fix: resolve PR branch issues (#415)

Author: tenshiAMD

lib/modules/repository.js

@@ -192,12 +192,23 @@ class Repository {
     await Promise.all(createOrUpdateFilesMultiple);
   }
 
+  async getPullRequestsBy({ branchName, state }) {
+    try {
+      return await this.octokit.pulls.list({
+        owner: this.owner,
+        repo: this.repo,
+        state,
+        head: `${this.owner}:${branchName}`,
+      });
+    } catch(error) {
+      return { data: [] }
+    }
+  }
+
   async getPullRequestURL({ branchName }) {
-    const results = await this.octokit.pulls.list({
-      owner: this.owner,
-      repo: this.repo,
+    const results = await this.getPullRequestsBy({
+      branchName,
       state: "open",
-      head: `${this.owner}:${branchName}`,
     });
     return results.data[0].html_url;
   }
@@ -259,6 +270,23 @@ class Repository {
       branchName,
     });
   }
+
+  async deleteBranch({branchName}) {
+    try {
+        await this.octokit.git.deleteRef({
+          owner: this.owner,
+          repo: this.repo,
+          ref: `heads/${branchName}`
+        });
+    } catch (error) {
+      // /* istanbul ignore if */
+      // if (error.status !== 404) {
+      //   throw error;
+      // }
+
+      // throw new BranchNotFoundError(branchName);
+    }
+  }
 }
 
 module.exports = Repository;

lib/setup-repository.js

@@ -6,11 +6,28 @@ const { BranchNotFoundError } = require("./modules/errors");
 async function setupRepository({ context, branchName }) {
   const repository = new Repository(context);
 
+  const hasOpenPullRequest = async ({branchName}) => {
+    const result = await repository.getPullRequestsBy({
+      branchName,
+      state: "open"
+    });
+
+    // TODO: Possibly make sure the existing pull request is created by the bot?
+    return result.data.length > 0;
+  };
+
   try {
     await repository.getRef(branchName);
+    const openPrExists = await hasOpenPullRequest(branchName)
+
     context.log.debug(
       `Branch "${branchName}" exists, will work from this branch`
     );
+ 
+    if (!openPrExists) {
+      repository.deleteBranch(branchName);
+    }
+
     repository.setBaseBranch(branchName);
   } catch (error) {
     const isBranchNotFoundError = error instanceof BranchNotFoundError;

test/unit/setup-repository.test.js

@@ -0,0 +1,57 @@
+const Repository = require("../../lib/modules/repository");
+const { BranchNotFoundError } = require("../../lib/modules/errors");
+const setupRepository = require("../../lib/setup-repository");
+
+jest.mock("../../lib/modules/repository");
+
+describe("Setup Repository", () => {
+  const mockBranchName = "all-contributors/add-hertzg-tenshiAMD";
+  const mockContext = {
+    log: {
+      debug() {},
+    },
+  };
+
+  afterEach(() => jest.clearAllMocks());
+
+  it("should base off latest on first time request", async () => {
+    Repository.prototype.getRef.mockReturnValue(
+      Promise.reject(new BranchNotFoundError(mockBranchName))
+    );
+
+    await setupRepository({ branchName: mockBranchName, context: mockContext });
+
+    expect(Repository.prototype.getRef).toBeCalledWith(mockBranchName);
+    expect(Repository.prototype.deleteBranch).not.toBeCalled();
+    expect(Repository.prototype.getPullRequestsBy).not.toBeCalled();
+    expect(Repository.prototype.setBaseBranch).not.toBeCalled();
+  });
+
+  it("should delete existing dangling (already merged) branches then recreate new pr", async () => {
+    Repository.prototype.getRef.mockReturnValue(Promise.resolve());
+    Repository.prototype.getPullRequestsBy.mockReturnValue(
+      Promise.resolve({ data: [] })
+    );
+
+    await setupRepository({ branchName: mockBranchName, context: mockContext });
+
+    expect(Repository.prototype.getRef).toBeCalledWith(mockBranchName);
+    expect(Repository.prototype.deleteBranch).toBeCalledTimes(1);
+    expect(Repository.prototype.setBaseBranch).toBeCalledTimes(1);
+    expect(Repository.prototype.getPullRequestsBy).toBeCalledTimes(1);
+  });
+
+  it("should use existing branch only if pr for it was not merged yet", async () => {
+    Repository.prototype.getRef.mockReturnValue(Promise.resolve());
+    Repository.prototype.getPullRequestsBy.mockReturnValue(
+      Promise.resolve({ data: [{}] })
+    );
+
+    await setupRepository({ branchName: mockBranchName, context: mockContext });
+
+    expect(Repository.prototype.getRef).toBeCalledWith(mockBranchName);
+    expect(Repository.prototype.deleteBranch).not.toBeCalled();
+    expect(Repository.prototype.getPullRequestsBy).toBeCalledTimes(1);
+    expect(Repository.prototype.setBaseBranch).toBeCalledTimes(1);
+  });
+});