	return configurationManager().getCurrent().getActiveLocations();

and might also be worth a look

[jshiell]

Cheers, I'll have a butchers in a couple of weeks when I'm back from work travel.

It's probably either a case of
a) avoiding premature optimisation
b) stupidity

I'd like to think (a), but (b) is just as likely 😭