Add none option for inverse matching the changes to a label

README.md

@@ -46,7 +46,7 @@ The base match object is defined as:
 - head-branch: ['list', 'of', 'regexps']
 ```
 
-There are two top-level keys, `any` and `all`, which both accept the same configuration options:
+There are three top-level keys, `any`, `all` and `none`, which all accept the same configuration options:
 ```yml
 - any:
   - changed-files:
@@ -66,12 +66,13 @@ There are two top-level keys, `any` and `all`, which both accept the same config
   - head-branch: ['list', 'of', 'regexps']
 ```
 
-From a boolean logic perspective, top-level match objects, and options within `all` are `AND`-ed together and individual match rules within the `any` object are `OR`-ed.
+From a boolean logic perspective, top-level match objects, and options within `all` are `AND`-ed together and individual match rules within the `any` object are `OR`-ed. `none` is the inverse of `any`.
 
 One or all fields can be provided for fine-grained matching.
 The fields are defined as follows:
 - `all`: ALL of the provided options must match for the label to be applied
 - `any`: if ANY of the provided options match then the label will be applied
+- `none`: will assign the label if none of the provided options match - e.g. missing changes to documentation or unit tests
   - `base-branch`: match regexps against the base branch name
   - `head-branch`: match regexps against the head branch name
   - `changed-files`: match glob patterns against the changed paths
@@ -137,6 +138,12 @@ Documentation:
 - changed-files:
   - any-glob-to-any-file: '**/*.md'
 
+# Add `Missing Documentation` label to any code change which doesn't include doc changes
+Missing Documentation:
+- none:
+  - changed-files:
+    - any-glob-to-any-file: '**/*.md'
+
 # Add 'source' label to any change to src files within the source dir EXCEPT for the docs sub-folder
 source:
 - all:

__tests__/fixtures/all_options.yml

@@ -9,6 +9,11 @@ label1:
           - all-globs-to-all-files: ['glob']
       - head-branch: ['regexp']
       - base-branch: ['regexp']
+  - none:
+      - changed-files:
+          - all-globs-to-all-files: ['notthisglob']
+      - head-branch: ['notthisone']
+      - base-branch: ['notthisone']
 
 label2:
   - changed-files:

__tests__/labeler.test.ts

@@ -40,6 +40,13 @@ describe('getLabelConfigMapFromObject', () => {
         {baseBranch: undefined, headBranch: ['regexp']},
         {baseBranch: ['regexp'], headBranch: undefined}
       ]
+    },
+    {
+      none: [
+        {changedFiles: [{allGlobsToAllFiles: ['notthisglob']}]},
+        {baseBranch: undefined, headBranch: ['notthisone']},
+        {baseBranch: ['notthisone'], headBranch: undefined}
+      ]
     }
   ]);
   expected.set('label2', [
@@ -135,6 +142,36 @@ describe('checkMatchConfigs', () => {
 
       expect(result).toBeTruthy();
     });
+
+    it('returns true when no files match the "none" config', () => {
+      const matchConfig: MatchConfig[] = [
+        {
+          none: [
+            {changedFiles: [{anyGlobToAnyFile: ['*.md']}]},
+            {headBranch: ['some-branch']}
+          ]
+        }
+      ];
+      const changedFiles = ['foo.txt', 'bar.txt'];
+
+      const result = checkMatchConfigs(changedFiles, matchConfig, false);
+      expect(result).toBe(true);
+    });
+
+    it('returns false when files match the "none" config', () => {
+      const matchConfig: MatchConfig[] = [
+        {
+          none: [
+            {changedFiles: [{anyGlobToAnyFile: ['*.md']}]},
+            {headBranch: ['some-branch']}
+          ]
+        }
+      ];
+      const changedFiles = ['foo.md', 'bar.md'];
+
+      const result = checkMatchConfigs(changedFiles, matchConfig, false);
+      expect(result).toBe(false);
+    });
   });
 
   describe('when multiple MatchConfigs are supplied', () => {

src/api/get-label-configs.ts

@@ -14,6 +14,7 @@ import {toBranchMatchConfig, BranchMatchConfig} from '../branch';
 export interface MatchConfig {
   all?: BaseMatchConfig[];
   any?: BaseMatchConfig[];
+  none?: BaseMatchConfig[];
 }
 
 export type BaseMatchConfig = BranchMatchConfig & ChangedFilesMatchConfig;
@@ -79,9 +80,9 @@ export function getLabelConfigMapFromObject(
         }
 
         Object.entries(configValue).forEach(([key, value]) => {
-          // If the top level `any` or `all` keys are provided then set them, and convert their values to
+          // If the top level `any`, `all` or `none` keys are provided then set them, and convert their values to
           // our config objects.
-          if (key === 'any' || key === 'all') {
+          if (key === 'any' || key === 'all' || key === 'none') { 
             if (Array.isArray(value)) {
               const newConfigs = value.map(toMatchConfig);
               updatedConfig.push({[key]: newConfigs});

src/labeler.ts

@@ -134,6 +134,12 @@ function checkMatch(
     }
   }
 
+  if (matchConfig.none) {
+    if (checkAny(matchConfig.none, changedFiles, dot)) {
+      return false;
+    }
+  }
+
   return true;
 }