build: automate version resolution in build.zig

Removes manual git flags from CI and build scripts.
Versioning is now automatically derived from git and build.zig.zon.

With this PR, we follow https://semver.org/
Logic:

1. Read the version from build.zig.zon
2. If it doesn't have a `.pre` field (i.e. dev/alpha/beta) it will use that
3. Otherwise it will get the info from git: hash and number of commits since last `.0` version
4. Then build the version: `0.3.0-dev.1493+0896edc3`

Note that, since the latest stable version is `0.2.6`.
The convention is to use `0.3.0-dev`, as:
- `0.2.6` < `0.3.0.dev` < `0.3.0`

.github/workflows/e2e-integration-test.yml

@@ -27,7 +27,7 @@ jobs:
       - uses: ./.github/actions/install
 
       - name: zig build release
-        run: zig build -Dprebuilt_v8_path=v8/libc_v8.a -Doptimize=ReleaseFast -Dcpu=x86_64 -Dgit_commit=$(git rev-parse --short ${{ github.sha }})
+        run: zig build -Dprebuilt_v8_path=v8/libc_v8.a -Doptimize=ReleaseFast -Dcpu=x86_64
 
       - name: upload artifact
         uses: actions/upload-artifact@v7

.github/workflows/e2e-test.yml

@@ -52,7 +52,7 @@ jobs:
       - uses: ./.github/actions/install
 
       - name: zig build release
-        run: zig build -Dprebuilt_v8_path=v8/libc_v8.a -Doptimize=ReleaseFast -Dcpu=x86_64 -Dgit_commit=$(git rev-parse --short ${{ github.sha }})
+        run: zig build -Dprebuilt_v8_path=v8/libc_v8.a -Doptimize=ReleaseFast -Dcpu=x86_64
 
       - name: upload artifact
         uses: actions/upload-artifact@v7

.github/workflows/nightly.yml

@@ -7,7 +7,6 @@ env:
   AWS_REGION: ${{ vars.NIGHTLY_BUILD_AWS_REGION }}
 
   RELEASE: ${{ github.ref_type == 'tag' && github.ref_name || 'nightly' }}
-  GIT_VERSION_FLAG: ${{ github.ref_type == 'tag' && format('-Dgit_version={0}', github.ref_name) || '' }}
 
 on:
   push:
@@ -45,7 +44,7 @@ jobs:
         run: zig build -Dprebuilt_v8_path=v8/libc_v8.a -Doptimize=ReleaseFast snapshot_creator -- src/snapshot.bin
 
       - name: zig build
-        run: zig build -Dsnapshot_path=../../snapshot.bin -Dprebuilt_v8_path=v8/libc_v8.a -Doptimize=ReleaseFast -Dcpu=x86_64 -Dgit_commit=$(git rev-parse --short ${{ github.sha }}) ${{ env.GIT_VERSION_FLAG }}
+        run: zig build -Dsnapshot_path=../../snapshot.bin -Dprebuilt_v8_path=v8/libc_v8.a -Doptimize=ReleaseFast -Dcpu=x86_64
 
       - name: Rename binary
         run: mv zig-out/bin/lightpanda lightpanda-${{ env.ARCH }}-${{ env.OS }}
@@ -85,7 +84,7 @@ jobs:
         run: zig build -Dprebuilt_v8_path=v8/libc_v8.a -Doptimize=ReleaseFast snapshot_creator -- src/snapshot.bin
 
       - name: zig build
-        run: zig build -Dsnapshot_path=../../snapshot.bin -Dprebuilt_v8_path=v8/libc_v8.a -Doptimize=ReleaseFast -Dcpu=generic -Dgit_commit=$(git rev-parse --short ${{ github.sha }}) ${{ env.GIT_VERSION_FLAG }}
+        run: zig build -Dsnapshot_path=../../snapshot.bin -Dprebuilt_v8_path=v8/libc_v8.a -Doptimize=ReleaseFast -Dcpu=generic
 
       - name: Rename binary
         run: mv zig-out/bin/lightpanda lightpanda-${{ env.ARCH }}-${{ env.OS }}
@@ -127,7 +126,7 @@ jobs:
         run: zig build -Dprebuilt_v8_path=v8/libc_v8.a -Doptimize=ReleaseFast snapshot_creator -- src/snapshot.bin
 
       - name: zig build
-        run: zig build -Dsnapshot_path=../../snapshot.bin -Dprebuilt_v8_path=v8/libc_v8.a -Doptimize=ReleaseFast -Dgit_commit=$(git rev-parse --short ${{ github.sha }}) ${{ env.GIT_VERSION_FLAG }}
+        run: zig build -Dsnapshot_path=../../snapshot.bin -Dprebuilt_v8_path=v8/libc_v8.a -Doptimize=ReleaseFast
 
       - name: Rename binary
         run: mv zig-out/bin/lightpanda lightpanda-${{ env.ARCH }}-${{ env.OS }}
@@ -167,7 +166,7 @@ jobs:
         run: zig build -Dprebuilt_v8_path=v8/libc_v8.a -Doptimize=ReleaseFast snapshot_creator -- src/snapshot.bin
 
       - name: zig build
-        run: zig build -Dsnapshot_path=../../snapshot.bin -Dprebuilt_v8_path=v8/libc_v8.a -Doptimize=ReleaseFast -Dgit_commit=$(git rev-parse --short ${{ github.sha }}) ${{ env.GIT_VERSION_FLAG }}
+        run: zig build -Dsnapshot_path=../../snapshot.bin -Dprebuilt_v8_path=v8/libc_v8.a -Doptimize=ReleaseFast
 
       - name: Rename binary
         run: mv zig-out/bin/lightpanda lightpanda-${{ env.ARCH }}-${{ env.OS }}

.github/workflows/wpt.yml

@@ -30,7 +30,7 @@ jobs:
       - uses: ./.github/actions/install
 
       - name: zig build release
-        run: zig build -Dprebuilt_v8_path=v8/libc_v8.a -Doptimize=ReleaseFast -Dcpu=x86_64 -Dgit_commit=$(git rev-parse --short ${{ github.sha }})
+        run: zig build -Dprebuilt_v8_path=v8/libc_v8.a -Doptimize=ReleaseFast -Dcpu=x86_64
 
       - name: upload artifact
         uses: actions/upload-artifact@v7

Dockerfile

@@ -53,8 +53,7 @@ RUN zig build -Doptimize=ReleaseFast \
 # build release
 RUN zig build -Doptimize=ReleaseFast \
     -Dsnapshot_path=../../snapshot.bin \
-    -Dprebuilt_v8_path=v8/libc_v8.a \
-    -Dgit_commit=$(git rev-parse --short HEAD)
+    -Dprebuilt_v8_path=v8/libc_v8.a
 
 FROM debian:stable-slim
 

Makefile

@@ -58,13 +58,13 @@ build-v8-snapshot:
 ## Build in release-fast mode
 build: build-v8-snapshot
 	@printf "\033[36mBuilding (release fast)...\033[0m\n"
-	@$(ZIG) build -Doptimize=ReleaseFast -Dsnapshot_path=../../snapshot.bin -Dgit_commit=$$(git rev-parse --short HEAD) || (printf "\033[33mBuild ERROR\033[0m\n"; exit 1;)
+	@$(ZIG) build -Doptimize=ReleaseFast -Dsnapshot_path=../../snapshot.bin || (printf "\033[33mBuild ERROR\033[0m\n"; exit 1;)
 	@printf "\033[33mBuild OK\033[0m\n"
 
 ## Build in debug mode
 build-dev:
 	@printf "\033[36mBuilding (debug)...\033[0m\n"
-	@$(ZIG) build -Dgit_commit=$$(git rev-parse --short HEAD) || (printf "\033[33mBuild ERROR\033[0m\n"; exit 1;)
+	@$(ZIG) build || (printf "\033[33mBuild ERROR\033[0m\n"; exit 1;)
 	@printf "\033[33mBuild OK\033[0m\n"
 
 ## Run the server in release mode

build.zig

@@ -17,24 +17,37 @@
 // along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 const std = @import("std");
+const builtin = @import("builtin");
 
-const Build = std.Build;
+const lightpanda_version = std.SemanticVersion.parse(@import("build.zig.zon").version) catch unreachable;
+const min_zig_version = std.SemanticVersion.parse(@import("build.zig.zon").minimum_zig_version) catch unreachable;
+
+const Build = blk: {
+    if (builtin.zig_version.order(min_zig_version) == .lt) {
+        const message = std.fmt.comptimePrint(
+            \\Zig version is too old:
+            \\  current Zig version: {f}
+            \\  minimum Zig version: {f}
+        , .{ builtin.zig_version, min_zig_version });
+        @compileError(message);
+    } else {
+        break :blk std.Build;
+    }
+};
 
 pub fn build(b: *Build) !void {
     const target = b.standardTargetOptions(.{});
     const optimize = b.standardOptimizeOption(.{});
 
-    const manifest = Manifest.init(b);
-
-    const git_commit = b.option([]const u8, "git_commit", "Current git commit");
-    const git_version = b.option([]const u8, "git_version", "Current git version (from tag)");
     const prebuilt_v8_path = b.option([]const u8, "prebuilt_v8_path", "Path to prebuilt libc_v8.a");
     const snapshot_path = b.option([]const u8, "snapshot_path", "Path to v8 snapshot");
 
+    const version = resolveVersion(b);
+    var stdout = std.fs.File.stdout().writer(&.{});
+    try stdout.interface.print("Lightpanda {f}\n", .{version});
+
     var opts = b.addOptions();
-    opts.addOption([]const u8, "version", manifest.version);
-    opts.addOption([]const u8, "git_commit", git_commit orelse "dev");
-    opts.addOption(?[]const u8, "git_version", git_version orelse null);
+    opts.addOption([]const u8, "version", b.fmt("{f}", .{version}));
     opts.addOption(?[]const u8, "snapshot_path", snapshot_path);
 
     const enable_tsan = b.option(bool, "tsan", "Enable Thread Sanitizer") orelse false;
@@ -96,6 +109,11 @@ pub fn build(b: *Build) !void {
         }
         const run_step = b.step("run", "Run the app");
         run_step.dependOn(&run_cmd.step);
+
+        const version_info_step = b.step("version", "Print the resolved version information");
+        const version_info_run = b.addRunArtifact(exe);
+        version_info_run.addArg("version");
+        version_info_step.dependOn(&version_info_run.step);
     }
 
     {
@@ -701,27 +719,56 @@ fn buildCurl(
     return lib;
 }
 
-const Manifest = struct {
-    version: []const u8,
-    minimum_zig_version: []const u8,
-
-    fn init(b: *std.Build) Manifest {
-        const input = @embedFile("build.zig.zon");
-
-        var diagnostics: std.zon.parse.Diagnostics = .{};
-        defer diagnostics.deinit(b.allocator);
-
-        return std.zon.parse.fromSlice(Manifest, b.allocator, input, &diagnostics, .{
-            .free_on_error = true,
-            .ignore_unknown_fields = true,
-        }) catch |err| {
-            switch (err) {
-                error.OutOfMemory => @panic("OOM"),
-                error.ParseZon => {
-                    std.debug.print("Parse diagnostics:\n{f}\n", .{diagnostics});
-                    std.process.exit(1);
-                },
-            }
+/// Returns `MAJOR.MINOR.PATCH-dev` when `git describe` fails.
+fn resolveVersion(b: *std.Build) std.SemanticVersion {
+    const version_string = b.option([]const u8, "version_string", "Override the version of this build");
+    if (version_string) |semver_string| {
+        return std.SemanticVersion.parse(semver_string) catch |err| {
+            std.debug.panic("Expected -Dversion-string={s} to be a semantic version: {}", .{ semver_string, err });
         };
     }
-};
+
+    if (lightpanda_version.pre == null and lightpanda_version.build == null) return lightpanda_version;
+    // Check if we're exactly on a tagged release
+    _ = runGit(b, &.{ "describe", "--tags", "--exact-match" }) catch {
+        // Not on a tag, need to create a dev version
+        const git_hash_raw = runGit(b, &.{ "rev-parse", "--short", "HEAD" }) catch return lightpanda_version;
+        const commit_hash = std.mem.trim(u8, git_hash_raw, " \n\r");
+        // Get the commit count - either from base tag or total
+        const commit_count = blk: {
+            // Try to find the most recent base version tag (ending with .0)
+            const base_tag_raw = runGit(b, &.{ "describe", "--tags", "--match=*.0", "--abbrev=0" }) catch {
+                // No .0 tags found, fall back to total commit count
+                const git_count_raw = runGit(b, &.{ "rev-list", "--count", "HEAD" }) catch return lightpanda_version;
+                break :blk std.mem.trim(u8, git_count_raw, " \n\r");
+            };
+
+            const base_tag = std.mem.trim(u8, base_tag_raw, " \n\r");
+            // Count commits since the base tag
+            const count_cmd = b.fmt("{s}..HEAD", .{base_tag});
+            const git_count_raw = runGit(b, &.{ "rev-list", "--count", count_cmd }) catch return lightpanda_version;
+            break :blk std.mem.trim(u8, git_count_raw, " \n\r");
+        };
+
+        return .{
+            .major = lightpanda_version.major,
+            .minor = lightpanda_version.minor,
+            .patch = lightpanda_version.patch,
+            .pre = b.fmt("dev.{s}", .{commit_count}),
+            .build = commit_hash,
+        };
+    };
+    // We're exactly on a tag, return the version as-is
+    return lightpanda_version;
+}
+
+/// Helper function to run git commands and return stdout
+fn runGit(b: *std.Build, args: []const []const u8) ![]const u8 {
+    var code: u8 = undefined;
+    const dir = b.pathFromRoot(".");
+    var command: std.ArrayList([]const u8) = .empty;
+    defer command.deinit(b.allocator);
+    try command.appendSlice(b.allocator, &.{ "git", "-C", dir });
+    try command.appendSlice(b.allocator, args);
+    return b.runAllowFail(command.items, &code, .Ignore);
+}

build.zig.zon

@@ -1,6 +1,6 @@
 .{
     .name = .browser,
-    .version = "0.0.0",
+    .version = "0.3.0-dev",
     .fingerprint = 0xda130f3af836cea0, // Changing this has security and trust implications.
     .minimum_zig_version = "0.15.2",
     .dependencies = .{

src/crash_handler.zig

@@ -47,7 +47,7 @@ pub noinline fn crash(
                 writer.print("\nreason: {s}\n", .{reason}) catch abort();
                 writer.print("OS: {s}\n", .{@tagName(builtin.os.tag)}) catch abort();
                 writer.print("mode: {s}\n", .{@tagName(builtin.mode)}) catch abort();
-                writer.print("version: {s}\n", .{lp.build_config.git_commit}) catch abort();
+                writer.print("version: {s}\n", .{lp.build_config.version}) catch abort();
                 inline for (@typeInfo(@TypeOf(args)).@"struct".fields) |f| {
                     writer.writeAll(f.name ++ ": ") catch break;
                     @import("log.zig").writeValue(.pretty, @field(args, f.name), writer) catch abort();
@@ -86,7 +86,7 @@ fn report(reason: []const u8, begin_addr: usize, args: anytype) !void {
     var url_buffer: [4096]u8 = undefined;
     const url = blk: {
         var writer: std.Io.Writer = .fixed(&url_buffer);
-        try writer.print("https://crash.lightpanda.io/c?v={s}&r=", .{lp.build_config.git_commit});
+        try writer.print("https://crash.lightpanda.io/c?v={s}&r=", .{lp.build_config.version});
         for (reason) |b| {
             switch (b) {
                 'A'...'Z', 'a'...'z', '0'...'9', '-', '.', '_' => try writer.writeByte(b),

src/main.zig

@@ -59,11 +59,8 @@ fn run(allocator: Allocator, main_arena: Allocator) !void {
             return std.process.cleanExit();
         },
         .version => {
-            if (lp.build_config.git_version) |version| {
-                std.debug.print("{s} ({s})\n", .{ version, lp.build_config.git_commit });
-            } else {
-                std.debug.print("{s}\n", .{lp.build_config.git_commit});
-            }
+            var stdout = std.fs.File.stdout().writer(&.{});
+            try stdout.interface.print("{s}\n", .{lp.build_config.version});
             return std.process.cleanExit();
         },
         else => {},

src/telemetry/lightpanda.zig

@@ -145,7 +145,7 @@ const LightPandaEvent = struct {
         try writer.write(builtin.cpu.arch);
 
         try writer.objectField("version");
-        try writer.write(build_config.git_version orelse build_config.git_commit);
+        try writer.write(build_config.version);
 
         try writer.objectField("event");
         try writer.write(@tagName(std.meta.activeTag(self.event)));