feat(add): Merge deletions support (#1836)

* init

* add fixture

* add tests

* refactor test errors

* add new bracnhes in merge fixture rep

* fix grammar

* add "delete poth" in fixture rep

* add "delete by both"

* fix test "delete by both"

* add data in MergeConflictError

* change docs

* docs: add @DanilKazanov as a contributor

* revert change docs for some reason

* fix-eslint

* Revert "refactor test errors"

This reverts commit 4e627f7.

.all-contributorsrc

@@ -631,6 +631,17 @@
         "test",
         "bug"
       ]
+    },
+    {
+      "login": "DanilKazanov",
+      "name": "DanilKazanov",
+      "avatar_url": "https://avatars.githubusercontent.com/u/139755256?v=4",
+      "profile": "https://github.com/DanilKazanov",
+      "contributions": [
+        "code",
+        "doc",
+        "test"
+      ]
     }
   ],
   "commitConvention": "angular"

README.md

@@ -363,6 +363,9 @@ Thanks goes to these wonderful people ([emoji key](https://github.com/kentcdodds
     <td align="center"><a href="https://github.com/barry963"><img src="https://avatars.githubusercontent.com/u/5289896?v=4?s=60" width="60px;" alt=""/><br /><sub><b>Barry</b></sub></a><br /><a href="https://github.com/isomorphic-git/isomorphic-git/commits?author=barry963" title="Code">💻</a> <a href="https://github.com/isomorphic-git/isomorphic-git/commits?author=barry963" title="Documentation">📖</a> <a href="https://github.com/isomorphic-git/isomorphic-git/commits?author=barry963" title="Tests">⚠️</a></td>
     <td align="center"><a href="https://stackoverflow.com/users/1493081/alireza-mirian"><img src="https://avatars.githubusercontent.com/u/3150694?v=4?s=60" width="60px;" alt=""/><br /><sub><b>Alireza Mirian</b></sub></a><br /><a href="https://github.com/isomorphic-git/isomorphic-git/commits?author=alirezamirian" title="Code">💻</a> <a href="https://github.com/isomorphic-git/isomorphic-git/commits?author=alirezamirian" title="Documentation">📖</a> <a href="https://github.com/isomorphic-git/isomorphic-git/commits?author=alirezamirian" title="Tests">⚠️</a> <a href="https://github.com/isomorphic-git/isomorphic-git/issues?q=author%3Aalirezamirian" title="Bug reports">🐛</a></td>
   </tr>
+  <tr>
+    <td align="center"><a href="https://github.com/DanilKazanov"><img src="https://avatars.githubusercontent.com/u/139755256?v=4?s=60" width="60px;" alt=""/><br /><sub><b>DanilKazanov</b></sub></a><br /><a href="https://github.com/isomorphic-git/isomorphic-git/commits?author=DanilKazanov" title="Code">💻</a> <a href="https://github.com/isomorphic-git/isomorphic-git/commits?author=DanilKazanov" title="Documentation">📖</a> <a href="https://github.com/isomorphic-git/isomorphic-git/commits?author=DanilKazanov" title="Tests">⚠️</a></td>
+  </tr>
 </table>
 
 <!-- markdownlint-restore -->

__tests__/__fixtures__/test-merge.git/objects/1a/13b59272076e3288ad75ef173b4a8ffb0b00af

@@ -0,0 +1,2 @@
+x
��K
+�0@]���4I�D\����m+5����������4}
���"�c������e�m��椁IB��IC-�+�2plS�Թ	9Khȫ`��);����c4���4Á��Gz�8�a���?�����K5/;�C�SL��M���#a�YNUy�1�M�

__tests__/__fixtures__/test-merge.git/objects/4c/0eab9b75df8b070d3037307839de49d3d350aa

@@ -0,0 +1 @@
+x
��1�0@Q��;�J�&u%��8�qQ
-*!N��#0����t�ia�*P�P�-e�:)�D�BOQ1)u�H�ʳ�Xb����}͉۪^�j���&���n�i������qz��|؜~�r[�����SN9$��G�|GM�H��gS�{�{�L]

__tests__/__fixtures__/test-merge.git/objects/8a/631ca301310f67e0a30fa154b69ed3ba32346b

@@ -0,0 +1 @@
+x
��An�0@Q�>����I채*�z��x,"B�ҡ�8}=B�o��e��&��eg�*P�A�ƞ��,�HD!���RnX�Grw�t1�ˈ1�*��z�6��-({ؓ�]�μL3|���������$_�ɺ��
!˜cB�{���{��	WuVSX;�1�?�L�

__tests__/__fixtures__/test-merge.git/objects/f1/b74b9c2a160e9a3ebec4857886f69443bcc4f4

@@ -0,0 +1 @@
+x
��A�0E]��7��CKI�q��Sөc<��Gp�����2�}��R�ʓ*���TG��]�R��Z�ra)��މ��C��i)�3FY��.rjS�T*�:�`x��q�����a|�6~���p��}��b�wP�&��-!���|�f�c�ș���X�g6o�M�

__tests__/__fixtures__/test-merge.git/refs/heads/g

@@ -1 +1 @@
-3d29b3f3368a0dce65a4fe0ccfbfd3f1ea0e5a08
+f1b74b9c2a160e9a3ebec4857886f69443bcc4f4

__tests__/__fixtures__/test-merge.git/refs/heads/g-delete-file

@@ -0,0 +1 @@
+8a631ca301310f67e0a30fa154b69ed3ba32346b

__tests__/__fixtures__/test-merge.git/refs/heads/h

@@ -0,0 +1 @@
+1a13b59272076e3288ad75ef173b4a8ffb0b00af

__tests__/__fixtures__/test-merge.git/refs/heads/h-added-both-files-merge

@@ -0,0 +1 @@
+48056666b859c10e54f8f1c634efb4de35b1622f

__tests__/__fixtures__/test-merge.git/refs/heads/i

@@ -0,0 +1 @@
+ffc8e759595572caa7a6ee0ee97695405a2ecaa2

__tests__/__fixtures__/test-merge.git/refs/heads/i-delete-both

@@ -0,0 +1 @@
+4c0eab9b75df8b070d3037307839de49d3d350aa

__tests__/test-merge.js

@@ -496,6 +496,77 @@ describe('merge', () => {
     expect(error.code).toBe(Errors.MergeNotSupportedError.code)
   })
 
+  it("merge 'g' and 'g-delete-file' (delete by theirs)", async () => {
+    // Setup
+    const { fs, gitdir } = await makeFixture('test-merge')
+    // Test
+    let error = null
+    try {
+      await merge({
+        fs,
+        gitdir,
+        ours: 'g',
+        theirs: 'g-delete-file',
+        author: {
+          name: 'Mr. Test',
+          email: 'mrtest@example.com',
+          timestamp: 1262356920,
+          timezoneOffset: -0,
+        },
+      })
+    } catch (e) {
+      error = e
+    }
+    expect(error).not.toBeNull()
+    expect(error.code).toBe(Errors.MergeConflictError.code)
+  })
+
+  it("merge 'g-delete-file' and 'g' (delete by us)", async () => {
+    // Setup
+    const { fs, gitdir } = await makeFixture('test-merge')
+    // Test
+    let error = null
+    try {
+      await merge({
+        fs,
+        gitdir,
+        ours: 'g-delete-file',
+        theirs: 'g',
+        author: {
+          name: 'Mr. Test',
+          email: 'mrtest@example.com',
+          timestamp: 1262356920,
+          timezoneOffset: -0,
+        },
+      })
+    } catch (e) {
+      error = e
+    }
+    expect(error).not.toBeNull()
+    expect(error.code).toBe(Errors.MergeConflictError.code)
+  })
+
+  it("merge 'i' and 'i-delete-both' (delete by both)", async () => {
+    // Setup
+    const { fs, gitdir, dir } = await makeFixture('test-merge')
+    const deletedFile = `${dir}/o.txt`
+    // Test
+    const mergeReuslt = await merge({
+      fs,
+      gitdir,
+      ours: 'i',
+      theirs: 'i-delete-both',
+      author: {
+        name: 'Mr. Test',
+        email: 'mrtest@example.com',
+        timestamp: 1262356920,
+        timezoneOffset: -0,
+      },
+    })
+    expect(mergeReuslt).toBeTruthy()
+    expect(await fs.exists(deletedFile)).toBeFalsy()
+  })
+
   it("merge two branches that modified the same file (no conflict)'", async () => {
     // Setup
     const { fs, gitdir } = await makeFixture('test-merge')

src/errors/MergeConflictError.js

@@ -3,13 +3,16 @@ import { BaseError } from './BaseError.js'
 export class MergeConflictError extends BaseError {
   /**
    * @param {Array<string>} filepaths
+   * @param {Array<string>} bothModified
+   * @param {Array<string>} deleteByUs
+   * @param {Array<string>} deleteByTheirs
    */
-  constructor(filepaths) {
+  constructor(filepaths, bothModified, deleteByUs, deleteByTheirs) {
     super(
       `Automatic merge failed with one or more merge conflicts in the following files: ${filepaths.toString()}. Fix conflicts then commit the result.`
     )
     this.code = this.name = MergeConflictError.code
-    this.data = { filepaths }
+    this.data = { filepaths, bothModified, deleteByUs, deleteByTheirs }
   }
 }
 /** @type {'MergeConflictError'} */

src/utils/mergeTree.js

@@ -55,6 +55,9 @@ export async function mergeTree({
   const theirTree = TREE({ ref: theirOid })
 
   const unmergedFiles = []
+  const bothModified = []
+  const deleteByUs = []
+  const deleteByTheirs = []
 
   const results = await _walk({
     fs,
@@ -120,6 +123,7 @@ export async function mergeTree({
             }).then(async r => {
               if (!r.cleanMerge) {
                 unmergedFiles.push(filepath)
+                bothModified.push(filepath)
                 if (!abortOnConflict) {
                   const baseOid = await base.oid()
                   const ourOid = await ours.oid()
@@ -137,8 +141,70 @@ export async function mergeTree({
               return r.mergeResult
             })
           }
+
+          // deleted by us
+          if (
+            base &&
+            !ours &&
+            theirs &&
+            (await base.type()) === 'blob' &&
+            (await theirs.type()) === 'blob'
+          ) {
+            unmergedFiles.push(filepath)
+            deleteByUs.push(filepath)
+            if (!abortOnConflict) {
+              const baseOid = await base.oid()
+              const theirOid = await theirs.oid()
+
+              index.delete({ filepath })
+
+              index.insert({ filepath, oid: baseOid, stage: 1 })
+              index.insert({ filepath, oid: theirOid, stage: 3 })
+            }
+
+            return {
+              mode: await theirs.mode(),
+              oid: await theirs.oid(),
+              type: 'blob',
+              path,
+            }
+          }
+
+          // deleted by theirs
+          if (
+            base &&
+            ours &&
+            !theirs &&
+            (await base.type()) === 'blob' &&
+            (await ours.type()) === 'blob'
+          ) {
+            unmergedFiles.push(filepath)
+            deleteByTheirs.push(filepath)
+            if (!abortOnConflict) {
+              const baseOid = await base.oid()
+              const ourOid = await ours.oid()
+
+              index.delete({ filepath })
+
+              index.insert({ filepath, oid: baseOid, stage: 1 })
+              index.insert({ filepath, oid: ourOid, stage: 2 })
+            }
+
+            return {
+              mode: await ours.mode(),
+              oid: await ours.oid(),
+              type: 'blob',
+              path,
+            }
+          }
+
+          // deleted by both
+          if (base && !ours && !theirs && (await base.type()) === 'blob') {
+            return undefined
+          }
+
           // all other types of conflicts fail
-          // TODO: Merge conflicts involving deletions/additions
+          // TODO: Merge conflicts involving additions
           throw new MergeNotSupportedError()
         }
       }
@@ -194,7 +260,12 @@ export async function mergeTree({
         },
       })
     }
-    return new MergeConflictError(unmergedFiles)
+    return new MergeConflictError(
+      unmergedFiles,
+      bothModified,
+      deleteByUs,
+      deleteByTheirs
+    )
   }
 
   return results.oid