From 328284fb34e86ab076c5c1061252fc6975bc76f9 Mon Sep 17 00:00:00 2001
From: Tim Culverhouse <tim@timculverhouse.com>
Date: Tue, 6 May 2025 08:36:16 -0500
Subject: [PATCH] add version info

---
 build.zig     | 37 +++++++++++++++++++++++++++++++++++++
 build.zig.zon |  2 +-
 src/main.zig  |  5 +++++
 3 files changed, 43 insertions(+), 1 deletion(-)

diff --git a/build.zig b/build.zig
index 185e9c4..8a5ea7b 100644
--- a/build.zig
+++ b/build.zig
@@ -1,5 +1,8 @@
 const std = @import("std");
 
+/// Must be kept in sync with git tags
+const version: std.SemanticVersion = .{ .major = 0, .minor = 0, .patch = 0 };
+
 pub fn build(b: *std.Build) void {
     const target = b.standardTargetOptions(.{});
     const optimize = b.standardOptimizeOption(.{});
@@ -18,6 +21,15 @@ pub fn build(b: *std.Build) void {
     const zeit_mod = zeit_dep.module("zeit");
     exe_mod.addImport("zeit", zeit_mod);
 
+    const opts = b.addOptions();
+    const version_string = genVersion(b) catch |err| {
+        std.debug.print("{}", .{err});
+        @compileError("couldn't get version");
+    };
+    opts.addOption([]const u8, "version", version_string);
+
+    exe_mod.addOptions("build_options", opts);
+
     const exe = b.addExecutable(.{
         .name = "lsr",
         .root_module = exe_mod,
@@ -45,3 +57,28 @@ pub fn build(b: *std.Build) void {
     const test_step = b.step("test", "Run unit tests");
     test_step.dependOn(&run_exe_unit_tests.step);
 }
+
+fn genVersion(b: *std.Build) ![]const u8 {
+    if (!std.process.can_spawn) {
+        std.debug.print("error: version info cannot be retrieved from git. Zig version must be provided using -Dversion-string\n", .{});
+        std.process.exit(1);
+    }
+    const version_string = b.fmt("v{d}.{d}.{d}", .{ version.major, version.minor, version.patch });
+
+    var code: u8 = undefined;
+    const git_describe_untrimmed = b.runAllowFail(&[_][]const u8{
+        "git",
+        "-C",
+        b.build_root.path orelse ".",
+        "describe",
+        "--tags",
+        "--abbrev=9",
+    }, &code, .Ignore) catch {
+        return version_string;
+    };
+    if (!std.mem.startsWith(u8, git_describe_untrimmed, version_string)) {
+        std.debug.print("error: tagged version does not match internal version\n", .{});
+        std.process.exit(1);
+    }
+    return std.mem.trim(u8, git_describe_untrimmed, " \n\r");
+}
diff --git a/build.zig.zon b/build.zig.zon
index f1b21fa..9559aa0 100644
--- a/build.zig.zon
+++ b/build.zig.zon
@@ -1,6 +1,6 @@
 .{
     .name = .lsr,
-    .version = "0.0.0",
+    .version = "0.1.0",
     .fingerprint = 0x495d173f6002e86, // Changing this has security and trust implications.
 
     .minimum_zig_version = "0.14.0",
diff --git a/src/main.zig b/src/main.zig
index 02f788d..b8eec25 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -2,6 +2,7 @@ const std = @import("std");
 const builtin = @import("builtin");
 const ourio = @import("ourio");
 const zeit = @import("zeit");
+const build_options = @import("build_options");
 
 const posix = std.posix;
 
@@ -200,6 +201,10 @@ pub fn main() !void {
                     cmd.opts.shortview = if (o) .oneline else .columns;
                 } else if (eql(opt, "help")) {
                     return stderr.writeAll(usage);
+                } else if (eql(opt, "version")) {
+                    try bw.writer().print("lsr {s}", .{build_options.version});
+                    try bw.flush();
+                    return;
                 } else {
                     try stderr.print("Invalid opt: '{s}'", .{opt});
                     std.process.exit(1);
-- 
2.51.2