[runx] Allow unknown file types (#403)

## Summary

This tweaks the logic in
#401 to allow unknown file
types if there are no known file types in the list of released
artifacts. This is needed because some releases don't have file types at
all (e.g. https://github.com/mvdan/gofumpt/releases). We try to return a
known archive, otherwise we just return the last artifact that matches
the platform (if any)

Note: this is a revert to how the logic behaved before
#401 but keeps the artifact
name improvements from that PR.

cc: @edorizzardi

## How was it tested?

* `runx --install mvdan/gofumpt`
* unit tests

pkg/runx/devbox.json

@@ -5,7 +5,8 @@
   "shell": {
     "scripts": {
       "build": "go build -o dist/runx cmd/runx/main.go",
-      "build-pkg": "go build -o dist/pkg cmd/pkg/main.go"
+      "build-pkg": "go build -o dist/pkg cmd/pkg/main.go",
+      "test": "go test ./..."
     }
   }
 }

pkg/runx/impl/registry/artifact.go

@@ -8,23 +8,25 @@ import (
 )
 
 func findArtifactForPlatform(artifacts []types.ArtifactMetadata, platform types.Platform) (types.ArtifactMetadata, error) {
-	foundPlatform := false
+	var artifactForPlatform types.ArtifactMetadata
 	for _, artifact := range artifacts {
 		if isArtifactForPlatform(artifact.Name, platform) {
-			foundPlatform = true
+			artifactForPlatform = artifact
 			if isKnownArchive(artifact.Name) {
-				// We only consider known archives because sometimes releases contain multiple files
+				// We prefer known archives because sometimes releases contain multiple files
 				// for the same platform. Some times those files are alternative installation methods
 				// like `.dmg`, `.msi`, or `.deb`, and sometimes they are metadata files like `.sha256`
 				// or a `.sig` file. We don't want to install those.
+				// If no known archive is found, but the platform is supported, we return the last artifact
+				// with a matching platform. This is useful when releases don't have extensions.
 				return artifact, nil
 			}
 		}
 	}
-	if !foundPlatform {
-		return types.ArtifactMetadata{}, types.ErrPlatformNotSupported
+	if artifactForPlatform.Name != "" {
+		return artifactForPlatform, nil
 	}
-	return types.ArtifactMetadata{}, types.ErrNoKnownArchive
+	return types.ArtifactMetadata{}, types.ErrPlatformNotSupported
 }
 
 func isArtifactForPlatform(artifactName string, platform types.Platform) bool {

pkg/runx/impl/registry/registry_test.go

@@ -98,8 +98,8 @@ func TestFindArtifactForPlatform(t *testing.T) {
 		errTypeWant error
 	}{
 		{[]types.ArtifactMetadata{{Name: "mac-amd64.tar.gz"}}, types.NewPlatform("darwin", "amd64"), true, nil},
-		{[]types.ArtifactMetadata{{Name: "linux-amd64.deb"}}, types.NewPlatform("linux", "amd64"), false, types.ErrNoKnownArchive},
-		{[]types.ArtifactMetadata{{Name: "linux-amd64"}}, types.NewPlatform("linux", "amd64"), false, types.ErrNoKnownArchive},
+		{[]types.ArtifactMetadata{{Name: "linux-amd64.deb"}}, types.NewPlatform("linux", "amd64"), true, nil},
+		{[]types.ArtifactMetadata{{Name: "linux-amd64"}}, types.NewPlatform("linux", "amd64"), true, nil},
 		{[]types.ArtifactMetadata{{Name: "darwin_arm64.tar"}}, types.NewPlatform("windows", "amd64"), false, types.ErrPlatformNotSupported},
 		{[]types.ArtifactMetadata{{Name: "darwin_arm64"}}, types.NewPlatform("windows", "amd64"), false, types.ErrPlatformNotSupported},
 		{[]types.ArtifactMetadata{{Name: "mac-amd64.tar.gz"}}, types.NewPlatform("", ""), false, types.ErrPlatformNotSupported},

pkg/runx/impl/types/errors.go

@@ -5,4 +5,3 @@ import "errors"
 var ErrPackageNotFound = errors.New("package not found")
 var ErrReleaseNotFound = errors.New("release not found")
 var ErrPlatformNotSupported = errors.New("package doesn't support platform")
-var ErrNoKnownArchive = errors.New("package doesn't come in a known archive")