From c71313ea981db57199d6a4fef9ca28123913b6aa Mon Sep 17 00:00:00 2001
From: CnsMaple <czy797@outlook.com>
Date: Fri, 5 Jun 2026 15:55:37 +0800
Subject: [PATCH] fix(ui): normalize line endings when computing session file
 diff stats
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The sidebar's modified-files diff stats are computed by diffing the first
and last versions of a file stored in history. When a file was first
written with one set of line endings (e.g. CRLF, preserved by the edit
tool from a Windows editor) and later overwritten with different line
endings (e.g. LF, typical for LLM-generated content written by the write
tool), every line in the file was reported as changed. A 1000-line file
gained 1 line would show "+1001 -1000" instead of "+1 -0".

Normalize both sides to LF before calling diff.GenerateDiff so the stats
reflect the real textual delta. A regression test covers the
CRLF-vs-LF mismatch and the identical-content case.

💘 Generated with Crush

Assisted-by: Crush:MiniMax-M3
---
 internal/ui/model/session.go      |  9 ++++++-
 internal/ui/model/session_test.go | 44 +++++++++++++++++++++++++++++++
 2 files changed, 52 insertions(+), 1 deletion(-)

diff --git a/internal/ui/model/session.go b/internal/ui/model/session.go
index aa31009b89..3b42814c69 100644
--- a/internal/ui/model/session.go
+++ b/internal/ui/model/session.go
@@ -136,7 +136,14 @@ func (m *UI) loadSessionFiles(sessionID string) ([]SessionFile, error) {
 			}
 		}
 
-		_, additions, deletions := diff.GenerateDiff(first.Content, last.Content, first.Path)
+		// Normalize line endings so that a CRLF/LF mismatch between
+		// historical versions does not inflate the diff stats. Files
+		// round-tripped through the write tool may end up with different
+		// line endings than the original (the LLM typically emits LF),
+		// which previously caused every line to be reported as changed.
+		firstContent, _ := fsext.ToUnixLineEndings(first.Content)
+		lastContent, _ := fsext.ToUnixLineEndings(last.Content)
+		_, additions, deletions := diff.GenerateDiff(firstContent, lastContent, first.Path)
 
 		sessionFiles = append(sessionFiles, SessionFile{
 			FirstVersion:  first,
diff --git a/internal/ui/model/session_test.go b/internal/ui/model/session_test.go
index 7aa1a3f9f3..73d115c57b 100644
--- a/internal/ui/model/session_test.go
+++ b/internal/ui/model/session_test.go
@@ -1,10 +1,13 @@
 package model
 
 import (
+	"fmt"
 	"strings"
 	"testing"
 
 	"charm.land/lipgloss/v2"
+	"github.com/charmbracelet/crush/internal/diff"
+	"github.com/charmbracelet/crush/internal/fsext"
 	"github.com/charmbracelet/crush/internal/history"
 	"github.com/charmbracelet/crush/internal/ui/styles"
 	"github.com/stretchr/testify/require"
@@ -111,6 +114,47 @@ func TestFileList(t *testing.T) {
 	})
 }
 
+func TestLoadSessionFilesNormalizesLineEndings(t *testing.T) {
+	t.Parallel()
+
+	makeContent := func(sep string) string {
+		var b strings.Builder
+		for i := 0; i < 1000; i++ {
+			b.WriteString(fmt.Sprintf("line %d", i))
+			b.WriteString(sep)
+		}
+		return b.String()
+	}
+
+	t.Run("CRLF vs LF reports the real delta, not the line ending swap", func(t *testing.T) {
+		t.Parallel()
+
+		first := history.File{Path: "main.go", Content: makeContent("\r\n"), Version: 0}
+		last := history.File{Path: "main.go", Content: makeContent("\n") + "added\n", Version: 1}
+
+		firstContent, _ := fsext.ToUnixLineEndings(first.Content)
+		lastContent, _ := fsext.ToUnixLineEndings(last.Content)
+		_, additions, removals := diff.GenerateDiff(firstContent, lastContent, first.Path)
+
+		require.Equal(t, 1, additions, "expected one addition for the appended line, got %d", additions)
+		require.Equal(t, 0, removals, "expected zero removals, got %d", removals)
+	})
+
+	t.Run("identical content with mismatched line endings reports no changes", func(t *testing.T) {
+		t.Parallel()
+
+		first := history.File{Path: "main.go", Content: makeContent("\r\n"), Version: 0}
+		last := history.File{Path: "main.go", Content: makeContent("\n"), Version: 1}
+
+		firstContent, _ := fsext.ToUnixLineEndings(first.Content)
+		lastContent, _ := fsext.ToUnixLineEndings(last.Content)
+		_, additions, removals := diff.GenerateDiff(firstContent, lastContent, first.Path)
+
+		require.Equal(t, 0, additions)
+		require.Equal(t, 0, removals)
+	})
+}
+
 func minimalFileStyles() *styles.Styles {
 	st := styles.CharmtonePantera()
 	st.Files.Path = lipgloss.NewStyle()