core: move build version reading to its own package (#25806)

This fixes the build with Go 1.17, which does not have BuildInfo.Settings yet.

internal/version/vcs_fallback.go

@@ -0,0 +1,28 @@
+// Copyright 2022 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+//go:build !go1.18
+// +build !go1.18
+
+package version
+
+import "runtime/debug"
+
+// In Go versions before 1.18, VCS information is not available.
+
+func vcsInfo(info *debug.BuildInfo) (gitStatus, bool) {
+	return gitStatus{}, false
+}

internal/version/vcs_go1.18.go

@@ -0,0 +1,48 @@
+// Copyright 2022 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+//go:build go1.18
+// +build go1.18
+
+package version
+
+import "runtime/debug"
+
+// In go 1.18 and beyond, the go tool embeds VCS information into the build.
+
+// vcsInfo returns VCS information of the build.
+func vcsInfo(info *debug.BuildInfo) (s gitStatus, ok bool) {
+	for _, v := range info.Settings {
+		switch v.Key {
+		case "vcs.revision":
+			if len(v.Value) < 8 {
+				s.revision = v.Value
+			} else {
+				s.revision = v.Value[:8]
+			}
+		case "vcs.modified":
+			if v.Value == "true" {
+				s.modified = true
+			}
+		case "vcs.time":
+			s.time = v.Value
+		}
+	}
+	if s.revision != "" && s.time != "" {
+		ok = true
+	}
+	return
+}

internal/version/version.go

@@ -0,0 +1,105 @@
+// Copyright 2022 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+// Package version implements reading of build version information.
+package version
+
+import (
+	"fmt"
+	"runtime/debug"
+	"strings"
+
+	"github.com/ethereum/go-ethereum/params"
+)
+
+const ourPath = "github.com/ethereum/go-ethereum" // Path to our module
+
+// runtimeInfo returns build and platform information about the current binary.
+//
+// If the package that is currently executing is a prefixed by our go-ethereum
+// module path, it will print out commit and date VCS information. Otherwise,
+// it will assume it's imported by a third-party and will return the imported
+// version and whether it was replaced by another module.
+func Info() (version, vcs string) {
+	version = params.VersionWithMeta
+	buildInfo, ok := debug.ReadBuildInfo()
+	if !ok {
+		return version, ""
+	}
+	version = versionInfo(buildInfo)
+	if status, ok := vcsInfo(buildInfo); ok {
+		modified := ""
+		if status.modified {
+			modified = " (dirty)"
+		}
+		vcs = status.revision + "-" + status.time + modified
+	}
+	return version, vcs
+}
+
+type gitStatus struct {
+	revision string
+	time     string
+	modified bool
+}
+
+// versionInfo returns version information for the currently executing
+// implementation.
+//
+// Depending on how the code is instansiated, it returns different amounts of
+// information. If it is unable to determine which module is related to our
+// package it falls back to the hardcoded values in the params package.
+func versionInfo(info *debug.BuildInfo) string {
+	// If the main package is from our repo, prefix version with "geth".
+	if strings.HasPrefix(info.Path, ourPath) {
+		return fmt.Sprintf("geth %s", info.Main.Version)
+	}
+	// Not our main package, so explicitly print out the module path and
+	// version.
+	var version string
+	if info.Main.Path != "" && info.Main.Version != "" {
+		// These can be empty when invoked with "go run".
+		version = fmt.Sprintf("%s@%s ", info.Main.Path, info.Main.Version)
+	}
+	mod := findModule(info, ourPath)
+	if mod == nil {
+		// If our module path wasn't imported, it's unclear which
+		// version of our code they are running. Fallback to hardcoded
+		// version.
+		return version + fmt.Sprintf("geth %s", params.VersionWithMeta)
+	}
+	// Our package is a dependency for the main module. Return path and
+	// version data for both.
+	version += fmt.Sprintf("%s@%s", mod.Path, mod.Version)
+	if mod.Replace != nil {
+		// If our package was replaced by something else, also note that.
+		version += fmt.Sprintf(" (replaced by %s@%s)", mod.Replace.Path, mod.Replace.Version)
+	}
+	return version
+}
+
+// findModule returns the module at path.
+func findModule(info *debug.BuildInfo, path string) *debug.Module {
+	if info.Path == ourPath {
+		return &info.Main
+	}
+	for _, mod := range info.Deps {
+		if mod.Path == path {
+			return mod
+		}
+	}
+	return nil
+}