Fix unstaging

lib/git-service.js

@@ -336,7 +336,7 @@ export default class GitService {
           if (selected) {
             newCount++
             patchLines.push(`${origin}${content}`)
-          } else if (!stage) {
+          } else if ((!line.isStaged() || stage) && (line.isStaged() || !stage)) {
             oldCount++
             newCount++
             patchLines.push(` ${content}`)
@@ -346,7 +346,7 @@ export default class GitService {
           if (selected) {
             oldCount++
             patchLines.push(`${origin}${content}`)
-          } else if (stage) {
+          } else if ((line.isStaged() && !stage) || (!line.isStaged() && stage)) {
             oldCount++
             newCount++
             patchLines.push(` ${content}`)
@@ -434,7 +434,8 @@ export default class GitService {
     const newPath = fileDiff.getNewPathName()
 
     return Git.Repository
-      .open(this.repoPath).then(repo => {
+      .open(this.repoPath)
+      .then(repo => {
         data.repo = repo
         return repo.openIndex()
       })

spec/diff-view-model-spec.js

@@ -507,6 +507,46 @@ describe('DiffViewModel', function () {
     })
 
     describe('.stage()/.unstage()', () => {
+      it('stages a single line', async () => {
+        fs.writeFileSync(filePath, "oh the files, they are a'changin'\nCome writers and critics\nWho prophesize with your code")
+
+        await refresh()
+        expectStatus('unstaged')
+
+        let selection = new DiffSelection(viewModel, {
+          mode: 'line',
+          headPosition: [0, 0, 1],
+          tailPosition: [0, 0, 1]
+        })
+        viewModel.setSelection(selection)
+        await viewModel.toggleSelectedLinesStageStatus()
+
+        await refresh()
+        expectStatus('partial')
+      })
+
+      it('stages the entire file and unstages a single line', async () => {
+        fs.writeFileSync(filePath, "oh the files, they are a'changin'\nCome writers and critics\nWho prophesize with your code")
+
+        await refresh()
+        expectStatus('unstaged')
+
+        await toggleAll()
+        await refresh()
+        expectStatus('staged')
+
+        let selection = new DiffSelection(viewModel, {
+          mode: 'line',
+          headPosition: [0, 0, 1],
+          tailPosition: [0, 0, 1]
+        })
+        viewModel.setSelection(selection)
+        await viewModel.toggleSelectedLinesStageStatus()
+
+        await refresh()
+        expectStatus('partial')
+      })
+
       it('stages/unstages the entirety of a modified file', async () => {
         fs.writeFileSync(filePath, "oh the files, they are a'changin'")