chore: apply go fix cleanups

Author: takai

internal/config/config.go

@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"embed"
 	"fmt"
+	"maps"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -26,9 +27,9 @@ type Config struct {
 
 // FilterConfig holds diff filtering configuration.
 type FilterConfig struct {
-	MaxFileLines           int      `toml:"max_file_lines"`            // Max lines per file (0 = use default)
-	DefaultExcludePatterns []string `toml:"default_exclude_patterns"`  // Override built-in defaults
-	ExcludePatterns        []string `toml:"exclude_patterns"`          // Additional patterns to exclude
+	MaxFileLines           int      `toml:"max_file_lines"`           // Max lines per file (0 = use default)
+	DefaultExcludePatterns []string `toml:"default_exclude_patterns"` // Override built-in defaults
+	ExcludePatterns        []string `toml:"exclude_patterns"`         // Additional patterns to exclude
 }
 
 // rawConfig is the TOML structure used to detect mutual exclusivity in a single layer.
@@ -134,9 +135,7 @@ func Load() (Config, error) {
 				if cfg.Engines == nil {
 					cfg.Engines = map[string]EngineConfig{}
 				}
-				for name, ec := range repoCfg.Engines {
-					cfg.Engines[name] = ec
-				}
+				maps.Copy(cfg.Engines, repoCfg.Engines)
 			}
 			// Merge filter config from repo
 			if repoCfg.Filter.MaxFileLines != 0 {
@@ -196,9 +195,7 @@ func loadConfigLayer(data []byte, cfg *Config, source string) error {
 		if cfg.Engines == nil {
 			cfg.Engines = map[string]EngineConfig{}
 		}
-		for name, ec := range raw.Engines {
-			cfg.Engines[name] = ec
-		}
+		maps.Copy(cfg.Engines, raw.Engines)
 	}
 	// Merge filter config
 	if raw.Filter.MaxFileLines != 0 {

internal/git/filter.go

@@ -3,6 +3,7 @@ package git
 import (
 	"fmt"
 	"path/filepath"
+	"slices"
 	"sort"
 	"strings"
 )
@@ -103,7 +104,7 @@ func splitDiffByFile(diff string) map[string]string {
 	var currentContent strings.Builder
 	var inFile bool
 
-	for i := 0; i < len(lines); i++ {
+	for i := range lines {
 		line := lines[i]
 
 		// Detect start of a new file diff
@@ -221,12 +222,7 @@ func truncateFileDiff(content string, maxLines int, fileName string) (bool, stri
 
 // containsFile checks if filePath is in the given list of exact paths.
 func containsFile(filePath string, files []string) bool {
-	for _, f := range files {
-		if f == filePath {
-			return true
-		}
-	}
-	return false
+	return slices.Contains(files, filePath)
 }
 
 // matchesAnyPattern checks if the file path matches any of the glob patterns.

internal/git/filter_test.go

@@ -1,6 +1,7 @@
 package git
 
 import (
+	"slices"
 	"strings"
 	"testing"
 )
@@ -53,7 +54,7 @@ index abc123..def456 100644
 +++ b/large.go
 @@ -1,100 +1,110 @@
 `)
-	for i := 0; i < 50; i++ {
+	for range 50 {
 		sb.WriteString("+new line\n")
 	}
 	diff := sb.String()
@@ -246,7 +247,7 @@ index abc123..def456 100644
 +++ b/large.go
 @@ -1,100 +1,150 @@
 `)
-	for i := 0; i < 100; i++ {
+	for range 100 {
 		sb.WriteString("+new line\n")
 	}
 	diff := sb.String()
@@ -270,13 +271,7 @@ func TestDefaultExcludePatterns(t *testing.T) {
 		"**/go.sum",
 	}
 	for _, exp := range expected {
-		found := false
-		for _, p := range patterns {
-			if p == exp {
-				found = true
-				break
-			}
-		}
+		found := slices.Contains(patterns, exp)
 		if !found {
 			t.Errorf("expected pattern %q in defaults", exp)
 		}