feat(betterer ✨): borrow merge conflict handler from yarn (#141)

.betterer.results

@@ -21,14 +21,15 @@ exports[`new eslint rules`] = {
       [29, 19, 8, "Don\'t use \`Function\` as a type. The \`Function\` type accepts any function-like value.\\nIt provides no type safety when calling the function, which can be a common source of bugs.\\nIt also accepts things like class declarations, which will throw at runtime as they will not be called with \`new\`.\\nIf you are expecting the function to accept certain arguments, you should explicitly define the function shape.", "4136871687"],
       [152, 6, 9, "Unsafe assignment of an any value.", "166477157"]
     ],
-    "packages/betterer/src/errors.ts:29397898": [
+    "packages/betterer/src/errors.ts:2984110573": [
       [7, 96, 10, "Invalid type \\"string | Error | BettererError\\" of template literal expression.", "3805115554"],
       [8, 99, 11, "Invalid type \\"string | Error | BettererError\\" of template literal expression.", "2365839858"],
       [9, 99, 11, "Invalid type \\"string | Error | BettererError\\" of template literal expression.", "2365839858"],
       [11, 91, 12, "Invalid type \\"string | Error | BettererError\\" of template literal expression.", "362595323"],
       [12, 70, 12, "Invalid type \\"string | Error | BettererError\\" of template literal expression.", "362595323"],
       [13, 65, 8, "Invalid type \\"string | Error | BettererError\\" of template literal expression.", "92641249"],
-      [14, 67, 8, "Invalid type \\"string | Error | BettererError\\" of template literal expression.", "92641249"]
+      [14, 67, 8, "Invalid type \\"string | Error | BettererError\\" of template literal expression.", "92641249"],
+      [17, 59, 11, "Invalid type \\"string | Error | BettererError\\" of template literal expression.", "2365839858"]
     ],
     "packages/betterer/src/register.ts:845928349": [
       [17, 8, 39, "Unsafe assignment of an any value.", "2552944516"],

packages/betterer/src/errors.ts

@@ -13,3 +13,7 @@ export const COULDNT_LOAD_REPORTER = registerError((reporterName) => `could not
 export const NO_REPORTER_LOADED = registerError((reporterName) => `"${reporterName}" didn't create a reporter. 😔`);
 export const UNKNOWN_HOOK_NAME = registerError((hookName) => `"${hookName}" is not a valid reporter hook name. 😔`);
 export const HOOK_NOT_A_FUNCTION = registerError((hookName) => `"${hookName}" is not a function. 😔`);
+
+export const COULDNT_RESOLVE_MERGE_CONFLICT = registerError(
+  (resultsPath) => `could not resolve merge conflict in "${resultsPath}". 😔`
+);

packages/betterer/src/results/reader.ts

@@ -1,9 +1,15 @@
+import * as assert from 'assert';
 import { promises as fs } from 'fs';
 
 import { requireText } from '../require';
-import { COULDNT_READ_RESULTS } from '../errors';
+import { COULDNT_READ_RESULTS, COULDNT_RESOLVE_MERGE_CONFLICT } from '../errors';
 import { BettererExpectedResults } from './types';
 
+const MERGE_CONFLICT_ANCESTOR = '|||||||';
+const MERGE_CONFLICT_END = '>>>>>>>';
+const MERGE_CONFLICT_SEP = '=======';
+const MERGE_CONFLICT_START = '<<<<<<<';
+
 export async function read(resultsPath: string): Promise<BettererExpectedResults> {
   let file = '';
   try {
@@ -12,9 +18,65 @@ export async function read(resultsPath: string): Promise<BettererExpectedResults
     return {};
   }
 
+  if (hasMergeConflicts(file)) {
+    try {
+      const [ours, theirs] = extractConflicts(file);
+      return { ...requireText(ours), ...requireText(theirs) };
+    } catch (e) {
+      throw COULDNT_RESOLVE_MERGE_CONFLICT(resultsPath, e);
+    }
+  }
+
   try {
     return requireText(file);
   } catch {
     throw COULDNT_READ_RESULTS(resultsPath);
   }
 }
+
+function hasMergeConflicts(str: string): boolean {
+  return str.includes(MERGE_CONFLICT_START) && str.includes(MERGE_CONFLICT_SEP) && str.includes(MERGE_CONFLICT_END);
+}
+
+function extractConflicts(file: string): [string, string] {
+  const ours = [];
+  const theirs = [];
+  const lines = file.split(/\r?\n/g);
+  let skip = false;
+
+  while (lines.length) {
+    const line = lines.shift();
+    assert(line);
+    if (line.startsWith(MERGE_CONFLICT_START)) {
+      // get our file
+      while (lines.length) {
+        const conflictLine = lines.shift();
+        assert(conflictLine);
+        if (conflictLine === MERGE_CONFLICT_SEP) {
+          skip = false;
+          break;
+        } else if (skip || conflictLine.startsWith(MERGE_CONFLICT_ANCESTOR)) {
+          skip = true;
+          continue;
+        } else {
+          ours.push(conflictLine);
+        }
+      }
+
+      // get their file
+      while (lines.length) {
+        const conflictLine = lines.shift();
+        assert(conflictLine);
+        if (conflictLine.startsWith(MERGE_CONFLICT_END)) {
+          break;
+        } else {
+          theirs.push(conflictLine);
+        }
+      }
+    } else {
+      ours.push(line);
+      theirs.push(line);
+    }
+  }
+  return [ours.join('\n'), theirs.join('\n')];
+}

test/__snapshots__/betterer-conflict.spec.ts.snap

@@ -0,0 +1,34 @@
+// Jest Snapshot v1, https://goo.gl/fbAQLP
+
+exports[`betterer should work when there is a merge conflict in the results file 1`] = `
+Array [
+  "
+   / | /     _          _   _                     
+ '-.ooo.-'  | |__   ___| |_| |_ ___ _ __ ___ _ __ 
+---ooooo--- | '_ / / _ / __| __/ _ / '__/ _ / '__|
+ .-'ooo'-.  | |_) |  __/ |_| ||  __/ | |  __/ |   
+   / | /    |_.__/ /___|/__|/__/___|_|  /___|_|   
+ ",
+  " ☀️  betterer  info  💬  - ",
+  "running \\"no raw console calls\\"!",
+  " ☀️  betterer  warn  🚨  - ",
+  "\\"no raw console calls\\" stayed the same. 😐",
+  " ☀️  betterer  info  💬  - ",
+  "1 test got checked. 🤔",
+  " ☀️  betterer  warn  🚨  - ",
+  "1 test stayed the same. 😐",
+]
+`;
+
+exports[`betterer should work when there is a merge conflict in the results file 2`] = `
+"// BETTERER RESULTS V1.
+exports[\`no raw console calls\`] = {
+  timestamp: 0,
+  value: \`{
+    \\"src/index.ts:1884655653\\": [
+      [0, 0, 11, \\"TSQuery match\\", \\"3870399096\\"]
+    ]
+  }\`
+};
+"
+`;

test/betterer-conflict.spec.ts

@@ -0,0 +1,68 @@
+import { betterer } from '@betterer/betterer';
+
+import { createFixture } from './fixture';
+
+describe('betterer', () => {
+  it('should work when there is a merge conflict in the results file', async () => {
+    const { logs, paths, readFile, cleanup } = await createFixture('test-betterer-conflict', {
+      '.betterer.ts': `
+import { tsquery } from '@betterer/tsquery';
+
+export default {
+  'no raw console calls': tsquery(
+    './tsconfig.json',
+    'CallExpression > PropertyAccessExpression[expression.name="console"][name.name="log"]'
+  )
+};
+              `,
+      '.betterer.results': `
+// BETTERER RESULTS V1.
+exports[\`no raw console calls\`] = {
+  timestamp: 0,
+  value: \`{
+|||<<<<<<< our-change
+    \\"src/index.ts:315583663\\": [
+      [0, 0, 11, \\"TSQuery match\\", \\"3870399096\\"],
+      [1, 0, 11, \\"TSQuery match\\", \\"3870399096\\"]
+    ]
+|||=======
+    \\"src/index.ts:913095150\\": [
+      [0, 0, 11, \\"TSQuery match\\", \\"3870399096\\"]
+    ]
+|||>>>>>>> their-change
+  }\`
+};
+      `.replace(/\|||/g, ''), // Mess with it a bit so that tooling doesn't think this is a real conflict:
+      'tsconfig.json': `
+{
+  "compilerOptions": {
+    "noEmit": true,
+    "lib": ["esnext"],
+    "moduleResolution": "node",
+    "target": "ES5",
+    "typeRoots": ["../../node_modules/@types/"],
+    "resolveJsonModule": true
+  },
+  "include": ["./src/**/*", ".betterer.ts"]
+}      
+      `,
+      'src/index.ts': `
+console.log('foo');
+console.info('foo');
+      `
+    });
+
+    const configPaths = [paths.config];
+    const resultsPath = paths.results;
+
+    await betterer({ configPaths, resultsPath });
+
+    expect(logs).toMatchSnapshot();
+
+    const result = await readFile(resultsPath);
+
+    expect(result).toMatchSnapshot();
+
+    await cleanup();
+  });
+});