improve merge conflict flow

4 files changed, 146 insertions, 28 deletions

diff --git a/pkg/gui/mergeconflicts/find_conflicts.go b/pkg/gui/mergeconflicts/find_conflicts.go
index 80e487f85..14a08fd68 100644
--- a/pkg/gui/mergeconflicts/find_conflicts.go
+++ b/pkg/gui/mergeconflicts/find_conflicts.go
@@ -1,6 +1,10 @@
 package mergeconflicts
 
 import (
+	"bufio"
+	"bytes"
+	"io"
+	"os"
 	"strings"
 
 	"github.com/jesseduffield/lazygit/pkg/utils"
@@ -53,19 +57,59 @@ func findConflicts(content string) []*mergeConflict {
 	return conflicts
 }
 
+var CONFLICT_START = "<<<<<<< "
+var CONFLICT_END = ">>>>>>> "
+var CONFLICT_START_BYTES = []byte(CONFLICT_START)
+var CONFLICT_END_BYTES = []byte(CONFLICT_END)
+
 func determineLineType(line string) LineType {
+	// TODO: find out whether we ever actually get this prefix
 	trimmedLine := strings.TrimPrefix(line, "++")
 
 	switch {
-	case strings.HasPrefix(trimmedLine, "<<<<<<< "):
+	case strings.HasPrefix(trimmedLine, CONFLICT_START):
 		return START
 	case strings.HasPrefix(trimmedLine, "||||||| "):
 		return ANCESTOR
 	case trimmedLine == "=======":
 		return TARGET
-	case strings.HasPrefix(trimmedLine, ">>>>>>> "):
+	case strings.HasPrefix(trimmedLine, CONFLICT_END):
 		return END
 	default:
 		return NOT_A_MARKER
 	}
 }
+
+// tells us whether a file actually has inline merge conflicts. We need to run this
+// because git will continue showing a status of 'UU' even after the conflicts have
+// been resolved in the user's editor
+func FileHasConflictMarkers(path string) (bool, error) {
+	file, err := os.Open(path)
+	if err != nil {
+		return false, err
+	}
+
+	defer file.Close()
+
+	return fileHasConflictMarkersAux(file), nil
+}
+
+// Efficiently scans through a file looking for merge conflict markers. Returns true if it does
+func fileHasConflictMarkersAux(file io.Reader) bool {
+	scanner := bufio.NewScanner(file)
+	scanner.Split(bufio.ScanLines)
+	for scanner.Scan() {
+		line := scanner.Bytes()
+
+		// only searching for start/end markers because the others are more ambiguous
+		if bytes.HasPrefix(line, CONFLICT_START_BYTES) {
+			return true
+		}
+
+		if bytes.HasPrefix(line, CONFLICT_END_BYTES) {
+			return true
+		}
+	}
+
+	return false
+}
diff --git a/pkg/gui/mergeconflicts/find_conflicts_test.go b/pkg/gui/mergeconflicts/find_conflicts_test.go
index bcc70ce73..f4ab4d30c 100644
--- a/pkg/gui/mergeconflicts/find_conflicts_test.go
+++ b/pkg/gui/mergeconflicts/find_conflicts_test.go
@@ -1,6 +1,7 @@
 package mergeconflicts
 
 import (
+	"strings"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -59,3 +60,42 @@ func TestDetermineLineType(t *testing.T) {
 		assert.EqualValues(t, s.expected, determineLineType(s.line))
 	}
 }
+
+func TestFindConflictsAux(t *testing.T) {
+	type scenario struct {
+		content  string
+		expected bool
+	}
+
+	scenarios := []scenario{
+		{
+			content:  "",
+			expected: false,
+		},
+		{
+			content:  "blah",
+			expected: false,
+		},
+		{
+			content:  ">>>>>>> ",
+			expected: true,
+		},
+		{
+			content:  "<<<<<<< ",
+			expected: true,
+		},
+		{
+			content:  " <<<<<<< ",
+			expected: false,
+		},
+		{
+			content:  "a\nb\nc\n<<<<<<< ",
+			expected: true,
+		},
+	}
+
+	for _, s := range scenarios {
+		reader := strings.NewReader(s.content)
+		assert.EqualValues(t, s.expected, fileHasConflictMarkersAux(reader))
+	}
+}
diff --git a/pkg/gui/mergeconflicts/rendering.go b/pkg/gui/mergeconflicts/rendering.go
index 5b44f2a14..54fc4e836 100644
--- a/pkg/gui/mergeconflicts/rendering.go
+++ b/pkg/gui/mergeconflicts/rendering.go
@@ -8,7 +8,8 @@ import (
 	"github.com/jesseduffield/lazygit/pkg/utils"
 )
 
-func ColoredConflictFile(content string, state *State, hasFocus bool) string {
+func ColoredConflictFile(state *State, hasFocus bool) string {
+	content := state.GetContent()
 	if len(state.conflicts) == 0 {
 		return content
 	}
diff --git a/pkg/gui/mergeconflicts/state.go b/pkg/gui/mergeconflicts/state.go
index f202cf772..0889aaf41 100644
--- a/pkg/gui/mergeconflicts/state.go
+++ b/pkg/gui/mergeconflicts/state.go
@@ -3,13 +3,19 @@ package mergeconflicts
 import (
 	"sync"
 
-	"github.com/golang-collections/collections/stack"
 	"github.com/jesseduffield/lazygit/pkg/utils"
 )
 
 type State struct {
 	sync.Mutex
 
+	// path of the file with the conflicts
+	path string
+
+	// This is a stack of the file content. It is used to undo changes.
+	// The last item is the current file content.
+	contents []string
+
 	conflicts []*mergeConflict
 	// this is the index of the above `conflicts` field which is currently selected
 	conflictIndex int
@@ -17,9 +23,6 @@ type State struct {
 	// this is the index of the selected conflict's available selections slice e.g. [TOP, MIDDLE, BOTTOM]
 	// We use this to know which hunk of the conflict is selected.
 	selectionIndex int
-
-	// this allows us to undo actions
-	EditHistory *stack.Stack
 }
 
 func NewState() *State {
@@ -28,7 +31,7 @@ func NewState() *State {
 		conflictIndex:  0,
 		selectionIndex: 0,
 		conflicts:      []*mergeConflict{},
-		EditHistory:    stack.New(),
+		contents:       []string{},
 	}
 }
 
@@ -63,28 +66,56 @@ func (s *State) SelectPrevConflict() {
 	s.setConflictIndex(s.conflictIndex - 1)
 }
 
-func (s *State) PushFileSnapshot(content string) {
-	s.EditHistory.Push(content)
+func (s *State) currentConflict() *mergeConflict {
+	if len(s.conflicts) == 0 {
+		return nil
+	}
+
+	return s.conflicts[s.conflictIndex]
 }
 
-func (s *State) PopFileSnapshot() (string, bool) {
-	if s.EditHistory.Len() == 0 {
-		return "", false
+// this is for starting a new merge conflict session
+func (s *State) SetContent(content string, path string) {
+	if content == s.GetContent() && path == s.path {
+		return
 	}
 
-	return s.EditHistory.Pop().(string), true
+	s.path = path
+	s.contents = []string{}
+	s.PushContent(content)
 }
 
-func (s *State) currentConflict() *mergeConflict {
-	if len(s.conflicts) == 0 {
-		return nil
+// this is for when you've resolved a conflict. This allows you to undo to a previous
+// state
+func (s *State) PushContent(content string) {
+	s.contents = append(s.contents, content)
+	s.setConflicts(findConflicts(content))
+}
+
+func (s *State) GetContent() string {
+	if len(s.contents) == 0 {
+		return ""
 	}
 
-	return s.conflicts[s.conflictIndex]
+	return s.contents[len(s.contents)-1]
 }
 
-func (s *State) SetConflictsFromCat(cat string) {
-	s.setConflicts(findConflicts(cat))
+func (s *State) GetPath() string {
+	return s.path
+}
+
+func (s *State) Undo() bool {
+	if len(s.contents) <= 1 {
+		return false
+	}
+
+	s.contents = s.contents[:len(s.contents)-1]
+
+	newContent := s.GetContent()
+	// We could be storing the old conflicts and selected index on a stack too.
+	s.setConflicts(findConflicts(newContent))
+
+	return true
 }
 
 func (s *State) setConflicts(conflicts []*mergeConflict) {
@@ -110,29 +141,31 @@ func (s *State) availableSelections() []Selection {
 	return nil
 }
 
-func (s *State) IsFinalConflict() bool {
-	return len(s.conflicts) == 1
+func (s *State) AllConflictsResolved() bool {
+	return len(s.conflicts) == 0
 }
 
 func (s *State) Reset() {
-	s.EditHistory = stack.New()
+	s.contents = []string{}
+	s.path = ""
+}
+
+func (s *State) Active() bool {
+	return s.path != ""
 }
 
 func (s *State) GetConflictMiddle() int {
 	return s.currentConflict().target
 }
 
-func (s *State) ContentAfterConflictResolve(
-	path string,
-	selection Selection,
-) (bool, string, error) {
+func (s *State) ContentAfterConflictResolve(selection Selection) (bool, string, error) {
 	conflict := s.currentConflict()
 	if conflict == nil {
 		return false, "", nil
 	}
 
 	content := ""
-	err := utils.ForEachLineInFile(path, func(line string, i int) {
+	err := utils.ForEachLineInFile(s.path, func(line string, i int) {
 		if selection.isIndexToKeep(conflict, i) {
 			content += line
 		}