Fixes rebase and cherry-pick conflict resolution

.yarn/versions/a95040d3.yml

@@ -0,0 +1,34 @@
+releases:
+  "@yarnpkg/cli": patch
+  "@yarnpkg/core": patch
+  "@yarnpkg/plugin-essentials": patch
+
+declined:
+  - "@yarnpkg/plugin-compat"
+  - "@yarnpkg/plugin-constraints"
+  - "@yarnpkg/plugin-dlx"
+  - "@yarnpkg/plugin-exec"
+  - "@yarnpkg/plugin-file"
+  - "@yarnpkg/plugin-git"
+  - "@yarnpkg/plugin-github"
+  - "@yarnpkg/plugin-http"
+  - "@yarnpkg/plugin-init"
+  - "@yarnpkg/plugin-interactive-tools"
+  - "@yarnpkg/plugin-link"
+  - "@yarnpkg/plugin-nm"
+  - "@yarnpkg/plugin-npm"
+  - "@yarnpkg/plugin-npm-cli"
+  - "@yarnpkg/plugin-pack"
+  - "@yarnpkg/plugin-patch"
+  - "@yarnpkg/plugin-pnp"
+  - "@yarnpkg/plugin-pnpm"
+  - "@yarnpkg/plugin-stage"
+  - "@yarnpkg/plugin-typescript"
+  - "@yarnpkg/plugin-version"
+  - "@yarnpkg/plugin-workspace-tools"
+  - "@yarnpkg/builder"
+  - "@yarnpkg/doctor"
+  - "@yarnpkg/extensions"
+  - "@yarnpkg/nm"
+  - "@yarnpkg/pnpify"
+  - "@yarnpkg/sdks"

packages/acceptance-tests/pkg-tests-specs/sources/features/__snapshots__/mergeConflictResolution.test.js.snap

@@ -97,3 +97,52 @@ exports[`Features Merge Conflict Resolution it should properly fix merge conflic
 ",
 }
 `;
+
+exports[`Features Merge Conflict Resolution it should support fixing rebase conflicts 1`] = `
+"# This file is generated by running "yarn install" inside your project.
+# Manual changes might be lost - proceed with caution!
+
+__metadata:
+  version: 7
+  cacheKey: 0
+
+"no-deps@npm:*":
+<<<<<<< HEAD
+  version: 2.0.0
+  resolution: "no-deps@npm:2.0.0"
+  checksum: <checksum stripped>
+=======
+  version: 1.0.0
+  resolution: "no-deps@npm:1.0.0"
+  checksum: <checksum stripped>
+>>>>>>> 0000000 (commit-1.0.0)
+  languageName: node
+  linkType: hard
+
+"root-workspace-0b6124@workspace:.":
+  version: 0.0.0-use.local
+  resolution: "root-workspace-0b6124@workspace:."
+  dependencies:
+    no-deps: "npm:*"
+  languageName: unknown
+  linkType: soft
+"
+`;
+
+exports[`Features Merge Conflict Resolution it should support fixing rebase conflicts 2`] = `
+{
+  "code": 0,
+  "stderr": "",
+  "stdout": "➤ YN0048: Automatically fixed merge conflicts 👍
+
+➤ YN0000: ┌ Resolution step
+➤ YN0000: └ Completed
+➤ YN0000: ┌ Fetch step
+➤ YN0019: │ no-deps-npm-1.0.0-cf533b267a-8bd88a447c.zip appears to be unused - removing
+➤ YN0000: └ Completed
+➤ YN0000: ┌ Link step
+➤ YN0000: └ Completed
+➤ YN0000: Done
+",
+}
+`;

packages/acceptance-tests/pkg-tests-specs/sources/features/mergeConflictResolution.test.js

@@ -62,7 +62,7 @@ describe(`Features`, () => {
           let lockfile = await xfs.readFilePromise(`${path}/yarn.lock`, `utf8`);
           lockfile = lockfile.replace(/(checksum: ).*/g, `$1<checksum stripped>`);
 
-          await expect(lockfile).toMatchSnapshot();
+          expect(lockfile).toMatchSnapshot();
           await expect(run(`install`)).resolves.toMatchSnapshot();
         },
       ),
@@ -103,7 +103,50 @@ describe(`Features`, () => {
           let lockfile = await xfs.readFilePromise(`${path}/yarn.lock`, `utf8`);
           lockfile = lockfile.replace(/(checksum: ).*/g, `$1<checksum stripped>`);
 
-          await expect(lockfile).toMatchSnapshot();
+          expect(lockfile).toMatchSnapshot();
+          await expect(run(`install`)).resolves.toMatchSnapshot();
+        },
+      ),
+    );
+
+    test(
+      `it should support fixing rebase conflicts`,
+      makeTemporaryEnv(
+        {},
+        async ({path, run, source}) => {
+          await execFile(`git`, [`init`], {cwd: path});
+          await execFile(`git`, [`config`, `user.email`, `[email protected]`], {cwd: path});
+          await execFile(`git`, [`config`, `user.name`, `Your Name`], {cwd: path});
+          await execFile(`git`, [`config`, `commit.gpgSign`, `false`], {cwd: path});
+
+          await run(`install`);
+          await xfs.writeJsonPromise(`${path}/package.json`, {dependencies: {[`no-deps`]: `*`}});
+
+          await execFile(`git`, [`add`, `-A`], {cwd: path});
+          await execFile(`git`, [`commit`, `-a`, `-m`, `my-commit`], {cwd: path});
+
+          await execFile(`git`, [`checkout`, `master`], {cwd: path});
+          await execFile(`git`, [`checkout`, `-b`, `1.0.0`], {cwd: path});
+          await run(`set`, `resolution`, `no-deps@npm:*`, `npm:1.0.0`);
+          await execFile(`git`, [`add`, `-A`], {cwd: path});
+          await execFile(`git`, [`commit`, `-a`, `-m`, `commit-1.0.0`], {cwd: path});
+
+          await execFile(`git`, [`checkout`, `master`], {cwd: path});
+          await execFile(`git`, [`checkout`, `-b`, `2.0.0`], {cwd: path});
+          await run(`set`, `resolution`, `no-deps@npm:*`, `npm:2.0.0`);
+          await execFile(`git`, [`add`, `-A`], {cwd: path});
+          await execFile(`git`, [`commit`, `-a`, `-m`, `commit-2.0.0`], {cwd: path});
+
+          await execFile(`git`, [`checkout`, `master`], {cwd: path});
+          await execFile(`git`, [`merge`, `1.0.0`], {cwd: path});
+
+          await expect(execFile(`git`, [`rebase`, `2.0.0`], {cwd: path, env: {LC_ALL: `C`}})).rejects.toThrow(/CONFLICT/);
+
+          let lockfile = await xfs.readFilePromise(`${path}/yarn.lock`, `utf8`);
+          lockfile = lockfile.replace(/(checksum: ).*/g, `$1<checksum stripped>`);
+          lockfile = lockfile.replace(/(>>>>>>>).*(\(commit-1.0.0\))/g, `$1 0000000 $2`);
+
+          expect(lockfile).toMatchSnapshot();
           await expect(run(`install`)).resolves.toMatchSnapshot();
         },
       ),

packages/gatsby/content/advanced/error-codes.md

@@ -404,3 +404,12 @@ Yarn failed to locate a package version that could satisfy the requested range.
 - The registry may not have been set properly (so Yarn is querying the public npm registry instead of your internal one)
 
 - The version may have been unpublished (although this shouldn't be possible for the public registry)
+
+## YN0083 - `AUTOMERGE_GIT_ERROR`
+
+When autofixing merge conflicts, Yarn needs to know what are the two lockfile versions it must merge together. To do that, it'll run `git rev-parse MERGE_HEAD HEAD` and/or `git rev-parse REBASE_HEAD HEAD`, depending on the situation. If both of those commands fail, the merge cannot succeed.
+
+This may happen if someone accidentally committed the lockfile without first resolving the merge conflicts - should that happen, you'll need to revert the lockfile to an earlier working version and run `yarn install`.
+
+## YN0084 - `AUTOMERGE_LOCKFILE_VERSION_MISMATCH`
+

packages/plugin-essentials/sources/commands/install.ts

@@ -360,12 +360,18 @@ async function autofixMergeConflicts(configuration: Configuration, immutable: bo
   if (immutable)
     throw new ReportError(MessageName.AUTOMERGE_IMMUTABLE, `Cannot autofix a lockfile when running an immutable install`);
 
-  const commits = await execUtils.execvp(`git`, [`rev-parse`, `MERGE_HEAD`, `HEAD`], {
+  let commits = await execUtils.execvp(`git`, [`rev-parse`, `MERGE_HEAD`, `HEAD`], {
     cwd: configuration.projectCwd,
   });
 
+  if (commits.code !== 0) {
+    commits = await execUtils.execvp(`git`, [`rev-parse`, `REBASE_HEAD`, `HEAD`], {
+      cwd: configuration.projectCwd,
+    });
+  }
+
   if (commits.code !== 0)
-    throw new ReportError(MessageName.AUTOMERGE_GIT_ERROR, `Git returned an error when trying to find the commits pertaining to the merge conflict`);
+    throw new ReportError(MessageName.AUTOMERGE_GIT_ERROR, `Git returned an error when trying to find the commits pertaining to the merge or rebase conflict`);
 
   let variants = await Promise.all(commits.stdout.trim().split(/\n/).map(async hash => {
     const content = await execUtils.execvp(`git`, [`show`, `${hash}:./${Filename.lockfile}`], {

packages/yarnpkg-core/sources/MessageName.ts

@@ -95,7 +95,6 @@ export enum MessageName {
   NETWORK_UNSAFE_HTTP = 81,
   RESOLUTION_FAILED = 82,
   AUTOMERGE_GIT_ERROR = 83,
-  AUTOMERGE_LOCKFILE_VERSION_MISMATCH = 84,
 }
 
 export function stringifyMessageName(name: MessageName | number): string {