go-delve/delve · error

could not determine location (scope is nil)

Error message

could not determine location (scope is nil)

What it means

RegexLocationSpec.Find resolves a regex location spec (e.g. breakpoints like b /main\..*/) by filtering scope.BinInfo.Functions. It needs an EvalScope to access the binary info; when scope is nil there is no current frame to obtain it from, so the search cannot run and this error is returned.

Source

Thrown at pkg/locspec/locations.go:283

	}
	return true
}

func packageMatch(specPkg, symPkg string, packageMap map[string][]string) bool {
	for _, pkg := range packageMap[specPkg] {
		if partialPackageMatch(pkg, symPkg) {
			return true
		}
	}
	return partialPackageMatch(specPkg, symPkg)
}

// Find will search all functions in the target program and filter them via the
// regex location spec. Only functions matching the regex will be returned.
func (loc *RegexLocationSpec) Find(t *proc.Target, _ []string, scope *proc.EvalScope, locStr string, includeNonExecutableLines bool, _ [][2]string) ([]api.Location, string, error) {
	if scope == nil {
		//TODO(aarzilli): this needs only the list of function we should make it work
		return nil, "", errors.New("could not determine location (scope is nil)")
	}
	funcs := scope.BinInfo.Functions
	matches, err := regexFilterFuncs(loc.FuncRegex, funcs)
	if err != nil {
		return nil, "", err
	}
	r := make([]api.Location, 0, len(matches))
	for i := range matches {
		addrs, _ := proc.FindFunctionLocation(t, matches[i], 0)
		if len(addrs) > 0 {
			r = append(r, addressesToLocation(addrs))
		}
	}
	return r, "", nil
}

// Find returns the locations specified via the address location spec.
func (loc *AddrLocationSpec) Find(t *proc.Target, _ []string, scope *proc.EvalScope, locStr string, includeNonExecutableLines bool, _ [][2]string) ([]api.Location, string, error) {

View on GitHub (pinned to a23773e6c3)

Solutions

1. Start/attach to the target before setting regex breakpoints so a valid scope exists
2. Resolve the function list independently (proc.Functions from the loaded BinInfo) and filter it yourself
3. Check scope != nil before invoking Find and report a clearer error to the user

Example fix

// before
locs, err := locspec.Find(target, funcs, nil, "/main\..*/", false, nil)
// after
if scope == nil {
    return errors.New("target must be running to use regex breakpoints")
}
locs, err := locspec.Find(target, funcs, scope, "/main\..*/", false, nil)

if scope == nil {
    return errors.New("regex breakpoints require a running target")
}
locs, err := spec.Find(target, funcs, scope, locStr, false, dirs)

locs, _, err := spec.Find(t, funcs, scope, locStr, false, nil)
if err != nil && strings.Contains(err.Error(), "scope is nil") {
    return fmt.Errorf("start or attach to the target before setting this breakpoint: %w", err)
}

When it happens

Trigger: Calling Find with a nil *proc.EvalScope while the target is not running — e.g. setting a regex breakpoint before launch/attach, or calling the API without a current goroutine/frame.

Common situations: Scripting dlv via the API and setting breakpoints before starting the program; issuing regex breakpoints from a state where the process is not yet attached.

Related errors

• could not determine current location (scope is nil)
• Malformed breakpoint location, no line offset specified
• could not determine current location
• cannot write a breakpoint to a core file
• runtime.copystack has too many return instructions

AI-assisted analysis of go-delve/delve@a23773e6c3 (2026-08-31). Data as JSON: /api/errors/596b19ecaa5d8434. Report an issue: GitHub.