Add check for sketch.json invalid data format

This checks whether sketch.json is compliant with the expected data format.

Author: per1234

Diff for: check/checkconfigurations/checkconfigurations.go

@@ -1226,6 +1226,21 @@ var configurations = []Type{
 		ErrorModes:      []checkmode.Type{checkmode.Default},
 		CheckFunction:   checkfunctions.SketchDotJSONJSONFormat,
 	},
+	{
+		ProjectType:     projecttype.Sketch,
+		Category:        "metadata",
+		Subcategory:     "sketch.json",
+		ID:              "",
+		Brief:           "invalid sketch.json data format",
+		Description:     "",
+		MessageTemplate: "sketch.json has an invalid data format: {{.}}. See: https://arduino.github.io/arduino-cli/latest/sketch-specification/#metadata",
+		DisableModes:    nil,
+		EnableModes:     []checkmode.Type{checkmode.Default},
+		InfoModes:       nil,
+		WarningModes:    []checkmode.Type{checkmode.Permissive},
+		ErrorModes:      []checkmode.Type{checkmode.Default},
+		CheckFunction:   checkfunctions.SketchDotJSONFormat,
+	},
 	{
 		ProjectType:     projecttype.Sketch,
 		Category:        "code",

Diff for: check/checkfunctions/sketch.go

@@ -114,3 +114,17 @@ func SketchDotJSONJSONFormat() (result checkresult.Type, output string) {
 
 	return checkresult.Fail, ""
 }
+
+// SketchDotJSONFormat checks whether the sketch.json metadata file has the required data format.
+func SketchDotJSONFormat() (result checkresult.Type, output string) {
+	metadataPath := sketch.MetadataPath(checkdata.ProjectPath())
+	if metadataPath == nil {
+		return checkresult.NotRun, "No metadata file"
+	}
+
+	if checkdata.MetadataLoadError() == nil {
+		return checkresult.Pass, ""
+	}
+
+	return checkresult.Fail, checkdata.MetadataLoadError().Error()
+}

Diff for: check/checkfunctions/sketch_test.go

@@ -105,3 +105,14 @@ func TestSketchDotJSONJSONFormat(t *testing.T) {
 
 	checkSketchCheckFunction(SketchDotJSONJSONFormat, testTables, t)
 }
+
+func TestSketchDotJSONFormat(t *testing.T) {
+	testTables := []sketchCheckFunctionTestTable{
+		{"No metadata file", "NoMetadataFile", checkresult.NotRun, ""},
+		{"Valid", "ValidMetadataFile", checkresult.Pass, ""},
+		{"Invalid JSON", "InvalidJSONMetadataFile", checkresult.Fail, ""},
+		{"Invalid data", "InvalidDataMetadataFile", checkresult.Fail, ""},
+	}
+
+	checkSketchCheckFunction(SketchDotJSONFormat, testTables, t)
+}

Diff for: check/checkfunctions/testdata/sketches/InvalidDataMetadataFile/InvalidDataMetadataFile.ino

@@ -0,0 +1,2 @@
+void setup() {}
+void loop() {}

Diff for: check/checkfunctions/testdata/sketches/InvalidDataMetadataFile/sketch.json

@@ -0,0 +1,8 @@
+[
+  {
+    "foo": "bar"
+  },
+  {
+    "baz": "bat"
+  }
+]