chore: move the experiments package out of the internal/ dir

Closes #2014

experiments/experiments.go

@@ -0,0 +1,91 @@
+package experiments
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"github.com/joho/godotenv"
+
+	"github.com/go-task/task/v3/taskrc"
+)
+
+const envPrefix = "TASK_X_"
+
+// Active experiments.
+var (
+	GentleForce     Experiment
+	RemoteTaskfiles Experiment
+	EnvPrecedence   Experiment
+)
+
+// Inactive experiments. These are experiments that cannot be enabled, but are
+// preserved for error handling.
+var (
+	AnyVariables Experiment
+	MapVariables Experiment
+)
+
+// An internal list of all the initialized experiments used for iterating.
+var xList []Experiment
+
+func Parse(dir string) {
+	// Read any .env files
+	readDotEnv(dir)
+
+	// Create a node for the Task config reader
+	node, _ := taskrc.NewNode("", dir)
+
+	// Read the Task config file
+	reader := taskrc.NewReader()
+	config, _ := reader.Read(node)
+
+	// Initialize the experiments
+	GentleForce = New("GENTLE_FORCE", config, 1)
+	RemoteTaskfiles = New("REMOTE_TASKFILES", config, 1)
+	EnvPrecedence = New("ENV_PRECEDENCE", config, 1)
+	AnyVariables = New("ANY_VARIABLES", config)
+	MapVariables = New("MAP_VARIABLES", config)
+}
+
+// Validate checks if any experiments have been enabled while being inactive.
+// If one is found, the function returns an error.
+func Validate() error {
+	for _, x := range List() {
+		if err := x.Valid(); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func List() []Experiment {
+	return xList
+}
+
+func getEnv(xName string) string {
+	envName := fmt.Sprintf("%s%s", envPrefix, xName)
+	return os.Getenv(envName)
+}
+
+func getFilePath(filename, dir string) string {
+	if dir != "" {
+		return filepath.Join(dir, filename)
+	}
+	return filename
+}
+
+func readDotEnv(dir string) {
+	env, err := godotenv.Read(getFilePath(".env", dir))
+	if err != nil {
+		return
+	}
+
+	// If the env var is an experiment, set it.
+	for key, value := range env {
+		if strings.HasPrefix(key, envPrefix) {
+			os.Setenv(key, value)
+		}
+	}
+}