Replace string check with syscall.Errno

code-asher · code-asher · commit 53f1f3b63768 · 2025-09-10T16:52:39.000-08:00
diff --git a/agent/files.go b/agent/files.go
@@ -10,7 +10,7 @@ import (
 	"os"
 	"path/filepath"
 	"strconv"
-	"strings"
+	"syscall"
 
 	"golang.org/x/xerrors"
 
@@ -139,7 +139,7 @@ func (a *agent) writeFile(ctx context.Context, r *http.Request, path string) (Ht
 		switch {
 		case errors.Is(err, os.ErrPermission):
 			status = http.StatusForbidden
-		case strings.Contains(err.Error(), "not a directory"):
+		case errors.Is(err, syscall.ENOTDIR):
 			status = http.StatusBadRequest
 		}
 		return status, err
@@ -151,8 +151,7 @@ func (a *agent) writeFile(ctx context.Context, r *http.Request, path string) (Ht
 		switch {
 		case errors.Is(err, os.ErrPermission):
 			status = http.StatusForbidden
-		case strings.Contains(err.Error(), "is a directory") ||
-			strings.Contains(err.Error(), "not a directory"):
+		case errors.Is(err, syscall.EISDIR):
 			status = http.StatusBadRequest
 		}
 		return status, err
diff --git a/agent/files_test.go b/agent/files_test.go
@@ -7,11 +7,11 @@ import (
 	"net/http"
 	"os"
 	"path/filepath"
+	"syscall"
 	"testing"
 
 	"github.com/spf13/afero"
 	"github.com/stretchr/testify/require"
-	"golang.org/x/xerrors"
 
 	"github.com/coder/coder/v2/agent"
 	"github.com/coder/coder/v2/agent/agenttest"
@@ -48,11 +48,19 @@ func (fs *testFs) Create(name string) (afero.File, error) {
 	// lets you nest them underneath files, somehow.
 	stat, err := fs.Fs.Stat(name)
 	if err == nil && stat.IsDir() {
-		return nil, xerrors.New("is a directory")
+		return nil, &os.PathError{
+			Op:   "open",
+			Path: name,
+			Err:  syscall.EISDIR,
+		}
 	}
 	stat, err = fs.Fs.Stat(filepath.Dir(name))
 	if err == nil && !stat.IsDir() {
-		return nil, xerrors.New("not a directory")
+		return nil, &os.PathError{
+			Op:   "open",
+			Path: name,
+			Err:  syscall.ENOTDIR,
+		}
 	}
 	return fs.Fs.Create(name)
 }
@@ -65,11 +73,19 @@ func (fs *testFs) MkdirAll(name string, mode os.FileMode) error {
 	// lets you nest them underneath files somehow.
 	stat, err := fs.Fs.Stat(filepath.Dir(name))
 	if err == nil && !stat.IsDir() {
-		return xerrors.New("not a directory")
+		return &os.PathError{
+			Op:   "mkdir",
+			Path: name,
+			Err:  syscall.ENOTDIR,
+		}
 	}
 	stat, err = fs.Fs.Stat(name)
 	if err == nil && !stat.IsDir() {
-		return xerrors.New("not a directory")
+		return &os.PathError{
+			Op:   "mkdir",
+			Path: name,
+			Err:  syscall.ENOTDIR,
+		}
 	}
 	return fs.Fs.MkdirAll(name, mode)
 }
