Fix flaky "text file busy" error in gopls tests by adding retry logic

Co-authored-by: neongreen <1523306+neongreen@users.noreply.github.com>

Author: Copilot

dissect/pkg/gopls/add_import.go

@@ -24,14 +24,14 @@ func AddImport(goplsPath string, filePath string, importPath string, moduleRoot
 
 	// Construct the gopls command
 	cmd := exec.Command(goplsPath, "execute", "-write", "gopls.add_import", fmt.Sprintf(`{"ImportPath": "%s", "URI": "file://%s"}`, importPath, absFilePath)) //nolint:gosec // G204: intentional gopls execution with validated path
-	cmd.Dir = moduleRoot // Execute gopls in the Go module root
+	cmd.Dir = moduleRoot                                                                                                                                      // Execute gopls in the Go module root
 
 	slog.Debug("Calling gopls", "command", cmd.String(), "directory", cmd.Dir, "goplsPath", goplsPath)
 
 	var stderr bytes.Buffer
 	cmd.Stderr = &stderr
 
-	if err := cmd.Run(); err != nil {
+	if _, err := runWithTextFileBusyRetry(cmd); err != nil {
 		return fmt.Errorf("error executing gopls: %w\n%s", err, stderr.String())
 	}
 

dissect/pkg/gopls/extract_to_new_file.go

@@ -55,7 +55,7 @@ func ExtractToNewFile(goplsPath string, filePath string, funcName string, module
 	var stderr bytes.Buffer
 	cmd.Stderr = &stderr
 
-	if err := cmd.Run(); err != nil {
+	if _, err := runWithTextFileBusyRetry(cmd); err != nil {
 		return "", fmt.Errorf("error executing gopls: %w\n%s", err, stderr.String())
 	}
 

dissect/pkg/gopls/rename.go

@@ -1,13 +1,16 @@
 package gopls
 
 import (
+	"bytes"
 	"fmt"
 	"go/ast"
 	"go/parser"
 	"go/token"
 	"log/slog"
 	"os"
 	"os/exec"
+	"strings"
+	"time"
 )
 
 // Rename renames a symbol in a Go file using gopls.
@@ -32,12 +35,17 @@ func Rename(goplsPath string, filePath string, oldName string, newName string, m
 
 	cmd := exec.Command(goplsPath, "rename", "-w", positionSpec, newName)
 	cmd.Dir = moduleRoot
-	output, err := cmd.CombinedOutput()
+
+	var combinedOutput bytes.Buffer
+	cmd.Stdout = &combinedOutput
+	cmd.Stderr = &combinedOutput
+
+	_, err = runWithTextFileBusyRetry(cmd)
 	if err != nil {
-		return fmt.Errorf("gopls rename failed: %w\nOutput: %s", err, string(output))
+		return fmt.Errorf("gopls rename failed: %w\nOutput: %s", err, combinedOutput.String())
 	}
 
-	slog.Debug("Successfully renamed symbol", "old", oldName, "new", newName, "output", string(output), "goplsPath", goplsPath)
+	slog.Debug("Successfully renamed symbol", "old", oldName, "new", newName, "output", combinedOutput.String(), "goplsPath", goplsPath)
 	return nil
 }
 
@@ -106,3 +114,41 @@ func findSymbolOffset(filePath string, symbolName string) (int, error) {
 	position := fset.Position(symbolPos)
 	return position.Offset, nil
 }
+
+// runWithTextFileBusyRetry runs a command and retries if it fails with "text file busy" error.
+// This error can occur when a binary was just installed by "go install" and the OS hasn't
+// fully released the file handle yet. The function retries up to 3 times with exponential backoff.
+// Note: This function uses cmd.Run(), so caller should capture output via cmd.Stdout/Stderr if needed.
+func runWithTextFileBusyRetry(cmd *exec.Cmd) ([]byte, error) {
+	const maxRetries = 3
+	var lastErr error
+
+	for attempt := 0; attempt < maxRetries; attempt++ {
+		// Create a new command for each attempt since exec.Cmd can only be used once
+		if attempt > 0 {
+			newCmd := exec.Command(cmd.Path, cmd.Args[1:]...)
+			newCmd.Dir = cmd.Dir
+			newCmd.Env = cmd.Env
+			newCmd.Stdout = cmd.Stdout
+			newCmd.Stderr = cmd.Stderr
+			cmd = newCmd
+
+			// Wait before retrying with exponential backoff
+			waitTime := time.Duration(50*(1<<attempt)) * time.Millisecond
+			slog.Debug("Retrying command after text file busy error", "attempt", attempt+1, "wait", waitTime)
+			time.Sleep(waitTime)
+		}
+
+		lastErr = cmd.Run()
+		if lastErr == nil {
+			return nil, nil
+		}
+
+		// Check if this is a "text file busy" error
+		if !strings.Contains(lastErr.Error(), "text file busy") {
+			return nil, lastErr
+		}
+	}
+
+	return nil, lastErr
+}