[BUG] CompoDoc not inheriting docs from implemented Interfaces

Overview of the issue

When a class A implements Interface B, the interface-documentation does not get inherited to the implemented class properties:

// documented-interface.ts
export interface DocumentedInterface {
  /** Some docs for the property, that does not get inherited into implementing classes. :( */
  test: boolean;
}

// my-class.ts
import { DocumentedInterface } from '.';

/** The "test"-property will not be documented in compodoc output, even that the interface provides docs for it.  */
export class MyClass implements DocumentedInterface {
  public test = true;
}

Operating System, Node.js, npm, compodoc version(s)

• OS: Windows 10
• npm: 6.13.2
• Nodejs: 12.13.1
• CompoDoc: 1.1.11

Angular configuration, a package.json file in the root folder

• Please note: Changed the real project name to “package-name”, for legal reasons. But there is nothing special with the name, so should not be relevant here anyway.

angular.json:

{
  "$schema": "./node_modules/@angular/cli/lib/config/schema.json",
  "version": 1,
  "newProjectRoot": "projects",
  "projects": {
    "package-name": {
      "root": "projects/package-name",
      "sourceRoot": "projects/package-name/src",
      "projectType": "library",
      "prefix": "package-name",
      "architect": {
        "build": {
          "builder": "@angular-devkit/build-ng-packagr:build",
          "options": {
            "tsConfig": "projects/package-name/tsconfig.lib.json",
            "project": "projects/package-name/ng-package.json"
          }
        },
        "test": {
          "builder": "@angular-builders/jest:run"
        },
        "lint": {
          "builder": "@angular-devkit/build-angular:tslint",
          "options": {
            "tsConfig": ["projects/package-name/tsconfig.lib.json", "projects/package-name/tsconfig.spec.json"],
            "exclude": ["**/node_modules/**"]
          }
        }
      }
    }
  },
  "schematics": {
    "@schematics/angular:component": {
      "styleext": "scss"
    }
  },
  "defaultProject": "package-name"
}

tsconfig.json & tsconfig.lib.json:

{
  "compileOnSave": false,
  "compilerOptions": {
    "baseUrl": "./",
    "downlevelIteration": true,
    "outDir": "./dist/out-tsc",
    "sourceMap": true,
    "declaration": false,
    "module": "esnext",
    "moduleResolution": "node",
    "emitDecoratorMetadata": true,
    "experimentalDecorators": true,
    "importHelpers": true,
    "target": "es2015",
    "typeRoots": ["node_modules/@types"],
    "types": ["jest", "mdx"],
    "lib": ["es2018", "dom"],
    "paths": {
      "package-name": ["dist/package-name"],
      "package-name/*": ["dist/package-name/*"]
    }
  },
  "exclude": ["dist"]
}

{
  "extends": "../../tsconfig.json",
  "compilerOptions": {
    "outDir": "../../out-tsc/lib",
    "target": "es2015",
    "module": "es2015",
    "moduleResolution": "node",
    "declaration": true,
    "sourceMap": true,
    "inlineSources": true,
    "emitDecoratorMetadata": true,
    "experimentalDecorators": true,
    "importHelpers": true,
    "types": [],
    "lib": ["dom", "es2018"]
  },
  "angularCompilerOptions": {
    "annotateForClosureCompiler": true,
    "skipTemplateCodegen": true,
    "strictMetadataEmit": true,
    "fullTemplateTypeCheck": true,
    "strictInjectionParameters": true,
    "enableResourceInlining": true
  },
  "exclude": ["**/*.spec.ts", "**/spec.functions.ts"]
}

package.json:

{
  "name": "package-name",
  "version": "0.0.0",
  "scripts": {
    "ng": "ng",
    "doc": "compodoc -p projects/package-name/tsconfig.lib.json -s",
    "doc:json": "compodoc -p projects/package-name/tsconfig.lib.json -e json -d ."
  },
  "private": true,
  "dependencies": {
    "@angular/animations": "~8.2.14",
    "@angular/cdk": "~8.2.3",
    "@angular/common": "~8.2.14",
    "@angular/compiler": "~8.2.14",
    "@angular/core": "~8.2.14",
    "@angular/forms": "~8.2.14",
    "@angular/material": "~8.2.3",
    "@angular/platform-browser": "~8.2.14",
    "@angular/platform-browser-dynamic": "~8.2.14",
    "@angular/router": "~8.2.14",
    "core-js": "^2.5.4",
    "hammerjs": "^2.0.8",
    "react": "^16.12.0",
    "rxjs": "~6.5.3",
    "tslib": "^1.9.0",
    "zone.js": "~0.9.1"
  },
  "devDependencies": {
    "@angular-builders/jest": "^8.3.1",
    "@angular-devkit/build-angular": "~0.803.19",
    "@angular-devkit/build-ng-packagr": "~0.803.19",
    "@angular/cli": "^8.3.19",
    "@angular/compiler-cli": "~8.2.14",
    "@angular/language-service": "~8.2.14",
    "@babel/core": "^7.7.2",
    "@compodoc/compodoc": "^1.1.10",
    "@storybook/addon-actions": "^5.3.6",
    "@storybook/addon-docs": "^5.3",
    "@storybook/addons": "^5.3",
    "@storybook/angular": "^5.3",
    "@types/jest": "^24.0.23",
    "@types/node": "~8.9.4",
    "babel-loader": "^8.0.6",
    "codelyzer": "^5.0.1",
    "copy-webpack-plugin": "^5.0.5",
    "cross-env": "^6.0.3",
    "css-loader": "^3.2.1",
    "fs-extra": "^8.1.0",
    "ignore-not-found-export-webpack-plugin": "^1.0.1",
    "jest": "^24.9.0",
    "ng-packagr": "^5.7.1",
    "prettier": "^1.19.1",
    "scss-bundle": "^3.0.2",
    "shx": "^0.3.2",
    "ts-node": "~7.0.0",
    "tsickle": "^0.37.0",
    "tslint": "~5.11.0",
    "typescript": "~3.5.3"
  }
}

Compodoc installed globally or locally ?

• locally

If possible sourcecode of the file where it breaks

See example above configs

If possible your terminal logs before the error

• no error output.

Motivation for or Use Case

• Don’t want to have to manually copy over all docs from interfaces into my classes implementing them.
• This is error-prone and very likely to get out of sync soon; also it is really tedious to do so.

Reproduce the error

1. Create an Interface containing one property that is documented.
2. Create a class that implements that interface, but do not add docs to the implemented property.
3. Generate docs using compodoc and see the result: The classes’ property appears undocumented.

Related issues

• Maybe BUG: Extended interfaces not showing properties of parent

Suggest a Fix

• Sorry, no idea about that

[ghost]

@manekinekko any thoughts on adding this?

[sleidig]

Is there any chance for this feature? Looks like there might have been a related issue already: #242 ?

I would love to get this doc inheritance.