refact: improve null analysis

org.eclipse.tm4e.core/src/main/java/org/eclipse/tm4e/core/internal/parser/TMParserJSON.java

@@ -12,7 +12,7 @@
  */
 package org.eclipse.tm4e.core.internal.parser;
 
-import static org.eclipse.tm4e.core.internal.utils.NullSafetyHelper.assertNonNull;
+import static org.eclipse.tm4e.core.internal.utils.NullSafetyHelper.castNonNull;
 
 import java.io.BufferedReader;
 import java.io.Reader;
@@ -53,7 +53,7 @@ protected TMParserJSON() {
 	protected Map<String, Object> loadRaw(final Reader source) {
 		// GSON does not support trailing commas so we have to manually remove them -> maybe better switch to jackson json parser?
 		final var jsonString = removeTrailingCommas(new BufferedReader(source).lines().collect(Collectors.joining("\n")));
-		return assertNonNull(LOADER.fromJson(jsonString, Map.class));
+		return castNonNull(LOADER.fromJson(jsonString, Map.class));
 	}
 
 	@Override

org.eclipse.tm4e.core/src/main/java/org/eclipse/tm4e/core/internal/utils/NullSafetyHelper.java

@@ -19,28 +19,28 @@
 
 public final class NullSafetyHelper {
 
-	public static <T> @NonNull T assertNonNull(final @Nullable T value) {
-		if (value == null)
-			throw new IllegalStateException("Null value!");
-		return value;
-	}
-
 	/**
-	 * Casts non-null value marked as {@link Nullable} to {@link NonNull}.
+	 * Casts a non-null value marked as {@link Nullable} to {@link NonNull}.
 	 * <p>
 	 * Only use if you are sure the value is non-null but annotation-based null analysis was not able to determine it.
 	 * <p>
 	 * This method is not meant for non-null input validation.
 	 *
-	 * @throws AssertionError if JVM assertions are enabled and the given value is null
+	 * @throws IllegalStateException if the given value is null
 	 */
 	public static <T> @NonNull T castNonNull(final @Nullable T value) {
-		assert value != null;
+		if (value == null)
+			throw new IllegalStateException("Unexpected null value present!");
 		return value;
 	}
 
+	/**
+	 * Casts the elements of given array to {@link NonNull} without any validation.
+	 * <p>
+	 * Only use if you are sure the value is non-null but annotation-based null analysis was not able to determine it.
+	 */
 	@SuppressWarnings("null")
-	private static <T> @NonNull T castNonNullUnsafe(final T value) {
+	public static <T> @NonNull T castNonNullUnsafe(final T value) {
 		return value;
 	}
 
@@ -58,18 +58,19 @@ public static <T> T defaultIfNull(final @Nullable T object, final T defaultValue
 		return object;
 	}
 
-	public static <T> T defaultIfNull(@Nullable final T object, final Supplier<T> defaultValue) {
+	public static <T> T defaultIfNull(final @Nullable T object, final Supplier<T> defaultValue) {
 		if (object == null) {
 			return defaultValue.get();
 		}
 		return object;
 	}
 
 	/**
-	 * Allows to initializes a @NonNull field with <code>null</code> that is lazy initialized
+	 * Allows to initializes a @NonNull field with <code>null</code> that is
+	 * initialized later.
 	 */
 	@SuppressWarnings("unchecked")
-	public static <T> @NonNull T lazyNonNull() {
+	public static <T> @NonNull T lateNonNull() {
 		return (T) castNonNullUnsafe(null);
 	}
 

org.eclipse.tm4e.core/src/main/java/org/eclipse/tm4e/core/model/TMModel.java

@@ -15,7 +15,7 @@
 package org.eclipse.tm4e.core.model;
 
 import static java.lang.System.Logger.Level.*;
-import static org.eclipse.tm4e.core.internal.utils.NullSafetyHelper.lazyNonNull;
+import static org.eclipse.tm4e.core.internal.utils.NullSafetyHelper.lateNonNull;
 
 import java.lang.System.Logger;
 import java.time.Duration;
@@ -99,7 +99,7 @@ public String toString() {
 	/** The background thread performing async line tokenizations */
 	private volatile @Nullable TokenizerThread tokenizerThread;
 	private volatile boolean tokenizerThreadHasWork;
-	private TMTokenizationSupport tokenizer = lazyNonNull();
+	private TMTokenizationSupport tokenizer = lateNonNull();
 
 	/** package visibility for tests **/
 	final ArrayList<LineTokens> lines;

org.eclipse.tm4e.languageconfiguration/src/main/java/org/eclipse/tm4e/languageconfiguration/internal/model/LanguageConfiguration.java

@@ -267,7 +267,7 @@ private static String removeTrailingCommas(final String jsonString) {
 				.create();
 
 		try {
-			final var langCfg = assertNonNull(gsonBuilder.fromJson(jsonString, LanguageConfiguration.class));
+			final var langCfg = castNonNull(gsonBuilder.fromJson(jsonString, LanguageConfiguration.class));
 			if (castNullable(langCfg.autoClosingPairs) == null) {
 				langCfg.autoClosingPairs = Collections.emptyList();
 			} else {
@@ -364,7 +364,7 @@ private static boolean getAsBoolean(final @Nullable JsonElement element, final b
 		return comments;
 	}
 
-	private List<CharacterPair> brackets = lazyNonNull();
+	private List<CharacterPair> brackets = lateNonNull();
 
 	/**
 	 * Returns the language's brackets. This configuration implicitly affects pressing Enter around these brackets.
@@ -395,7 +395,7 @@ public List<CharacterPair> getBrackets() {
 		return indentationRules;
 	}
 
-	private List<OnEnterRule> onEnterRules = lazyNonNull();
+	private List<OnEnterRule> onEnterRules = lateNonNull();
 
 	/**
 	 * Returns the language's rules to be evaluated when pressing Enter.
@@ -406,7 +406,7 @@ public List<OnEnterRule> getOnEnterRules() {
 		return onEnterRules;
 	}
 
-	private List<AutoClosingPairConditional> autoClosingPairs = lazyNonNull();
+	private List<AutoClosingPairConditional> autoClosingPairs = lateNonNull();
 
 	/**
 	 * Returns the language's auto closing pairs. The 'close' character is automatically inserted with the 'open'
@@ -418,7 +418,7 @@ public List<AutoClosingPairConditional> getAutoClosingPairs() {
 		return autoClosingPairs;
 	}
 
-	private List<AutoClosingPair> surroundingPairs = lazyNonNull();
+	private List<AutoClosingPair> surroundingPairs = lateNonNull();
 
 	/**
 	 * Returns the language's surrounding pairs. When the 'open' character is typed on a selection, the selected string
@@ -430,7 +430,7 @@ public List<AutoClosingPair> getSurroundingPairs() {
 		return surroundingPairs;
 	}
 
-	private List<CharacterPair> colorizedBracketPairs = lazyNonNull();
+	private List<CharacterPair> colorizedBracketPairs = lateNonNull();
 
 	/**
 	 * Defines a list of bracket pairs that are colorized depending on their nesting level.

org.eclipse.tm4e.languageconfiguration/src/main/java/org/eclipse/tm4e/languageconfiguration/internal/preferences/LanguageConfigurationPreferencePage.java

@@ -13,7 +13,7 @@
  */
 package org.eclipse.tm4e.languageconfiguration.internal.preferences;
 
-import static org.eclipse.tm4e.core.internal.utils.NullSafetyHelper.lazyNonNull;
+import static org.eclipse.tm4e.core.internal.utils.NullSafetyHelper.lateNonNull;
 import static org.eclipse.tm4e.languageconfiguration.internal.LanguageConfigurationMessages.*;
 
 import org.eclipse.jdt.annotation.NonNullByDefault;
@@ -46,7 +46,7 @@ public final class LanguageConfigurationPreferencePage extends AbstractPreferenc
 	static final String PAGE_ID = "org.eclipse.tm4e.languageconfiguration.preferences.LanguageConfigurationPreferencePage"; //$NON-NLS-1$
 
 	private ILanguageConfigurationRegistryManager.EditSession manager = LanguageConfigurationRegistryManager.getInstance().newEditSession();
-	private TableWidget<ILanguageConfigurationDefinition> langCfgsTable = lazyNonNull();
+	private TableWidget<ILanguageConfigurationDefinition> langCfgsTable = lateNonNull();
 
 	public LanguageConfigurationPreferencePage() {
 		super(LanguageConfigurationPreferencePage_title, LanguageConfigurationPreferencePage_description);

org.eclipse.tm4e.languageconfiguration/src/main/java/org/eclipse/tm4e/languageconfiguration/internal/widgets/LanguageConfigurationInfoWidget.java

@@ -11,7 +11,7 @@
  */
 package org.eclipse.tm4e.languageconfiguration.internal.widgets;
 
-import static org.eclipse.tm4e.core.internal.utils.NullSafetyHelper.lazyNonNull;
+import static org.eclipse.tm4e.core.internal.utils.NullSafetyHelper.lateNonNull;
 import static org.eclipse.tm4e.languageconfiguration.internal.LanguageConfigurationMessages.*;
 
 import java.util.List;
@@ -52,32 +52,32 @@ public class LanguageConfigurationInfoWidget extends Composite {
 		LanguageConfigurationInfoWidget_colorizedBracketPairs_title,
 	};
 
-	private Text lineCommentText = lazyNonNull();
-	private Text blockCommentStartText = lazyNonNull();
-	private Text blockCommentEndText = lazyNonNull();
+	private Text lineCommentText = lateNonNull();
+	private Text blockCommentStartText = lateNonNull();
+	private Text blockCommentEndText = lateNonNull();
 
-	private CharacterPairsTableWidget bracketsTable = lazyNonNull();
+	private CharacterPairsTableWidget bracketsTable = lateNonNull();
 
-	private AutoClosingPairConditionalTableWidget autoClosingPairsTable = lazyNonNull();
+	private AutoClosingPairConditionalTableWidget autoClosingPairsTable = lateNonNull();
 
-	private Text autoCloseBeforeText = lazyNonNull();
+	private Text autoCloseBeforeText = lateNonNull();
 
-	private CharacterPairsTableWidget surroundingPairsTable = lazyNonNull();
+	private CharacterPairsTableWidget surroundingPairsTable = lateNonNull();
 
-	private Text foldingOffsideText = lazyNonNull();
-	private Text foldingMarkersStartText = lazyNonNull();
-	private Text foldingMarkersEndText = lazyNonNull();
+	private Text foldingOffsideText = lateNonNull();
+	private Text foldingMarkersStartText = lateNonNull();
+	private Text foldingMarkersEndText = lateNonNull();
 
-	private Text wordPatternText = lazyNonNull();
+	private Text wordPatternText = lateNonNull();
 
-	private OnEnterRuleTableWidget onEnterRuleTable = lazyNonNull();
+	private OnEnterRuleTableWidget onEnterRuleTable = lateNonNull();
 
-	private Text indentationDecreaseIndentPattern = lazyNonNull();
-	private Text indentationIncreaseIndentPattern = lazyNonNull();
-	private Text indentationIndentNextLinePattern = lazyNonNull();
-	private Text indentationUnIndentedLinePattern = lazyNonNull();
+	private Text indentationDecreaseIndentPattern = lateNonNull();
+	private Text indentationIncreaseIndentPattern = lateNonNull();
+	private Text indentationIndentNextLinePattern = lateNonNull();
+	private Text indentationUnIndentedLinePattern = lateNonNull();
 
-	private CharacterPairsTableWidget colorizedBracketPairsTable = lazyNonNull();
+	private CharacterPairsTableWidget colorizedBracketPairsTable = lateNonNull();
 
 	public LanguageConfigurationInfoWidget(final Composite parent, final int style) {
 		super(parent, style);

org.eclipse.tm4e.languageconfiguration/src/main/java/org/eclipse/tm4e/languageconfiguration/internal/widgets/LanguageConfigurationPreferencesWidget.java

@@ -12,7 +12,7 @@
 package org.eclipse.tm4e.languageconfiguration.internal.widgets;
 
 import static org.eclipse.swt.events.SelectionListener.widgetSelectedAdapter;
-import static org.eclipse.tm4e.core.internal.utils.NullSafetyHelper.lazyNonNull;
+import static org.eclipse.tm4e.core.internal.utils.NullSafetyHelper.lateNonNull;
 import static org.eclipse.tm4e.languageconfiguration.internal.LanguageConfigurationMessages.*;
 
 import org.eclipse.jdt.annotation.NonNullByDefault;
@@ -31,8 +31,8 @@ public final class LanguageConfigurationPreferencesWidget extends LanguageConfig
 	private @NonNullByDefault({}) Button toggleBracketAutoClosingButton;
 	private @NonNullByDefault({}) Button toggleMatchingPairsButton;
 
-	private ILanguageConfigurationDefinition definition = lazyNonNull();
-	private ILanguageConfigurationRegistryManager.EditSession manager = lazyNonNull();
+	private ILanguageConfigurationDefinition definition = lateNonNull();
+	private ILanguageConfigurationRegistryManager.EditSession manager = lateNonNull();
 
 	public LanguageConfigurationPreferencesWidget(final Composite parent, final int style) {
 		super(parent, style);

org.eclipse.tm4e.languageconfiguration/src/main/java/org/eclipse/tm4e/languageconfiguration/internal/wizards/LanguageConfigurationImportWizard.java

@@ -11,7 +11,7 @@
  */
 package org.eclipse.tm4e.languageconfiguration.internal.wizards;
 
-import static org.eclipse.tm4e.core.internal.utils.NullSafetyHelper.lazyNonNull;
+import static org.eclipse.tm4e.core.internal.utils.NullSafetyHelper.lateNonNull;
 
 import org.eclipse.jdt.annotation.Nullable;
 import org.eclipse.jface.viewers.IStructuredSelection;
@@ -31,8 +31,8 @@ public final class LanguageConfigurationImportWizard extends Wizard implements I
 	private final ILanguageConfigurationRegistryManager.EditSession manager;
 	private final boolean saveOnFinish;
 
-	private SelectLanguageConfigurationWizardPage mainPage = lazyNonNull();
-	private ILanguageConfigurationDefinition createdDefinition = lazyNonNull();
+	private SelectLanguageConfigurationWizardPage mainPage = lateNonNull();
+	private ILanguageConfigurationDefinition createdDefinition = lateNonNull();
 
 	public LanguageConfigurationImportWizard(final ILanguageConfigurationRegistryManager.EditSession manager, final boolean saveOnFinish) {
 		this.manager = manager;

org.eclipse.tm4e.languageconfiguration/src/main/java/org/eclipse/tm4e/languageconfiguration/internal/wizards/SelectLanguageConfigurationWizardPage.java

@@ -63,9 +63,9 @@ final class SelectLanguageConfigurationWizardPage extends WizardPage implements
 
 	private static final String[] TEXTMATE_EXTENSIONS = { "*language-configuration.json" }; //$NON-NLS-1$
 
-	private Text fileText = lazyNonNull();
-	private Text contentTypeText = lazyNonNull();
-	private LanguageConfigurationInfoWidget infoWidget = lazyNonNull();
+	private Text fileText = lateNonNull();
+	private Text contentTypeText = lateNonNull();
+	private LanguageConfigurationInfoWidget infoWidget = lateNonNull();
 
 	private final ILanguageConfigurationRegistryManager registryManager;
 
@@ -306,7 +306,7 @@ ILanguageConfigurationDefinition getDefinition() {
 			path = castNonNull(ResourcesPlugin.getWorkspace().getRoot().getFile(path).getLocation());
 		}
 
-		final var contentType = assertNonNull(ContentTypeHelper.getContentTypeById(contentTypeText.getText()));
+		final var contentType = castNonNull(ContentTypeHelper.getContentTypeById(contentTypeText.getText()));
 		return new LanguageConfigurationDefinition(contentType, path.toString());
 	}
 }

org.eclipse.tm4e.languageconfiguration/src/test/java/org/eclipse/tm4e/languageconfiguration/internal/utils/MockDocument.java

@@ -16,7 +16,7 @@
 import java.io.LineNumberReader;
 import java.io.StringReader;
 
-import org.eclipse.jdt.annotation.NonNullByDefault;
+import org.eclipse.jdt.annotation.Nullable;
 import org.eclipse.jface.text.BadLocationException;
 import org.eclipse.jface.text.DefaultLineTracker;
 import org.eclipse.jface.text.IDocument;
@@ -33,7 +33,6 @@
  * Partially implemented {@link IDocument}. Especially all methods related to {@link IDocumentListener}, {@link IDocumentPartitioner},
  * {@link Position} are not implemented.
  */
-@NonNullByDefault({})
 public class MockDocument implements IDocument {
 
 	private String contentType;
@@ -164,7 +163,7 @@ public int getLength() {
 	}
 
 	@Override
-	public String getLineDelimiter(final int lineIndex) throws BadLocationException {
+	public @Nullable String getLineDelimiter(final int lineIndex) throws BadLocationException {
 		final String[] lines = text.split("\n");
 		if (lines.length <= lineIndex)
 			throw new BadLocationException("Line " + lineIndex + " not present.");
@@ -305,7 +304,7 @@ public void set(final String text) {
 	}
 
 	@Override
-	public void setDocumentPartitioner(IDocumentPartitioner partitioner) {
+	public void setDocumentPartitioner(@Nullable IDocumentPartitioner partitioner) {
 		throw new UnsupportedOperationException();
 	}
 

org.eclipse.tm4e.ui/src/main/java/org/eclipse/tm4e/ui/internal/hover/TMTokenTextHover.java

@@ -44,7 +44,7 @@ private static final class RegionWithTMToken extends Region {
 	}
 
 	@Override
-	public IInformationControlCreator getHoverControlCreator() {
+	public @Nullable IInformationControlCreator getHoverControlCreator() {
 		// setup a hover control that interprets basic HTML input
 		return new AbstractReusableInformationControlCreator() {
 			@Override

org.eclipse.tm4e.ui/src/main/java/org/eclipse/tm4e/ui/internal/preferences/GrammarPreferencePage.java

@@ -13,7 +13,7 @@
  *******************************************************************************/
 package org.eclipse.tm4e.ui.internal.preferences;
 
-import static org.eclipse.tm4e.core.internal.utils.NullSafetyHelper.lazyNonNull;
+import static org.eclipse.tm4e.core.internal.utils.NullSafetyHelper.lateNonNull;
 
 import java.util.stream.Collectors;
 
@@ -65,14 +65,14 @@ public final class GrammarPreferencePage extends AbstractPreferencePage {
 	private IThemeManager.EditSession themeManager = ThemeManager.getInstance().newEditSession();
 	private final ISnippetManager snippetManager = TMUIPlugin.getSnippetManager();
 
-	private TableWidget<IGrammarDefinition> grammarsTable = lazyNonNull();
+	private TableWidget<IGrammarDefinition> grammarsTable = lateNonNull();
 
 	// Grammar info tabs
-	private GrammarInfoWidget grammarInfoWidget = lazyNonNull();
-	private TableWithControlsWidget<IContentType> contentTypesWidget = lazyNonNull();
-	private ThemeAssociationsWidget themeAssociationsWidget = lazyNonNull();
+	private GrammarInfoWidget grammarInfoWidget = lateNonNull();
+	private TableWithControlsWidget<IContentType> contentTypesWidget = lateNonNull();
+	private ThemeAssociationsWidget themeAssociationsWidget = lateNonNull();
 
-	private TMViewer grammarPreview = lazyNonNull();
+	private TMViewer grammarPreview = lateNonNull();
 
 	public GrammarPreferencePage() {
 		super(TMUIMessages.GrammarPreferencePage_title, TMUIMessages.GrammarPreferencePage_description);

org.eclipse.tm4e.ui/src/main/java/org/eclipse/tm4e/ui/internal/preferences/PreferenceHelper.java

@@ -66,7 +66,7 @@ public void write(final JsonWriter out, final @Nullable MarkerConfig value) thro
 
 						@Override
 						public @Nullable MarkerConfig read(final JsonReader in) throws IOException {
-							final var objectJson = assertNonNull(jsonElementAdapter.read(in)).getAsJsonObject();
+							final var objectJson = castNonNull(jsonElementAdapter.read(in)).getAsJsonObject();
 							return switch (MarkerConfig.Type.valueOf(objectJson.get("type").getAsString())) {
 								case PROBLEM -> problemAdapter.fromJsonTree(objectJson);
 								case TASK -> taskAdapter.fromJsonTree(objectJson);
@@ -77,7 +77,7 @@ public void write(final JsonWriter out, final @Nullable MarkerConfig value) thro
 			}).create();
 
 	public static IThemeAssociation[] loadThemeAssociations(final String json) {
-		return assertNonNull(DEFAULT_GSON.fromJson(json, ThemeAssociation[].class));
+		return castNonNull(DEFAULT_GSON.fromJson(json, ThemeAssociation[].class));
 	}
 
 	public static String toJsonThemeAssociations(final Collection<IThemeAssociation> themeAssociations) {
@@ -97,7 +97,7 @@ public static Set<MarkerConfig> loadMarkerConfigs() {
 	}
 
 	public static Set<MarkerConfig> loadMarkerConfigs(final String json) {
-		return assertNonNull(DEFAULT_GSON.fromJson(json, new TypeToken<Set<MarkerConfig>>() {
+		return castNonNull(DEFAULT_GSON.fromJson(json, new TypeToken<Set<MarkerConfig>>() {
 		}.getType()));
 	}