Refactor `docsBaseUrl` related code

We are planning to add a docs link to `gr-revisions-parents` and the
existing code for creating Documentation links was in such a bad shape
that we are refactoring it here.

`getDocsBaseUrl` was moved from `gr-rest-api` to `config-model`, which
is a much better place for it.

`getDocsBaseUrl` generally falls back to `gerrit-review`, not just in
some places.

The construction of urls from base and relative URL was moved to
url-util.

Release-Notes: skip
Change-Id: Ic991426b60cffa62e5c0dd27d38b4fecba3e8409
(cherry picked from commit 2d6ad54a532487333fda2b8921ecff041cb1c21e)

12 files changed, 238 insertions, 323 deletions

diff --git a/polygerrit-ui/app/elements/core/gr-main-header/gr-main-header.ts b/polygerrit-ui/app/elements/core/gr-main-header/gr-main-header.ts
index a55173cd69..34950b013f 100644
--- a/polygerrit-ui/app/elements/core/gr-main-header/gr-main-header.ts
+++ b/polygerrit-ui/app/elements/core/gr-main-header/gr-main-header.ts
@@ -8,7 +8,7 @@ import '../../shared/gr-dropdown/gr-dropdown';
 import '../../shared/gr-icon/gr-icon';
 import '../gr-account-dropdown/gr-account-dropdown';
 import '../gr-smart-search/gr-smart-search';
-import {getBaseUrl} from '../../../utils/url-util';
+import {getBaseUrl, getDocUrl} from '../../../utils/url-util';
 import {getAdminLinks, NavLink} from '../../../models/views/admin';
 import {
   AccountDetailInfo,
@@ -85,6 +85,18 @@ const DOCUMENTATION_LINKS: MainHeaderLink[] = [
   },
 ];
 
+// visible for testing
+export function getDocLinks(docBaseUrl: string, docLinks: MainHeaderLink[]) {
+  if (!docBaseUrl) return [];
+  return docLinks.map(link => {
+    return {
+      url: getDocUrl(docBaseUrl, link.url),
+      name: link.name,
+      target: '_blank',
+    };
+  });
+}
+
 // Set of authentication methods that can provide custom registration page.
 const AUTH_TYPES_WITH_REGISTER_URL: Set<AuthType> = new Set([
   AuthType.LDAP,
@@ -121,7 +133,7 @@ export class GrMainHeader extends LitElement {
 
   @state() private adminLinks: NavLink[] = [];
 
-  @state() private docBaseUrl: string | null = null;
+  @state() private docsBaseUrl = '';
 
   @state() private userLinks: MainHeaderLink[] = [];
 
@@ -165,7 +177,7 @@ export class GrMainHeader extends LitElement {
     subscribe(
       this,
       () => this.getConfigModel().docsBaseUrl$,
-      docsBaseUrl => (this.docBaseUrl = docsBaseUrl)
+      docsBaseUrl => (this.docsBaseUrl = docsBaseUrl)
     );
     subscribe(
       this,
@@ -359,12 +371,9 @@ export class GrMainHeader extends LitElement {
       </gr-endpoint-decorator>
     </a>
     <ul class="links">
-      ${this.computeLinks(
-        this.userLinks,
-        this.adminLinks,
-        this.topMenus,
-        this.docBaseUrl
-      ).map(linkGroup => this.renderLinkGroup(linkGroup))}
+      ${this.computeLinks(this.userLinks, this.adminLinks, this.topMenus).map(
+        linkGroup => this.renderLinkGroup(linkGroup)
+      )}
     </ul>
     <div class="rightItems">
       <gr-endpoint-decorator
@@ -488,15 +497,13 @@ export class GrMainHeader extends LitElement {
     userLinks?: MainHeaderLink[],
     adminLinks?: NavLink[],
     topMenus?: TopMenuEntryInfo[],
-    docBaseUrl?: string | null,
     // defaultLinks parameter is used in tests only
     defaultLinks = DEFAULT_LINKS
   ) {
     if (
       userLinks === undefined ||
       adminLinks === undefined ||
-      topMenus === undefined ||
-      docBaseUrl === undefined
+      topMenus === undefined
     ) {
       return [];
     }
@@ -513,7 +520,7 @@ export class GrMainHeader extends LitElement {
         links: userLinks.slice(),
       });
     }
-    const docLinks = this.getDocLinks(docBaseUrl, DOCUMENTATION_LINKS);
+    const docLinks = getDocLinks(this.docsBaseUrl, DOCUMENTATION_LINKS);
     if (docLinks.length) {
       links.push({
         title: 'Documentation',
@@ -550,24 +557,6 @@ export class GrMainHeader extends LitElement {
   }
 
   // private but used in test
-  getDocLinks(docBaseUrl: string | null, docLinks: MainHeaderLink[]) {
-    if (!docBaseUrl) {
-      return [];
-    }
-    return docLinks.map(link => {
-      let url = docBaseUrl;
-      if (url && url[url.length - 1] === '/') {
-        url = url.substring(0, url.length - 1);
-      }
-      return {
-        url: url + link.url,
-        name: link.name,
-        target: '_blank',
-      };
-    });
-  }
-
-  // private but used in test
   loadAccount() {
     this.loading = true;
 
diff --git a/polygerrit-ui/app/elements/core/gr-main-header/gr-main-header_test.ts b/polygerrit-ui/app/elements/core/gr-main-header/gr-main-header_test.ts
index 4b9c313d23..dfb44b70e1 100644
--- a/polygerrit-ui/app/elements/core/gr-main-header/gr-main-header_test.ts
+++ b/polygerrit-ui/app/elements/core/gr-main-header/gr-main-header_test.ts
@@ -11,7 +11,7 @@ import {
   stubRestApi,
 } from '../../../test/test-utils';
 import './gr-main-header';
-import {GrMainHeader} from './gr-main-header';
+import {GrMainHeader, getDocLinks} from './gr-main-header';
 import {
   createAccountDetailWithId,
   createGerritInfo,
@@ -51,6 +51,11 @@ suite('gr-main-header tests', () => {
                 <span class="linksTitle" id="Changes"> Changes </span>
               </gr-dropdown>
             </li>
+            <li class="hideOnMobile">
+              <gr-dropdown down-arrow="" horizontal-align="left" link="">
+                <span class="linksTitle" id="Documentation">Documentation</span>
+              </gr-dropdown>
+            </li>
             <li>
               <gr-dropdown down-arrow="" horizontal-align="left" link="">
                 <span class="linksTitle" id="Browse"> Browse </span>
@@ -168,36 +173,24 @@ suite('gr-main-header tests', () => {
 
     // When no admin links are passed, it should use the default.
     assert.deepEqual(
-      element.computeLinks(
-        /* userLinks= */ [],
-        adminLinks,
-        /* topMenus= */ [],
-        /* docBaseUrl= */ '',
-        defaultLinks
-      ),
-      defaultLinks.concat({
-        title: 'Browse',
-        links: adminLinks,
-      })
+      element
+        .computeLinks(
+          /* userLinks= */ [],
+          adminLinks,
+          /* topMenus= */ [],
+          defaultLinks
+        )
+        .find(i => i.title === 'Faves'),
+      defaultLinks[0]
     );
     assert.deepEqual(
-      element.computeLinks(
-        userLinks,
-        adminLinks,
-        /* topMenus= */ [],
-        /* docBaseUrl= */ '',
-        defaultLinks
-      ),
-      defaultLinks.concat([
-        {
-          title: 'Your',
-          links: userLinks,
-        },
-        {
-          title: 'Browse',
-          links: adminLinks,
-        },
-      ])
+      element
+        .computeLinks(userLinks, adminLinks, /* topMenus= */ [], defaultLinks)
+        .find(i => i.title === 'Your'),
+      {
+        title: 'Your',
+        links: userLinks,
+      }
     );
   });
 
@@ -209,11 +202,10 @@ suite('gr-main-header tests', () => {
       },
     ];
 
-    assert.deepEqual(element.getDocLinks(null, docLinks), []);
-    assert.deepEqual(element.getDocLinks('', docLinks), []);
-    assert.deepEqual(element.getDocLinks('base', []), []);
+    assert.deepEqual(getDocLinks('', docLinks), []);
+    assert.deepEqual(getDocLinks('base', []), []);
 
-    assert.deepEqual(element.getDocLinks('base', docLinks), [
+    assert.deepEqual(getDocLinks('base', docLinks), [
       {
         name: 'Table of Contents',
         target: '_blank',
@@ -221,7 +213,7 @@ suite('gr-main-header tests', () => {
       },
     ]);
 
-    assert.deepEqual(element.getDocLinks('base/', docLinks), [
+    assert.deepEqual(getDocLinks('base/', docLinks), [
       {
         name: 'Table of Contents',
         target: '_blank',
@@ -255,24 +247,17 @@ suite('gr-main-header tests', () => {
         /* userLinks= */ [],
         adminLinks,
         topMenus,
-        /* baseDocUrl= */ '',
         /* defaultLinks= */ []
-      ),
-      [
-        {
-          title: 'Browse',
-          links: adminLinks,
-        },
-        {
-          title: 'Plugins',
-          links: [
-            {
-              name: 'Manage',
-              url: 'https://gerrit/plugins/plugin-manager/static/index.html',
-            },
-          ],
-        },
-      ]
+      )[2],
+      {
+        title: 'Plugins',
+        links: [
+          {
+            name: 'Manage',
+            url: 'https://gerrit/plugins/plugin-manager/static/index.html',
+          },
+        ],
+      }
     );
   });
 
@@ -306,24 +291,17 @@ suite('gr-main-header tests', () => {
         /* userLinks= */ [],
         adminLinks,
         topMenus,
-        /* baseDocUrl= */ '',
         /* defaultLinks= */ []
-      ),
-      [
-        {
-          title: 'Browse',
-          links: adminLinks,
-        },
-        {
-          title: 'Projects',
-          links: [
-            {
-              name: 'Project List',
-              url: '/plugins/myplugin/index.html',
-            },
-          ],
-        },
-      ]
+      )[2],
+      {
+        title: 'Projects',
+        links: [
+          {
+            name: 'Project List',
+            url: '/plugins/myplugin/index.html',
+          },
+        ],
+      }
     );
   });
 
@@ -362,28 +340,21 @@ suite('gr-main-header tests', () => {
         /* userLinks= */ [],
         adminLinks,
         topMenus,
-        /* baseDocUrl= */ '',
         /* defaultLinks= */ []
-      ),
-      [
-        {
-          title: 'Browse',
-          links: adminLinks,
-        },
-        {
-          title: 'Plugins',
-          links: [
-            {
-              name: 'Manage',
-              url: 'https://gerrit/plugins/plugin-manager/static/index.html',
-            },
-            {
-              name: 'Create',
-              url: 'https://gerrit/plugins/plugin-manager/static/create.html',
-            },
-          ],
-        },
-      ]
+      )[2],
+      {
+        title: 'Plugins',
+        links: [
+          {
+            name: 'Manage',
+            url: 'https://gerrit/plugins/plugin-manager/static/index.html',
+          },
+          {
+            name: 'Create',
+            url: 'https://gerrit/plugins/plugin-manager/static/create.html',
+          },
+        ],
+      }
     );
   });
 
@@ -416,24 +387,17 @@ suite('gr-main-header tests', () => {
         /* userLinks= */ [],
         /* adminLinks= */ [],
         topMenus,
-        /* baseDocUrl= */ '',
         defaultLinks
-      ),
-      [
-        {
-          title: 'Faves',
-          links: defaultLinks[0].links.concat([
-            {
-              name: 'Manage',
-              url: 'https://gerrit/plugins/plugin-manager/static/index.html',
-            },
-          ]),
-        },
-        {
-          title: 'Browse',
-          links: [],
-        },
-      ]
+      )[0],
+      {
+        title: 'Faves',
+        links: defaultLinks[0].links.concat([
+          {
+            name: 'Manage',
+            url: 'https://gerrit/plugins/plugin-manager/static/index.html',
+          },
+        ]),
+      }
     );
   });
 
@@ -462,29 +426,22 @@ suite('gr-main-header tests', () => {
         userLinks,
         /* adminLinks= */ [],
         topMenus,
-        /* baseDocUrl= */ '',
         /* defaultLinks= */ []
-      ),
-      [
-        {
-          title: 'Your',
-          links: [
-            {
-              name: 'Facebook',
-              url: 'https://facebook.com',
-              target: '',
-            },
-            {
-              name: 'Manage',
-              url: 'https://gerrit/plugins/plugin-manager/static/index.html',
-            },
-          ],
-        },
-        {
-          title: 'Browse',
-          links: [],
-        },
-      ]
+      )[0],
+      {
+        title: 'Your',
+        links: [
+          {
+            name: 'Facebook',
+            url: 'https://facebook.com',
+            target: '',
+          },
+          {
+            name: 'Manage',
+            url: 'https://gerrit/plugins/plugin-manager/static/index.html',
+          },
+        ],
+      }
     );
   });
 
@@ -513,21 +470,18 @@ suite('gr-main-header tests', () => {
         /* userLinks= */ [],
         adminLinks,
         topMenus,
-        /* baseDocUrl= */ '',
         /* defaultLinks= */ []
-      ),
-      [
-        {
-          title: 'Browse',
-          links: [
-            adminLinks[0],
-            {
-              name: 'Manage',
-              url: 'https://gerrit/plugins/plugin-manager/static/index.html',
-            },
-          ],
-        },
-      ]
+      )[1],
+      {
+        title: 'Browse',
+        links: [
+          adminLinks[0],
+          {
+            name: 'Manage',
+            url: 'https://gerrit/plugins/plugin-manager/static/index.html',
+          },
+        ],
+      }
     );
   });
 
diff --git a/polygerrit-ui/app/elements/core/gr-search-bar/gr-search-bar.ts b/polygerrit-ui/app/elements/core/gr-search-bar/gr-search-bar.ts
index a0187f9a8d..98e9eba8c1 100644
--- a/polygerrit-ui/app/elements/core/gr-search-bar/gr-search-bar.ts
+++ b/polygerrit-ui/app/elements/core/gr-search-bar/gr-search-bar.ts
@@ -30,6 +30,7 @@ import {
   ValueChangedEvent,
 } from '../../../types/events';
 import {fireNoBubbleNoCompose} from '../../../utils/event-util';
+import {getDocUrl} from '../../../utils/url-util';
 
 // Possible static search options for auto complete, without negations.
 const SEARCH_OPERATORS: ReadonlyArray<string> = [
@@ -168,7 +169,7 @@ export class GrSearchBar extends LitElement {
   @state() inputVal = '';
 
   // private but used in test
-  @state() docsBaseUrl: string | null = null;
+  @state() docsBaseUrl = '';
 
   @state() private query: AutocompleteQuery;
 
@@ -240,7 +241,7 @@ export class GrSearchBar extends LitElement {
           <a
             class="help"
             slot="suffix"
-            href=${this.computeHelpDocLink()}
+            href=${getDocUrl(this.docsBaseUrl, 'user-search.html')}
             target="_blank"
             rel="noopener noreferrer"
             tabindex="-1"
@@ -276,18 +277,6 @@ export class GrSearchBar extends LitElement {
     return set;
   }
 
-  // private but used in test
-  computeHelpDocLink() {
-    // fallback to gerrit's official doc
-    let baseUrl =
-      this.docsBaseUrl ||
-      'https://gerrit-review.googlesource.com/Documentation/';
-    if (baseUrl.endsWith('/')) {
-      baseUrl = baseUrl.substring(0, baseUrl.length - 1);
-    }
-    return `${baseUrl}/user-search.html`;
-  }
-
   private handleInputCommit(e: AutocompleteCommitEvent) {
     this.preventDefaultAndNavigateToInputVal(e);
   }
diff --git a/polygerrit-ui/app/elements/core/gr-search-bar/gr-search-bar_test.ts b/polygerrit-ui/app/elements/core/gr-search-bar/gr-search-bar_test.ts
index 2f955de896..f67024fffc 100644
--- a/polygerrit-ui/app/elements/core/gr-search-bar/gr-search-bar_test.ts
+++ b/polygerrit-ui/app/elements/core/gr-search-bar/gr-search-bar_test.ts
@@ -91,23 +91,6 @@ suite('gr-search-bar tests', () => {
     );
   });
 
-  test('falls back to gerrit docs url', async () => {
-    const configWithoutDocsUrl = createServerInfo();
-    configWithoutDocsUrl.gerrit.doc_url = undefined;
-
-    configModel.updateServerConfig(configWithoutDocsUrl);
-    await waitUntilObserved(
-      configModel.docsBaseUrl$,
-      docsBaseUrl => docsBaseUrl === 'https://mydocumentationurl.google.com/'
-    );
-    await element.updateComplete;
-
-    assert.equal(
-      queryAndAssert<HTMLAnchorElement>(element, 'a')!.href,
-      'https://mydocumentationurl.google.com/user-search.html'
-    );
-  });
-
   test('value is propagated to inputVal', async () => {
     element.value = 'foo';
     await element.updateComplete;
@@ -303,29 +286,4 @@ suite('gr-search-bar tests', () => {
       });
     });
   });
-
-  suite('doc url', () => {
-    setup(async () => {
-      element = await fixture(html`<gr-search-bar></gr-search-bar>`);
-    });
-
-    test('compute help doc url with correct path', async () => {
-      element.docsBaseUrl = 'https://doc.com/';
-      await element.updateComplete;
-      assert.equal(
-        element.computeHelpDocLink(),
-        'https://doc.com/user-search.html'
-      );
-    });
-
-    test('compute help doc url fallback to gerrit url', async () => {
-      element.docsBaseUrl = null;
-      await element.updateComplete;
-      assert.equal(
-        element.computeHelpDocLink(),
-        'https://gerrit-review.googlesource.com/Documentation/' +
-          'user-search.html'
-      );
-    });
-  });
 });
diff --git a/polygerrit-ui/app/models/config/config-model.ts b/polygerrit-ui/app/models/config/config-model.ts
index 66ee2e8eba..dd7828b640 100644
--- a/polygerrit-ui/app/models/config/config-model.ts
+++ b/polygerrit-ui/app/models/config/config-model.ts
@@ -11,7 +11,10 @@ import {ChangeModel} from '../change/change-model';
 import {select} from '../../utils/observable-util';
 import {Model} from '../base/model';
 import {define} from '../dependency';
-import {loginUrl} from '../../utils/url-util';
+import {getBaseUrl, loginUrl} from '../../utils/url-util';
+
+export const PROBE_PATH = '/Documentation/index.html';
+export const DOCS_BASE_PATH = '/Documentation';
 
 export interface ConfigState {
   repoConfig?: ConfigInfo;
@@ -56,9 +59,7 @@ export class ConfigModel extends Model<ConfigState> {
 
   public docsBaseUrl$ = select(
     this.serverConfig$.pipe(
-      switchMap(serverConfig =>
-        from(this.restApiService.getDocsBaseUrl(serverConfig))
-      )
+      switchMap(serverConfig => from(this.getDocsBaseUrl(serverConfig)))
     ),
     url => url
   );
@@ -86,6 +87,16 @@ export class ConfigModel extends Model<ConfigState> {
   }
 
   // visible for testing
+  async getDocsBaseUrl(config: ServerInfo | undefined): Promise<string> {
+    if (config?.gerrit?.doc_url) return config.gerrit.doc_url;
+
+    const ok = await this.restApiService.probePath(getBaseUrl() + PROBE_PATH);
+    if (ok) return getBaseUrl() + DOCS_BASE_PATH;
+
+    return 'https://gerrit-review.googlesource.com/Documentation';
+  }
+
+  // visible for testing
   updateRepoConfig(repoConfig?: ConfigInfo) {
     this.updateState({repoConfig});
   }
diff --git a/polygerrit-ui/app/models/config/config-model_test.ts b/polygerrit-ui/app/models/config/config-model_test.ts
new file mode 100644
index 0000000000..b78a93362f
--- /dev/null
+++ b/polygerrit-ui/app/models/config/config-model_test.ts
@@ -0,0 +1,84 @@
+/**
+ * @license
+ * Copyright 2023 Google LLC
+ * SPDX-License-Identifier: Apache-2.0
+ */
+import '../../test/common-test-setup';
+import {assert} from '@open-wc/testing';
+import {getBaseUrl} from '../../utils/url-util';
+import {
+  createGerritInfo,
+  createServerInfo,
+} from '../../test/test-data-generators';
+import {ConfigModel} from './config-model';
+import {testResolver} from '../../test/common-test-setup';
+import {getAppContext} from '../../services/app-context';
+import {changeModelToken} from '../change/change-model';
+import {ServerInfo} from '../../api/rest-api';
+
+suite('getDocsBaseUrl tests', () => {
+  let model: ConfigModel;
+
+  setup(async () => {
+    model = new ConfigModel(
+      testResolver(changeModelToken),
+      getAppContext().restApiService
+    );
+  });
+
+  test('null config', async () => {
+    const probePathMock = sinon
+      .stub(model.restApiService, 'probePath')
+      .resolves(true);
+    const docsBaseUrl = await model.getDocsBaseUrl(undefined);
+    assert.equal(
+      probePathMock.lastCall.args[0],
+      `${getBaseUrl()}/Documentation/index.html`
+    );
+    assert.equal(docsBaseUrl, `${getBaseUrl()}/Documentation`);
+  });
+
+  test('no doc config', async () => {
+    const probePathMock = sinon
+      .stub(model.restApiService, 'probePath')
+      .resolves(true);
+    const config: ServerInfo = {
+      ...createServerInfo(),
+      gerrit: createGerritInfo(),
+    };
+    const docsBaseUrl = await model.getDocsBaseUrl(config);
+    assert.equal(
+      probePathMock.lastCall.args[0],
+      `${getBaseUrl()}/Documentation/index.html`
+    );
+    assert.equal(docsBaseUrl, `${getBaseUrl()}/Documentation`);
+  });
+
+  test('has doc config', async () => {
+    const probePathMock = sinon
+      .stub(model.restApiService, 'probePath')
+      .resolves(true);
+    const config: ServerInfo = {
+      ...createServerInfo(),
+      gerrit: {...createGerritInfo(), doc_url: 'foobar'},
+    };
+    const docsBaseUrl = await model.getDocsBaseUrl(config);
+    assert.isFalse(probePathMock.called);
+    assert.equal(docsBaseUrl, 'foobar');
+  });
+
+  test('no probe', async () => {
+    const probePathMock = sinon
+      .stub(model.restApiService, 'probePath')
+      .resolves(false);
+    const docsBaseUrl = await model.getDocsBaseUrl(undefined);
+    assert.equal(
+      probePathMock.lastCall.args[0],
+      `${getBaseUrl()}/Documentation/index.html`
+    );
+    assert.equal(
+      docsBaseUrl,
+      'https://gerrit-review.googlesource.com/Documentation'
+    );
+  });
+});
diff --git a/polygerrit-ui/app/services/gr-rest-api/gr-rest-api-impl.ts b/polygerrit-ui/app/services/gr-rest-api/gr-rest-api-impl.ts
index acc7cdd964..2350594216 100644
--- a/polygerrit-ui/app/services/gr-rest-api/gr-rest-api-impl.ts
+++ b/polygerrit-ui/app/services/gr-rest-api/gr-rest-api-impl.ts
@@ -151,8 +151,6 @@ import {escapeAndWrapSearchOperatorValue} from '../../utils/string-util';
 import {FlagsService, KnownExperimentId} from '../flags/flags';
 
 const MAX_PROJECT_RESULTS = 25;
-export const PROBE_PATH = '/Documentation/index.html';
-export const DOCS_BASE_PATH = '/Documentation';
 
 const Requests = {
   SEND_DIFF_DRAFT: 'sendDiffDraft',
@@ -290,8 +288,6 @@ export class GrRestApiServiceImpl implements RestApiService, Finalizable {
 
   readonly _etags = grEtagDecorator; // Shared across instances.
 
-  getDocsBaseUrlCachedPromise: Promise<string | null> | undefined;
-
   // readonly, but set in tests.
   _projectLookup = projectLookup; // Shared across instances.
 
@@ -3399,26 +3395,6 @@ export class GrRestApiServiceImpl implements RestApiService, Finalizable {
     }) as Promise<DashboardInfo | undefined>;
   }
 
-  /**
-   * Get the docs base URL from either the server config or by probing.
-   *
-   * @return A promise that resolves with the docs base URL.
-   */
-  getDocsBaseUrl(config: ServerInfo | undefined): Promise<string | null> {
-    if (!this.getDocsBaseUrlCachedPromise) {
-      this.getDocsBaseUrlCachedPromise = new Promise(resolve => {
-        if (config?.gerrit?.doc_url) {
-          resolve(config.gerrit.doc_url);
-        } else {
-          this.probePath(getBaseUrl() + PROBE_PATH).then(ok => {
-            resolve(ok ? getBaseUrl() + DOCS_BASE_PATH : null);
-          });
-        }
-      });
-    }
-    return this.getDocsBaseUrlCachedPromise;
-  }
-
   getDocumentationSearches(filter: string): Promise<DocResult[] | undefined> {
     filter = filter.trim();
     const encodedFilter = encodeURIComponent(filter);
diff --git a/polygerrit-ui/app/services/gr-rest-api/gr-rest-api-impl_test.ts b/polygerrit-ui/app/services/gr-rest-api/gr-rest-api-impl_test.ts
index 624bcb5aa6..1e1439d8e4 100644
--- a/polygerrit-ui/app/services/gr-rest-api/gr-rest-api-impl_test.ts
+++ b/polygerrit-ui/app/services/gr-rest-api/gr-rest-api-impl_test.ts
@@ -17,7 +17,6 @@ import {
   createAccountDetailWithId,
   createChange,
   createComment,
-  createGerritInfo,
   createParsedChange,
   createServerInfo,
 } from '../../test/test-data-generators';
@@ -54,7 +53,6 @@ import {
   RevisionId,
   RevisionPatchSetNum,
   RobotCommentInfo,
-  ServerInfo,
   Timestamp,
   UrlEncodedCommentId,
 } from '../../types/common';
@@ -1629,51 +1627,4 @@ suite('gr-rest-api-service-impl tests', () => {
       anonymizedUrl: '/accounts/self/starred.changes/*',
     });
   });
-
-  suite('getDocsBaseUrl tests', () => {
-    test('null config', async () => {
-      const probePathMock = sinon.stub(element, 'probePath').resolves(true);
-      const docsBaseUrl = await element.getDocsBaseUrl(undefined);
-      assert.equal(
-        probePathMock.lastCall.args[0],
-        `${getBaseUrl()}/Documentation/index.html`
-      );
-      assert.equal(docsBaseUrl, `${getBaseUrl()}/Documentation`);
-    });
-
-    test('no doc config', async () => {
-      const probePathMock = sinon.stub(element, 'probePath').resolves(true);
-      const config: ServerInfo = {
-        ...createServerInfo(),
-        gerrit: createGerritInfo(),
-      };
-      const docsBaseUrl = await element.getDocsBaseUrl(config);
-      assert.equal(
-        probePathMock.lastCall.args[0],
-        `${getBaseUrl()}/Documentation/index.html`
-      );
-      assert.equal(docsBaseUrl, `${getBaseUrl()}/Documentation`);
-    });
-
-    test('has doc config', async () => {
-      const probePathMock = sinon.stub(element, 'probePath').resolves(true);
-      const config: ServerInfo = {
-        ...createServerInfo(),
-        gerrit: {...createGerritInfo(), doc_url: 'foobar'},
-      };
-      const docsBaseUrl = await element.getDocsBaseUrl(config);
-      assert.isFalse(probePathMock.called);
-      assert.equal(docsBaseUrl, 'foobar');
-    });
-
-    test('no probe', async () => {
-      const probePathMock = sinon.stub(element, 'probePath').resolves(false);
-      const docsBaseUrl = await element.getDocsBaseUrl(undefined);
-      assert.equal(
-        probePathMock.lastCall.args[0],
-        `${getBaseUrl()}/Documentation/index.html`
-      );
-      assert.isNotOk(docsBaseUrl);
-    });
-  });
 });
diff --git a/polygerrit-ui/app/services/gr-rest-api/gr-rest-api.ts b/polygerrit-ui/app/services/gr-rest-api/gr-rest-api.ts
index c70f7803f3..c96e9783ac 100644
--- a/polygerrit-ui/app/services/gr-rest-api/gr-rest-api.ts
+++ b/polygerrit-ui/app/services/gr-rest-api/gr-rest-api.ts
@@ -371,8 +371,6 @@ export interface RestApiService extends Finalizable {
     endpoint: string
   ): Promise<string>;
 
-  getDocsBaseUrl(config?: ServerInfo): Promise<string | null>;
-
   createChange(
     repo: RepoName,
     branch: BranchName,
diff --git a/polygerrit-ui/app/test/mocks/gr-rest-api_mock.ts b/polygerrit-ui/app/test/mocks/gr-rest-api_mock.ts
index e0a16825bb..7969264741 100644
--- a/polygerrit-ui/app/test/mocks/gr-rest-api_mock.ts
+++ b/polygerrit-ui/app/test/mocks/gr-rest-api_mock.ts
@@ -77,11 +77,6 @@ import {
   createDefaultPreferences,
 } from '../../constants/constants';
 import {ParsedChangeInfo} from '../../types/types';
-import {getBaseUrl} from '../../utils/url-util';
-import {
-  DOCS_BASE_PATH,
-  PROBE_PATH,
-} from '../../services/gr-rest-api/gr-rest-api-impl';
 
 export const grRestApiMock: RestApiService = {
   addAccountEmail(): Promise<Response> {
@@ -317,16 +312,6 @@ export const grRestApiMock: RestApiService = {
     // eslint-disable-next-line @typescript-eslint/no-explicit-any
     return Promise.resolve({}) as any;
   },
-  getDocsBaseUrl(config?: ServerInfo): Promise<string | null> {
-    if (config?.gerrit?.doc_url) {
-      return Promise.resolve(config.gerrit.doc_url);
-    } else {
-      return this.probePath(getBaseUrl() + PROBE_PATH).then(ok =>
-        Promise.resolve(ok ? getBaseUrl() + DOCS_BASE_PATH : null)
-      );
-    }
-    return Promise.resolve('');
-  },
   getDocumentationSearches(): Promise<DocResult[] | undefined> {
     return Promise.resolve([]);
   },
diff --git a/polygerrit-ui/app/utils/url-util.ts b/polygerrit-ui/app/utils/url-util.ts
index 3d1bf7e715..96edc7e35e 100644
--- a/polygerrit-ui/app/utils/url-util.ts
+++ b/polygerrit-ui/app/utils/url-util.ts
@@ -17,6 +17,16 @@ export function getBaseUrl(): string {
   return self.CANONICAL_PATH || '';
 }
 
+export function getDocUrl(docsBaseUrl: string, relativeUrl: string): string {
+  if (docsBaseUrl.endsWith('/')) {
+    docsBaseUrl = docsBaseUrl.slice(0, -1);
+  }
+  if (relativeUrl.startsWith('/')) {
+    relativeUrl = relativeUrl.slice(1);
+  }
+  return `${docsBaseUrl}/${relativeUrl}`;
+}
+
 /**
  * Return the url to use for login. If the server configuration
  * contains the `loginUrl` in the `auth` section then that custom url
diff --git a/polygerrit-ui/app/utils/url-util_test.ts b/polygerrit-ui/app/utils/url-util_test.ts
index f8be92a2ee..a92d8b158c 100644
--- a/polygerrit-ui/app/utils/url-util_test.ts
+++ b/polygerrit-ui/app/utils/url-util_test.ts
@@ -16,6 +16,7 @@ import {
   toPathname,
   toSearchParams,
   sameOrigin,
+  getDocUrl,
 } from './url-util';
 import {assert} from '@open-wc/testing';
 import {createAuth} from '../test/test-data-generators';
@@ -38,6 +39,15 @@ suite('url-util tests', () => {
     });
   });
 
+  suite('getDocUrl tests', () => {
+    test('getDocUrl', () => {
+      assert.deepEqual(getDocUrl('a', 'b'), 'a/b');
+      assert.deepEqual(getDocUrl('a/', 'b'), 'a/b');
+      assert.deepEqual(getDocUrl('a', '/b'), 'a/b');
+      assert.deepEqual(getDocUrl('a/', '/b'), 'a/b');
+    });
+  });
+
   suite('loginUrl tests', () => {
     const authConfig = createAuth();