Fallback best PHP version detection to major if the minor is not available (#6)

Author: tucksaun

store.go

@@ -140,12 +140,34 @@ func (s *PHPStore) BestVersionForDir(dir string) (*Version, string, string, erro
 // bestVersion returns the latest patch version for the given major (X), minor (X.Y), or patch (X.Y.Z)
 // version can be 7 or 7.1 or 7.1.2
 // non-symlinked versions have priority
+// If the asked version is a patch one (X.Y.Z) and is not available, the lookup
+// will fallback to the last path version for the minor version (X.Y).
+// There's no fallback to the major version because PHP is known to occasionally
+// break BC in minor versions, so we can't safely fall back.
 func (s *PHPStore) bestVersion(versionPrefix, source string) (*Version, string, string, error) {
+	warning := ""
+
+	// Check if versionPrefix is actually a patch version, if so first do an
+	// exact match lookup and fallback to a minor version check
+	if pos := strings.LastIndexByte(versionPrefix, '.'); pos != strings.IndexByte(versionPrefix, '.') {
+		// look for an exact match, the order does not matter here
+		for _, v := range s.versions {
+			if v.Version == versionPrefix {
+				return v, source, "", nil
+			}
+		}
+
+		// exact match not found, fallback to minor version check
+		newVersionPrefix := versionPrefix[:pos]
+		warning = fmt.Sprintf(`the current dir requires PHP %s (%s), but this version is not available: fallback to %s`, versionPrefix, source, newVersionPrefix)
+		versionPrefix = newVersionPrefix
+	}
+
 	// start from the end as versions are always sorted
 	for i := len(s.versions) - 1; i >= 0; i-- {
 		v := s.versions[i]
-		if v.Version == versionPrefix || strings.HasPrefix(v.Version, versionPrefix) {
-			return v, source, "", nil
+		if strings.HasPrefix(v.Version, versionPrefix) {
+			return v, source, warning, nil
 		}
 	}
 

store_test.go

@@ -0,0 +1,49 @@
+package phpstore
+
+import (
+	"path/filepath"
+	"testing"
+)
+
+func TestBestVersion(t *testing.T) {
+	store := New("/dev/null", false, nil)
+	for _, v := range []string{"7.4.33", "8.0.27", "8.1.2", "8.1.14", "8.2.1"} {
+		store.addVersion(&Version{
+			Version: v,
+			PHPPath: filepath.Join("/foo", v, "bin", "php"),
+		})
+
+		if !store.IsVersionAvailable(v) {
+			t.Errorf("Version %s should be shown as available", v)
+		}
+	}
+
+	{
+		bestVersion, _, _, _ := store.bestVersion("8", "testing")
+		if bestVersion == nil {
+			t.Error("8 requirement should find a best version")
+		} else if bestVersion.Version != "8.2.1" {
+			t.Error("8 requirement should find 8.2.1 as best version")
+		}
+	}
+
+	{
+		bestVersion, _, _, _ := store.bestVersion("8.1", "testing")
+		if bestVersion == nil {
+			t.Error("8.1 requirement should find a best version")
+		} else if bestVersion.Version != "8.1.14" {
+			t.Error("8.1 requirement should find 8.1.14 as best version")
+		}
+	}
+
+	{
+		bestVersion, _, warning, _ := store.bestVersion("8.0.10", "testing")
+		if bestVersion == nil {
+			t.Error("8.0.10 requirement should find a best version")
+		} else if bestVersion.Version != "8.0.27" {
+			t.Error("8.0.10 requirement should find 8.0.27 as best version")
+		} else if warning == "" {
+			t.Error("8.0.10 requirement should trigger a warning")
+		}
+	}
+}