Improve null safety

.eslintrc.js

@@ -42,6 +42,7 @@ module.exports = {
         '@typescript-eslint/no-implicit-any-catch': 'off',
         '@typescript-eslint/no-invalid-this': 'off',
         '@typescript-eslint/no-magic-numbers': 'off',
+        '@typescript-eslint/no-non-null-assertion': 'off',
         '@typescript-eslint/no-parameter-properties': 'off',
         //had to add this rule to prevent eslint from crashing
         '@typescript-eslint/no-restricted-imports': ['off', {}],
@@ -61,6 +62,7 @@ module.exports = {
         '@typescript-eslint/no-type-alias': 'off',
         '@typescript-eslint/no-unnecessary-boolean-literal-compare': 'off',
         '@typescript-eslint/no-unnecessary-condition': 'off',
+        '@typescript-eslint/no-unnecessary-type-assertion': 'off',
         '@typescript-eslint/no-unsafe-assignment': 'off',
         '@typescript-eslint/no-unsafe-call': 'off',
         '@typescript-eslint/no-unsafe-member-access': 'off',
@@ -240,8 +242,6 @@ module.exports = {
         files: ['benchmarks/**/*.ts'],
         rules: {
             '@typescript-eslint/dot-notation': 'off',
-            '@typescript-eslint/no-unnecessary-type-assertion': 'off',
-            '@typescript-eslint/no-non-null-assertion': 'off',
             'camelcase': 'off'
         }
     }]

package.json

@@ -18,7 +18,8 @@
     "docs": "ts-node scripts/compile-doc-examples.ts",
     "benchmark": "cd ./benchmarks && ts-node ./index.ts",
     "scrape-roku-docs": "ts-node scripts/scrape-roku-docs.ts",
-    "rescrape-roku-docs": "rm scripts/.cache.json && ts-node scripts/scrape-roku-docs.ts"
+    "rescrape-roku-docs": "rm scripts/.cache.json && ts-node scripts/scrape-roku-docs.ts",
+    "null-check": "tsc -p tsconfig-null-safe.json"
   },
   "mocha": {
     "spec": "src/**/*.spec.ts",

src/BusyStatusTracker.spec.ts

@@ -89,9 +89,9 @@ describe('BusyStatusTracker', () => {
         try {
             tracker.run((finalize) => {
                 expect(latestStatus).to.eql(BusyStatus.busy);
-                finalize();
+                finalize?.();
                 expect(latestStatus).to.eql(BusyStatus.idle);
-                finalize();
+                finalize?.();
                 expect(latestStatus).to.eql(BusyStatus.idle);
             });
         } catch { }
@@ -125,7 +125,7 @@ describe('BusyStatusTracker', () => {
     });
 
     it('supports unsubscribing from events', () => {
-        const changes = []; //contains every busy/idle status change
+        const changes: BusyStatus[] = []; //contains every busy/idle status change
         const disconnect = tracker.on('change', (status) => changes.push(status));
 
         expect(changes.length).to.eql(0);

src/CodeActionUtil.ts

@@ -12,15 +12,15 @@ export class CodeActionUtil {
             const uri = URI.file(change.filePath).toString();
 
             //create the edit changes array for this uri
-            if (!edit.changes[uri]) {
-                edit.changes[uri] = [];
+            if (!edit.changes![uri]) {
+                edit.changes![uri] = [];
             }
             if (change.type === 'insert') {
-                edit.changes[uri].push(
+                edit.changes![uri].push(
                     TextEdit.insert(change.position, change.newText)
                 );
             } else if (change.type === 'replace') {
-                edit.changes[uri].push(
+                edit.changes![uri].push(
                     TextEdit.replace(change.range, change.newText)
                 );
             }
@@ -31,7 +31,7 @@ export class CodeActionUtil {
         return action;
     }
 
-    public serializableDiagnostics(diagnostics: Diagnostic[]) {
+    public serializableDiagnostics(diagnostics: Diagnostic[] | undefined) {
         return diagnostics?.map(({ range, severity, code, source, message, relatedInformation }) => ({
             range: range,
             severity: severity,

src/CommentFlagProcessor.spec.ts

@@ -2,13 +2,16 @@ import { expect } from './chai-config.spec';
 import { Range } from 'vscode-languageserver';
 import { CommentFlagProcessor } from './CommentFlagProcessor';
 import { Lexer } from './lexer/Lexer';
+import type { BscFile } from '.';
 
 describe('CommentFlagProcessor', () => {
     let processor: CommentFlagProcessor;
 
+    const mockBscFile: BscFile = null as any;
+
     describe('tokenizeByWhitespace', () => {
         beforeEach(() => {
-            processor = new CommentFlagProcessor(null);
+            processor = new CommentFlagProcessor(mockBscFile);
         });
 
         it('works with single chars', () => {
@@ -66,18 +69,18 @@ describe('CommentFlagProcessor', () => {
 
     describe('tokenize', () => {
         beforeEach(() => {
-            processor = new CommentFlagProcessor(null, [`'`]);
+            processor = new CommentFlagProcessor(mockBscFile, [`'`]);
         });
 
         it('skips non disable comments', () => {
             expect(
-                processor['tokenize'](`'not disable comment`, null)
+                processor['tokenize'](`'not disable comment`, null as any as Range)
             ).not.to.exist;
         });
 
         it('tokenizes bs:disable-line comment', () => {
             expect(
-                processor['tokenize'](`'bs:disable-line`, null)
+                processor['tokenize'](`'bs:disable-line`, null as any as Range)
             ).to.eql({
                 commentTokenText: `'`,
                 disableType: 'line',

src/CommentFlagProcessor.ts

@@ -51,11 +51,12 @@ export class CommentFlagProcessor {
         let affectedRange: Range;
         if (tokenized.disableType === 'line') {
             affectedRange = util.createRange(range.start.line, 0, range.start.line, range.start.character);
-        } else if (tokenized.disableType === 'next-line') {
+        } else {
+            // tokenized.disableType must be 'next-line'
             affectedRange = util.createRange(range.start.line + 1, 0, range.start.line + 1, Number.MAX_SAFE_INTEGER);
         }
 
-        let commentFlag: CommentFlag;
+        let commentFlag: CommentFlag | null = null;
 
         //statement to disable EVERYTHING
         if (tokenized.codes.length === 0) {
@@ -115,10 +116,10 @@ export class CommentFlagProcessor {
     /**
      * Small tokenizer for bs:disable comments
      */
-    private tokenize(text: string, range: Range) {
+    private tokenize(text: string, range: Range): DisableToken | null {
         let lowerText = text.toLowerCase();
         let offset = 0;
-        let commentTokenText: string;
+        let commentTokenText: string | null = null;
 
         for (const starter of this.commentStarters) {
             if (text.startsWith(starter)) {
@@ -177,9 +178,10 @@ export class CommentFlagProcessor {
      * Given a string, extract each item split by whitespace
      * @param text the text to tokenize
      */
-    private tokenizeByWhitespace(text: string) {
-        let tokens = [] as Array<{ startIndex: number; text: string }>;
-        let currentToken = null;
+    private tokenizeByWhitespace(text: string): Token[] {
+        let tokens = [] as Array<Token>;
+        let currentToken: Token | null = null;
+
         for (let i = 0; i < text.length; i++) {
             let char = text[i];
             //if we hit whitespace
@@ -206,3 +208,17 @@ export class CommentFlagProcessor {
         return tokens;
     }
 }
+
+interface Token {
+    startIndex: number;
+    text: string;
+}
+
+interface DisableToken {
+    commentTokenText: string | null;
+    disableType: 'line' | 'next-line';
+    codes: {
+        code: string;
+        range: Range;
+    }[];
+}

src/DependencyGraph.ts

@@ -137,17 +137,19 @@ export class Node {
     ) {
         if (dependencies.length > 0) {
             this.subscriptions = [];
-        }
-        for (let dependency of this.dependencies) {
-            let sub = this.graph.onchange(dependency, (event) => {
-                //notify the graph that we changed since one of our dependencies changed
-                this.graph.emit(this.key, event);
-            });
 
-            this.subscriptions.push(sub);
+            for (let dependency of this.dependencies) {
+                let sub = this.graph.onchange(dependency, (event) => {
+                    //notify the graph that we changed since one of our dependencies changed
+                    this.graph.emit(this.key, event);
+                });
+
+                this.subscriptions.push(sub);
+            }
         }
     }
-    private subscriptions: Array<() => void>;
+
+    private subscriptions: Array<() => void> | undefined;
 
     /**
      * Return the full list of unique dependencies for this node by traversing all descendents
@@ -161,7 +163,7 @@ export class Node {
             let dependency = dependencyStack.pop();
 
             //if this is a new dependency and we aren't supposed to skip it
-            if (!dependencyMap[dependency] && !exclude.includes(dependency)) {
+            if (dependency && !dependencyMap[dependency] && !exclude.includes(dependency)) {
                 dependencyMap[dependency] = true;
 
                 //get the node for this dependency

src/DiagnosticCollection.spec.ts

@@ -35,7 +35,7 @@ describe('DiagnosticCollection', () => {
 
     it('does not crash for diagnostics with missing locations', () => {
         const [d1] = addDiagnostics('file1.brs', ['I have no location']);
-        delete d1.range;
+        delete (d1 as any).range;
         testPatch({
             'file1.brs': ['I have no location']
         });
@@ -104,7 +104,7 @@ describe('DiagnosticCollection', () => {
     }
 
     function addDiagnostics(srcPath: string, messages: string[]) {
-        const newDiagnostics = [];
+        const newDiagnostics: BsDiagnostic[] = [];
         for (const message of messages) {
             newDiagnostics.push({
                 file: {
@@ -117,6 +117,6 @@ describe('DiagnosticCollection', () => {
             });
         }
         diagnostics.push(...newDiagnostics);
-        return newDiagnostics as typeof diagnostics;
+        return newDiagnostics;
     }
 });

src/DiagnosticFilterer.ts

@@ -6,8 +6,12 @@ import { standardizePath as s } from './util';
 
 export class DiagnosticFilterer {
     private byFile: Record<string, BsDiagnostic[]>;
-    private filters: Array<{ src?: string; codes?: (number | string)[] }>;
-    private rootDir: string;
+    private filters: Array<{ src?: string; codes?: (number | string)[] }> | undefined;
+    private rootDir: string | undefined;
+
+    constructor() {
+        this.byFile = {};
+    }
 
     /**
      * Filter a list of diagnostics based on the provided filters
@@ -24,7 +28,7 @@ export class DiagnosticFilterer {
         let result = this.getDiagnostics();
 
         //clean up
-        delete this.byFile;
+        this.byFile = {};
         delete this.rootDir;
         delete this.filters;
 
@@ -108,7 +112,7 @@ export class DiagnosticFilterer {
             let fileDiagnostics = this.byFile[filePath];
             for (let i = 0; i < fileDiagnostics.length; i++) {
                 let diagnostic = fileDiagnostics[i];
-                if (filter.codes.includes(diagnostic.code)) {
+                if (filter.codes.includes(diagnostic.code!)) {
                     //remove this diagnostic
                     fileDiagnostics.splice(i, 1);
                     //repeat this loop iteration (with the new item at this index)
@@ -123,7 +127,7 @@ export class DiagnosticFilterer {
         let globalIgnoreCodes: (number | string)[] = [...config1.ignoreErrorCodes ?? []];
         let diagnosticFilters = [...config1.diagnosticFilters ?? []];
 
-        let result = [];
+        let result: Array<{ src?: string; codes: (number | string)[] }> = [];
 
         for (let filter of diagnosticFilters as any[]) {
             if (typeof filter === 'number') {
@@ -151,6 +155,6 @@ export class DiagnosticFilterer {
                 codes: globalIgnoreCodes
             });
         }
-        return result as Array<{ src?: string; codes: (number | string)[] }>;
+        return result;
     }
 }

src/DiagnosticSeverityAdjuster.ts

@@ -16,6 +16,11 @@ export class DiagnosticSeverityAdjuster {
 
     public createSeverityMap(diagnosticSeverityOverrides: BsConfig['diagnosticSeverityOverrides']): Map<string, DiagnosticSeverity> {
         const map = new Map<string, DiagnosticSeverity>();
+
+        if (!diagnosticSeverityOverrides) {
+            return map;
+        }
+
         Object.keys(diagnosticSeverityOverrides).forEach(key => {
             const value = diagnosticSeverityOverrides[key];
             switch (value) {

src/FunctionScope.spec.ts

@@ -1,6 +1,7 @@
 import { expect } from './chai-config.spec';
 
 import { FunctionScope } from './FunctionScope';
+import type { FunctionExpression } from './parser/Expression';
 import { Program } from './Program';
 
 describe('FunctionScope', () => {
@@ -9,7 +10,7 @@ describe('FunctionScope', () => {
     let program: Program;
     beforeEach(() => {
         program = new Program({ rootDir: rootDir });
-        scope = new FunctionScope(null);
+        scope = new FunctionScope(null as any as FunctionExpression);
     });
 
     afterEach(() => {

src/FunctionScope.ts

@@ -22,7 +22,7 @@ export class FunctionScope {
     /**
      * The parent scope of this scope
      */
-    public parentScope: FunctionScope;
+    public parentScope: FunctionScope | undefined;
     public variableDeclarations = [] as VariableDeclaration[];
     public labelStatements = [] as LabelDeclaration[];