Implements pull request search to GitLab integration using GitLab's API

(#3788, #3795)

src/plus/integrations/providers/gitlab.ts

@@ -312,6 +312,29 @@ abstract class GitLabIntegrationBase<
 			.filter((result): result is SearchedIssue => result != null);
 	}
 
+	protected override async searchProviderPullRequests(
+		{ accessToken }: AuthenticationSession,
+		searchQuery: string,
+		repos?: GitLabRepositoryDescriptor[],
+		cancellation?: CancellationToken,
+	): Promise<PullRequest[] | undefined> {
+		const api = await this.container.gitlab;
+		if (!api) {
+			return undefined;
+		}
+
+		return api.searchPullRequests(
+			this,
+			accessToken,
+			{
+				search: searchQuery,
+				repos: repos?.map(r => `${r.owner}/${r.name}`),
+				baseUrl: this.apiBaseUrl,
+			},
+			cancellation,
+		);
+	}
+
 	protected override async mergeProviderPullRequest(
 		_session: AuthenticationSession,
 		pr: PullRequest,

src/plus/integrations/providers/gitlab/gitlab.ts

@@ -661,6 +661,50 @@ export class GitLabApi implements Disposable {
 		}
 	}
 
+	@debug<GitLabApi['searchPullRequests']>({ args: { 0: p => p.name, 1: '<token>' } })
+	async searchPullRequests(
+		provider: Provider,
+		token: string,
+		options?: { search?: string; user?: string; repos?: string[]; baseUrl?: string; avatarSize?: number },
+		cancellation?: CancellationToken,
+	): Promise<PullRequest[]> {
+		const scope = getLogScope();
+		const search = options?.search;
+		if (!search) {
+			return [];
+		}
+		try {
+			const gitlabPRs = await this.request<GitLabMergeRequestREST[]>(
+				provider,
+				token,
+				options?.baseUrl,
+				`v4/search/?scope=merge_requests&search=${search}`,
+				{
+					method: 'GET',
+				},
+				cancellation,
+				scope,
+			);
+			if (gitlabPRs.length === 0) {
+				return [];
+			}
+
+			const prs: PullRequest[] = gitlabPRs.map(pr => {
+				const fullRef = pr.references.full;
+				const project = {
+					owner: fullRef.substring(0, fullRef.lastIndexOf('/')),
+					repo: fullRef.substring(fullRef.lastIndexOf('/') + 1, fullRef.lastIndexOf('!')),
+				};
+				return fromGitLabMergeRequestREST(pr, provider, project);
+			});
+			return prs;
+		} catch (ex) {
+			if (ex instanceof RequestNotFoundError) return [];
+
+			throw this.handleException(ex, provider, scope);
+		}
+	}
+
 	private async findUser(
 		provider: Provider,
 		token: string,

src/plus/integrations/providers/gitlab/models.ts

@@ -1,6 +1,6 @@
 import { HostingIntegrationId } from '../../../../constants.integrations';
 import type { PullRequestState } from '../../../../git/models/pullRequest';
-import { PullRequest } from '../../../../git/models/pullRequest';
+import { PullRequest, PullRequestMergeableState } from '../../../../git/models/pullRequest';
 import type { PullRequestUrlIdentity } from '../../../../git/models/pullRequest.utils';
 import type { Provider } from '../../../../git/models/remoteProvider';
 import type { Integration } from '../../integration';
@@ -93,7 +93,12 @@ export interface GitLabMergeRequestREST {
 	updated_at: string;
 	closed_at: string | null;
 	merged_at: string | null;
+	detailed_merge_status: 'conflict' | 'mergeable' | string; // https://docs.gitlab.com/ee/api/merge_requests.html#merge-status
 	web_url: string;
+	references: {
+		full: string;
+		short: string;
+	};
 }
 
 export function fromGitLabMergeRequestREST(
@@ -110,7 +115,7 @@ export function fromGitLabMergeRequestREST(
 			url: pr.author?.web_url ?? '',
 		},
 		String(pr.iid),
-		undefined,
+		String(pr.id),
 		pr.title,
 		pr.web_url,
 		repo,
@@ -119,6 +124,11 @@ export function fromGitLabMergeRequestREST(
 		new Date(pr.updated_at),
 		pr.closed_at == null ? undefined : new Date(pr.closed_at),
 		pr.merged_at == null ? undefined : new Date(pr.merged_at),
+		pr.detailed_merge_status === 'mergeable'
+			? PullRequestMergeableState.Mergeable
+			: pr.detailed_merge_status === 'conflict'
+			  ? PullRequestMergeableState.Conflicting
+			  : PullRequestMergeableState.Unknown,
 	);
 }