build: use own script instead of svu

We use a slightly different handling of features between prereleases.

script/next-version.go

@@ -0,0 +1,118 @@
+//go:build ignore
+// +build ignore
+
+package main
+
+import (
+	"flag"
+	"fmt"
+	"os"
+	"os/exec"
+	"strconv"
+	"strings"
+
+	"github.com/coreos/go-semver/semver"
+)
+
+const suffix = "rc"
+
+func main() {
+	pre := flag.Bool("pre", false, "Create a prerelease")
+	flag.Parse()
+
+	// Get the latest "v1.22.3" or "v1.22.3-rc.1" style tag.
+	latestTag, err := cmd("git", "describe", "--abbrev=0", "--match", "v[0-9].*")
+	if err != nil {
+		fmt.Println(err)
+		os.Exit(1)
+	}
+	latest, err := semver.NewVersion(latestTag[1:])
+	if err != nil {
+		fmt.Println(err)
+		os.Exit(1)
+	}
+
+	// Get the latest "v1.22.3" style tag, excludeing prereleases.
+	latestStableTag, err := cmd("git", "describe", "--abbrev=0", "--match", "v[0-9].*", "--exclude", "*-*")
+	if err != nil {
+		fmt.Println(err)
+		os.Exit(1)
+	}
+	latestStable, err := semver.NewVersion(latestStableTag[1:])
+	if err != nil {
+		fmt.Println(err)
+		os.Exit(1)
+	}
+
+	// Get the commit logs since the latest stable tag.
+	logsSinceLatest, err := cmd("git", "log", "--pretty=format:%s", latestStableTag+"..HEAD")
+	if err != nil {
+		fmt.Println(err)
+		os.Exit(1)
+	}
+
+	// Check if the next version should be a feature or a patch release
+	nextIsFeature := false
+	for _, line := range strings.Split(logsSinceLatest, "\n") {
+		if strings.HasPrefix(line, "feat") {
+			nextIsFeature = true
+			break
+		}
+	}
+	next := *latestStable
+	if nextIsFeature {
+		next.BumpMinor()
+	} else {
+		next.BumpPatch()
+	}
+
+	if latest.PreRelease != "" {
+		if !*pre {
+			// We want a stable release. Simply remove the prerelease
+			// suffix.
+			latest.PreRelease = ""
+			fmt.Println(latest)
+			return
+		}
+
+		// We want the next prerelease. We are already on a prerelease. If
+		// it's the correct prerelease compared to the logs we just got, we
+		// should just bump the prerelease counter.
+		if next.LessThan(*latest) {
+			parts := latest.PreRelease.Slice()
+			for i, p := range parts {
+				if v, err := strconv.Atoi(p); err == nil {
+					parts[i] = strconv.Itoa(v + 1)
+					latest.PreRelease = semver.PreRelease(strings.Join(parts, "."))
+					fmt.Println(latest)
+					return
+				}
+			}
+		}
+
+		// Otherwise we generate a new rc.1 for the correct next version.
+		next.PreRelease = suffix + ".1"
+		fmt.Println(next)
+		return
+	}
+
+	if nextIsFeature {
+		latest.BumpMinor()
+	} else {
+		latest.BumpPatch()
+	}
+	if *pre {
+		latest.PreRelease = suffix + ".1"
+	}
+
+	fmt.Println(latest)
+}
+
+func cmd(name string, args ...string) (string, error) {
+	cmd := exec.Command(name, args...)
+	bs, err := cmd.CombinedOutput()
+	if err != nil {
+		return "", err
+	}
+	return strings.TrimSpace(string(bs)), nil
+}