version: support major.minor.patch tags without breaking Apple builds.

Signed-off-by: David Anderson <danderson@tailscale.com>

version/.gitignore

@@ -1,3 +1,4 @@
+describe.txt
 long.txt
 short.txt
 version.h

version/clean.do

@@ -1 +1 @@
-rm -f *~ .*~ long.txt short.txt version.xcconfig ver.go version.h version
+rm -f *~ .*~ describe.txt long.txt short.txt version.xcconfig ver.go version.h version

version/describe.txt.do

@@ -0,0 +1,4 @@
+describe=$(cd ../.. && git describe)
+echo "$describe" >$3
+redo-always
+redo-stamp <$3

version/long.txt.do

@@ -1,10 +1,4 @@
-ver=$(cd ../.. && git describe | sed 's/^v//')
-if [ "$ver" = "${ver%-*}" ]; then
-	# no sub-version. ie. it's 0.05 and not 0.05-341
-	# so add a sub-version.
-	ver=$ver-0
-fi
+redo-ifchange mkversion.sh describe.txt
+read -r describe <describe.txt
+ver=$(./mkversion.sh long "$describe")
 echo "$ver" >$3
-
-redo-always
-redo-stamp <$3

version/mkversion.sh

@@ -0,0 +1,93 @@
+#!/bin/sh
+
+set -eu
+
+mode=$1
+describe=$2
+
+long() {
+    ver="${describe#v}"
+    stem="${ver%%-*}"
+    case "$stem" in
+        *.*.*)
+            # Full SemVer, nothing to do.
+            semver="${stem}"
+        ;;
+        *.*)
+            # Old style major.minor, add a .0
+            semver="${stem}.0"
+            ;;
+        *)
+            echo "Unparseable version $stem" >&2
+            exit 1
+            ;;
+    esac
+    suffix="${ver#$stem}"
+    case "$suffix" in
+        -*-*)
+            # Has a change count in addition to the commit hash.
+        ;;
+        -*)
+            # Missing change count, add one.
+            suffix="-0${suffix}"
+            ;;
+        *)
+            echo "Unexpected version suffix" >&2
+            exit 1
+    esac
+    echo "${semver}${suffix}"
+}
+
+short() {
+    ver="$(long)"
+    case "$ver" in
+        *-*-*)
+            echo "${ver%-*}"
+            ;;
+        *-*)
+            echo "$ver"
+            ;;
+        *)
+            echo "Long version in invalid format" >&2
+            exit 1
+            ;;
+    esac
+}
+
+xcode() {
+    ver=$(short | sed -e 's/-/./')
+    major=$(echo "$ver" | cut -f1 -d.)
+    minor=$(echo "$ver" | cut -f2 -d.)
+    patch=$(echo "$ver" | cut -f3 -d.)
+    changecount=$(echo "$ver" | cut -f4 -d.)
+
+    # Apple version numbers must be major.minor.patch. We have 4 fields
+    # because we need major.minor.patch for go module compatibility, and
+    # changecount for automatic version numbering of unstable builds. To
+    # resolve this, for Apple builds, we combine changecount into patch:
+    patch=$((patch*10000 + changecount))
+
+    # CFBundleShortVersionString: the "short name" used in the App Store.
+    # eg. 0.92.98
+    echo "VERSION_NAME = $major.$minor.$patch"
+    # CFBundleVersion: the build number. Needs to be 3 numeric sections
+    # that increment for each release according to SemVer rules.
+    #
+    # We start counting at 100 because we submitted using raw build
+    # numbers before, and Apple doesn't let you start over.
+    # e.g. 0.98.3-123 -> 100.98.3123
+    major=$((major + 100))
+    echo "VERSION_ID = $major.$minor.$patch"
+}
+
+case "$mode" in
+    long)
+        long
+    ;;
+    short)
+        short
+    ;;
+    xcode)
+        xcode
+    ;;
+esac

version/mkversion_test.go

@@ -0,0 +1,57 @@
+// Copyright (c) 2020 Tailscale Inc & AUTHORS All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package version
+
+import (
+	"fmt"
+	"os/exec"
+	"strings"
+	"testing"
+)
+
+func xcode(short, long string) string {
+	return fmt.Sprintf("VERSION_NAME = %s\nVERSION_ID = %s", short, long)
+}
+
+func mkversion(t *testing.T, mode, in string) string {
+	t.Helper()
+	bs, err := exec.Command("./mkversion.sh", mode, in).CombinedOutput()
+	if err != nil {
+		t.Logf("mkversion.sh output: %s", string(bs))
+		t.Fatalf("mkversion.sh %s %s: %v", mode, in, err)
+	}
+	return strings.TrimSpace(string(bs))
+}
+
+func TestMkversion(t *testing.T) {
+	tests := []struct {
+		in    string
+		long  string
+		short string
+		xcode string
+	}{
+		{"v0.98-abcdef", "0.98.0-0-abcdef", "0.98.0-0", xcode("0.98.0", "100.98.0")},
+		{"v0.98-123-abcdef", "0.98.0-123-abcdef", "0.98.0-123", xcode("0.98.123", "100.98.123")},
+		{"v0.99.5-123-abcdef", "0.99.5-123-abcdef", "0.99.5-123", xcode("0.99.50123", "100.99.50123")},
+		{"v0.99.5-123-abcdef", "0.99.5-123-abcdef", "0.99.5-123", xcode("0.99.50123", "100.99.50123")},
+		{"v2.3-0-abcdef", "2.3.0-0-abcdef", "2.3.0-0", xcode("2.3.0", "102.3.0")},
+		{"1.2.3-4-abcdef", "1.2.3-4-abcdef", "1.2.3-4", xcode("1.2.30004", "101.2.30004")},
+	}
+
+	for _, test := range tests {
+		gotlong := mkversion(t, "long", test.in)
+		gotshort := mkversion(t, "short", test.in)
+		gotxcode := mkversion(t, "xcode", test.in)
+		if gotlong != test.long {
+			t.Errorf("mkversion.sh long %q: got %q, want %q", test.in, gotlong, test.long)
+		}
+		if gotshort != test.short {
+			t.Errorf("mkversion.sh short %q: got %q, want %q", test.in, gotshort, test.short)
+		}
+		if gotxcode != test.xcode {
+			t.Errorf("mkversion.sh xcode %q: got %q, want %q", test.in, gotxcode, test.xcode)
+		}
+	}
+}

version/short.txt.do

@@ -1,18 +1,4 @@
-redo-ifchange long.txt
-read -r LONGVER junk <long.txt
-
-# Convert a version like "0.92-98-g123456" into "0.92-98".
-# Sometimes the version is just "0.92-0", in which case we leave it as is.
-case $LONGVER in
-	*-*-*)
-		echo "${LONGVER%-*}" >$3
-		;;
-	*-*)
-		echo "$LONGVER" >$3
-		;;
-	*)
-		echo "Fatal: long version in invalid format." >&2
-		exit 44
-esac
-
-redo-stamp <$3
+redo-ifchange mkversion.sh describe.txt
+read -r describe <describe.txt
+ver=$(./mkversion.sh short "$describe")
+echo "$ver" >$3

version/version.xcconfig.do

@@ -1,17 +1,4 @@
-redo-ifchange short.txt
-read -r ver <short.txt
-
-# get it into "major.minor.patch" format
-ver=$(echo "$ver" | sed -e 's/-/./')
-
-# CFBundleShortVersionString: the "short name" used in the App Store.
-# eg. 0.92.98
-echo "VERSION_NAME = $ver" >$3
-# CFBundleVersion: the build number. Needs to increment each release.
-# start counting at 100 because we submitted using raw build numbers
-# before (and Apple doesn't let you start over).
-# eg. 100.92.98
-
-major=$((${ver%%.*} + 100))
-minor=${ver#*.}
-echo "VERSION_ID = $major.$minor" >>$3
+redo-ifchange mkversion.sh describe.txt
+read -r describe <describe.txt
+ver=$(./mkversion.sh xcode "$describe")
+echo "$ver" >$3