Don't do project discovery when explicitly defined

Previously, the project path discovery and type detection were done even when the user's settings explicitely defined
these things. When the contents of the given path did not contain something slightly resembling a project of the given
type, the process exited.

That behavior is the only one possible when a project is not explicitely defined by the user, but in the case of an
explicit definition, this is an unnecessary short circuiting of the process. The checks can still be run. This will
result in the same exit status as before, but the check results may provide the user with helpful information about why
their project is invalid.

Author: per1234

Diff for: project/project.go

@@ -57,8 +57,18 @@ func findProjects(targetPath *paths.Path) ([]Type, error) {
 	// If targetPath is a file, targetPath itself is the project, so it's only necessary to determine/verify the type.
 	if targetPath.IsNotDir() {
 		logrus.Debug("Projects path is file")
-		// The filename provides additional information about the project type. So rather than using isProject(), which doesn't make use this information, use a specialized function that does.
-		isProject, projectType := isProjectIndicatorFile(targetPath, configuration.SuperprojectTypeFilter())
+		var isProject bool
+		var projectType projecttype.Type
+		if configuration.SuperprojectTypeFilter() == projecttype.All {
+			// Project type detection is required.
+			// The filename provides additional information about the project type. So rather than using isProject(), which doesn't make use this information, use a specialized function that does.
+			isProject, projectType = isProjectIndicatorFile(targetPath, configuration.SuperprojectTypeFilter())
+		} else {
+			// Project was explicitly defined by user.
+			isProject = true
+			projectType = configuration.SuperprojectTypeFilter()
+		}
+
 		if isProject {
 			var projectPath *paths.Path
 			if projectType == projecttype.PackageIndex {
@@ -81,10 +91,22 @@ func findProjects(targetPath *paths.Path) ([]Type, error) {
 		return nil, fmt.Errorf("specified path %s is not an Arduino project", targetPath)
 	}
 
-	foundParentProjects := findProjectsUnderPath(targetPath, configuration.SuperprojectTypeFilter(), configuration.Recursive())
-	for _, foundParentProject := range foundParentProjects {
-		foundProjects = append(foundProjects, foundParentProject)
-		foundProjects = append(foundProjects, findSubprojects(foundParentProject, foundParentProject.ProjectType)...)
+	if configuration.SuperprojectTypeFilter() == projecttype.All || configuration.Recursive() {
+		// Project discovery and/or type detection is required.
+		foundParentProjects := findProjectsUnderPath(targetPath, configuration.SuperprojectTypeFilter(), configuration.Recursive())
+		for _, foundParentProject := range foundParentProjects {
+			foundProjects = append(foundProjects, foundParentProject)
+			foundProjects = append(foundProjects, findSubprojects(foundParentProject, foundParentProject.ProjectType)...)
+		}
+	} else {
+		// Project was explicitly defined by user.
+		foundProjects = append(foundProjects,
+			Type{
+				Path:             targetPath,
+				ProjectType:      configuration.SuperprojectTypeFilter(),
+				SuperprojectType: configuration.SuperprojectTypeFilter(),
+			},
+		)
 	}
 
 	if foundProjects == nil {

Diff for: project/project_test.go

@@ -130,6 +130,20 @@ func TestFindProjects(t *testing.T) {
 				},
 			},
 		},
+		{
+			"Explicit file",
+			"sketch",
+			"",
+			[]string{libraryPath.Join("Library.h").String()},
+			assert.NoError,
+			[]Type{
+				{
+					Path:             libraryPath,
+					ProjectType:      projecttype.Sketch,
+					SuperprojectType: projecttype.Sketch,
+				},
+			},
+		},
 		{
 			"Sketch folder",
 			"all",
@@ -201,6 +215,20 @@ func TestFindProjects(t *testing.T) {
 				},
 			},
 		},
+		{
+			"Explicit folder",
+			"sketch",
+			"false",
+			[]string{libraryPath.String()},
+			assert.NoError,
+			[]Type{
+				{
+					Path:             libraryPath,
+					ProjectType:      projecttype.Sketch,
+					SuperprojectType: projecttype.Sketch,
+				},
+			},
+		},
 		{
 			"Projects folder, recursive",
 			"all",