feat: handling for using versions that are not installed (#14)

* feat: handling for using versions that are not installed

* test: coverage for installed version list

* chore: increment version to 0.0.8

commands.go

@@ -1,10 +1,9 @@
 package main
 
 import (
-	"errors"
 	"fmt"
 	"os"
-	"strings"
+	"slices"
 )
 
 var DIRECTORIES = []string{
@@ -54,6 +53,12 @@ func UninstallPython(args []string, flags Flags, currentState State) error {
 	return err
 }
 
+func InstallPython(args []string, flags Flags, currentState State) error {
+	version := args[1]
+
+	return InstallPythonDistribution(version, flags.NoCache, flags.Verbose)
+}
+
 func Use(args []string, flags Flags, currentState State) error {
 	version := args[1]
 	if err := ValidateVersion(version); err != nil {
@@ -71,7 +76,8 @@ func Use(args []string, flags Flags, currentState State) error {
 	}
 
 	if !found {
-		return errors.New("Version not installed.")
+		fmt.Println("Version not installed. Installing it first.")
+		InstallPythonDistribution(version, flags.NoCache, flags.Verbose)
 	}
 
 	WriteState(version)
@@ -80,20 +86,19 @@ func Use(args []string, flags Flags, currentState State) error {
 	return nil
 }
 func ListVersions(args []string, flags Flags, currentState State) error {
-	runtimesDir := GetStatePath("runtimes")
+	installedVersions, err := ListInstalledVersions()
-	entries, err := os.ReadDir(runtimesDir)
 
 	if err != nil {
 		return err
 	}
 
-	if len(entries) == 0 {
+	if len(installedVersions) == 0 {
 		fmt.Println("No versions installed!")
 		return nil
 	}
 
-	for _, d := range entries {
+	for _, d := range installedVersions {
-		fmt.Println(strings.TrimPrefix(d.Name(), "py-"))
+		fmt.Println(d)
 	}
 
 	return nil
@@ -102,15 +107,20 @@ func ListVersions(args []string, flags Flags, currentState State) error {
 // Which prints out the system path to the executable being used by `python`.
 func Which(args []string, flags Flags, currentState State) error {
 	selectedVersion, _ := DetermineSelectedPythonVersion(currentState)
+	installedVersions, _ := ListInstalledVersions()
+	isInstalled := slices.Contains(installedVersions, selectedVersion.Version)
 
 	var printedPath string
 
 	if selectedVersion.Source == "system" {
 		_, sysPath := DetermineSystemPython()
 		printedPath = fmt.Sprintf("%s (system)", sysPath)
-	} else {
+	} else if isInstalled {
 		tag := VersionStringToStruct(selectedVersion.Version)
 		printedPath = GetStatePath("runtimes", fmt.Sprintf("py-%s", selectedVersion.Version), "bin", fmt.Sprintf("python%s", tag.MajorMinor()))
+	} else {
+		fmt.Printf("The desired version (%s) is not installed.\n", selectedVersion.Version)
+		return nil
 	}
 
 	prefix := "Python path: "
@@ -130,6 +140,12 @@ func Which(args []string, flags Flags, currentState State) error {
 // under "source", if the system Python is used, "system" is returned as a source.
 func CurrentVersion(args []string, flags Flags, currentState State) error {
 	selectedVersion, _ := DetermineSelectedPythonVersion(currentState)
+	installedVersions, _ := ListInstalledVersions()
+	isInstalled := slices.Contains(installedVersions, selectedVersion.Version)
+
+	if !isInstalled {
+		fmt.Println(Bold(Yellow("WARNING: This version is not installed.")))
+	}
 
 	if flags.RawOutput {
 		fmt.Println(selectedVersion.Version)

install_python.go

@@ -30,15 +30,12 @@ func (t VersionTag) MajorMinor() string {
 	return fmt.Sprintf("%s.%s", t.Major, t.Minor)
 }
 
-func InstallPython(args []string, flags Flags, currentState State) error {
+func InstallPythonDistribution(version string, noCache bool, verbose bool) error {
-	verbose := flags.Verbose
-	version := args[1]
-
 	if err := ValidateVersion(version); err != nil {
 		return err
 	}
 
-	packageMetadata, dlerr := downloadSource(version, flags.NoCache)
+	packageMetadata, dlerr := downloadSource(version, noCache)
 
 	if dlerr != nil {
 		return dlerr

pythonversion.go

@@ -12,6 +12,23 @@ type SelectedVersion struct {
 	Source  string
 }
 
+func ListInstalledVersions() ([]string, error) {
+	runtimesDir := GetStatePath("runtimes")
+	entries, err := os.ReadDir(runtimesDir)
+
+	if err != nil {
+		return []string{}, err
+	}
+
+	installedVersions := []string{}
+
+	for _, d := range entries {
+		installedVersions = append(installedVersions, strings.TrimPrefix(d.Name(), "py-"))
+	}
+
+	return installedVersions, nil
+}
+
 // SearchForPythonVersionFile crawls up to the system root to find any
 // .python-version file that could set the current version.
 func SearchForPythonVersionFile() (SelectedVersion, bool) {

pythonversion_test.go

@@ -6,6 +6,7 @@ import (
 	"io/ioutil"
 	"os"
 	"path"
+	"slices"
 	"testing"
 )
 
@@ -131,5 +132,47 @@ func TestSearchForPythonVersionFileReturnsOnRootIfNoneFound(t *testing.T) {
 	if versionFound.Version != "" || found {
 		t.Errorf("Did not expect any result, found %s.", versionFound.Version)
 	}
-
+}
+
+func TestListInstalledVersion(t *testing.T) {
+	defer SetupAndCleanupEnvironment(t)()
+
+	versions := []string{"1.2.3", "4.5.6", "7.8.9"}
+
+	os.Mkdir(GetStatePath("runtimes"), 0750)
+	for _, version := range versions {
+		os.Mkdir(GetStatePath("runtimes", "py-"+version), 0750)
+	}
+
+	installedVersions, _ := ListInstalledVersions()
+
+	if !slices.Equal(installedVersions, versions) {
+		t.Errorf("Expected %s, got %s.", versions, installedVersions)
+	}
+}
+
+func TestListInstalledVersionNoVersionsInstalled(t *testing.T) {
+	defer SetupAndCleanupEnvironment(t)()
+
+	os.Mkdir(GetStatePath("runtimes"), 0750)
+
+	installedVersions, _ := ListInstalledVersions()
+
+	if len(installedVersions) != 0 {
+		t.Errorf("Expected 0 elements, got %d (%s).", len(installedVersions), installedVersions)
+	}
+}
+
+func TestListInstalledVersionNoRuntimesDir(t *testing.T) {
+	defer SetupAndCleanupEnvironment(t)()
+
+	installedVersions, err := ListInstalledVersions()
+
+	if len(installedVersions) != 0 {
+		t.Errorf("Expected 0 elements, got %d (%s).", len(installedVersions), installedVersions)
+	}
+
+	if err == nil {
+		t.Errorf("Expected error to be returned, got nil.")
+	}
 }

style.go

@@ -3,10 +3,15 @@ package main
 import "fmt"
 
 const (
-	RESET = "\033[0m"
+	RESET  = "\033[0m"
-	BOLD  = "\033[1m"
+	BOLD   = "\033[1m"
+	YELLOW = "\033[33m"
 )
 
+func Yellow(text string) string {
+	return fmt.Sprintf("%s%s%s", YELLOW, text, RESET)
+}
+
 func Bold(text string) string {
 	return fmt.Sprintf("%s%s%s", BOLD, text, RESET)
 }

v.go

@@ -5,7 +5,7 @@ import (
 )
 
 const (
-	Version  = "0.0.7"
+	Version  = "0.0.8"
 	Author   = "Marc Cataford <hello@karnov.club>"
 	Homepage = "https://github.com/mcataford/v"
 )