Do not fully rewrite sketch.yaml when a key is automatically updated

arduino/sketch/profiles.go

@@ -262,9 +262,3 @@ func LoadProjectFile(file *paths.Path) (*Project, error) {
 	}
 	return res, nil
 }
-
-// SaveProjectFile save the sketch project to a file
-func (s *Sketch) SaveProjectFile() error {
-	projectFile := s.GetProjectPath()
-	return projectFile.WriteFile([]byte(s.Project.AsYaml()))
-}

arduino/sketch/sketch.go

@@ -252,15 +252,18 @@ func (s *Sketch) GetDefaultPortAddressAndProtocol() (string, string) {
 // SetDefaultFQBN sets the default FQBN for the sketch and saves it in the sketch.yaml project file.
 func (s *Sketch) SetDefaultFQBN(fqbn string) error {
 	s.Project.DefaultFqbn = fqbn
-	return s.SaveProjectFile()
+	return updateOrAddYamlRootEntry(s.GetProjectPath(), "default_fqbn", fqbn)
 }
 
 // SetDefaultPort sets the default port address and port protocol for the sketch and saves it in the
 // sketch.yaml project file.
 func (s *Sketch) SetDefaultPort(address, protocol string) error {
 	s.Project.DefaultPort = address
 	s.Project.DefaultProtocol = protocol
-	return s.SaveProjectFile()
+	if err := updateOrAddYamlRootEntry(s.GetProjectPath(), "default_port", address); err != nil {
+		return err
+	}
+	return updateOrAddYamlRootEntry(s.GetProjectPath(), "default_protocol", protocol)
 }
 
 // InvalidSketchFolderNameError is returned when the sketch directory doesn't match the sketch name

arduino/sketch/yaml.go

@@ -0,0 +1,68 @@
+// This file is part of arduino-cli.
+//
+// Copyright 2020-2022 ARDUINO SA (http://www.arduino.cc/)
+//
+// This software is released under the GNU General Public License version 3,
+// which covers the main part of arduino-cli.
+// The terms of this license can be found at:
+// https://www.gnu.org/licenses/gpl-3.0.en.html
+//
+// You can be released from the requirements of the above licenses by purchasing
+// a commercial license. Buying such a license is mandatory if you want to
+// modify or otherwise use the software for commercial activities involving the
+// Arduino software without disclosing the source code of your own applications.
+// To purchase a commercial license, send an email to license@arduino.cc.
+
+package sketch
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/arduino/go-paths-helper"
+	"gopkg.in/yaml.v3"
+)
+
+func updateOrAddYamlRootEntry(path *paths.Path, key, newValue string) error {
+	var srcYaml []string
+	if path.Exist() {
+		src, err := path.ReadFileAsLines()
+		if err != nil {
+			return err
+		}
+		srcYaml = src
+	}
+
+	// Generate the new yaml key/value pair
+	v, err := yaml.Marshal(newValue)
+	if err != nil {
+		return err
+	}
+	updatedLine := key + ": " + strings.TrimSpace(string(v))
+
+	// Update or add the key/value pair into the original yaml
+	addMissing := true
+	for i, line := range srcYaml {
+		if strings.HasPrefix(line, key+": ") {
+			srcYaml[i] = updatedLine
+			addMissing = false
+			break
+		}
+	}
+	if addMissing {
+		srcYaml = append(srcYaml, updatedLine)
+	}
+
+	// Validate the new yaml
+	dstYaml := []byte(strings.Join(srcYaml, fmt.Sprintln()))
+	var dst interface{}
+	if err := yaml.Unmarshal(dstYaml, &dst); err != nil {
+		return fmt.Errorf("%s: %w", tr("could not update sketch project file"), err)
+	}
+	if dstMap, ok := dst.(map[string]interface{}); !ok || dstMap[key] != newValue {
+		return fmt.Errorf(tr("could not update sketch project file"))
+	}
+
+	// Write back the updated YAML
+	return path.WriteFile(dstYaml)
+}

arduino/sketch/yaml_test.go

@@ -0,0 +1,78 @@
+// This file is part of arduino-cli.
+//
+// Copyright 2020-2022 ARDUINO SA (http://www.arduino.cc/)
+//
+// This software is released under the GNU General Public License version 3,
+// which covers the main part of arduino-cli.
+// The terms of this license can be found at:
+// https://www.gnu.org/licenses/gpl-3.0.en.html
+//
+// You can be released from the requirements of the above licenses by purchasing
+// a commercial license. Buying such a license is mandatory if you want to
+// modify or otherwise use the software for commercial activities involving the
+// Arduino software without disclosing the source code of your own applications.
+// To purchase a commercial license, send an email to license@arduino.cc.
+
+package sketch
+
+import (
+	"fmt"
+	"strings"
+	"testing"
+
+	"github.com/arduino/go-paths-helper"
+	"github.com/stretchr/testify/require"
+)
+
+func TestYamlUpdate(t *testing.T) {
+	{
+		sample, err := paths.New("testdata", "SketchWithProfiles", "sketch.yml").ReadFile()
+		require.NoError(t, err)
+		tmp, err := paths.WriteToTempFile(sample, nil, "")
+		require.NoError(t, err)
+		defer tmp.Remove()
+
+		err = updateOrAddYamlRootEntry(tmp, "default_fqbn", "arduino:avr:uno")
+		require.NoError(t, err)
+		err = updateOrAddYamlRootEntry(tmp, "default_port", "/dev/ttyACM0")
+		require.NoError(t, err)
+
+		updated, err := tmp.ReadFile()
+		require.NoError(t, err)
+		expected := string(sample) + fmt.Sprintln()
+		expected += fmt.Sprintln("default_fqbn: arduino:avr:uno")
+		expected += "default_port: /dev/ttyACM0"
+		require.Equal(t, expected, string(updated))
+	}
+	{
+		sample, err := paths.New("testdata", "SketchWithDefaultFQBNAndPort", "sketch.yml").ReadFile()
+		require.NoError(t, err)
+		tmp, err := paths.WriteToTempFile(sample, nil, "")
+		require.NoError(t, err)
+		defer tmp.Remove()
+
+		err = updateOrAddYamlRootEntry(tmp, "default_fqbn", "TEST1")
+		require.NoError(t, err)
+		err = updateOrAddYamlRootEntry(tmp, "default_port", "TEST2")
+		require.NoError(t, err)
+
+		updated, err := tmp.ReadFile()
+		fmt.Print(string(updated))
+		require.NoError(t, err)
+		expected := strings.Replace(string(sample), "arduino:avr:uno", "TEST1", 1)
+		expected = strings.Replace(expected, "/dev/ttyACM0", "TEST2", 1)
+		require.Equal(t, expected, string(updated))
+	}
+	{
+		tmp, err := paths.WriteToTempFile([]byte{}, nil, "")
+		require.NoError(t, err)
+		require.NoError(t, tmp.Remove())
+		err = updateOrAddYamlRootEntry(tmp, "default_fqbn", "TEST1")
+		require.NoError(t, err)
+
+		updated, err := tmp.ReadFile()
+		require.NoError(t, err)
+		expected := "default_fqbn: TEST1"
+		require.Equal(t, expected, string(updated))
+	}
+}

go.mod

@@ -53,6 +53,7 @@ require (
 require (
 	github.com/rogpeppe/go-internal v1.3.0
 	go.bug.st/testifyjson v1.1.1
+	gopkg.in/yaml.v3 v3.0.1
 )
 
 require (
@@ -89,5 +90,4 @@ require (
 	gopkg.in/ini.v1 v1.62.0 // indirect
 	gopkg.in/src-d/go-billy.v4 v4.3.2 // indirect
 	gopkg.in/warnings.v0 v0.1.2 // indirect
-	gopkg.in/yaml.v3 v3.0.1 // indirect
 )