Support `git config merge.conflictStyle diff3`

7 files changed, 140 insertions, 68 deletions

diff --git a/pkg/gui/keybindings.go b/pkg/gui/keybindings.go
index 4d593dbd0..a74f3c68c 100644
--- a/pkg/gui/keybindings.go
+++ b/pkg/gui/keybindings.go
@@ -1485,14 +1485,14 @@ func (gui *Gui) GetInitialKeybindings() []*Binding {
 			ViewName:    "main",
 			Contexts:    []string{string(MAIN_MERGING_CONTEXT_KEY)},
 			Key:         gui.getKey(config.Universal.PrevItem),
-			Handler:     gui.handleSelectTop,
+			Handler:     gui.handleSelectPrevConflictHunk,
 			Description: gui.Tr.SelectTop,
 		},
 		{
 			ViewName:    "main",
 			Contexts:    []string{string(MAIN_MERGING_CONTEXT_KEY)},
 			Key:         gui.getKey(config.Universal.NextItem),
-			Handler:     gui.handleSelectBottom,
+			Handler:     gui.handleSelectNextConflictHunk,
 			Description: gui.Tr.SelectBottom,
 		},
 		{
@@ -1500,14 +1500,14 @@ func (gui *Gui) GetInitialKeybindings() []*Binding {
 			Contexts: []string{string(MAIN_MERGING_CONTEXT_KEY)},
 			Key:      gocui.MouseWheelUp,
 			Modifier: gocui.ModNone,
-			Handler:  gui.handleSelectTop,
+			Handler:  gui.handleSelectPrevConflictHunk,
 		},
 		{
 			ViewName: "main",
 			Contexts: []string{string(MAIN_MERGING_CONTEXT_KEY)},
 			Key:      gocui.MouseWheelDown,
 			Modifier: gocui.ModNone,
-			Handler:  gui.handleSelectBottom,
+			Handler:  gui.handleSelectNextConflictHunk,
 		},
 		{
 			ViewName: "main",
@@ -1528,14 +1528,14 @@ func (gui *Gui) GetInitialKeybindings() []*Binding {
 			Contexts: []string{string(MAIN_MERGING_CONTEXT_KEY)},
 			Key:      gui.getKey(config.Universal.PrevItemAlt),
 			Modifier: gocui.ModNone,
-			Handler:  gui.handleSelectTop,
+			Handler:  gui.handleSelectPrevConflictHunk,
 		},
 		{
 			ViewName: "main",
 			Contexts: []string{string(MAIN_MERGING_CONTEXT_KEY)},
 			Key:      gui.getKey(config.Universal.NextItemAlt),
 			Modifier: gocui.ModNone,
-			Handler:  gui.handleSelectBottom,
+			Handler:  gui.handleSelectNextConflictHunk,
 		},
 		{
 			ViewName:    "main",
diff --git a/pkg/gui/merge_panel.go b/pkg/gui/merge_panel.go
index 51376ccf8..0206ba164 100644
--- a/pkg/gui/merge_panel.go
+++ b/pkg/gui/merge_panel.go
@@ -14,18 +14,18 @@ import (
 	"github.com/jesseduffield/lazygit/pkg/gui/mergeconflicts"
 )
 
-func (gui *Gui) handleSelectTop() error {
+func (gui *Gui) handleSelectPrevConflictHunk() error {
 	return gui.withMergeConflictLock(func() error {
 		gui.takeOverMergeConflictScrolling()
-		gui.State.Panels.Merging.SelectTopOption()
+		gui.State.Panels.Merging.SelectPrevConflictHunk()
 		return gui.refreshMergePanel()
 	})
 }
 
-func (gui *Gui) handleSelectBottom() error {
+func (gui *Gui) handleSelectNextConflictHunk() error {
 	return gui.withMergeConflictLock(func() error {
 		gui.takeOverMergeConflictScrolling()
-		gui.State.Panels.Merging.SelectBottomOption()
+		gui.State.Panels.Merging.SelectNextConflictHunk()
 		return gui.refreshMergePanel()
 	})
 }
@@ -135,6 +135,8 @@ func (gui *Gui) resolveConflict(selection mergeconflicts.Selection) (bool, error
 	switch selection {
 	case mergeconflicts.TOP:
 		logStr = "Picking top hunk"
+	case mergeconflicts.MIDDLE:
+		logStr = "Picking middle hunk"
 	case mergeconflicts.BOTTOM:
 		logStr = "Picking bottom hunk"
 	case mergeconflicts.BOTH:
diff --git a/pkg/gui/mergeconflicts/find_conflicts.go b/pkg/gui/mergeconflicts/find_conflicts.go
index dc6e99189..80e487f85 100644
--- a/pkg/gui/mergeconflicts/find_conflicts.go
+++ b/pkg/gui/mergeconflicts/find_conflicts.go
@@ -12,7 +12,8 @@ type LineType int
 
 const (
 	START LineType = iota
-	MIDDLE
+	ANCESTOR
+	TARGET
 	END
 	NOT_A_MARKER
 )
@@ -28,10 +29,14 @@ func findConflicts(content string) []*mergeConflict {
 	for i, line := range utils.SplitLines(content) {
 		switch determineLineType(line) {
 		case START:
-			newConflict = &mergeConflict{start: i}
-		case MIDDLE:
+			newConflict = &mergeConflict{start: i, ancestor: -1}
+		case ANCESTOR:
 			if newConflict != nil {
-				newConflict.middle = i
+				newConflict.ancestor = i
+			}
+		case TARGET:
+			if newConflict != nil {
+				newConflict.target = i
 			}
 		case END:
 			if newConflict != nil {
@@ -54,8 +59,10 @@ func determineLineType(line string) LineType {
 	switch {
 	case strings.HasPrefix(trimmedLine, "<<<<<<< "):
 		return START
+	case strings.HasPrefix(trimmedLine, "||||||| "):
+		return ANCESTOR
 	case trimmedLine == "=======":
-		return MIDDLE
+		return TARGET
 	case strings.HasPrefix(trimmedLine, ">>>>>>> "):
 		return END
 	default:
diff --git a/pkg/gui/mergeconflicts/find_conflicts_test.go b/pkg/gui/mergeconflicts/find_conflicts_test.go
index c0a8e3e5b..bcc70ce73 100644
--- a/pkg/gui/mergeconflicts/find_conflicts_test.go
+++ b/pkg/gui/mergeconflicts/find_conflicts_test.go
@@ -43,12 +43,16 @@ func TestDetermineLineType(t *testing.T) {
 		},
 		{
 			line:     "=======",
-			expected: MIDDLE,
+			expected: TARGET,
 		},
 		{
 			line:     ">>>>>>> blah",
 			expected: END,
 		},
+		{
+			line:     "||||||| adf33b9",
+			expected: ANCESTOR,
+		},
 	}
 
 	for _, s := range scenarios {
diff --git a/pkg/gui/mergeconflicts/rendering.go b/pkg/gui/mergeconflicts/rendering.go
index 45fff634a..8255b6ce9 100644
--- a/pkg/gui/mergeconflicts/rendering.go
+++ b/pkg/gui/mergeconflicts/rendering.go
@@ -16,11 +16,11 @@ func ColoredConflictFile(content string, state *State, hasFocus bool) string {
 	var outputBuffer bytes.Buffer
 	for i, line := range utils.SplitLines(content) {
 		textStyle := theme.DefaultTextColor
-		if i == conflict.start || i == conflict.middle || i == conflict.end {
+		if i == conflict.start || i == conflict.ancestor || i == conflict.target || i == conflict.end {
 			textStyle = style.FgRed
 		}
 
-		if hasFocus && state.conflictIndex < len(state.conflicts) && *state.conflicts[state.conflictIndex] == *conflict && shouldHighlightLine(i, conflict, state.conflictTop) {
+		if hasFocus && state.conflictIndex < len(state.conflicts) && *state.conflicts[state.conflictIndex] == *conflict && shouldHighlightLine(i, conflict, state.conflictSelection) {
 			textStyle = textStyle.MergeStyle(theme.SelectedRangeBgColor).SetBold()
 		}
 		if i == conflict.end && len(remainingConflicts) > 0 {
@@ -35,6 +35,19 @@ func shiftConflict(conflicts []*mergeConflict) (*mergeConflict, []*mergeConflict
 	return conflicts[0], conflicts[1:]
 }
 
-func shouldHighlightLine(index int, conflict *mergeConflict, top bool) bool {
-	return (index >= conflict.start && index <= conflict.middle && top) || (index >= conflict.middle && index <= conflict.end && !top)
+func shouldHighlightLine(index int, conflict *mergeConflict, selection Selection) bool {
+	switch selection {
+	case TOP:
+		if conflict.ancestor >= 0 {
+			return index >= conflict.start && index <= conflict.ancestor
+		} else {
+			return index >= conflict.start && index <= conflict.target
+		}
+	case MIDDLE:
+		return index >= conflict.ancestor && index <= conflict.target
+	case BOTTOM:
+		return index >= conflict.target && index <= conflict.end
+	default:
+		return false
+	}
 }
diff --git a/pkg/gui/mergeconflicts/state.go b/pkg/gui/mergeconflicts/state.go
index 9d8320ffb..343f282ad 100644
--- a/pkg/gui/mergeconflicts/state.go
+++ b/pkg/gui/mergeconflicts/state.go
@@ -11,42 +11,62 @@ type Selection int
 
 const (
 	TOP Selection = iota
+	MIDDLE
 	BOTTOM
 	BOTH
 )
 
-// mergeConflict : A git conflict with a start middle and end corresponding to line
+// mergeConflict : A git conflict with a start, ancestor (if exists), target, and end corresponding to line
 // numbers in the file where the conflict markers appear
 type mergeConflict struct {
-	start  int
-	middle int
-	end    int
+	start    int
+	ancestor int
+	target   int
+	end      int
 }
 
 type State struct {
 	sync.Mutex
-	conflictIndex int
-	conflictTop   bool
-	conflicts     []*mergeConflict
-	EditHistory   *stack.Stack
+	conflictIndex     int
+	conflictSelection Selection
+	conflicts         []*mergeConflict
+	EditHistory       *stack.Stack
 }
 
 func NewState() *State {
 	return &State{
-		Mutex:         sync.Mutex{},
-		conflictIndex: 0,
-		conflictTop:   true,
-		conflicts:     []*mergeConflict{},
-		EditHistory:   stack.New(),
+		Mutex:             sync.Mutex{},
+		conflictIndex:     0,
+		conflictSelection: TOP,
+		conflicts:         []*mergeConflict{},
+		EditHistory:       stack.New(),
 	}
 }
 
-func (s *State) SelectTopOption() {
-	s.conflictTop = true
+func (s *State) SelectPrevConflictHunk() {
+	switch s.conflictSelection {
+	case MIDDLE:
+		s.conflictSelection = TOP
+	case BOTTOM:
+		if s.currentConflict().ancestor >= 0 {
+			s.conflictSelection = MIDDLE
+		} else {
+			s.conflictSelection = TOP
+		}
+	}
 }
 
-func (s *State) SelectBottomOption() {
-	s.conflictTop = false
+func (s *State) SelectNextConflictHunk() {
+	switch s.conflictSelection {
+	case TOP:
+		if s.currentConflict().ancestor >= 0 {
+			s.conflictSelection = MIDDLE
+		} else {
+			s.conflictSelection = BOTTOM
+		}
+	case MIDDLE:
+		s.conflictSelection = BOTTOM
+	}
 }
 
 func (s *State) SelectNextConflict() {
@@ -100,11 +120,7 @@ func (s *State) NoConflicts() bool {
 }
 
 func (s *State) Selection() Selection {
-	if s.conflictTop {
-		return TOP
-	} else {
-		return BOTTOM
-	}
+	return s.conflictSelection
 }
 
 func (s *State) IsFinalConflict() bool {
@@ -116,7 +132,7 @@ func (s *State) Reset() {
 }
 
 func (s *State) GetConflictMiddle() int {
-	return s.currentConflict().middle
+	return s.currentConflict().target
 }
 
 func (s *State) ContentAfterConflictResolve(path string, selection Selection) (bool, string, error) {
@@ -141,13 +157,23 @@ func (s *State) ContentAfterConflictResolve(path string, selection Selection) (b
 
 func isIndexToDelete(i int, conflict *mergeConflict, selection Selection) bool {
 	isMarkerLine :=
-		i == conflict.middle ||
-			i == conflict.start ||
+		i == conflict.start ||
+			i == conflict.ancestor ||
+			i == conflict.target ||
 			i == conflict.end
 
-	isUnwantedContent :=
-		(selection == BOTTOM && conflict.start < i && i < conflict.middle) ||
-			(selection == TOP && conflict.middle < i && i < conflict.end)
-
-	return isMarkerLine || isUnwantedContent
+	var isWantedContent bool
+	switch selection {
+	case TOP:
+		if conflict.ancestor >= 0 {
+			isWantedContent = conflict.start < i && i < conflict.ancestor
+		} else {
+			isWantedContent = conflict.start < i && i < conflict.target
+		}
+	case MIDDLE:
+		isWantedContent = conflict.ancestor < i && i < conflict.target
+	case BOTTOM:
+		isWantedContent = conflict.target < i && i < conflict.end
+	}
+	return isMarkerLine || !isWantedContent
 }
diff --git a/pkg/gui/mergeconflicts/state_test.go b/pkg/gui/mergeconflicts/state_test.go
index a71d05a7a..861833d32 100644
--- a/pkg/gui/mergeconflicts/state_test.go
+++ b/pkg/gui/mergeconflicts/state_test.go
@@ -58,37 +58,57 @@ bar
 =======
 baz
 >>>>>>> branch
+
+<<<<<<< HEAD
+foo
+||||||| fffffff
+bar
+=======
+baz
+>>>>>>> branch
 `,
 			expected: []*mergeConflict{
 				{
-					start:  0,
-					middle: 2,
-					end:    4,
+					start:    0,
+					ancestor: -1,
+					target:   2,
+					end:      4,
+				},
+				{
+					start:    6,
+					ancestor: -1,
+					target:   9,
+					end:      11,
 				},
 				{
-					start:  6,
-					middle: 9,
-					end:    11,
+					start:    13,
+					ancestor: -1,
+					target:   15,
+					end:      17,
 				},
 				{
-					start:  13,
-					middle: 15,
-					end:    17,
+					start:    19,
+					ancestor: -1,
+					target:   21,
+					end:      23,
 				},
 				{
-					start:  19,
-					middle: 21,
-					end:    23,
+					start:    25,
+					ancestor: -1,
+					target:   27,
+					end:      29,
 				},
 				{
-					start:  25,
-					middle: 27,
-					end:    29,
+					start:    31,
+					ancestor: -1,
+					target:   34,
+					end:      36,
 				},
 				{
-					start:  31,
-					middle: 34,
-					end:    36,
+					start:    38,
+					ancestor: 40,
+					target:   42,
+					end:      44,
 				},
 			},
 		},