build(aio): better error message for invalid links

aio/tools/transforms/links-package/inline-tag-defs/link.js

@@ -26,7 +26,7 @@ module.exports = function linkInlineTagDef(getLinkInfo, createDocMessage, log) {
         var linkInfo = getLinkInfo(uri, title, doc);
 
         if (!linkInfo.valid) {
-          const message = createDocMessage(linkInfo.error, doc);
+          const message = createDocMessage(`Error in {@${tagName} ${tagDescription}} - ${linkInfo.error}`, doc);
           if (this.failOnBadLink) {
             throw new Error(message);
           } else {

aio/tools/transforms/links-package/inline-tag-defs/link.spec.js

@@ -0,0 +1,61 @@
+var testPackageFactory = require('../../helpers/test-package');
+var Dgeni = require('dgeni');
+
+describe('link inline-tag-def', function() {
+  let injector, tag, getLinkInfo, log;
+
+  beforeEach(() => {
+    getLinkInfo = jasmine.createSpy('getLinkInfo');
+    const testPackage = testPackageFactory('links-package', true)
+      .factory('getLinkInfo', function() { return getLinkInfo; });
+    getLinkInfo.disambiguators = [];
+
+    const dgeni = new Dgeni([testPackage]);
+    injector = dgeni.configureInjector();
+    tag = injector.get('linkInlineTagDef');
+    log = injector.get('log');
+  });
+
+  it('should be available as a service', () => {
+    expect(tag).toBeDefined();
+    expect(tag.name).toEqual('link');
+    expect(tag.aliases).toEqual(['linkDocs']);
+  });
+
+  it('should call getLinkInfo', () => {
+    const doc = {};
+    const tagName = 'link';
+    const tagDescription = 'doc-id link text';
+    getLinkInfo.and.returnValue({ url: 'url/to/doc', title: 'link text' });
+    tag.handler(doc, tagName, tagDescription);
+    expect(getLinkInfo).toHaveBeenCalledWith('doc-id', 'link text', doc);
+  });
+
+  it('should return an HTML anchor tag', () => {
+    const doc = {};
+    const tagName = 'link';
+    const tagDescription = 'doc-id link text';
+    getLinkInfo.and.returnValue({ url: 'url/to/doc', title: 'link text' });
+    const result = tag.handler(doc, tagName, tagDescription);
+    expect(result).toEqual('<a href=\'url/to/doc\'>link text</a>');
+  });
+
+  it('should log a warning if not failOnBadLink and the link is "bad"', () => {
+    const doc = {};
+    const tagName = 'link';
+    const tagDescription = 'doc-id link text';
+    getLinkInfo.and.returnValue({ valid: false, error: 'Error message', errorType: 'error' });
+    expect(() => tag.handler(doc, tagName, tagDescription)).not.toThrow();
+    expect(log.warn).toHaveBeenCalledWith('Error in {@link doc-id link text} - Error message - doc');
+  });
+
+  it('should throw an error if failOnBadLink and the link is "bad"', () => {
+    const doc = {};
+    const tagName = 'link';
+    const tagDescription = 'doc-id link text';
+    getLinkInfo.and.returnValue({ valid: false, error: 'Error message', errorType: 'error' });
+    tag.failOnBadLink = true;
+    expect(() => tag.handler(doc, tagName, tagDescription)).toThrowError('Error in {@link doc-id link text} - Error message - doc');
+  });
+});
+

aio/tools/transforms/links-package/services/getLinkInfo.js

@@ -74,6 +74,8 @@ module.exports = function getLinkInfo(getDocFromAlias, encodeCodeBlock, log) {
 
     if (linkInfo.title === undefined) {
       linkInfo.valid = false;
+      linkInfo.errorType = 'no-title';
+      linkInfo.error = 'The link is missing a title';
     }
 
     return linkInfo;

aio/tools/transforms/links-package/services/getLinkInfo.spec.js

@@ -23,6 +23,8 @@ describe('getLinkInfo', () => {
     const currentDoc = { };
     const linkInfo = getLinkInfo('browser-support', undefined, currentDoc);
     expect(linkInfo.valid).toBe(false);
+    expect(linkInfo.errorType).toEqual('no-title');
+    expect(linkInfo.error).toEqual('The link is missing a title');
   });
 
   it('should use the target document title if available and no title is specified', () => {