Support content filters that only post a comment when a regex is not found

.github/nitpicks.yml

@@ -20,3 +20,10 @@
   blocking: true
   pathFilter:
     - '+**/*.dll'
+
+- markdown: |
+    Testing - fail if the file doesn't include "always()"
+  pathFilter:
+    - '.github/workflows/example.yml'
+  contentFilter:
+    - '!always()'

.github/workflows/example.yml

@@ -0,0 +1,21 @@
+name: Build
+on:
+  pull_request:
+  push:
+    branches:
+      - master
+      - 'releases/*'
+
+jobs:
+  build-and-test:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v1
+
+      - run: npm ci
+      - run: npm run all
+      - name: nitpicker
+        uses: ./
+        with:
+          nitpicks: './.github/nitpicks.yml'
+          token: '${{ secrets.GITHUB_TOKEN }}'

README.md

@@ -103,6 +103,17 @@ A comment's `contentFilter` parameter accepts an array of regular expressions th
     - '(\+\s*debugger)'
 ```
 
+If you would like nitpicker to only post a comment when the regular expression is _not_ found, you can use a `!` in front of the contentFilter. For example:
+
+```yaml
+- markdown: |
+    Please ensure that all .ts files include the word 'unicorn!'
+  pathFilter:
+    - 'src/**/*.ts'
+  contentFilter:
+    - '!(unicorn)'
+```
+
 ## Development
 
 Install the dependencies

__tests__/configReader.test.ts

@@ -29,6 +29,15 @@ test('contentFilter defaults to undefined', () => {
   expect(comments.every(c => !c.contentFilter)).toBeTruthy();
 });
 
+test('contentFilter is negated', () => {
+  const configFile = './data/default_content_filter.yml';
+  const inputPath = path.join(__dirname, configFile);
+
+  const comments = getConfiguredComments(inputPath);
+
+  expect(comments.every(c => !c.contentFilter)).toBeTruthy();
+});
+
 test('read invalid config file', () => {
   const configFile = './data/invalid_nitpicks.yml';
   const inputPath = path.join(__dirname, configFile);

__tests__/data/negated_content_filter.yml

@@ -0,0 +1,8 @@
+- markdown: |
+    ## Notice
+    Thanks for this contribution. We _really_ appreciate your help!
+
+- markdown: |
+    ## Blocking issue
+  contentFilter:
+    - '!(\+\s*console.log\(.*\))'

__tests__/services/state.test.ts

@@ -309,6 +309,52 @@ test('getMatchingContentChanges returns single changes with multiple matching co
   expect(result).toHaveLength(1);
 });
 
+test('getMatchingContentChanges returns single changes with negated contentFilter', () => {
+  const comment: Comment = {
+    pathFilter: ['*'],
+    markdown: 'Everything',
+    blocking: false,
+    contentFilter: [`!(\\+\\s*debugger)`]
+  };
+
+  const changes: Change[] = [
+    {
+      file: 'src/services/configReader.ts',
+      changeType: ChangeType.edit,
+      patch:
+        "@@ -4,14 +4,19 @@ import { safeLoad } from 'js-yaml';\n" +
+        " import { Constants } from '../constants';\n" +
+        ' \n' +
+        ' export function getConfiguredComments(filePath: string): Comment[] {\n' +
+        '+  if (!fs.existsSync(filePath)) {\n' +
+        '+    throw Error(`Nitpicks file does not exist: ${filePath}`);\n' +
+        '+  }\n' +
+        '+\n' +
+        "   const contents = fs.readFileSync(filePath, 'utf8');\n" +
+        '   const yaml: Comment[] = safeLoad(contents);\n' +
+        ' \n' +
+        '+  nope!\n' +
+        '+  console.log("this shouldnt have been committed!")\n' +
+        ' \n' +
+        '   const comments: Comment[] = yaml\n' +
+        '-    .filter(y => y.markdown && y.pathFilter?.length > 0)\n' +
+        '+    .filter(y => y.markdown)\n' +
+        '     .map(c => ({\n' +
+        '       ...c,\n' +
+        "-      markdown: `${c.markdown}${c.blocking ? Constants.BlockingText : ''}`\n" +
+        "+      markdown: `${c.markdown}${c.blocking ? Constants.BlockingText : ''}`,\n" +
+        '+      pathFilter: c.pathFilter ?? Constants.DefaultPathFilter // Default to match everything\n' +
+        '     }));\n' +
+        ' \n' +
+        '   return comments;'
+    }
+  ];
+
+  const result = getMatchingContentChanges(comment, changes);
+
+  expect(result).toHaveLength(1);
+});
+
 test('getMatchingContentChanges throws error if unable to parse regexpr', () => {
   const comment: Comment = {
     pathFilter: ['*'],