support creating patches from files in diff mode

1 files changed, 16 insertions, 1 deletions

diff --git a/pkg/gui/patch_building_panel.go b/pkg/gui/patch_building_panel.go
index fc39a2e43..38a03859a 100644
--- a/pkg/gui/patch_building_panel.go
+++ b/pkg/gui/patch_building_panel.go
@@ -5,6 +5,19 @@ import (
 	"github.com/jesseduffield/lazygit/pkg/utils"
 )
 
+// getFromAndReverseArgsForDiff tells us the from and reverse args to be used in a diff command. If we're not in diff mode we'll end up with the equivalent of a `git show` i.e `git diff blah^..blah`.
+func (gui *Gui) getFromAndReverseArgsForDiff(to string) (string, bool) {
+	from := to + "^"
+	reverse := false
+
+	if gui.State.Modes.Diffing.Active() {
+		reverse = gui.State.Modes.Diffing.Reverse
+		from = gui.State.Modes.Diffing.Ref
+	}
+
+	return from, reverse
+}
+
 func (gui *Gui) refreshPatchBuildingPanel(selectedLineIdx int) error {
 	if !gui.GitCommand.PatchManager.Active() {
 		return gui.handleEscapePatchBuildingPanel()
@@ -22,7 +35,9 @@ func (gui *Gui) refreshPatchBuildingPanel(selectedLineIdx int) error {
 		return nil
 	}
 
-	diff, err := gui.GitCommand.ShowCommitFile(commitFile.Parent, commitFile.Name, true)
+	to := commitFile.Parent
+	from, reverse := gui.getFromAndReverseArgsForDiff(to)
+	diff, err := gui.GitCommand.ShowFileDiff(from, to, reverse, commitFile.Name, true)
 	if err != nil {
 		return err
 	}