[skip-changelog] Return error instead of nil in package/library manager getters (#2476)

It makes explicit that the function may fails to get the package manager
or the library manager.

commands/board/details.go

@@ -28,9 +28,9 @@ import (
 // Details returns all details for a board including tools and HW identifiers.
 // This command basically gather al the information and translates it into the required grpc struct properties
 func Details(ctx context.Context, req *rpc.BoardDetailsRequest) (*rpc.BoardDetailsResponse, error) {
-	pme, release := instances.GetPackageManagerExplorer(req.GetInstance())
-	if pme == nil {
-		return nil, &cmderrors.InvalidInstanceError{}
+	pme, release, err := instances.GetPackageManagerExplorer(req.GetInstance())
+	if err != nil {
+		return nil, err
 	}
 	defer release()
 

commands/board/list.go

@@ -205,9 +205,9 @@ func identify(pme *packagemanager.Explorer, port *discovery.Port) ([]*rpc.BoardL
 // In case of errors partial results from discoveries that didn't fail
 // are returned.
 func List(req *rpc.BoardListRequest) (r []*rpc.DetectedPort, discoveryStartErrors []error, e error) {
-	pme, release := instances.GetPackageManagerExplorer(req.GetInstance())
-	if pme == nil {
-		return nil, nil, &cmderrors.InvalidInstanceError{}
+	pme, release, err := instances.GetPackageManagerExplorer(req.GetInstance())
+	if err != nil {
+		return nil, nil, err
 	}
 	defer release()
 
@@ -260,9 +260,9 @@ func hasMatchingBoard(b *rpc.DetectedPort, fqbnFilter *cores.FQBN) bool {
 
 // Watch returns a channel that receives boards connection and disconnection events.
 func Watch(ctx context.Context, req *rpc.BoardListWatchRequest) (<-chan *rpc.BoardListWatchResponse, error) {
-	pme, release := instances.GetPackageManagerExplorer(req.GetInstance())
-	if pme == nil {
-		return nil, &cmderrors.InvalidInstanceError{}
+	pme, release, err := instances.GetPackageManagerExplorer(req.GetInstance())
+	if err != nil {
+		return nil, err
 	}
 	defer release()
 	dm := pme.DiscoveryManager()

commands/board/listall.go

@@ -21,7 +21,6 @@ import (
 	"strings"
 
 	"github.com/arduino/arduino-cli/commands"
-	"github.com/arduino/arduino-cli/commands/cmderrors"
 	"github.com/arduino/arduino-cli/commands/internal/instances"
 	"github.com/arduino/arduino-cli/internal/arduino/cores"
 	"github.com/arduino/arduino-cli/internal/arduino/utils"
@@ -30,9 +29,9 @@ import (
 
 // ListAll FIXMEDOC
 func ListAll(ctx context.Context, req *rpc.BoardListAllRequest) (*rpc.BoardListAllResponse, error) {
-	pme, release := instances.GetPackageManagerExplorer(req.GetInstance())
-	if pme == nil {
-		return nil, &cmderrors.InvalidInstanceError{}
+	pme, release, err := instances.GetPackageManagerExplorer(req.GetInstance())
+	if err != nil {
+		return nil, err
 	}
 	defer release()
 

commands/board/search.go

@@ -21,7 +21,6 @@ import (
 	"strings"
 
 	"github.com/arduino/arduino-cli/commands"
-	"github.com/arduino/arduino-cli/commands/cmderrors"
 	"github.com/arduino/arduino-cli/commands/internal/instances"
 	"github.com/arduino/arduino-cli/internal/arduino/utils"
 	rpc "github.com/arduino/arduino-cli/rpc/cc/arduino/cli/commands/v1"
@@ -32,9 +31,9 @@ import (
 // installed. Note that platforms that are not installed don't include boards' FQBNs.
 // If no search argument is used all boards are returned.
 func Search(ctx context.Context, req *rpc.BoardSearchRequest) (*rpc.BoardSearchResponse, error) {
-	pme, release := instances.GetPackageManagerExplorer(req.GetInstance())
-	if pme == nil {
-		return nil, &cmderrors.InvalidInstanceError{}
+	pme, release, err := instances.GetPackageManagerExplorer(req.GetInstance())
+	if err != nil {
+		return nil, err
 	}
 	defer release()
 

commands/compile/compile.go

@@ -57,15 +57,15 @@ func Compile(ctx context.Context, req *rpc.CompileRequest, outStream, errStream
 		exportBinaries = reqExportBinaries.GetValue()
 	}
 
-	pme, release := instances.GetPackageManagerExplorer(req.GetInstance())
-	if pme == nil {
-		return nil, &cmderrors.InvalidInstanceError{}
+	pme, release, err := instances.GetPackageManagerExplorer(req.GetInstance())
+	if err != nil {
+		return nil, err
 	}
 	defer release()
 
-	lm := instances.GetLibraryManager(req.GetInstance())
-	if lm == nil {
-		return nil, &cmderrors.InvalidInstanceError{}
+	lm, err := instances.GetLibraryManager(req.GetInstance())
+	if err != nil {
+		return nil, err
 	}
 
 	logrus.Tracef("Compile %s for %s started", req.GetSketchPath(), req.GetFqbn())

commands/core/download.go

@@ -30,9 +30,9 @@ var tr = i18n.Tr
 
 // PlatformDownload FIXMEDOC
 func PlatformDownload(ctx context.Context, req *rpc.PlatformDownloadRequest, downloadCB rpc.DownloadProgressCB) (*rpc.PlatformDownloadResponse, error) {
-	pme, release := instances.GetPackageManagerExplorer(req.GetInstance())
-	if pme == nil {
-		return nil, &cmderrors.InvalidInstanceError{}
+	pme, release, err := instances.GetPackageManagerExplorer(req.GetInstance())
+	if err != nil {
+		return nil, err
 	}
 	defer release()
 

commands/core/install.go

@@ -29,9 +29,9 @@ import (
 // PlatformInstall FIXMEDOC
 func PlatformInstall(ctx context.Context, req *rpc.PlatformInstallRequest, downloadCB rpc.DownloadProgressCB, taskCB rpc.TaskProgressCB) (*rpc.PlatformInstallResponse, error) {
 	install := func() error {
-		pme, release := instances.GetPackageManagerExplorer(req.GetInstance())
-		if pme == nil {
-			return &cmderrors.InvalidInstanceError{}
+		pme, release, err := instances.GetPackageManagerExplorer(req.GetInstance())
+		if err != nil {
+			return err
 		}
 		defer release()
 

commands/core/search.go

@@ -21,7 +21,6 @@ import (
 	"strings"
 
 	"github.com/arduino/arduino-cli/commands"
-	"github.com/arduino/arduino-cli/commands/cmderrors"
 	"github.com/arduino/arduino-cli/commands/internal/instances"
 	"github.com/arduino/arduino-cli/internal/arduino/cores"
 	"github.com/arduino/arduino-cli/internal/arduino/utils"
@@ -30,9 +29,9 @@ import (
 
 // PlatformSearch FIXMEDOC
 func PlatformSearch(req *rpc.PlatformSearchRequest) (*rpc.PlatformSearchResponse, error) {
-	pme, release := instances.GetPackageManagerExplorer(req.GetInstance())
-	if pme == nil {
-		return nil, &cmderrors.InvalidInstanceError{}
+	pme, release, err := instances.GetPackageManagerExplorer(req.GetInstance())
+	if err != nil {
+		return nil, err
 	}
 	defer release()
 

commands/core/uninstall.go

@@ -38,8 +38,8 @@ func PlatformUninstall(ctx context.Context, req *rpc.PlatformUninstallRequest, t
 
 // platformUninstall is the implementation of platform unistaller
 func platformUninstall(ctx context.Context, req *rpc.PlatformUninstallRequest, taskCB rpc.TaskProgressCB) error {
-	pme, release := instances.GetPackageManagerExplorer(req.GetInstance())
-	if pme == nil {
+	pme, release, err := instances.GetPackageManagerExplorer(req.GetInstance())
+	if err != nil {
 		return &cmderrors.InvalidInstanceError{}
 	}
 	defer release()

commands/core/upgrade.go

@@ -19,7 +19,6 @@ import (
 	"context"
 
 	"github.com/arduino/arduino-cli/commands"
-	"github.com/arduino/arduino-cli/commands/cmderrors"
 	"github.com/arduino/arduino-cli/commands/internal/instances"
 	"github.com/arduino/arduino-cli/internal/arduino/cores"
 	"github.com/arduino/arduino-cli/internal/arduino/cores/packagemanager"
@@ -29,9 +28,9 @@ import (
 // PlatformUpgrade FIXMEDOC
 func PlatformUpgrade(ctx context.Context, req *rpc.PlatformUpgradeRequest, downloadCB rpc.DownloadProgressCB, taskCB rpc.TaskProgressCB) (*rpc.PlatformUpgradeResponse, error) {
 	upgrade := func() (*cores.PlatformRelease, error) {
-		pme, release := instances.GetPackageManagerExplorer(req.GetInstance())
-		if pme == nil {
-			return nil, &cmderrors.InvalidInstanceError{}
+		pme, release, err := instances.GetPackageManagerExplorer(req.GetInstance())
+		if err != nil {
+			return nil, err
 		}
 		defer release()
 

commands/debug/debug.go

@@ -44,9 +44,9 @@ var tr = i18n.Tr
 func Debug(ctx context.Context, req *rpc.GetDebugConfigRequest, inStream io.Reader, out io.Writer, interrupt <-chan os.Signal) (*rpc.DebugResponse, error) {
 
 	// Get debugging command line to run debugger
-	pme, release := instances.GetPackageManagerExplorer(req.GetInstance())
-	if pme == nil {
-		return nil, &cmderrors.InvalidInstanceError{}
+	pme, release, err := instances.GetPackageManagerExplorer(req.GetInstance())
+	if err != nil {
+		return nil, err
 	}
 	defer release()
 

commands/debug/debug_info.go

@@ -38,9 +38,9 @@ import (
 
 // GetDebugConfig returns metadata to start debugging with the specified board
 func GetDebugConfig(ctx context.Context, req *rpc.GetDebugConfigRequest) (*rpc.GetDebugConfigResponse, error) {
-	pme, release := instances.GetPackageManagerExplorer(req.GetInstance())
-	if pme == nil {
-		return nil, &cmderrors.InvalidInstanceError{}
+	pme, release, err := instances.GetPackageManagerExplorer(req.GetInstance())
+	if err != nil {
+		return nil, err
 	}
 	defer release()
 	return getDebugProperties(req, pme, false)
@@ -48,9 +48,9 @@ func GetDebugConfig(ctx context.Context, req *rpc.GetDebugConfigRequest) (*rpc.G
 
 // IsDebugSupported checks if the given board/programmer configuration supports debugging.
 func IsDebugSupported(ctx context.Context, req *rpc.IsDebugSupportedRequest) (*rpc.IsDebugSupportedResponse, error) {
-	pme, release := instances.GetPackageManagerExplorer(req.GetInstance())
-	if pme == nil {
-		return nil, &cmderrors.InvalidInstanceError{}
+	pme, release, err := instances.GetPackageManagerExplorer(req.GetInstance())
+	if err != nil {
+		return nil, err
 	}
 	defer release()
 	configRequest := &rpc.GetDebugConfigRequest{

commands/instances.go

@@ -190,7 +190,11 @@ func Init(req *rpc.InitRequest, responseCallback func(r *rpc.InitResponse)) erro
 		// after reinitializing an instance after installing or uninstalling a core.
 		// If this is not done the information of the uninstall core is kept in memory,
 		// even if it should not.
-		pmb, commitPackageManager := instances.GetPackageManager(instance).NewBuilder()
+		pm, err := instances.GetPackageManager(instance)
+		if err != nil {
+			return err
+		}
+		pmb, commitPackageManager := pm.NewBuilder()
 
 		// Load packages index
 		for _, URL := range allPackageIndexUrls {
@@ -285,7 +289,10 @@ func Init(req *rpc.InitRequest, responseCallback func(r *rpc.InitResponse)) erro
 		commitPackageManager()
 	}
 
-	pme, release := instances.GetPackageManagerExplorer(instance)
+	pme, release, err := instances.GetPackageManagerExplorer(instance)
+	if err != nil {
+		return err
+	}
 	defer release()
 
 	for _, err := range pme.LoadDiscoveries() {
@@ -389,9 +396,9 @@ func Destroy(ctx context.Context, req *rpc.DestroyRequest) (*rpc.DestroyResponse
 // UpdateLibrariesIndex updates the library_index.json
 func UpdateLibrariesIndex(ctx context.Context, req *rpc.UpdateLibrariesIndexRequest, downloadCB rpc.DownloadProgressCB) error {
 	logrus.Info("Updating libraries index")
-	lm := instances.GetLibraryManager(req.GetInstance())
-	if lm == nil {
-		return &cmderrors.InvalidInstanceError{}
+	lm, err := instances.GetLibraryManager(req.GetInstance())
+	if err != nil {
+		return err
 	}
 
 	if err := lm.IndexFile.Parent().MkdirAll(); err != nil {

commands/internal/instances/instances.go

@@ -3,6 +3,7 @@ package instances
 import (
 	"sync"
 
+	"github.com/arduino/arduino-cli/commands/cmderrors"
 	"github.com/arduino/arduino-cli/internal/arduino/cores/packagemanager"
 	"github.com/arduino/arduino-cli/internal/arduino/libraries/librariesmanager"
 	rpc "github.com/arduino/arduino-cli/rpc/cc/arduino/cli/commands/v1"
@@ -26,36 +27,37 @@ var instancesMux sync.Mutex
 // GetPackageManager returns a PackageManager. If the package manager is not found
 // (because the instance is invalid or has been destroyed), nil is returned.
 // Deprecated: use GetPackageManagerExplorer instead.
-func GetPackageManager(inst *rpc.Instance) *packagemanager.PackageManager {
+func GetPackageManager(inst *rpc.Instance) (*packagemanager.PackageManager, error) {
 	instancesMux.Lock()
 	i := instances[inst.GetId()]
 	instancesMux.Unlock()
 	if i == nil {
-		return nil
+		return nil, &cmderrors.InvalidInstanceError{}
 	}
-	return i.pm
+	return i.pm, nil
 }
 
 // GetPackageManagerExplorer returns a new package manager Explorer. The
 // explorer holds a read lock on the underlying PackageManager and it should
 // be released by calling the returned "release" function.
-func GetPackageManagerExplorer(req *rpc.Instance) (explorer *packagemanager.Explorer, release func()) {
-	pm := GetPackageManager(req)
-	if pm == nil {
-		return nil, nil
+func GetPackageManagerExplorer(req *rpc.Instance) (explorer *packagemanager.Explorer, release func(), _err error) {
+	pm, err := GetPackageManager(req)
+	if err != nil {
+		return nil, nil, err
 	}
-	return pm.NewExplorer()
+	pme, release := pm.NewExplorer()
+	return pme, release, nil
 }
 
 // GetLibraryManager returns the library manager for the given instance.
-func GetLibraryManager(inst *rpc.Instance) *librariesmanager.LibrariesManager {
+func GetLibraryManager(inst *rpc.Instance) (*librariesmanager.LibrariesManager, error) {
 	instancesMux.Lock()
 	i := instances[inst.GetId()]
 	instancesMux.Unlock()
 	if i == nil {
-		return nil
+		return nil, &cmderrors.InvalidInstanceError{}
 	}
-	return i.lm
+	return i.lm, nil
 }
 
 // SetLibraryManager sets the library manager for the given instance.

commands/lib/download.go

@@ -35,9 +35,9 @@ var tr = i18n.Tr
 func LibraryDownload(ctx context.Context, req *rpc.LibraryDownloadRequest, downloadCB rpc.DownloadProgressCB) (*rpc.LibraryDownloadResponse, error) {
 	logrus.Info("Executing `arduino-cli lib download`")
 
-	lm := instances.GetLibraryManager(req.GetInstance())
-	if lm == nil {
-		return nil, &cmderrors.InvalidInstanceError{}
+	lm, err := instances.GetLibraryManager(req.GetInstance())
+	if err != nil {
+		return nil, err
 	}
 
 	logrus.Info("Preparing download")

commands/lib/install.go

@@ -33,9 +33,9 @@ import (
 
 // LibraryInstall resolves the library dependencies, then downloads and installs the libraries into the install location.
 func LibraryInstall(ctx context.Context, req *rpc.LibraryInstallRequest, downloadCB rpc.DownloadProgressCB, taskCB rpc.TaskProgressCB) error {
-	lm := instances.GetLibraryManager(req.GetInstance())
-	if lm == nil {
-		return &cmderrors.InvalidInstanceError{}
+	lm, err := instances.GetLibraryManager(req.GetInstance())
+	if err != nil {
+		return err
 	}
 
 	toInstall := map[string]*rpc.LibraryDependencyStatus{}
@@ -145,7 +145,10 @@ func installLibrary(lm *librariesmanager.LibrariesManager, libRelease *libraries
 
 // ZipLibraryInstall FIXMEDOC
 func ZipLibraryInstall(ctx context.Context, req *rpc.ZipLibraryInstallRequest, taskCB rpc.TaskProgressCB) error {
-	lm := instances.GetLibraryManager(req.GetInstance())
+	lm, err := instances.GetLibraryManager(req.GetInstance())
+	if err != nil {
+		return err
+	}
 	if err := lm.InstallZipLib(ctx, paths.New(req.GetPath()), req.GetOverwrite()); err != nil {
 		return &cmderrors.FailedLibraryInstallError{Cause: err}
 	}
@@ -155,7 +158,10 @@ func ZipLibraryInstall(ctx context.Context, req *rpc.ZipLibraryInstallRequest, t
 
 // GitLibraryInstall FIXMEDOC
 func GitLibraryInstall(ctx context.Context, req *rpc.GitLibraryInstallRequest, taskCB rpc.TaskProgressCB) error {
-	lm := instances.GetLibraryManager(req.GetInstance())
+	lm, err := instances.GetLibraryManager(req.GetInstance())
+	if err != nil {
+		return err
+	}
 	if err := lm.InstallGitLib(req.GetUrl(), req.GetOverwrite()); err != nil {
 		return &cmderrors.FailedLibraryInstallError{Cause: err}
 	}

commands/lib/list.go

@@ -36,15 +36,15 @@ type installedLib struct {
 
 // LibraryList FIXMEDOC
 func LibraryList(ctx context.Context, req *rpc.LibraryListRequest) (*rpc.LibraryListResponse, error) {
-	pme, release := instances.GetPackageManagerExplorer(req.GetInstance())
-	if pme == nil {
-		return nil, &cmderrors.InvalidInstanceError{}
+	pme, release, err := instances.GetPackageManagerExplorer(req.GetInstance())
+	if err != nil {
+		return nil, err
 	}
 	defer release()
 
-	lm := instances.GetLibraryManager(req.GetInstance())
-	if lm == nil {
-		return nil, &cmderrors.InvalidInstanceError{}
+	lm, err := instances.GetLibraryManager(req.GetInstance())
+	if err != nil {
+		return nil, err
 	}
 
 	nameFilter := strings.ToLower(req.GetName())

commands/lib/resolve_deps.go

@@ -30,9 +30,9 @@ import (
 
 // LibraryResolveDependencies FIXMEDOC
 func LibraryResolveDependencies(ctx context.Context, req *rpc.LibraryResolveDependenciesRequest) (*rpc.LibraryResolveDependenciesResponse, error) {
-	lm := instances.GetLibraryManager(req.GetInstance())
-	if lm == nil {
-		return nil, &cmderrors.InvalidInstanceError{}
+	lm, err := instances.GetLibraryManager(req.GetInstance())
+	if err != nil {
+		return nil, err
 	}
 
 	// Search the requested lib

commands/lib/search.go

@@ -20,7 +20,6 @@ import (
 	"sort"
 	"strings"
 
-	"github.com/arduino/arduino-cli/commands/cmderrors"
 	"github.com/arduino/arduino-cli/commands/internal/instances"
 	"github.com/arduino/arduino-cli/internal/arduino/libraries/librariesindex"
 	"github.com/arduino/arduino-cli/internal/arduino/libraries/librariesmanager"
@@ -30,9 +29,9 @@ import (
 
 // LibrarySearch FIXMEDOC
 func LibrarySearch(ctx context.Context, req *rpc.LibrarySearchRequest) (*rpc.LibrarySearchResponse, error) {
-	lm := instances.GetLibraryManager(req.GetInstance())
-	if lm == nil {
-		return nil, &cmderrors.InvalidInstanceError{}
+	lm, err := instances.GetLibraryManager(req.GetInstance())
+	if err != nil {
+		return nil, err
 	}
 	return searchLibrary(req, lm), nil
 }

commands/lib/uninstall.go

@@ -27,7 +27,11 @@ import (
 
 // LibraryUninstall FIXMEDOC
 func LibraryUninstall(ctx context.Context, req *rpc.LibraryUninstallRequest, taskCB rpc.TaskProgressCB) error {
-	lm := instances.GetLibraryManager(req.GetInstance())
+	lm, err := instances.GetLibraryManager(req.GetInstance())
+	if err != nil {
+		return err
+	}
+
 	ref, err := createLibIndexReference(lm, req)
 	if err != nil {
 		return &cmderrors.InvalidLibraryError{Cause: err}

commands/lib/upgrade.go

@@ -26,9 +26,9 @@ import (
 
 // LibraryUpgradeAll upgrades all the available libraries
 func LibraryUpgradeAll(req *rpc.LibraryUpgradeAllRequest, downloadCB rpc.DownloadProgressCB, taskCB rpc.TaskProgressCB) error {
-	lm := instances.GetLibraryManager(req.GetInstance())
-	if lm == nil {
-		return &cmderrors.InvalidInstanceError{}
+	lm, err := instances.GetLibraryManager(req.GetInstance())
+	if err != nil {
+		return err
 	}
 
 	if err := upgrade(req.GetInstance(), listLibraries(lm, true, false), downloadCB, taskCB); err != nil {
@@ -44,9 +44,9 @@ func LibraryUpgradeAll(req *rpc.LibraryUpgradeAllRequest, downloadCB rpc.Downloa
 
 // LibraryUpgrade upgrades a library
 func LibraryUpgrade(ctx context.Context, req *rpc.LibraryUpgradeRequest, downloadCB rpc.DownloadProgressCB, taskCB rpc.TaskProgressCB) error {
-	lm := instances.GetLibraryManager(req.GetInstance())
-	if lm == nil {
-		return &cmderrors.InvalidInstanceError{}
+	lm, err := instances.GetLibraryManager(req.GetInstance())
+	if err != nil {
+		return err
 	}
 
 	// Get the library to upgrade

commands/monitor/monitor.go

@@ -61,9 +61,9 @@ func (p *PortProxy) Close() error {
 // Monitor opens a communication port. It returns a PortProxy to communicate with the port and a PortDescriptor
 // that describes the available configuration settings.
 func Monitor(ctx context.Context, req *rpc.MonitorRequest) (*PortProxy, *pluggableMonitor.PortDescriptor, error) {
-	pme, release := instances.GetPackageManagerExplorer(req.GetInstance())
-	if pme == nil {
-		return nil, nil, &cmderrors.InvalidInstanceError{}
+	pme, release, err := instances.GetPackageManagerExplorer(req.GetInstance())
+	if err != nil {
+		return nil, nil, err
 	}
 	defer release()
 

commands/monitor/settings.go

@@ -26,9 +26,9 @@ import (
 
 // EnumerateMonitorPortSettings returns a description of the configuration settings of a monitor port
 func EnumerateMonitorPortSettings(ctx context.Context, req *rpc.EnumerateMonitorPortSettingsRequest) (*rpc.EnumerateMonitorPortSettingsResponse, error) {
-	pme, release := instances.GetPackageManagerExplorer(req.GetInstance())
-	if pme == nil {
-		return nil, &cmderrors.InvalidInstanceError{}
+	pme, release, err := instances.GetPackageManagerExplorer(req.GetInstance())
+	if err != nil {
+		return nil, err
 	}
 	defer release()
 

commands/upload/burnbootloader.go

@@ -19,7 +19,6 @@ import (
 	"context"
 	"io"
 
-	"github.com/arduino/arduino-cli/commands/cmderrors"
 	"github.com/arduino/arduino-cli/commands/internal/instances"
 	rpc "github.com/arduino/arduino-cli/rpc/cc/arduino/cli/commands/v1"
 	"github.com/sirupsen/logrus"
@@ -33,13 +32,13 @@ func BurnBootloader(ctx context.Context, req *rpc.BurnBootloaderRequest, outStre
 		WithField("programmer", req.GetProgrammer()).
 		Trace("BurnBootloader started", req.GetFqbn())
 
-	pme, release := instances.GetPackageManagerExplorer(req.GetInstance())
-	if pme == nil {
-		return nil, &cmderrors.InvalidInstanceError{}
+	pme, release, err := instances.GetPackageManagerExplorer(req.GetInstance())
+	if err != nil {
+		return nil, err
 	}
 	defer release()
 
-	_, err := runProgramAction(
+	if _, err := runProgramAction(
 		pme,
 		nil, // sketch
 		"",  // importFile
@@ -54,8 +53,7 @@ func BurnBootloader(ctx context.Context, req *rpc.BurnBootloaderRequest, outStre
 		errStream,
 		req.GetDryRun(),
 		map[string]string{}, // User fields
-	)
-	if err != nil {
+	); err != nil {
 		return nil, err
 	}
 	return &rpc.BurnBootloaderResponse{}, nil

commands/upload/programmers_list.go

@@ -26,9 +26,9 @@ import (
 
 // ListProgrammersAvailableForUpload FIXMEDOC
 func ListProgrammersAvailableForUpload(ctx context.Context, req *rpc.ListProgrammersAvailableForUploadRequest) (*rpc.ListProgrammersAvailableForUploadResponse, error) {
-	pme, release := instances.GetPackageManagerExplorer(req.GetInstance())
-	if pme == nil {
-		return nil, &cmderrors.InvalidInstanceError{}
+	pme, release, err := instances.GetPackageManagerExplorer(req.GetInstance())
+	if err != nil {
+		return nil, err
 	}
 	defer release()
 

commands/upload/upload.go

@@ -49,12 +49,11 @@ func SupportedUserFields(ctx context.Context, req *rpc.SupportedUserFieldsReques
 		return nil, &cmderrors.MissingPortProtocolError{}
 	}
 
-	pme, release := instances.GetPackageManagerExplorer(req.GetInstance())
-	defer release()
-
-	if pme == nil {
-		return nil, &cmderrors.InvalidInstanceError{}
+	pme, release, err := instances.GetPackageManagerExplorer(req.GetInstance())
+	if err != nil {
+		return nil, err
 	}
+	defer release()
 
 	fqbn, err := cores.ParseFQBN(req.GetFqbn())
 	if err != nil {
@@ -136,9 +135,9 @@ func Upload(ctx context.Context, req *rpc.UploadRequest, outStream io.Writer, er
 		return nil, &cmderrors.CantOpenSketchError{Cause: err}
 	}
 
-	pme, pmeRelease := instances.GetPackageManagerExplorer(req.GetInstance())
-	if pme == nil {
-		return nil, &cmderrors.InvalidInstanceError{}
+	pme, pmeRelease, err := instances.GetPackageManagerExplorer(req.GetInstance())
+	if err != nil {
+		return nil, err
 	}
 	defer pmeRelease()