New Rule: enforce-min-coverage-comments-sync (#277)

* initial updateCommentThreshold

* on second thought it should be separate rule

enforce-min-coverage-comments-sync

* create not under meta

* fix func name

* introduce getMinCoverageDirectiveCommentNodeAndPercent

* fix works!?

TODO: how to revert test file after spec fixes it?

* 4.5.0-pre0.1

* floor

* remove comment if coverage above global threshold

* add coverage-sync-* examples

* add to codebases

* Update format.spec.js.snap

* handle expected fixes

* no js ext on fixed examples

so they won't be fixed themselves

* percent is 33 apparently ok flow

* version

* remove leftover copypasta from enforce-min-coverage

* 0.4

* address pr review comments

.npmignore

@@ -0,0 +1,3 @@
+src/
+flow-typed/
+test/

src/index.js

@@ -155,6 +155,24 @@ function createFilteredErrorRule(filter: (CollectOutputElement) => any): (contex
   };
 }
 
+const MIN_COVERAGE_DIRECTIVE_COMMENT_PATTERN =
+  /(\s*eslint\s*['"]flowtype-errors\/enforce-min-coverage['"]\s*:\s*\[\s*(?:2|['"]error['"])\s*,\s*)(\d+)(\]\s*)/
+
+function getMinCoverageDirectiveCommentNodeAndPercent(sourceCode) {
+  let commentNode
+  let minPercent
+  // eslint-disable-next-line no-restricted-syntax
+  for (const comment of sourceCode.getAllComments()) {
+    const match = comment.value.match(MIN_COVERAGE_DIRECTIVE_COMMENT_PATTERN)
+    if (match && match[2]) {
+      commentNode = comment
+      minPercent = parseInt(match[2], 10)
+      break
+    }
+  }
+  return [commentNode, minPercent]
+}
+
 const getCoverage = (context, node) => {
   const source = context.getSourceCode();
   const info = lookupInfo(context, source, node);
@@ -242,6 +260,57 @@ export default {
         },
       };
     },
+    'enforce-min-coverage-comments-sync': {
+      meta: {
+        fixable: 'code',
+      },
+      create: function enforceMinCoverageCommentsSync(
+        context: EslintContext
+      ): ReturnRule {
+        return {
+          Program(node: Object) {
+            const res = getCoverage(context, node);
+            if (!res) {
+              return;
+            }
+
+            const sourceCode = context.getSourceCode()
+            const [minCoverageDirectiveCommentNode, requiredCoverage] = getMinCoverageDirectiveCommentNodeAndPercent(sourceCode)
+              if (!minCoverageDirectiveCommentNode || !requiredCoverage) {
+              return;
+            }
+
+            // Get global requiredCoverage outside the inline module comment.
+            const enforceMinCoverage = context.options[0];
+            // If flow coverage is >=updateCommentThreshold% greater than allowed, update the eslint comment.
+            const updateCommentThreshold = context.options[1];
+            const { coveredCount, uncoveredCount } = res.coverageInfo;
+
+            /* eslint prefer-template: 0 */
+            const percentage = Number(
+              Math.round(
+                (coveredCount / (coveredCount + uncoveredCount)) * 10000
+              ) + 'e-2'
+            );
+
+            if (percentage - requiredCoverage > updateCommentThreshold) {
+              context.report({
+                loc: res.program.loc,
+                message: `Expected coverage comment to be within ${updateCommentThreshold}% of ${requiredCoverage}%, but is: ${percentage}%`,
+                fix(fixer) {
+                  if (percentage >= enforceMinCoverage) {
+                    // If coverage >= global required amount, remove comment entirely.
+                    return fixer.replaceText(minCoverageDirectiveCommentNode, '')
+                  }
+
+                  return fixer.replaceText(minCoverageDirectiveCommentNode, minCoverageDirectiveCommentNode.value.replace(MIN_COVERAGE_DIRECTIVE_COMMENT_PATTERN, `/*$1${Math.floor(percentage)}$3*/`))
+                }
+              });
+            }
+          },
+        };
+      },
+    },
     'show-errors': (createFilteredErrorRule(
       ({ level }) => level !== FlowSeverity.Warning
     ) : (context: EslintContext) => ReturnRule),

test/__snapshots__/format.spec.js.snap

@@ -33,6 +33,10 @@ exports[`Check codebases coverage-ok - eslint should give expected output 1`] =
 
 exports[`Check codebases coverage-ok2 - eslint should give expected output 1`] = `""`;
 
+exports[`Check codebases coverage-sync-remove - eslint should give expected output 1`] = `""`;
+
+exports[`Check codebases coverage-sync-update - eslint should give expected output 1`] = `""`;
+
 exports[`Check codebases flow-pragma-1 - eslint should give expected output 1`] = `
 "
 ./example.js

test/codebases/coverage-sync-remove/.flowconfig

@@ -0,0 +1,4 @@
+[options]
+esproposal.class_static_fields=enable
+esproposal.class_instance_fields=enable
+esproposal.export_star_as=enable

test/codebases/coverage-sync-remove/example.fixed

@@ -0,0 +1,8 @@
+// @flow
+
+
+let x: number = 100;
+let x2: number = 100;
+let x3: number = 100;
+let x4;
+let x5;

test/codebases/coverage-sync-remove/example.js

@@ -0,0 +1,8 @@
+// @flow
+/* eslint "flowtype-errors/enforce-min-coverage": [2, 30] */
+
+let x: number = 100;
+let x2: number = 100;
+let x3: number = 100;
+let x4;
+let x5;

test/codebases/coverage-sync-update/.flowconfig

@@ -0,0 +1,4 @@
+[options]
+esproposal.class_static_fields=enable
+esproposal.class_instance_fields=enable
+esproposal.export_star_as=enable

test/codebases/coverage-sync-update/example.fixed

@@ -0,0 +1,8 @@
+// @flow
+/* eslint "flowtype-errors/enforce-min-coverage": [2, 33] */
+
+let x: number = 100;
+let x2;
+let x3;
+let x4;
+let x5;

test/codebases/coverage-sync-update/example.js

@@ -0,0 +1,8 @@
+// @flow
+/* eslint "flowtype-errors/enforce-min-coverage": [2, 5] */
+
+let x: number = 100;
+let x2;
+let x3;
+let x4;
+let x5;

test/format.spec.js

@@ -1,6 +1,7 @@
+/* eslint-disable no-nested-ternary */
 import path from 'path';
 import { expect as chaiExpect } from 'chai';
-import { readFileSync, writeFileSync, unlinkSync } from 'fs';
+import { existsSync, readFileSync, writeFileSync, unlinkSync } from 'fs';
 // $FlowIgnore
 import execa from 'execa';
 import { collect } from '../src/collect';
@@ -60,7 +61,7 @@ describe('Format', () => {
 const ESLINT_PATH = path.resolve('./node_modules/eslint/bin/eslint.js');
 
 async function runEslint(cwd) {
-  const result = await execa(ESLINT_PATH, ['**/*.{js,vue}'], { cwd, stripEof: false });
+  const result = await execa(ESLINT_PATH, ['**/*.{js,vue}', '--fix'], { cwd, stripEof: false });
   result.stdout = result.stdout && result.stdout.toString();
   result.stderr = result.stderr && result.stderr.toString();
   return result;
@@ -72,6 +73,8 @@ const codebases = [
   'coverage-fail2',
   'coverage-ok',
   'coverage-ok2',
+  'coverage-sync-remove',
+  'coverage-sync-update',
   'flow-pragma-1',
   'flow-pragma-2',
   'html-support',
@@ -86,7 +89,7 @@ const codebases = [
   'uncovered-example'
 ];
 
-const eslintConfig = (enforceMinCoverage, checkUncovered, html) => `
+const eslintConfig = (enforceMinCoverage, updateCommentThreshold, checkUncovered, html) => `
   const Module = require('module');
   const path = require('path');
   const original = Module._resolveFilename;
@@ -119,8 +122,15 @@ const eslintConfig = (enforceMinCoverage, checkUncovered, html) => `
       }
     },
     rules: {
-      ${enforceMinCoverage
-        ? `'flowtype-errors/enforce-min-coverage': [2, ${enforceMinCoverage}],` : ``}
+      ${updateCommentThreshold
+        ? [
+          `'flowtype-errors/enforce-min-coverage': [2, ${enforceMinCoverage}],`,
+          `'flowtype-errors/enforce-min-coverage-comments-sync': [2, ${enforceMinCoverage}, ${updateCommentThreshold}],`,
+        ].join('\n')
+        : enforceMinCoverage
+          ? `'flowtype-errors/enforce-min-coverage': [2, ${enforceMinCoverage}],`
+          : ``
+        }
         ${checkUncovered ? `'flowtype-errors/uncovered': 2,` : ''}
         'flowtype-errors/show-errors': 2,
         'flowtype-errors/show-warnings': 1
@@ -144,13 +154,20 @@ describe('Check codebases', () => {
      // eslint-disable-next-line no-loop-func
     it(`${title} - eslint should give expected output`, async() => {
       const fullFolder = path.resolve(`./test/codebases/${folder}`);
+      const exampleJsFilePath = path.resolve(`./test/codebases/${folder}/example.js`);
+      const exampleJsFixedFilePath = path.resolve(`./test/codebases/${folder}/example.fixed`);
+      const hasFix = existsSync(exampleJsFixedFilePath)
       const configPath = path.resolve(fullFolder, '.eslintrc.js');
 
+      const contentsBefore = hasFix && readFileSync(exampleJsFilePath, 'utf8')
+      const contentsExpected = hasFix && readFileSync(exampleJsFixedFilePath, 'utf8')
+
       // Write config file
       writeFileSync(
         configPath,
         eslintConfig(
           folder.match(/^coverage-/) ? 50 : 0,
+          folder.match(/^coverage-sync/) ? 10 : 0,
           !!folder.match(/^uncovered-/),
           /html-support/.test(folder)
         )
@@ -164,6 +181,11 @@ describe('Check codebases', () => {
         'gm'
       ); // Escape regexp
 
+      const contentsAfter = hasFix && readFileSync(exampleJsFilePath, 'utf8')
+
+      // Revert the file to before it was fixed, since this file is checked into git.
+      if (hasFix && contentsBefore !== contentsAfter) writeFileSync(exampleJsFilePath, contentsBefore)
+
       // Strip root from filenames
       expect(
         stdout.replace(regexp, match =>
@@ -173,6 +195,10 @@ describe('Check codebases', () => {
 
       expect(stderr).toEqual('');
 
+      if (hasFix) {
+        expect(contentsAfter).toEqual(contentsExpected);
+      }
+
       // Clean up
       unlinkSync(configPath);
     });