Do library rescan on compile (if no profies are used)

Fix arduino#1755

Author: cmaglie

Diff for: arduino/cores/packagemanager/package_manager.go

@@ -24,6 +24,7 @@ import (
 	"github.com/arduino/arduino-cli/arduino/cores"
 	"github.com/arduino/arduino-cli/arduino/cores/packageindex"
 	"github.com/arduino/arduino-cli/arduino/discovery/discoverymanager"
+	"github.com/arduino/arduino-cli/arduino/sketch"
 	"github.com/arduino/arduino-cli/i18n"
 	paths "github.com/arduino/go-paths-helper"
 	properties "github.com/arduino/go-properties-orderedmap"
@@ -44,6 +45,7 @@ type PackageManager struct {
 	DownloadDir            *paths.Path
 	TempDir                *paths.Path
 	CustomGlobalProperties *properties.Map
+	profile                *sketch.Profile
 	discoveryManager       *discoverymanager.DiscoveryManager
 	userAgent              string
 }
@@ -65,6 +67,11 @@ func NewPackageManager(indexDir, packagesDir, downloadDir, tempDir *paths.Path,
 	}
 }
 
+// GetProfile returns the active profile for this package manager, or nil if no profile is selected.
+func (pm *PackageManager) GetProfile() *sketch.Profile {
+	return pm.profile
+}
+
 // GetEnvVarsForSpawnedProcess produces a set of environment variables that
 // must be sent to all processes spawned from the arduino-cli.
 func (pm *PackageManager) GetEnvVarsForSpawnedProcess() []string {

Diff for: arduino/cores/packagemanager/profiles.go

@@ -33,6 +33,8 @@ import (
 // LoadHardwareForProfile load the hardware platforms for the given profile.
 // If installMissing is true then possibly missing tools and platforms will be downloaded and installed.
 func (pm *PackageManager) LoadHardwareForProfile(p *sketch.Profile, installMissing bool, downloadCB rpc.DownloadProgressCB, taskCB rpc.TaskProgressCB) []error {
+	pm.profile = p
+
 	// Load required platforms
 	var merr []error
 	var platformReleases []*cores.PlatformRelease

Diff for: commands/compile/compile.go

@@ -111,7 +111,9 @@ func Compile(ctx context.Context, req *rpc.CompileRequest, outStream, errStream
 
 	builderCtx := &types.Context{}
 	builderCtx.PackageManager = pm
-	builderCtx.LibrariesManager = lm
+	if pm.GetProfile() != nil {
+		builderCtx.LibrariesManager = lm
+	}
 	builderCtx.FQBN = fqbn
 	builderCtx.SketchLocation = sk.FullPath
 	builderCtx.ProgressCB = progressCB
@@ -124,9 +126,6 @@ func Compile(ctx context.Context, req *rpc.CompileRequest, outStream, errStream
 	builderCtx.OtherLibrariesDirs = paths.NewPathList(req.GetLibraries()...)
 	builderCtx.OtherLibrariesDirs.Add(configuration.LibrariesDir(configuration.Settings))
 	builderCtx.LibraryDirs = paths.NewPathList(req.Library...)
-	if len(req.GetLibraries()) > 0 || len(req.GetLibrary()) > 0 {
-		builderCtx.LibrariesManager = nil // let the builder rebuild the library manager
-	}
 	if req.GetBuildPath() == "" {
 		builderCtx.BuildPath = sk.BuildPath
 	} else {