Merge branch 'master' into https-ask-for-username-password

31 files changed, 1282 insertions, 10 deletions

diff --git a/pkg/commands/commit.go b/pkg/commands/commit.go
index 54e94ef60..4c304271d 100644
--- a/pkg/commands/commit.go
+++ b/pkg/commands/commit.go
@@ -13,6 +13,7 @@ type Commit struct {
 	DisplayString string
 }
 
+// GetDisplayStrings is a function.
 func (c *Commit) GetDisplayStrings() []string {
 	red := color.New(color.FgRed)
 	yellow := color.New(color.FgGreen)
diff --git a/pkg/commands/git.go b/pkg/commands/git.go
index 2d2710a42..584558d7e 100644
--- a/pkg/commands/git.go
+++ b/pkg/commands/git.go
@@ -267,6 +267,7 @@ func (c *GitCommand) NewBranch(name string) error {
 	return c.OSCommand.RunCommand(fmt.Sprintf("git checkout -b %s", name))
 }
 
+// CurrentBranchName is a function.
 func (c *GitCommand) CurrentBranchName() (string, error) {
 	branchName, err := c.OSCommand.RunCommandWithOutput("git symbolic-ref --short HEAD")
 	if err != nil {
@@ -490,7 +491,6 @@ func (c *GitCommand) getMergeBase() (string, error) {
 	output, err := c.OSCommand.RunCommandWithOutput(fmt.Sprintf("git merge-base HEAD %s", baseBranch))
 	if err != nil {
 		// swallowing error because it's not a big deal; probably because there are no commits yet
-		c.Log.Error(err)
 	}
 	return output, nil
 }
@@ -576,9 +576,10 @@ func (c *GitCommand) CheckRemoteBranchExists(branch *Branch) bool {
 }
 
 // Diff returns the diff of a file
-func (c *GitCommand) Diff(file *File) string {
+func (c *GitCommand) Diff(file *File, plain bool) string {
 	cachedArg := ""
 	trackedArg := "--"
+	colorArg := "--color"
 	fileName := c.OSCommand.Quote(file.Name)
 	if file.HasStagedChanges && !file.HasUnstagedChanges {
 		cachedArg = "--cached"
@@ -586,9 +587,25 @@ func (c *GitCommand) Diff(file *File) string {
 	if !file.Tracked && !file.HasStagedChanges {
 		trackedArg = "--no-index /dev/null"
 	}
-	command := fmt.Sprintf("git diff --color %s %s %s", cachedArg, trackedArg, fileName)
+	if plain {
+		colorArg = ""
+	}
+
+	command := fmt.Sprintf("git diff %s %s %s %s", colorArg, cachedArg, trackedArg, fileName)
 
 	// for now we assume an error means the file was deleted
 	s, _ := c.OSCommand.RunCommandWithOutput(command)
 	return s
 }
+
+func (c *GitCommand) ApplyPatch(patch string) (string, error) {
+	filename, err := c.OSCommand.CreateTempFile("patch", patch)
+	if err != nil {
+		c.Log.Error(err)
+		return "", err
+	}
+
+	defer func() { _ = c.OSCommand.RemoveFile(filename) }()
+
+	return c.OSCommand.RunCommandWithOutput(fmt.Sprintf("git apply --cached %s", filename))
+}
diff --git a/pkg/commands/git_test.go b/pkg/commands/git_test.go
index 0410ceb2c..da6a90c98 100644
--- a/pkg/commands/git_test.go
+++ b/pkg/commands/git_test.go
@@ -23,26 +23,32 @@ type fileInfoMock struct {
 	sys         interface{}
 }
 
+// Name is a function.
 func (f fileInfoMock) Name() string {
 	return f.name
 }
 
+// Size is a function.
 func (f fileInfoMock) Size() int64 {
 	return f.size
 }
 
+// Mode is a function.
 func (f fileInfoMock) Mode() os.FileMode {
 	return f.fileMode
 }
 
+// ModTime is a function.
 func (f fileInfoMock) ModTime() time.Time {
 	return f.fileModTime
 }
 
+// IsDir is a function.
 func (f fileInfoMock) IsDir() bool {
 	return f.isDir
 }
 
+// Sys is a function.
 func (f fileInfoMock) Sys() interface{} {
 	return f.sys
 }
@@ -64,6 +70,7 @@ func newDummyGitCommand() *GitCommand {
 	}
 }
 
+// TestVerifyInGitRepo is a function.
 func TestVerifyInGitRepo(t *testing.T) {
 	type scenario struct {
 		testName string
@@ -100,6 +107,7 @@ func TestVerifyInGitRepo(t *testing.T) {
 	}
 }
 
+// TestNavigateToRepoRootDirectory is a function.
 func TestNavigateToRepoRootDirectory(t *testing.T) {
 	type scenario struct {
 		testName string
@@ -156,6 +164,7 @@ func TestNavigateToRepoRootDirectory(t *testing.T) {
 	}
 }
 
+// TestSetupRepositoryAndWorktree is a function.
 func TestSetupRepositoryAndWorktree(t *testing.T) {
 	type scenario struct {
 		testName          string
@@ -224,6 +233,7 @@ func TestSetupRepositoryAndWorktree(t *testing.T) {
 	}
 }
 
+// TestNewGitCommand is a function.
 func TestNewGitCommand(t *testing.T) {
 	actual, err := os.Getwd()
 	assert.NoError(t, err)
@@ -271,6 +281,7 @@ func TestNewGitCommand(t *testing.T) {
 	}
 }
 
+// TestGitCommandGetStashEntries is a function.
 func TestGitCommandGetStashEntries(t *testing.T) {
 	type scenario struct {
 		testName string
@@ -323,6 +334,7 @@ func TestGitCommandGetStashEntries(t *testing.T) {
 	}
 }
 
+// TestGitCommandGetStashEntryDiff is a function.
 func TestGitCommandGetStashEntryDiff(t *testing.T) {
 	gitCmd := newDummyGitCommand()
 	gitCmd.OSCommand.command = func(cmd string, args ...string) *exec.Cmd {
@@ -337,6 +349,7 @@ func TestGitCommandGetStashEntryDiff(t *testing.T) {
 	assert.NoError(t, err)
 }
 
+// TestGitCommandGetStatusFiles is a function.
 func TestGitCommandGetStatusFiles(t *testing.T) {
 	type scenario struct {
 		testName string
@@ -423,6 +436,7 @@ func TestGitCommandGetStatusFiles(t *testing.T) {
 	}
 }
 
+// TestGitCommandStashDo is a function.
 func TestGitCommandStashDo(t *testing.T) {
 	gitCmd := newDummyGitCommand()
 	gitCmd.OSCommand.command = func(cmd string, args ...string) *exec.Cmd {
@@ -435,6 +449,7 @@ func TestGitCommandStashDo(t *testing.T) {
 	assert.NoError(t, gitCmd.StashDo(1, "drop"))
 }
 
+// TestGitCommandStashSave is a function.
 func TestGitCommandStashSave(t *testing.T) {
 	gitCmd := newDummyGitCommand()
 	gitCmd.OSCommand.command = func(cmd string, args ...string) *exec.Cmd {
@@ -447,6 +462,7 @@ func TestGitCommandStashSave(t *testing.T) {
 	assert.NoError(t, gitCmd.StashSave("A stash message"))
 }
 
+// TestGitCommandCommitAmend is a function.
 func TestGitCommandCommitAmend(t *testing.T) {
 	gitCmd := newDummyGitCommand()
 	gitCmd.OSCommand.command = func(cmd string, args ...string) *exec.Cmd {
@@ -460,6 +476,7 @@ func TestGitCommandCommitAmend(t *testing.T) {
 	assert.NoError(t, err)
 }
 
+// TestGitCommandMergeStatusFiles is a function.
 func TestGitCommandMergeStatusFiles(t *testing.T) {
 	type scenario struct {
 		testName string
@@ -540,6 +557,7 @@ func TestGitCommandMergeStatusFiles(t *testing.T) {
 	}
 }
 
+// TestGitCommandUpstreamDifferentCount is a function.
 func TestGitCommandUpstreamDifferentCount(t *testing.T) {
 	type scenario struct {
 		testName string
@@ -597,6 +615,7 @@ func TestGitCommandUpstreamDifferentCount(t *testing.T) {
 	}
 }
 
+// TestGitCommandGetCommitsToPush is a function.
 func TestGitCommandGetCommitsToPush(t *testing.T) {
 	type scenario struct {
 		testName string
@@ -635,6 +654,7 @@ func TestGitCommandGetCommitsToPush(t *testing.T) {
 	}
 }
 
+// TestGitCommandRenameCommit is a function.
 func TestGitCommandRenameCommit(t *testing.T) {
 	gitCmd := newDummyGitCommand()
 	gitCmd.OSCommand.command = func(cmd string, args ...string) *exec.Cmd {
@@ -647,6 +667,7 @@ func TestGitCommandRenameCommit(t *testing.T) {
 	assert.NoError(t, gitCmd.RenameCommit("test"))
 }
 
+// TestGitCommandResetToCommit is a function.
 func TestGitCommandResetToCommit(t *testing.T) {
 	gitCmd := newDummyGitCommand()
 	gitCmd.OSCommand.command = func(cmd string, args ...string) *exec.Cmd {
@@ -659,6 +680,7 @@ func TestGitCommandResetToCommit(t *testing.T) {
 	assert.NoError(t, gitCmd.ResetToCommit("78976bc"))
 }
 
+// TestGitCommandNewBranch is a function.
 func TestGitCommandNewBranch(t *testing.T) {
 	gitCmd := newDummyGitCommand()
 	gitCmd.OSCommand.command = func(cmd string, args ...string) *exec.Cmd {
@@ -671,6 +693,7 @@ func TestGitCommandNewBranch(t *testing.T) {
 	assert.NoError(t, gitCmd.NewBranch("test"))
 }
 
+// TestGitCommandDeleteBranch is a function.
 func TestGitCommandDeleteBranch(t *testing.T) {
 	type scenario struct {
 		testName string
@@ -720,6 +743,7 @@ func TestGitCommandDeleteBranch(t *testing.T) {
 	}
 }
 
+// TestGitCommandMerge is a function.
 func TestGitCommandMerge(t *testing.T) {
 	gitCmd := newDummyGitCommand()
 	gitCmd.OSCommand.command = func(cmd string, args ...string) *exec.Cmd {
@@ -732,6 +756,7 @@ func TestGitCommandMerge(t *testing.T) {
 	assert.NoError(t, gitCmd.Merge("test"))
 }
 
+// TestGitCommandUsingGpg is a function.
 func TestGitCommandUsingGpg(t *testing.T) {
 	type scenario struct {
 		testName           string
@@ -825,6 +850,7 @@ func TestGitCommandUsingGpg(t *testing.T) {
 	}
 }
 
+// TestGitCommandCommit is a function.
 func TestGitCommandCommit(t *testing.T) {
 	type scenario struct {
 		testName           string
@@ -894,6 +920,7 @@ func TestGitCommandCommit(t *testing.T) {
 	}
 }
 
+// TestGitCommandCommitAmendFromFiles is a function.
 func TestGitCommandCommitAmendFromFiles(t *testing.T) {
 	type scenario struct {
 		testName           string
@@ -963,6 +990,7 @@ func TestGitCommandCommitAmendFromFiles(t *testing.T) {
 	}
 }
 
+// TestGitCommandPush is a function.
 func TestGitCommandPush(t *testing.T) {
 	type scenario struct {
 		testName  string
@@ -1025,6 +1053,7 @@ func TestGitCommandPush(t *testing.T) {
 	}
 }
 
+// TestGitCommandSquashPreviousTwoCommits is a function.
 func TestGitCommandSquashPreviousTwoCommits(t *testing.T) {
 	type scenario struct {
 		testName string
@@ -1088,6 +1117,7 @@ func TestGitCommandSquashPreviousTwoCommits(t *testing.T) {
 	}
 }
 
+// TestGitCommandSquashFixupCommit is a function.
 func TestGitCommandSquashFixupCommit(t *testing.T) {
 	type scenario struct {
 		testName string
@@ -1151,6 +1181,7 @@ func TestGitCommandSquashFixupCommit(t *testing.T) {
 	}
 }
 
+// TestGitCommandCatFile is a function.
 func TestGitCommandCatFile(t *testing.T) {
 	gitCmd := newDummyGitCommand()
 	gitCmd.OSCommand.command = func(cmd string, args ...string) *exec.Cmd {
@@ -1165,6 +1196,7 @@ func TestGitCommandCatFile(t *testing.T) {
 	assert.Equal(t, "test", o)
 }
 
+// TestGitCommandStageFile is a function.
 func TestGitCommandStageFile(t *testing.T) {
 	gitCmd := newDummyGitCommand()
 	gitCmd.OSCommand.command = func(cmd string, args ...string) *exec.Cmd {
@@ -1177,6 +1209,7 @@ func TestGitCommandStageFile(t *testing.T) {
 	assert.NoError(t, gitCmd.StageFile("test.txt"))
 }
 
+// TestGitCommandUnstageFile is a function.
 func TestGitCommandUnstageFile(t *testing.T) {
 	type scenario struct {
 		testName string
@@ -1223,6 +1256,7 @@ func TestGitCommandUnstageFile(t *testing.T) {
 	}
 }
 
+// TestGitCommandIsInMergeState is a function.
 func TestGitCommandIsInMergeState(t *testing.T) {
 	type scenario struct {
 		testName string
@@ -1291,6 +1325,7 @@ func TestGitCommandIsInMergeState(t *testing.T) {
 	}
 }
 
+// TestGitCommandRemoveFile is a function.
 func TestGitCommandRemoveFile(t *testing.T) {
 	type scenario struct {
 		testName   string
@@ -1492,6 +1527,7 @@ func TestGitCommandRemoveFile(t *testing.T) {
 	}
 }
 
+// TestGitCommandShow is a function.
 func TestGitCommandShow(t *testing.T) {
 	gitCmd := newDummyGitCommand()
 	gitCmd.OSCommand.command = func(cmd string, args ...string) *exec.Cmd {
@@ -1505,6 +1541,7 @@ func TestGitCommandShow(t *testing.T) {
 	assert.NoError(t, err)
 }
 
+// TestGitCommandCheckout is a function.
 func TestGitCommandCheckout(t *testing.T) {
 	type scenario struct {
 		testName string
@@ -1551,6 +1588,7 @@ func TestGitCommandCheckout(t *testing.T) {
 	}
 }
 
+// TestGitCommandGetBranchGraph is a function.
 func TestGitCommandGetBranchGraph(t *testing.T) {
 	gitCmd := newDummyGitCommand()
 	gitCmd.OSCommand.command = func(cmd string, args ...string) *exec.Cmd {
@@ -1564,6 +1602,7 @@ func TestGitCommandGetBranchGraph(t *testing.T) {
 	assert.NoError(t, err)
 }
 
+// TestGitCommandGetCommits is a function.
 func TestGitCommandGetCommits(t *testing.T) {
 	type scenario struct {
 		testName string
@@ -1685,6 +1724,7 @@ func TestGitCommandGetCommits(t *testing.T) {
 	}
 }
 
+// TestGitCommandGetLog is a function.
 func TestGitCommandGetLog(t *testing.T) {
 	type scenario struct {
 		testName string
@@ -1727,11 +1767,13 @@ func TestGitCommandGetLog(t *testing.T) {
 	}
 }
 
+// TestGitCommandDiff is a function.
 func TestGitCommandDiff(t *testing.T) {
 	type scenario struct {
 		testName string
 		command  func(string, ...string) *exec.Cmd
 		file     *File
+		plain    bool
 	}
 
 	scenarios := []scenario{
@@ -1748,6 +1790,22 @@ func TestGitCommandDiff(t *testing.T) {
 				HasStagedChanges: false,
 				Tracked:          true,
 			},
+			false,
+		},
+		{
+			"Default case",
+			func(cmd string, args ...string) *exec.Cmd {
+				assert.EqualValues(t, "git", cmd)
+				assert.EqualValues(t, []string{"diff", "--", "test.txt"}, args)
+
+				return exec.Command("echo")
+			},
+			&File{
+				Name:             "test.txt",
+				HasStagedChanges: false,
+				Tracked:          true,
+			},
+			true,
 		},
 		{
 			"All changes staged",
@@ -1763,6 +1821,7 @@ func TestGitCommandDiff(t *testing.T) {
 				HasUnstagedChanges: false,
 				Tracked:            true,
 			},
+			false,
 		},
 		{
 			"File not tracked and file has no staged changes",
@@ -1777,6 +1836,7 @@ func TestGitCommandDiff(t *testing.T) {
 				HasStagedChanges: false,
 				Tracked:          false,
 			},
+			false,
 		},
 	}
 
@@ -1784,11 +1844,12 @@ func TestGitCommandDiff(t *testing.T) {
 		t.Run(s.testName, func(t *testing.T) {
 			gitCmd := newDummyGitCommand()
 			gitCmd.OSCommand.command = s.command
-			gitCmd.Diff(s.file)
+			gitCmd.Diff(s.file, s.plain)
 		})
 	}
 }
 
+// TestGitCommandGetMergeBase is a function.
 func TestGitCommandGetMergeBase(t *testing.T) {
 	type scenario struct {
 		testName string
@@ -1878,6 +1939,7 @@ func TestGitCommandGetMergeBase(t *testing.T) {
 	}
 }
 
+// TestGitCommandCurrentBranchName is a function.
 func TestGitCommandCurrentBranchName(t *testing.T) {
 	type scenario struct {
 		testName string
@@ -1939,3 +2001,61 @@ func TestGitCommandCurrentBranchName(t *testing.T) {
 		})
 	}
 }
+
+func TestGitCommandApplyPatch(t *testing.T) {
+	type scenario struct {
+		testName string
+		command  func(string, ...string) *exec.Cmd
+		test     func(string, error)
+	}
+
+	scenarios := []scenario{
+		{
+			"valid case",
+			func(cmd string, args ...string) *exec.Cmd {
+				assert.Equal(t, "git", cmd)
+				assert.EqualValues(t, []string{"apply", "--cached"}, args[0:2])
+				filename := args[2]
+				content, err := ioutil.ReadFile(filename)
+				assert.NoError(t, err)
+
+				assert.Equal(t, "test", string(content))
+
+				return exec.Command("echo", "done")
+			},
+			func(output string, err error) {
+				assert.NoError(t, err)
+				assert.EqualValues(t, "done\n", output)
+			},
+		},
+		{
+			"command returns error",
+			func(cmd string, args ...string) *exec.Cmd {
+				assert.Equal(t, "git", cmd)
+				assert.EqualValues(t, []string{"apply", "--cached"}, args[0:2])
+				filename := args[2]
+				// TODO: Ideally we want to mock out OSCommand here so that we're not
+				// double handling testing it's CreateTempFile functionality,
+				// but it is going to take a bit of work to make a proper mock for it
+				// so I'm leaving it for another PR
+				content, err := ioutil.ReadFile(filename)
+				assert.NoError(t, err)
+
+				assert.Equal(t, "test", string(content))
+
+				return exec.Command("test")
+			},
+			func(output string, err error) {
+				assert.Error(t, err)
+			},
+		},
+	}
+
+	for _, s := range scenarios {
+		t.Run(s.testName, func(t *testing.T) {
+			gitCmd := newDummyGitCommand()
+			gitCmd.OSCommand.command = s.command
+			s.test(gitCmd.ApplyPatch("test"))
+		})
+	}
+}
diff --git a/pkg/commands/os.go b/pkg/commands/os.go
index f64f0732e..faf6c5aec 100644
--- a/pkg/commands/os.go
+++ b/pkg/commands/os.go
@@ -2,6 +2,7 @@ package commands
 
 import (
 	"errors"
+	"io/ioutil"
 	"os"
 	"os/exec"
 	"regexp"
@@ -157,7 +158,7 @@ func (c *OSCommand) OpenFile(filename string) error {
 	return err
 }
 
-// OpenFile opens a file with the given
+// OpenLink opens a file with the given
 func (c *OSCommand) OpenLink(link string) error {
 	commandTemplate := c.Config.GetUserConfig().GetString("os.openLinkCommand")
 	templateValues := map[string]string{
@@ -224,3 +225,28 @@ func (c *OSCommand) AppendLineToFile(filename, line string) error {
 	_, err = f.WriteString("\n" + line)
 	return err
 }
+
+// CreateTempFile writes a string to a new temp file and returns the file's name
+func (c *OSCommand) CreateTempFile(filename, content string) (string, error) {
+	tmpfile, err := ioutil.TempFile("", filename)
+	if err != nil {
+		c.Log.Error(err)
+		return "", err
+	}
+
+	if _, err := tmpfile.Write([]byte(content)); err != nil {
+		c.Log.Error(err)
+		return "", err
+	}
+	if err := tmpfile.Close(); err != nil {
+		c.Log.Error(err)
+		return "", err
+	}
+
+	return tmpfile.Name(), nil
+}
+
+// RemoveFile removes a file at the specified path
+func (c *OSCommand) RemoveFile(filename string) error {
+	return os.Remove(filename)
+}
diff --git a/pkg/commands/os_test.go b/pkg/commands/os_test.go
index aeef4a6e5..a08c4b57d 100644
--- a/pkg/commands/os_test.go
+++ b/pkg/commands/os_test.go
@@ -1,6 +1,7 @@
 package commands
 
 import (
+	"io/ioutil"
 	"os"
 	"os/exec"
 	"testing"
@@ -29,6 +30,7 @@ func newDummyAppConfig() *config.AppConfig {
 	return appConfig
 }
 
+// TestOSCommandRunCommandWithOutput is a function.
 func TestOSCommandRunCommandWithOutput(t *testing.T) {
 	type scenario struct {
 		command string
@@ -56,6 +58,7 @@ func TestOSCommandRunCommandWithOutput(t *testing.T) {
 	}
 }
 
+// TestOSCommandRunCommand is a function.
 func TestOSCommandRunCommand(t *testing.T) {
 	type scenario struct {
 		command string
@@ -76,6 +79,7 @@ func TestOSCommandRunCommand(t *testing.T) {
 	}
 }
 
+// TestOSCommandOpenFile is a function.
 func TestOSCommandOpenFile(t *testing.T) {
 	type scenario struct {
 		filename string
@@ -126,6 +130,7 @@ func TestOSCommandOpenFile(t *testing.T) {
 	}
 }
 
+// TestOSCommandEditFile is a function.
 func TestOSCommandEditFile(t *testing.T) {
 	type scenario struct {
 		filename           string
@@ -255,6 +260,7 @@ func TestOSCommandEditFile(t *testing.T) {
 	}
 }
 
+// TestOSCommandQuote is a function.
 func TestOSCommandQuote(t *testing.T) {
 	osCommand := newDummyOSCommand()
 
@@ -278,7 +284,7 @@ func TestOSCommandQuoteSingleQuote(t *testing.T) {
 	assert.EqualValues(t, expected, actual)
 }
 
-// TestOSCommandQuoteSingleQuote tests the quote function with " quotes explicitly for Linux
+// TestOSCommandQuoteDoubleQuote tests the quote function with " quotes explicitly for Linux
 func TestOSCommandQuoteDoubleQuote(t *testing.T) {
 	osCommand := newDummyOSCommand()
 
@@ -291,6 +297,7 @@ func TestOSCommandQuoteDoubleQuote(t *testing.T) {
 	assert.EqualValues(t, expected, actual)
 }
 
+// TestOSCommandUnquote is a function.
 func TestOSCommandUnquote(t *testing.T) {
 	osCommand := newDummyOSCommand()
 
@@ -301,6 +308,7 @@ func TestOSCommandUnquote(t *testing.T) {
 	assert.EqualValues(t, expected, actual)
 }
 
+// TestOSCommandFileType is a function.
 func TestOSCommandFileType(t *testing.T) {
 	type scenario struct {
 		path  string
@@ -357,3 +365,34 @@ func TestOSCommandFileType(t *testing.T) {
 		_ = os.RemoveAll(s.path)
 	}
 }
+
+func TestOSCommandCreateTempFile(t *testing.T) {
+	type scenario struct {
+		testName string
+		filename string
+		content  string
+		test     func(string, error)
+	}
+
+	scenarios := []scenario{
+		{
+			"valid case",
+			"filename",
+			"content",
+			func(path string, err error) {
+				assert.NoError(t, err)
+
+				content, err := ioutil.ReadFile(path)
+				assert.NoError(t, err)
+
+				assert.Equal(t, "content", string(content))
+			},
+		},
+	}
+
+	for _, s := range scenarios {
+		t.Run(s.testName, func(t *testing.T) {
+			s.test(newDummyOSCommand().CreateTempFile(s.filename, s.content))
+		})
+	}
+}
diff --git a/pkg/commands/pull_request_test.go b/pkg/commands/pull_request_test.go
index a551ee081..774baf92e 100644
--- a/pkg/commands/pull_request_test.go
+++ b/pkg/commands/pull_request_test.go
@@ -8,6 +8,7 @@ import (
 	"github.com/stretchr/testify/assert"
 )
 
+// TestGetRepoInfoFromURL is a function.
 func TestGetRepoInfoFromURL(t *testing.T) {
 	type scenario struct {
 		testName string
@@ -41,6 +42,7 @@ func TestGetRepoInfoFromURL(t *testing.T) {
 	}
 }
 
+// TestCreatePullRequest is a function.
 func TestCreatePullRequest(t *testing.T) {
 	type scenario struct {
 		testName string
diff --git a/pkg/git/patch_modifier.go b/pkg/git/patch_modifier.go
new file mode 100644
index 000000000..3c523232e
--- /dev/null
+++ b/pkg/git/patch_modifier.go
@@ -0,0 +1,156 @@
+package git
+
+import (
+	"errors"
+	"regexp"
+	"strconv"
+	"strings"
+
+	"github.com/jesseduffield/lazygit/pkg/i18n"
+	"github.com/jesseduffield/lazygit/pkg/utils"
+	"github.com/sirupsen/logrus"
+)
+
+type PatchModifier struct {
+	Log *logrus.Entry
+	Tr  *i18n.Localizer
+}
+
+// NewPatchModifier builds a new branch list builder
+func NewPatchModifier(log *logrus.Entry) (*PatchModifier, error) {
+	return &PatchModifier{
+		Log: log,
+	}, nil
+}
+
+// ModifyPatchForHunk takes the original patch, which may contain several hunks,
+// and removes any hunks that aren't the selected hunk
+func (p *PatchModifier) ModifyPatchForHunk(patch string, hunkStarts []int, currentLine int) (string, error) {
+	// get hunk start and end
+	lines := strings.Split(patch, "\n")
+	hunkStartIndex := utils.PrevIndex(hunkStarts, currentLine)
+	hunkStart := hunkStarts[hunkStartIndex]
+	nextHunkStartIndex := utils.NextIndex(hunkStarts, currentLine)
+	var hunkEnd int
+	if nextHunkStartIndex == 0 {
+		hunkEnd = len(lines) - 1
+	} else {
+		hunkEnd = hunkStarts[nextHunkStartIndex]
+	}
+
+	headerLength, err := p.getHeaderLength(lines)
+	if err != nil {
+		return "", err
+	}
+
+	output := strings.Join(lines[0:headerLength], "\n") + "\n"
+	output += strings.Join(lines[hunkStart:hunkEnd], "\n") + "\n"
+
+	return output, nil
+}
+
+func (p *PatchModifier) getHeaderLength(patchLines []string) (int, error) {
+	for index, line := range patchLines {
+		if strings.HasPrefix(line, "@@") {
+			return index, nil
+		}
+	}
+	return 0, errors.New(p.Tr.SLocalize("CantFindHunks"))
+}
+
+// ModifyPatchForLine takes the original patch, which may contain several hunks,
+// and the line number of the line we want to stage
+func (p *PatchModifier) ModifyPatchForLine(patch string, lineNumber int) (string, error) {
+	lines := strings.Split(patch, "\n")
+	headerLength, err := p.getHeaderLength(lines)
+	if err != nil {
+		return "", err
+	}
+	output := strings.Join(lines[0:headerLength], "\n") + "\n"
+
+	hunkStart, err := p.getHunkStart(lines, lineNumber)
+	if err != nil {