web snapshots: add switch for saving/loading exports, update web version, web snapshot tooling

1 files changed, 60 insertions, 5 deletions

diff --git a/build.zig b/build.zig
index a387db9e..58179faf 100644
--- a/build.zig
+++ b/build.zig
@@ -1,7 +1,7 @@
 const std = @import("std");
 
 pub const Platform = enum { tty, gui, web };
-pub const TreeSitterGrammars = enum { disabled, minimal, full };
+pub const TreeSitterGrammars = enum { disabled, zig, minimal, full };
 const GhosttyArtifact = enum { ghostty, lib };
 
 pub fn build(b: *std.Build) void {
@@ -24,13 +24,62 @@ pub fn build(b: *std.Build) void {
     const is_emscripten = target.result.os.tag == .emscripten;
     // wasm: size is the budget
     const optimize = if (is_emscripten) .ReleaseSmall else requested_optimize;
-    const default_grammars: TreeSitterGrammars = if (is_emscripten) .minimal else .full;
-    const tree_sitter_grammars = b.option(TreeSitterGrammars, "tree-sitter", "tree-sitter grammar set: disabled, minimal, full") orelse default_grammars;
+    const default_grammars: TreeSitterGrammars = if (is_emscripten) .zig else .full;
+    const tree_sitter_grammars = b.option(TreeSitterGrammars, "tree-sitter", "tree-sitter grammar set: disabled, zig, minimal (c/c++/zig), full") orelse default_grammars;
     const tracy = b.option([]const u8, "tracy", "enable Tracy profiling; supply the path to a Tracy source checkout");
 
     // the browser shell: zig object + emcc link + html, installed to zig-out/web
     const web_step = b.step("web", "build the browser shell into zig-out/web (-Dplatform=web -Dtarget=wasm32-emscripten -Ddump=<dump.zon>)");
 
+    // Web LOOK has a tiny read-only source filesystem. Generate one Zig module
+    // on the host from every tracked .zig path + its current working-tree
+    // contents. The generator prefers Git as the tracked-file filter and has a
+    // conservative filesystem fallback for source archives without `.git`.
+    const source_gen = b.addExecutable(.{
+        .name = "pardes-embed-zig-sources",
+        .root_module = b.createModule(.{
+            .target = b.graph.host,
+            .optimize = .ReleaseSafe,
+            .root_source_file = b.path("tools/embed_zig_sources.zig"),
+        }),
+    });
+    const run_source_gen = b.addRunArtifact(source_gen);
+    run_source_gen.addDirectoryArg(b.path("."));
+    const embedded_sources = run_source_gen.addOutputFileArg("embedded_sources.zig");
+    // The tracked set can change without any already-known input changing, so
+    // discovery intentionally runs whenever a consumer builds it.
+    run_source_gen.has_side_effects = true;
+    const inspect_sources = b.addInstallFileWithDir(embedded_sources, .{ .custom = "web" }, "embedded_sources.zig");
+    b.step("embed-web-sources", "generate zig-out/web/embedded_sources.zig from tracked .zig files").dependOn(&inspect_sources.step);
+
+    // Browser regression suite: make an isolated web build from the real TTY
+    // dump captured after running `git ls-files '*.zig'`, with the Zig-only
+    // tree-sitter tier. The dependency-free CDP harness then drives
+    // its .snap script through real Chromium touch events. This recursive build
+    // selects `web`, not `web-snap`, so it bottoms out after one level.
+    const build_web_snap = b.addSystemCommand(&.{
+        b.graph.zig_exe,
+        "build",
+        "web",
+        "-Dplatform=web",
+        "-Dtarget=wasm32-emscripten",
+        "-Dtree-sitter=zig",
+        "-Ddump=test/web-snapshots/source-list.dump.zon",
+        "-p",
+        "zig-out/web-snap-test",
+    });
+    build_web_snap.setCwd(b.path("."));
+    const run_web_snap = b.addSystemCommand(&.{
+        "node",
+        "test/web_snapshot.mjs",
+        "zig-out/web-snap-test/web",
+        "test/web-snapshots/source-list.snap",
+    });
+    run_web_snap.setCwd(b.path("."));
+    run_web_snap.step.dependOn(&build_web_snap.step);
+    if (b.args) |args| run_web_snap.addArgs(args);
+    b.step("web-snap", "run browser touch/LOOK snapshots (-- --update regenerates goldens)").dependOn(&run_web_snap.step);
+
     const emscripten_sysroot = if (is_emscripten) detectEmscriptenSysroot(b) else null;
     if (platform == .web and !is_emscripten) return failBuild(b, web_step, "-Dplatform=web requires -Dtarget=wasm32-emscripten");
     if (platform != .web and is_emscripten) return failBuild(b, web_step, "-Dtarget=wasm32-emscripten requires -Dplatform=web");
@@ -88,7 +137,8 @@ pub fn build(b: *std.Build) void {
     const opts = b.addOptions();
     opts.addOption(Platform, "platform", platform);
     opts.addOption(bool, "syntax_highlighting", tree_sitter_grammars != .disabled);
-    opts.addOption(bool, "syntax_minimal_grammars", tree_sitter_grammars != .disabled);
+    opts.addOption(bool, "syntax_zig_grammar", tree_sitter_grammars != .disabled);
+    opts.addOption(bool, "syntax_minimal_grammars", tree_sitter_grammars == .minimal or tree_sitter_grammars == .full);
     opts.addOption(bool, "syntax_full_grammars", tree_sitter_grammars == .full);
     opts.addOption(bool, "enable_tracy", tracy != null);
     root_mod.addOptions("pardes_config", opts);
@@ -176,7 +226,10 @@ pub fn build(b: *std.Build) void {
         };
         const ts_queries = b.addOptions();
         inline for (grammars) |g| {
-            if (tree_sitter_grammars == .full or g.minimal) {
+            if (tree_sitter_grammars == .full or
+                (tree_sitter_grammars == .minimal and g.minimal) or
+                (tree_sitter_grammars == .zig and std.mem.eql(u8, g.name, "zig")))
+            {
                 const dep = b.dependency(g.dep, .{});
                 const query_path = dep.path(g.query);
                 const query = std.Io.Dir.cwd().readFileAlloc(io, query_path.getPath(b), b.allocator, .limited(0x100000)) catch @panic("read " ++ g.name ++ " highlights");
@@ -329,6 +382,7 @@ pub fn build(b: *std.Build) void {
             root_mod.addAnonymousImport("embedded.dump.zon", .{
                 .root_source_file = if (std.fs.path.isAbsolute(dp)) .{ .cwd_relative = dp } else b.path(dp),
             });
+            root_mod.addAnonymousImport("embedded_sources", .{ .root_source_file = embedded_sources });
         } else {
             root_mod.addAnonymousImport("ui.vert.spv", .{
                 .root_source_file = compileGlsl(b, "shaders/ui.vert.glsl", "vertex", "ui.vert.spv"),
@@ -376,6 +430,7 @@ pub fn build(b: *std.Build) void {
             "-sMIN_WEBGL_VERSION=2",
             "-sMAX_WEBGL_VERSION=2",
             "-sINCOMING_MODULE_JS_API=canvas",
+            "-sEXPORTED_FUNCTIONS=['_main','_pardes_web_test_cols','_pardes_web_test_rows','_pardes_web_test_cursor_x','_pardes_web_test_cursor_y','_pardes_web_test_cell','_pardes_web_test_cell_fg','_pardes_web_test_cell_bg','_pardes_web_test_cell_attrs','_pardes_web_test_cell_x','_pardes_web_test_cell_y']",
             "-o",
         });
         const js = emcc.addOutputFileArg("pardes.js");