docs: fix typo

.gitignore

@@ -1,4 +1,9 @@
-generated-version.go
+xversion.go
+zversion.go
+
+/go-gitver
+hello
+examples/*/*.sum
 
 # ---> Go
 # Binaries for programs and plugins

.prettierrc

@@ -0,0 +1 @@
+{}

README.md

@@ -1,17 +1,154 @@
-# git-version.go
+# [Go GitVer](https://git.rootprojects.org/root/go-gitver)
 
-Use git tags to add semver to your go package.
+Use **git tags** to add (GoReleaser-compatible) [**semver**](https://semver.org/)
+to your go package in under 150
+[lines of code](https://git.rootprojects.org/root/go-gitver/src/branch/master/gitver/gitver.go).
 
->     Goal: Either use an exact version like v1.0.0
+```txt
->           or translate the git version like v1.0.0-4-g0000000
+Goals:
->           to a semver like v1.0.1-pre4+g0000000
+
->
+      1. Use an exact `git tag` version, like v1.0.0, when clean
->           Fail gracefully when git repo isn't available.
+      2. Translate the `git describe` version  (v1.0.0-4-g0000000)
+	     to semver (1.0.1-pre4+g0000000) in between releases
+      3. Note when `dirty` (and have build timestamp)
+
+      Fail gracefully when git repo isn't available.
+```
+
+# GoDoc
+
+See <https://pkg.go.dev/git.rootprojects.org/root/go-gitver/v2>.
+
+# How it works
+
+1. You define the fallback version and version printing in `main.go`:
+
+```go
+//go:generate go run git.rootprojects.org/root/go-gitver/v2
+
+package main
+
+import (
+	"fmt"
+	"strings"
+)
+
+var (
+	commit  = "0000000"
+	version = "0.0.0-pre0+0000000"
+	date    = "0000-00-00T00:00:00+0000"
+)
+
+func main() {
+	if (len(os.Args) > 1 && "version" == strings.TrimLeft(os.Args[1], "-")) {
+		fmt.Printf("Foobar v%s (%s) %s\n", version, commit[:7], date)
+	}
+	// ...
+}
+```
+
+2. You `go generate` or `go run git.rootprojects.org/root/go-gitver/v2` to generate `xversion.go`:
+
+```go
+package main
+
+func init() {
+    commit  = "0921ed1e"
+    version = "1.1.2"
+    date    = "2019-07-01T02:32:58-06:00"
+}
+```
 
 # Demo
 
+Generate an `xversion.go` file:
+
 ```bash
-go run git.rootprojects.org/root/go-gitver
+go run git.rootprojects.org/root/go-gitver/v2
+cat xversion.go
+```
+
+```go
+// Code generated by go generate; DO NOT EDIT.
+package main
+
+func init() {
+	commit  = "6dace8255b52e123297a44629bc32c015add310a"
+	version = "1.1.4-pre2+g6dace82"
+	date    = "2020-07-16T20:48:15-06:00"
+}
+```
+
+<small>**Note**: The file is named `xversion.go` by default so that the
+generated file's `init()` will come later, and thus take priority, over
+most other files.</small>
+
+See `go-gitver`s self-generated version:
+
+```bash
+go run git.rootprojects.org/root/go-gitver/v2 version
+```
+
+```txt
+6dace8255b52e123297a44629bc32c015add310a
+v1.1.4-pre2+g6dace82
+2020-07-16T20:48:15-06:00
+```
+
+# QuickStart
+
+Add this to the top of your main file, so that it runs with `go generate`:
+
+```go
+//go:generate go run -mod=vendor git.rootprojects.org/root/go-gitver/v2
+
+```
+
+Add a file that imports go-gitver (for versioning)
+
+```go
+// +build tools
+
+package example
+
+import _ "git.rootprojects.org/root/go-gitver/v2"
+```
+
+Change you build instructions to be something like this:
+
+```bash
+go mod vendor
+go generate -mod=vendor ./...
+go build -mod=vendor -o example cmd/example/*.go
+```
+
+You don't have to use `-mod=vendor`, but I highly recommend it (just `go mod tidy; go mod vendor` to start).
+
+# Options
+
+```txt
+version           print version and exit
+--fail            exit with non-zero status code on failure
+--package <name>  will set the package name
+--outfile <name>  will replace `xversion.go` with the given file path
+```
+
+ENVs
+
+```bash
+# Alias for --fail
+GITVER_FAIL=true
+```
+
+For example:
+
+```go
+//go:generate go run -mod=vendor git.rootprojects.org/root/go-gitver/v2 --fail
+
+```
+
+```bash
+go run -mod=vendor git.rootprojects.org/root/go-gitver/v2 version
 ```
 
 # Usage
@@ -19,47 +156,65 @@ go run git.rootprojects.org/root/go-gitver
 See `examples/basic`
 
 1. Create a `tools` package in your project
-2. Guard it against regular builds with `// build +tools`
+2. Guard it against regular builds with `// +build tools`
-3. Include `_ "git.rootprojects.org/root/go-gitver"` in the imports
+3. Include `_ "git.rootprojects.org/root/go-gitver/v2"` in the imports
-4. Declare `var GitRev, GitVersion, GitTimestamp string` in your `package main`
+4. Declare `var commit, version, date string` in your `package main`
-5. Include `//go:generate go run -mod=vendor git.rootprojects.org/root/go-gitver` as well
+5. Include `//go:generate go run -mod=vendor git.rootprojects.org/root/go-gitver/v2` as well
 
 `tools/tools.go`:
 
 ```go
-// build +tools
+// +build tools
 
 // This is a dummy package for build tooling
 package tools
 
 import (
-  _ "git.rootprojects.org/root/go-gitver"
+	_ "git.rootprojects.org/root/go-gitver/v2"
 )
 ```
 
 `main.go`:
 
 ```go
-//go:generate go run -mod=vendor git.rootprojects.org/root/go-gitver
+//go:generate go run git.rootprojects.org/root/go-gitver/v2 --fail
 
 package main
 
 import "fmt"
 
 var (
-  GitRev = "0000000"
+	commit  = "0000000"
-  GitVersion = "v0.0.0-pre0+g0000000"
+	version = "0.0.0-pre0+0000000"
-  GitTimestamp = "0000-00-00T00:00:00+0000"
+	date    = "0000-00-00T00:00:00+0000"
 )
 
 func main() {
-  fmt.Println(GitRev)
+  fmt.Println(commit)
-  fmt.Println(GitVersion)
+  fmt.Println(version)
-  fmt.Println(GitTimestamp)
+  fmt.Println(date)
 }
 ```
 
-# Behind the curtain
+If you're using `go mod vendor` (which I highly recommend that you do),
+you'd modify the `go:generate` ever so slightly:
+
+```go
+//go:generate go run -mod=vendor git.rootprojects.org/root/go-gitver/v2 --fail
+```
+
+The only reason I didn't do that in the example is that I'd be included
+the repository in itself and that would be... weird.
+
+# Why a tools package?
+
+> import "git.rootprojects.org/root/go-gitver/v2" is a program, not an importable package
+
+Having a tools package with a build tag that you don't use is a nice way to add exact
+versions of a command package used for tooling to your `go.mod` with `go mod tidy`,
+without getting the error above.
+
+# git: behind the curtain
 
 These are the commands that are used under the hood to produce the versions.
 
@@ -87,3 +242,20 @@ Shows the most recent commit.
 git rev-parse HEAD
 # 0000000000000000000000000000000000000000
 ```
+
+# Errors
+
+### cannot find package "."
+
+```txt
+package git.rootprojects.org/root/go-gitver/v2: cannot find package "." in:
+	/Users/me/go-example/vendor/git.rootprojects.org/root/go-gitver/v2
+cmd/example/example.go:1: running "go": exit status 1
+```
+
+You forgot to update deps and re-vendor:
+
+```bash
+go mod tidy
+go mod vendor
+```

examples/basic/README.md

@@ -0,0 +1,32 @@
+# Example
+
+Prints the version or a nice message
+
+# Build
+
+Typically the developer would perform these steps
+and then commit the results (`go.mod`, `go.sum`, `vendor`).
+
+However, since this is an example within the project directory,
+that seemed a little redundant.
+
+```bash
+go mod tidy
+go mod vendor
+```
+
+These are the instructions that someone cloning the repo might use.
+
+```bash
+go generate -mod=vendor ./...
+go build -mod=vendor -o hello *.go
+./hello
+./hello --version
+```
+
+Note: If the source is distributed in a non-git tarball then
+`version-generated.go` will not be output, and whatever
+version info is in `package main` will remain as-is.
+
+If you would prefer the build process to fail (i.e. in a CI/CD pipeline),
+you can set the environment variable `GITVER_FAIL=true`.

examples/basic/go.mod

@@ -0,0 +1,5 @@
+module example.com/hello
+
+go 1.12
+
+require git.rootprojects.org/root/go-gitver/v2 v2.0.2

examples/basic/main.go

@@ -1,17 +1,28 @@
-//go:generate go run -mod=vendor git.rootprojects.org/root/go-gitver
+//go:generate go run -mod=vendor git.rootprojects.org/root/go-gitver/v2 --fail
 
 package main
 
-import "fmt"
+import (
+	"flag"
+	"fmt"
+)
 
 var (
-	GitRev       = "0000000"
+	commit  = "0000000"
-	GitVersion   = "v0.0.0-pre0+0000000"
+	version = "0.0.0-pre0+0000000"
-	GitTimestamp = "0000-00-00T00:00:00+0000"
+	date    = "0000-00-00T00:00:00+0000"
 )
 
 func main() {
-	fmt.Println(GitRev)
+	showVersion := flag.Bool("version", false, "Print version and exit")
-	fmt.Println(GitVersion)
+	flag.Parse()
-	fmt.Println(GitTimestamp)
+
+	if *showVersion {
+		fmt.Println(commit)
+		fmt.Println(version)
+		fmt.Println(date)
+		return
+	}
+
+	fmt.Println("Hello, World!")
 }

examples/basic/tools/tools.go

@@ -1,8 +1,8 @@
-// build +tools
+// +build tools
 
 // This is a dummy package for build tooling
 package tools
 
 import (
-	_ "git.rootprojects.org/root/go-gitver"
+	_ "git.rootprojects.org/root/go-gitver/v2"
 )

examples/no-tools/README.md

@@ -0,0 +1,25 @@
+# Example
+
+Prints the version or a nice message
+
+# Doesn't have a separate tools package
+
+This is just like `examples/basic`,
+but it uses a normal file with a build tag
+rather than a tools package.
+
+See `examples/basic` for more details.
+
+# Demo
+
+```bash
+go mod tidy
+go mod vendor
+```
+
+```bash
+go generate -mod=vendor ./...
+go build -mod=vendor -o hello *.go
+./hello
+./hello --version
+```

examples/no-tools/go.mod

@@ -0,0 +1,5 @@
+module example.com/hello
+
+go 1.12
+
+require git.rootprojects.org/root/go-gitver/v2 v2.0.2

examples/no-tools/main.go

@@ -0,0 +1,28 @@
+//go:generate go run -mod=vendor git.rootprojects.org/root/go-gitver/v2 --fail
+
+package main
+
+import (
+	"flag"
+	"fmt"
+)
+
+var (
+	commit  = "0000000"
+	version = "0.0.0-pre0+0000000"
+	date    = "0000-00-00T00:00:00+0000"
+)
+
+func main() {
+	showVersion := flag.Bool("version", false, "Print version and exit")
+	flag.Parse()
+
+	if *showVersion {
+		fmt.Println(commit)
+		fmt.Println(version)
+		fmt.Println(date)
+		return
+	}
+
+	fmt.Println("Hello, World!")
+}

examples/no-tools/tools.go

@@ -0,0 +1,6 @@
+// +build tools
+
+// This is a dummy file for build tooling
+package main
+
+import _ "git.rootprojects.org/root/go-gitver/v2"

examples/special-name/README.md

@@ -0,0 +1,24 @@
+# Example
+
+Prints the version or a nice message
+
+# Doesn't have a separate tools package
+
+This is just like `examples/sub-package` except that its `//go:generate` is in `main.go`
+and it outputs `./version/zversion.go` instead of `xversion.go`.
+
+See `examples/basic` for more details.
+
+# Demo
+
+```bash
+go mod tidy
+go mod vendor
+```
+
+```bash
+go generate -mod=vendor ./...
+go build -mod=vendor -o hello *.go
+./hello
+./hello --version
+```

examples/special-name/go.mod

@@ -0,0 +1,5 @@
+module example.com/hello
+
+go 1.12
+
+require git.rootprojects.org/root/go-gitver/v2 v2.0.2

examples/special-name/main.go

@@ -0,0 +1,24 @@
+//go:generate go run -mod=vendor git.rootprojects.org/root/go-gitver/v2 --package version --outfile ./version/zversion.go
+
+package main
+
+import (
+	"flag"
+	"fmt"
+
+	"example.com/hello/version"
+)
+
+func main() {
+	showVersion := flag.Bool("version", false, "Print version and exit")
+	flag.Parse()
+
+	if *showVersion {
+		fmt.Println(version.Commit())
+		fmt.Println(version.Version())
+		fmt.Println(version.Date())
+		return
+	}
+
+	fmt.Println("Hello, World!")
+}

examples/special-name/tools/tools.go

@@ -0,0 +1,8 @@
+// +build tools
+
+// This is a dummy package for build tooling
+package tools
+
+import (
+	_ "git.rootprojects.org/root/go-gitver/v2"
+)

examples/special-name/version/version.go

@@ -0,0 +1,22 @@
+package version
+
+var (
+	commit  = "0000000"
+	version = "0.0.0-pre0+0000000"
+	date    = "0000-00-00T00:00:00+0000"
+)
+
+// Commit returns the git commit reference
+func Commit() string {
+	return commit
+}
+
+// Version returns the git version, without the leading 'v'
+func Version() string {
+	return version
+}
+
+// Date returns the ISO-formatted date string
+func Date() string {
+	return date
+}

examples/sub-package/README.md

@@ -0,0 +1,24 @@
+# Example
+
+Prints the version or a nice message
+
+# Put version in its own packge
+
+This is just like `examples/basic`,
+but it uses the package name `version` instead of `main`.
+
+See `examples/basic` for more details.
+
+# Demo
+
+```bash
+go mod tidy
+go mod vendor
+```
+
+```bash
+go generate -mod=vendor ./...
+go build -mod=vendor -o hello *.go
+./hello
+./hello --version
+```

examples/sub-package/go.mod

@@ -0,0 +1,5 @@
+module example.com/hello
+
+go 1.12
+
+require git.rootprojects.org/root/go-gitver/v2 v2.0.2

examples/sub-package/main.go

@@ -0,0 +1,22 @@
+package main
+
+import (
+	"flag"
+	"fmt"
+
+	"example.com/hello/version"
+)
+
+func main() {
+	showVersion := flag.Bool("version", false, "Print version and exit")
+	flag.Parse()
+
+	if *showVersion {
+		fmt.Println(version.Commit())
+		fmt.Println(version.Version())
+		fmt.Println(version.Date())
+		return
+	}
+
+	fmt.Println("Hello, World!")
+}

examples/sub-package/tools/tools.go

@@ -0,0 +1,8 @@
+// +build tools
+
+// This is a dummy package for build tooling
+package tools
+
+import (
+	_ "git.rootprojects.org/root/go-gitver/v2"
+)

examples/sub-package/version/version.go

@@ -0,0 +1,24 @@
+//go:generate go run -mod=vendor git.rootprojects.org/root/go-gitver/v2 --package version
+
+package version
+
+var (
+	commit  = "0000000"
+	version = "0.0.0-pre0+0000000"
+	date    = "0000-00-00T00:00:00+0000"
+)
+
+// Commit returns the git commit reference
+func Commit() string {
+	return commit
+}
+
+// Version returns the git version, without the leading 'v'
+func Version() string {
+	return version
+}
+
+// Date returns the ISO-formatted date string
+func Date() string {
+	return date
+}

gitver.go

@@ -1,78 +1,71 @@
+//go:generate go run -mod=vendor git.rootprojects.org/root/go-gitver/v2
+
 package main
 
 import (
 	"bytes"
 	"fmt"
 	"go/format"
-	"log"
 	"os"
-	"os/exec"
-	"regexp"
-	"strconv"
-	"strings"
 	"text/template"
 	"time"
+
+	"git.rootprojects.org/root/go-gitver/v2/gitver"
 )
 
+var commit, version, date string
 var exitCode int
-var exactVer *regexp.Regexp
+var verFile = "xversion.go"
-var gitVer *regexp.Regexp
-var verFile = "generated-version.go"
-
-var (
-	GitRev       = "0000000"
-	GitVersion   = "v0.0.0-pre0+g0000000"
-	GitTimestamp = "0000-00-00T00:00:00+0000"
-)
-
-func init() {
-	// exactly vX.Y.Z (go-compatible semver)
-	exactVer = regexp.MustCompile(`^v\d+\.\d+\.\d+$`)
-
-	// vX.Y.Z-n-g0000000 git post-release, semver prerelease
-	// vX.Y.Z-dirty git post-release, semver prerelease
-	gitVer = regexp.MustCompile(`^(v\d+\.\d+)\.(\d+)(-(\d+))?(-(g[0-9a-f]+))?(-(dirty))?`)
-}
 
 func main() {
+	pkg := "main"
+
 	args := os.Args[1:]
 	for i := range args {
 		arg := args[i]
 		if "-f" == arg || "--fail" == arg {
 			exitCode = 1
+		} else if ("--outfile" == arg || "-o" == arg) && len(args) > i+1 {
+			verFile = args[i+1]
+			args[i+1] = ""
+		} else if "--package" == arg && len(args) > i+1 {
+			pkg = args[i+1]
+			args[i+1] = ""
 		} else if "-V" == arg || "version" == arg || "-version" == arg || "--version" == arg {
-			fmt.Println(GitRev)
+			fmt.Println(commit)
-			fmt.Println(GitVersion)
+			fmt.Println(version)
-			fmt.Println(GitTimestamp)
+			fmt.Println(date)
 			os.Exit(0)
 		}
 	}
+	if "" != os.Getenv("GITVER_FAIL") && "false" != os.Getenv("GITVER_FAIL") {
+		exitCode = 1
+	}
 
-	desc, err := gitDesc()
+	v, err := gitver.ExecAndParse()
 	if nil != err {
-		log.Fatalf("Failed to get git version: %s\n", err)
+		fmt.Fprintf(os.Stderr, "Failed to get git version: %s\n", err)
+		if exitCode > 0 {
 			os.Exit(exitCode)
 		}
-	rev := gitRev()
+		v = &gitver.Versions{
-	ver := semVer(desc)
+			Timestamp: time.Now(),
-	ts, err := gitTimestamp(desc)
-	if nil != err {
-		ts = time.Now()
 		}
-
-	v := struct {
-		Timestamp string
-		Version   string
-		GitRev    string
-	}{
-		Timestamp: ts.Format(time.RFC3339),
-		Version:   ver,
-		GitRev:    rev,
 	}
 
 	// Create or overwrite the go file from template
 	var buf bytes.Buffer
-	if err := versionTpl.Execute(&buf, v); nil != err {
+	if err := versionTpl.Execute(&buf, struct {
+		Package   string
+		Timestamp string
+		Version   string
+		Commit    string
+	}{
+		Package:   pkg,
+		Timestamp: v.Timestamp.Format(time.RFC3339),
+		Version:   v.Version,
+		Commit:    v.Rev,
+	}); nil != err {
 		panic(err)
 	}
 
@@ -93,92 +86,19 @@ func main() {
 	if err := f.Close(); nil != err {
 		panic(err)
 	}
-}
 
-func gitDesc() (string, error) {
-	args := strings.Split("git describe --tags --dirty --always", " ")
-	cmd := exec.Command(args[0], args[1:]...)
-	out, err := cmd.CombinedOutput()
-	if nil != err {
-		// Don't panic, just carry on
-		//out = []byte("v0.0.0-0-g0000000")
-		return "", err
-	}
-	return strings.TrimSpace(string(out)), nil
-}
-
-func gitRev() string {
-	args := strings.Split("git rev-parse HEAD", " ")
-	cmd := exec.Command(args[0], args[1:]...)
-	out, err := cmd.CombinedOutput()
-	if nil != err {
-		fmt.Fprintf(os.Stderr,
-			"\nUnexpected Error\n\n"+
-				"Please open an issue at https://git.rootprojects.org/root/go-gitver/issues/new \n"+
-				"Please include the following:\n\n"+
-				"Command: %s\n"+
-				"Output: %s\n"+
-				"Error: %s\n"+
-				"\nPlease and Thank You.\n\n", strings.Join(args, " "), out, err)
-		os.Exit(exitCode)
-	}
-	return strings.TrimSpace(string(out))
-}
-
-func semVer(desc string) string {
-	var ver string
-	if exactVer.MatchString(desc) {
-		// v1.0.0
-		ver = desc
-	} else if gitVer.MatchString(desc) {
-		// ((v1.0).(0)-(1))
-		vers := gitVer.FindStringSubmatch(desc)
-		patch, err := strconv.Atoi(vers[2])
-		if nil != err {
-			fmt.Fprintf(os.Stderr,
-				"\nUnexpected Error\n\n"+
-					"Please open an issue at https://git.rootprojects.org/root/go-gitver/issues/new \n"+
-					"Please include the following:\n\n"+
-					"git description: %s\n"+
-					"RegExp: %#v\n"+
-					"Error: %s\n"+
-					"\nPlease and Thank You.\n\n", desc, gitVer, err)
-			os.Exit(exitCode)
-		}
-		// v1.0.1-pre1
-		ver = fmt.Sprintf("%s.%d-pre%s", vers[1], patch+1, vers[4])
-		fmt.Println(desc, vers)
-		if "dirty" == vers[8] {
-			//if strings.Contains(desc, "dirty") {
-			ver += "+dirty"
-		}
-	}
-	return ver
-}
-
-func gitTimestamp(desc string) (time.Time, error) {
-	args := []string{
-		"git",
-		"show", desc,
-		"--format=%cd",
-		"--date=format:%Y-%m-%dT%H:%M:%SZ%z",
-		"--no-patch",
-	}
-	cmd := exec.Command(args[0], args[1:]...)
-	out, err := cmd.CombinedOutput()
-	if nil != err {
-		// a dirty desc was probably used
-		return time.Time{}, err
-	}
-	return time.Parse(time.RFC3339, strings.TrimSpace(string(out)))
 }
 
 var versionTpl = template.Must(template.New("").Parse(`// Code generated by go generate; DO NOT EDIT.
-package main
+package {{ .Package }}
 
 func init() {
-	GitRev = "{{ .GitRev }}"
+	{{ if .Commit -}}
-	GitVersion = "{{ .Version }}"
+	commit = "{{ .Commit }}"
-	GitTimestamp = "{{ .Timestamp }}"
+	{{ end -}}
+	{{ if .Version -}}
+	version = "{{ .Version }}"
+	{{ end -}}
+	date = "{{ .Timestamp }}"
 }
 `))

gitver/gitver.go

@@ -0,0 +1,154 @@
+package gitver
+
+import (
+	"fmt"
+	"os/exec"
+	"regexp"
+	"strconv"
+	"strings"
+	"time"
+)
+
+var exactVer *regexp.Regexp
+var gitVer *regexp.Regexp
+
+func init() {
+	// exactly vX.Y.Z (go-compatible semver)
+	exactVer = regexp.MustCompile(`^v\d+\.\d+\.\d+$`)
+
+	// vX.Y.Z-n-g0000000 git post-release, semver prerelease
+	// vX.Y.Z-dirty git post-release, semver prerelease
+	gitVer = regexp.MustCompile(`^(v\d+\.\d+)\.(\d+)(-(\d+))?(-(g[0-9a-f]+))?(-(dirty))?`)
+}
+
+// Versions describes the various version properties
+type Versions struct {
+	Timestamp time.Time
+	Version   string
+	Rev       string
+}
+
+// ExecAndParse will run git and parse the output
+func ExecAndParse() (*Versions, error) {
+	desc, err := gitDesc()
+	if nil != err {
+		return nil, err
+	}
+	rev, err := gitRev()
+	if nil != err {
+		return nil, err
+	}
+	ver, err := semVer(desc)
+	if nil != err {
+		return nil, err
+	}
+	ts, err := gitTimestamp(desc)
+	if nil != err {
+		ts = time.Now()
+	}
+
+	return &Versions{
+		Timestamp: ts,
+		Version:   ver,
+		Rev:       rev,
+	}, nil
+}
+
+func gitDesc() (string, error) {
+	args := strings.Split("git describe --tags --dirty --always", " ")
+	cmd := exec.Command(args[0], args[1:]...)
+	out, err := cmd.CombinedOutput()
+	if nil != err {
+		// Don't panic, just carry on
+		//out = []byte("0.0.0-0-g0000000")
+		return "", err
+	}
+	return strings.TrimSpace(string(out)), nil
+}
+
+func gitRev() (string, error) {
+	args := strings.Split("git rev-parse HEAD", " ")
+	cmd := exec.Command(args[0], args[1:]...)
+	out, err := cmd.CombinedOutput()
+	if nil != err {
+		return "", fmt.Errorf("\nUnexpected Error\n\n"+
+			"Please open an issue at https://git.rootprojects.org/root/go-gitver/issues/new \n"+
+			"Please include the following:\n\n"+
+			"Command: %s\n"+
+			"Output: %s\n"+
+			"Error: %s\n"+
+			"\nPlease and Thank You.\n\n", strings.Join(args, " "), out, err)
+	}
+	return strings.TrimSpace(string(out)), nil
+}
+
+func semVer(desc string) (string, error) {
+	if exactVer.MatchString(desc) {
+		// v1.0.0
+		return strings.TrimPrefix(desc, "v"), nil
+	}
+
+	if !gitVer.MatchString(desc) {
+		return "", nil
+	}
+
+	// (v1.0).(0)(-(1))(-(g0000000))(-(dirty))
+	vers := gitVer.FindStringSubmatch(desc)
+	patch, err := strconv.Atoi(vers[2])
+	if nil != err {
+		return "", fmt.Errorf("\nUnexpected Error\n\n"+
+			"Please open an issue at https://git.rootprojects.org/root/go-gitver/issues/new \n"+
+			"Please include the following:\n\n"+
+			"git description: %s\n"+
+			"RegExp: %#v\n"+
+			"Error: %s\n"+
+			"\nPlease and Thank You.\n\n", desc, gitVer, err)
+	}
+
+	// v1.0.1-pre1
+	// v1.0.1-pre1+g0000000
+	// v1.0.1-pre0+dirty
+	// v1.0.1-pre0+g0000000-dirty
+	if "" == vers[4] {
+		vers[4] = "0"
+	}
+	ver := fmt.Sprintf("%s.%d-pre%s", vers[1], patch+1, vers[4])
+	if "" != vers[6] || "dirty" == vers[8] {
+		ver += "+"
+		if "" != vers[6] {
+			ver += vers[6]
+			if "" != vers[8] {
+				ver += "-"
+			}
+		}
+		ver += vers[8]
+	}
+
+	return strings.TrimPrefix(ver, "v"), nil
+}
+
+func gitTimestamp(desc string) (time.Time, error) {
+	// Other options:
+	//
+	// Commit Date
+	//	git log -1 --format=%cd --date=format:%Y-%m-%dT%H:%M:%SZ%z
+	//
+	// Author Date
+	// git log -1 --format=%ad --date=format:%Y-%m-%dT%H:%M:%SZ%z
+	//
+	// I think I chose this because it would account for dirty-ness better... maybe?
+	args := []string{
+		"git",
+		"show", desc,
+		"--format=%cd",
+		"--date=format:%Y-%m-%dT%H:%M:%SZ%z",
+		"--no-patch",
+	}
+	cmd := exec.Command(args[0], args[1:]...)
+	out, err := cmd.CombinedOutput()
+	if nil != err {
+		// a dirty desc was probably used
+		return time.Time{}, err
+	}
+	return time.Parse(time.RFC3339, strings.TrimSpace(string(out)))
+}

go.mod

@@ -0,0 +1,3 @@
+module git.rootprojects.org/root/go-gitver/v2
+
+go 1.12

version.go

@@ -0,0 +1,9 @@
+package main
+
+// use recently generated version info as a fallback
+// for when git isn't present (i.e. go run <url>)
+func init() {
+	commit = "37c1fd4b5694fd62c9f0d6ad1df47d938accbeec"
+	version = "2.0.0-pre1-dirty"
+	date = "2020-10-10T16:05:59-06:00"
+}