go-delve/delve · error

could not rebuild process: %s

Error message

could not rebuild process: %s

What it means

When restarting a debug session (dlv restart --rebuild or Restart with rebuild=true) and the original process was launched from delve-generated code (ExecutingGeneratedFile), delve re-runs `go build` via gobuild.GoBuild. If the Go compiler reports errors, Restart aborts with "could not rebuild process: <compiler output>". The inner error is the actual go build failure.

Source

Thrown at service/debugger/debugger.go:531

	if err := d.detach(true); err != nil {
		return nil, err
	}
	if resetArgs {
		d.processArgs = append([]string{d.processArgs[0]}, newArgs...)
		d.config.Stdin = newRedirects[0]
		d.config.Stdout = proc.OutputRedirect{Path: newRedirects[1]}
		d.config.Stderr = proc.OutputRedirect{Path: newRedirects[2]}
	}
	var grp *proc.TargetGroup
	var err error

	if rebuild {
		switch d.config.ExecuteKind {
		case ExecutingGeneratedFile:
			err = gobuild.GoBuild(d.processArgs[0], d.config.Packages, d.config.BuildFlags)
			if err != nil {
				return nil, fmt.Errorf("could not rebuild process: %s", err)
			}
		case ExecutingGeneratedTest:
			err = gobuild.GoTestBuild(d.processArgs[0], d.config.Packages, d.config.BuildFlags)
			if err != nil {
				return nil, fmt.Errorf("could not rebuild process: %s", err)
			}
		default:
			// We cannot build a process that we didn't start, because we don't know how it was built.
			return nil, errors.New("cannot rebuild a binary")
		}
	}

	if recorded {
		run, stop, err2 := gdbserial.RecordAsync(d.processArgs, d.config.WorkingDir, false, d.config.Stdin, d.config.Stdout, d.config.Stderr)
		if err2 != nil {
			return nil, err2
		}

View on GitHub (pinned to a23773e6c3)

Solutions

1. Fix the Go compile errors shown after the colon in the message, then restart again with rebuild.
2. Restart without rebuild (`dlv restart` without -r) to reuse the existing binary while fixing the code.
3. Check d.config.BuildFlags / build flags config for stale flags (e.g. removed -tags).
4. Run `go build ./...` manually to see and fix the full error output.

Example fix

// before (broken code edited mid-session)
fmt.Println(x) // undefined: x
// after
x := computeX()
fmt.Println(x)
// then: dlv restart -r

// pre-check the package compiles before Restart(rebuild=true)
cmd := exec.Command("go", "build", "./...")
if err := cmd.Run(); err != nil {
    return fmt.Errorf("fix compile errors before restart: %w", err)
}

grp, err := dbg.Restart(rebuild)
if err != nil && strings.HasPrefix(err.Error(), "could not rebuild process:") {
    // surface the inner go build error to the user / editor problems panel
    return parseCompilerErrors(err)
}

When it happens

Trigger: Calling Debugger.Restart with rebuild=true after editing source files that no longer compile; `dlv restart -r` at the terminal while the package has compile errors; ExecutingGeneratedFile restart path invoking gobuild.GoBuild with d.config.Packages and BuildFlags.

Common situations: Editing code during a debug session and saving a broken intermediate state before restarting; build flags in .delverc or launch config conflicting with current code; missing imports after refactor; Go toolchain version mismatch causing new compile errors.

Related errors

• cannot rebuild a binary
• cannot restart process Delve did not create

AI-assisted analysis of go-delve/delve@a23773e6c3 (2026-08-31). Data as JSON: /api/errors/bf615078b18785dc. Report an issue: GitHub.