fix: support ESLint 10 by using context.sourceCode property

rules/max-function-length.ts

@@ -1,6 +1,7 @@
 import { Rule } from 'eslint';
 import { MaxFunctionLengthOptions } from '../types/rule-options.js';
 import { createRuleMeta, RULE_CATEGORIES } from '../utils/rule-meta.js';
+import { getSourceCode } from '../utils/node-helpers.js';
 
 const rule: Rule.RuleModule = {
   meta: createRuleMeta('max-function-length', {
@@ -44,7 +45,7 @@ Long functions are hard to understand and test. Consider:
     const skipBlankLines = options.skipBlankLines !== undefined ? options.skipBlankLines : true;
     const skipComments = options.skipComments !== undefined ? options.skipComments : true;
 
-    const sourceCode = context.getSourceCode();
+    const sourceCode = getSourceCode(context);
 
     function countLines(node: any): number {
       const body = node.body;

rules/no-complex-conditionals.ts

@@ -6,6 +6,7 @@
 import { Rule } from 'eslint';
 import { ComplexConditionalsOptions } from '../types/rule-options.js';
 import { createRuleMeta, RULE_CATEGORIES } from '../utils/rule-meta.js';
+import { getSourceCode } from '../utils/node-helpers.js';
 
 const rule: Rule.RuleModule = {
   meta: createRuleMeta('no-complex-conditionals', {
@@ -56,7 +57,7 @@ Refactoring suggestions:
 
     // Suggest a name based on context
     const suggestName = (node: any): string => {
-      const sourceCode = context.getSourceCode();
+      const sourceCode = getSourceCode(context);
       const text = sourceCode.getText(node).toLowerCase();
 
       if (text.includes('valid') || text.includes('invalid')) return 'isValid';
@@ -72,7 +73,7 @@ Refactoring suggestions:
 
     // Format condition breakdown for message
     const formatConditionBreakdown = (node: any): string => {
-      const sourceCode = context.getSourceCode();
+      const sourceCode = getSourceCode(context);
 
       // Split by operators to show each part
       const parts: string[] = [];

tests/eslint10-compatibility.test.ts

@@ -0,0 +1,73 @@
+/**
+ * @fileoverview Regression tests for ESLint 10 compatibility
+ *
+ * ESLint 10 removed the deprecated `context.getSourceCode()` method, so rules
+ * must read the `context.sourceCode` property instead. These tests drive the
+ * rules with a context that only exposes the property, which is what ESLint 10
+ * hands to a rule.
+ *
+ * @see https://github.com/aryelu/eslint-plugin-code-complete/issues/14
+ */
+
+import { describe, it, expect } from 'vitest';
+import { Rule, SourceCode } from 'eslint';
+import * as parser from '@typescript-eslint/parser';
+
+import noComplexConditionals from '../rules/no-complex-conditionals';
+import maxFunctionLength from '../rules/max-function-length';
+
+/**
+ * Builds a rule context that mimics ESLint 10: `sourceCode` is present and
+ * `getSourceCode` does not exist at all.
+ */
+function createEslint10Context(code: string, options: unknown[] = []) {
+  const { ast } = parser.parseForESLint(code, {
+    loc: true,
+    range: true,
+    tokens: true,
+    comment: true
+  });
+
+  const sourceCode = new SourceCode({ text: code, ast: ast as any });
+  const reports: any[] = [];
+
+  const context = {
+    options,
+    sourceCode,
+    report: (descriptor: any) => reports.push(descriptor)
+  } as unknown as Rule.RuleContext;
+
+  expect((context as any).getSourceCode).toBeUndefined();
+
+  return { ast, context, reports };
+}
+
+describe('ESLint 10 compatibility', () => {
+  it('no-complex-conditionals reports without context.getSourceCode', () => {
+    const { ast, context, reports } = createEslint10Context('if (a && b && c && d) {}');
+
+    const listener = noComplexConditionals.create(context);
+    (listener.IfStatement as any)(ast.body[0]);
+
+    expect(reports).toHaveLength(1);
+    expect(reports[0].messageId).toBe('complexConditional');
+    expect(reports[0].data.conditionBreakdown).toContain('1. a');
+    expect(reports[0].data.suggestedName).toBe('shouldProceed');
+  });
+
+  it('max-function-length reports without context.getSourceCode', () => {
+    const body = Array.from({ length: 5 }, (_unused, index) => `  const value${index} = ${index};`).join('\n');
+    const { ast, context, reports } = createEslint10Context(
+      `function longFunction() {\n${body}\n}`,
+      [{ maxLines: 3 }]
+    );
+
+    const listener = maxFunctionLength.create(context);
+    (listener.FunctionDeclaration as any)(ast.body[0]);
+
+    expect(reports).toHaveLength(1);
+    expect(reports[0].messageId).toBe('maxFunctionLength');
+    expect(reports[0].data.name).toBe('longFunction');
+    expect(reports[0].data.lines).toBe('5');
+  });
+});

utils/node-helpers.ts

@@ -3,6 +3,8 @@
  * @author eslint-plugin-code-complete
  */
 
+import type { Rule, SourceCode } from 'eslint';
+
 /**
  * Checks if a parameter name starts with an allowed prefix
  * @param {string} name - Parameter name
@@ -226,4 +228,17 @@ export function countFunctionParameters(
   }
 
   return count;
-} 
+} 
+/**
+ * Gets the SourceCode object for the current lint run.
+ *
+ * ESLint 10 removed the deprecated `context.getSourceCode()` method in favour of
+ * the `context.sourceCode` property, so prefer the property and only fall back to
+ * the method for older versions that predate it.
+ *
+ * @param {Rule.RuleContext} context - The rule context
+ * @returns {SourceCode} - The source code object
+ */
+export function getSourceCode(context: Rule.RuleContext): SourceCode {
+  return context.sourceCode ?? context.getSourceCode();
+}