Sample command to solve compile or upload issue is now shown to CLI users

cli/compile/compile.go

@@ -19,12 +19,17 @@ import (
 	"bytes"
 	"context"
 	"encoding/json"
+	"errors"
 	"os"
+	"strings"
 
+	"github.com/arduino/arduino-cli/arduino"
+	"github.com/arduino/arduino-cli/arduino/cores/packagemanager"
 	"github.com/arduino/arduino-cli/arduino/discovery"
 	"github.com/arduino/arduino-cli/arduino/sketch"
 	"github.com/arduino/arduino-cli/cli/arguments"
 	"github.com/arduino/arduino-cli/cli/feedback"
+	"github.com/arduino/arduino-cli/cli/globals"
 	"github.com/arduino/arduino-cli/cli/output"
 	"github.com/arduino/arduino-cli/commands"
 	"github.com/arduino/arduino-cli/configuration"
@@ -264,6 +269,28 @@ func runCompileCommand(cmd *cobra.Command, args []string) {
 	})
 	if compileError != nil && output.OutputFormat != "json" {
 		feedback.Errorf(tr("Error during build: %v"), compileError)
+
+		// Check the error type to give the user better feedback on how
+		// to resolve it
+		var platformErr *arduino.PlatformNotFoundError
+		if errors.As(compileError, &platformErr) {
+			split := strings.Split(platformErr.Platform, ":")
+			if len(split) < 2 {
+				panic(tr("Platform ID is not correct"))
+			}
+
+			pm := commands.GetPackageManager(inst.GetId())
+			platform := pm.FindPlatform(&packagemanager.PlatformReference{
+				Package:              split[0],
+				PlatformArchitecture: split[1],
+			})
+
+			if platform != nil {
+				feedback.Errorf(tr("Try running `%s core install %s`", globals.VersionInfo.Application, platformErr.Platform))
+			} else {
+				feedback.Errorf(tr("Platform %s is not found in any known index", platformErr.Platform))
+			}
+		}
 		os.Exit(errorcodes.ErrGeneric)
 	}
 }

cli/upload/upload.go

@@ -17,13 +17,19 @@ package upload
 
 import (
 	"context"
+	"errors"
 	"os"
+	"strings"
 
+	"github.com/arduino/arduino-cli/arduino"
+	"github.com/arduino/arduino-cli/arduino/cores/packagemanager"
 	"github.com/arduino/arduino-cli/arduino/sketch"
 	"github.com/arduino/arduino-cli/cli/arguments"
 	"github.com/arduino/arduino-cli/cli/errorcodes"
 	"github.com/arduino/arduino-cli/cli/feedback"
+	"github.com/arduino/arduino-cli/cli/globals"
 	"github.com/arduino/arduino-cli/cli/instance"
+	"github.com/arduino/arduino-cli/commands"
 	"github.com/arduino/arduino-cli/commands/upload"
 	"github.com/arduino/arduino-cli/i18n"
 	rpc "github.com/arduino/arduino-cli/rpc/cc/arduino/cli/commands/v1"
@@ -109,6 +115,28 @@ func runUploadCommand(command *cobra.Command, args []string) {
 	})
 	if err != nil {
 		feedback.Errorf(tr("Error during Upload: %v"), err)
+
+		// Check the error type to give the user better feedback on how
+		// to resolve it
+		var platformErr *arduino.PlatformNotFoundError
+		if errors.As(err, &platformErr) {
+			split := strings.Split(platformErr.Platform, ":")
+			if len(split) < 2 {
+				panic(tr("Platform ID is not correct"))
+			}
+
+			pm := commands.GetPackageManager(instance.GetId())
+			platform := pm.FindPlatform(&packagemanager.PlatformReference{
+				Package:              split[0],
+				PlatformArchitecture: split[1],
+			})
+
+			if platform != nil {
+				feedback.Errorf(tr("Try running `%s core install %s`", globals.VersionInfo.Application, platformErr.Platform))
+			} else {
+				feedback.Errorf(tr("Platform %s is not found in any known index", platformErr.Platform))
+			}
+		}
 		os.Exit(errorcodes.ErrGeneric)
 	}
 

commands/upload/upload.go

@@ -67,7 +67,12 @@ func SupportedUserFields(ctx context.Context, req *rpc.SupportedUserFieldsReques
 	}
 
 	_, platformRelease, _, boardProperties, _, err := pm.ResolveFQBN(fqbn)
-	if err != nil {
+	if platformRelease == nil {
+		return nil, &arduino.PlatformNotFoundError{
+			Platform: fmt.Sprintf("%s:%s", fqbn.Package, fqbn.PlatformArch),
+			Cause:    err,
+		}
+	} else if err != nil {
 		return nil, &arduino.UnknownFQBNError{Cause: err}
 	}
 
@@ -286,7 +291,12 @@ func runProgramAction(pm *packagemanager.PackageManager,
 
 	// Find target board and board properties
 	_, boardPlatform, board, boardProperties, buildPlatform, err := pm.ResolveFQBN(fqbn)
-	if err != nil {
+	if boardPlatform == nil {
+		return &arduino.PlatformNotFoundError{
+			Platform: fmt.Sprintf("%s:%s", fqbn.Package, fqbn.PlatformArch),
+			Cause:    err,
+		}
+	} else if err != nil {
 		return &arduino.UnknownFQBNError{Cause: err}
 	}
 	logrus.

test/test_compile_part_4.py

@@ -392,8 +392,26 @@ def test_compile_non_installed_platform_with_wrong_packager_and_arch(run_command
     res = run_command(["compile", "-b", "wrong:avr:uno", sketch_path])
     assert res.failed
     assert "Error during build: Platform 'wrong:avr' not found: platform not installed" in res.stderr
+    assert "Platform wrong:avr is not found in any known index" in res.stderr
 
     # Compile with wrong arch
     res = run_command(["compile", "-b", "arduino:wrong:uno", sketch_path])
     assert res.failed
     assert "Error during build: Platform 'arduino:wrong' not found: platform not installed" in res.stderr
+    assert "Platform arduino:wrong is not found in any known index" in res.stderr
+
+
+def test_compile_with_known_platform_not_installed(run_command, data_dir):
+    assert run_command(["update"])
+
+    # Create a sketch
+    sketch_name = "SketchSimple"
+    sketch_path = Path(data_dir, sketch_name)
+    assert run_command(["sketch", "new", sketch_path])
+
+    # Try to compile using a platform found in the index but not installed
+    res = run_command(["compile", "-b", "arduino:avr:uno", sketch_path])
+    assert res.failed
+    assert "Error during build: Platform 'arduino:avr' not found: platform not installed" in res.stderr
+    # Verifies command to fix error is shown to user
+    assert "Try running `arduino-cli core install arduino:avr`" in res.stderr