From d2e8d257e2083a2fa0c420bd8eced591a63dfaa2 Mon Sep 17 00:00:00 2001
From: Michael Fridman <mfridman@buf.build>
Date: Tue, 7 Mar 2023 12:42:15 -0500
Subject: [PATCH] Improve logic for versions with pre-release (#406)

---
 cmd/fetcher/main.go                 |  4 ----
 internal/fetchclient/fetchclient.go | 32 ++++++++++++++---------------
 internal/source/config.go           |  6 +-----
 3 files changed, 16 insertions(+), 26 deletions(-)

diff --git a/cmd/fetcher/main.go b/cmd/fetcher/main.go
index b1eb70768..5117000b3 100644
--- a/cmd/fetcher/main.go
+++ b/cmd/fetcher/main.go
@@ -206,10 +206,6 @@ func run(ctx context.Context, root string) ([]createdPlugin, error) {
 			}
 			latestVersions[config.CacheKey()] = newVersion
 		}
-		// For now we ignore prerelease versions. But this may change in the future.
-		if semver.Prerelease(newVersion) != "" && !config.IncludePrerelease {
-			continue
-		}
 		// example: library/grpc
 		pluginDir := filepath.Dir(config.Filename)
 		ok, err := checkDirExists(filepath.Join(pluginDir, newVersion))
diff --git a/internal/fetchclient/fetchclient.go b/internal/fetchclient/fetchclient.go
index 4be319943..2f4bd751e 100644
--- a/internal/fetchclient/fetchclient.go
+++ b/internal/fetchclient/fetchclient.go
@@ -153,8 +153,8 @@ func (c *Client) fetchCrate(ctx context.Context, name string) (string, error) {
 			// from the server's index.
 			continue
 		}
-		if versionWithPrefix, ok := ensureSemverPrefix(version.Num); ok {
-			versions = append(versions, versionWithPrefix)
+		if v, ok := ensureSemverPrefix(version.Num); ok {
+			versions = append(versions, v)
 		}
 	}
 	if len(versions) == 0 {
@@ -255,15 +255,13 @@ func (c *Client) fetchMaven(ctx context.Context, group string, name string) (str
 	}
 	latestVersion := ""
 	for _, version := range metadata.Versioning.Versions {
-		if !strings.HasPrefix(version, "v") {
-			version = "v" + version
-		}
-		if !semver.IsValid(version) || semver.Prerelease(version) != "" {
+		v, ok := ensureSemverPrefix(version)
+		if !ok {
 			continue
 		}
-		version = semver.Canonical(version)
-		if latestVersion == "" || semver.Compare(latestVersion, version) < 0 {
-			latestVersion = version
+		v = semver.Canonical(v)
+		if latestVersion == "" || semver.Compare(latestVersion, v) < 0 {
+			latestVersion = v
 		}
 	}
 	if latestVersion == "" {
@@ -295,12 +293,8 @@ func (c *Client) fetchGithub(ctx context.Context, owner string, repository strin
 			if tag.Name == nil {
 				continue
 			}
-			// Skip versions with pre-releases (e.g. v1.2.3-alpha.1).
-			if semver.Prerelease(*tag.Name) != "" {
-				continue
-			}
-			if version, ok := ensureSemverPrefix(*tag.Name); ok {
-				versions = append(versions, version)
+			if v, ok := ensureSemverPrefix(*tag.Name); ok {
+				versions = append(versions, v)
 			}
 		}
 		page = response.NextPage
@@ -315,9 +309,10 @@ func (c *Client) fetchGithub(ctx context.Context, owner string, repository strin
 	return versions[len(versions)-1], nil
 }
 
-// ensureSemverPrefix ensures the given version is valid semver, optionally
+// ensureSemverPrefix checks if the given version is valid semver, optionally
 // prefixing with "v". The output version is not guaranteed to be the same
-// as input.
+// as input. This function returns false if the version is not valid semver or
+// is a prerelease.
 func ensureSemverPrefix(version string) (string, bool) {
 	if !strings.HasPrefix(version, "v") {
 		version = "v" + version
@@ -325,5 +320,8 @@ func ensureSemverPrefix(version string) (string, bool) {
 	if !semver.IsValid(version) {
 		return "", false
 	}
+	if semver.Prerelease(version) != "" {
+		return "", false
+	}
 	return version, true
 }
diff --git a/internal/source/config.go b/internal/source/config.go
index a88ec7f51..d0996fe5a 100644
--- a/internal/source/config.go
+++ b/internal/source/config.go
@@ -2,7 +2,6 @@ package source
 
 import (
 	"io"
-	"strconv"
 
 	"gopkg.in/yaml.v3"
 )
@@ -28,13 +27,10 @@ type Cacheable interface {
 type Config struct {
 	Filename string `yaml:"-"`
 	Source   Source `yaml:"source"`
-	// IncludePrerelease includes semver prereleases when fetching versions
-	// from upstream.
-	IncludePrerelease bool `yaml:"include_prerelease"`
 }
 
 func (c Config) CacheKey() string {
-	return c.Source.CacheKey() + "-" + strconv.FormatBool(c.IncludePrerelease)
+	return c.Source.CacheKey()
 }
 
 var _ Cacheable = (*Config)(nil)