Implement `--inspect-brk` (#4222)

* Implement `--inspect-brk`

* Bump WebKit

---------

Co-authored-by: Jarred Sumner <709451+Jarred-Sumner@users.noreply.github.com>

9 files changed, 72 insertions, 12 deletions

diff --git a/src/bun.js/WebKit b/src/bun.js/WebKit
-Subproject fc705595a2e10361a64f1dab56527d7b112e75c
+Subproject fd79ce3120a692f4aed314c3da3dd452b4aa865
diff --git a/src/bun.js/bindings/BunDebugger.cpp b/src/bun.js/bindings/BunDebugger.cpp
index 41001a8f2..440a5125b 100644
--- a/src/bun.js/bindings/BunDebugger.cpp
+++ b/src/bun.js/bindings/BunDebugger.cpp
@@ -23,14 +23,40 @@ static WebCore::ScriptExecutionContext* debuggerScriptExecutionContext = nullptr
 static WTF::Lock inspectorConnectionsLock = WTF::Lock();
 static WTF::HashMap<ScriptExecutionContextIdentifier, Vector<BunInspectorConnection*, 8>>* inspectorConnections = nullptr;
 
+static bool waitingForConnection = false;
+extern "C" void Debugger__didConnect();
+
+class BunJSGlobalObjectDebuggable final : public JSC::JSGlobalObjectDebuggable {
+public:
+    using Base = JSC::JSGlobalObjectDebuggable;
+
+    BunJSGlobalObjectDebuggable(JSC::JSGlobalObject& globalObject)
+        : Base(globalObject)
+    {
+    }
+
+    ~BunJSGlobalObjectDebuggable() final
+    {
+    }
+
+    void pauseWaitingForAutomaticInspection() override
+    {
+    }
+    void unpauseForInitializedInspector() override
+    {
+        if (waitingForConnection) {
+            waitingForConnection = false;
+            Debugger__didConnect();
+        }
+    }
+};
+
 enum class ConnectionStatus : int32_t {
     Pending = 0,
     Connected = 1,
     Disconnecting = 2,
     Disconnected = 3,
 };
-static bool waitingForConnection = false;
-extern "C" void Debugger__didConnect();
 
 class BunInspectorConnection : public Inspector::FrontendChannel {
 
@@ -81,15 +107,9 @@ public:
                     Bun__eventLoop__incrementRefConcurrently(reinterpret_cast<Zig::GlobalObject*>(globalObject)->bunVM(), 1);
                 }
                 globalObject->setInspectable(true);
-
                 auto& inspector = globalObject->inspectorDebuggable();
                 inspector.setInspectable(true);
-
-                inspector.connect(*connection);
-                if (waitingForConnection) {
-                    waitingForConnection = false;
-                    Debugger__didConnect();
-                }
+                globalObject->inspectorController().connectFrontend(*connection, true, waitingForConnection);
 
                 Inspector::JSGlobalObjectDebugger* debugger = reinterpret_cast<Inspector::JSGlobalObjectDebugger*>(globalObject->debugger());
                 if (debugger) {
@@ -99,7 +119,6 @@ public:
                 }
 
                 connection->receiveMessagesOnInspectorThread(context, reinterpret_cast<Zig::GlobalObject*>(globalObject));
-
                 break;
             }
             default: {
@@ -415,6 +434,8 @@ extern "C" void Bun__ensureDebugger(ScriptExecutionContextIdentifier scriptId, b
 
     auto* globalObject = ScriptExecutionContext::getScriptExecutionContext(scriptId)->jsGlobalObject();
     globalObject->m_inspectorController = makeUnique<Inspector::JSGlobalObjectInspectorController>(*globalObject, Bun::BunInjectedScriptHost::create());
+    globalObject->m_inspectorDebuggable = makeUnique<BunJSGlobalObjectDebuggable>(*globalObject);
+
     globalObject->setInspectable(true);
 
     auto& inspector = globalObject->inspectorDebuggable();
diff --git a/src/bun.js/javascript.zig b/src/bun.js/javascript.zig
index 98e61f3b0..07d3f64cf 100644
--- a/src/bun.js/javascript.zig
+++ b/src/bun.js/javascript.zig
@@ -748,6 +748,8 @@ pub const VirtualMachine = struct {
         next_debugger_id: u64 = 1,
         poll_ref: JSC.PollRef = .{},
         wait_for_connection: bool = false,
+        set_breakpoint_on_first_line: bool = false,
+
         const debug = Output.scoped(.DEBUGGER, false);
 
         extern "C" fn Bun__createJSDebugger(*JSC.JSGlobalObject) u32;
@@ -784,6 +786,8 @@ pub const VirtualMachine = struct {
             Bun__ensureDebugger(debugger.script_execution_context_id, debugger.wait_for_connection);
             while (debugger.wait_for_connection) {
                 this.eventLoop().tick();
+                if (debugger.wait_for_connection)
+                    this.eventLoop().autoTickActive();
             }
         }
 
@@ -1136,6 +1140,7 @@ pub const VirtualMachine = struct {
                 this.debugger = Debugger{
                     .path_or_port = debugger.enable.path_or_port,
                     .wait_for_connection = debugger.enable.wait_for_connection,
+                    .set_breakpoint_on_first_line = debugger.enable.set_breakpoint_on_first_line,
                 };
             },
         }
@@ -1870,6 +1875,7 @@ pub const VirtualMachine = struct {
     pub fn reloadEntryPoint(this: *VirtualMachine, entry_path: []const u8) !*JSInternalPromise {
         this.has_loaded = false;
         this.main = entry_path;
+        this.main_hash = bun.JSC.Watcher.getHash(entry_path);
 
         try this.entry_point.generate(
             this.allocator,
diff --git a/src/bun.js/module_loader.zig b/src/bun.js/module_loader.zig
index be10b9722..dfb9077e2 100644
--- a/src/bun.js/module_loader.zig
+++ b/src/bun.js/module_loader.zig
@@ -403,6 +403,7 @@ pub const RuntimeTranspilerStore = struct {
                     vm.main.len == path.text.len and
                     vm.main_hash == hash and
                     strings.eqlLong(vm.main, path.text, false),
+                .set_breakpoint_on_first_line = vm.debugger != null and vm.debugger.?.set_breakpoint_on_first_line and strings.eqlLong(vm.main, path.text, false),
             };
 
             defer {
@@ -1439,6 +1440,7 @@ pub const ModuleLoader = struct {
                     .dont_bundle_twice = true,
                     .allow_commonjs = true,
                     .inject_jest_globals = jsc_vm.bundler.options.rewrite_jest_for_tests and is_main,
+                    .set_breakpoint_on_first_line = is_main and jsc_vm.debugger != null and jsc_vm.debugger.?.set_breakpoint_on_first_line,
                 };
                 defer {
                     if (should_close_input_file_fd and input_file_fd != 0) {
diff --git a/src/bundler.zig b/src/bundler.zig
index b5912a96f..ce7d9fc42 100644
--- a/src/bundler.zig
+++ b/src/bundler.zig
@@ -1188,6 +1188,7 @@ pub const Bundler = struct {
         virtual_source: ?*const logger.Source = null,
         replace_exports: runtime.Runtime.Features.ReplaceableExport.Map = .{},
         inject_jest_globals: bool = false,
+        set_breakpoint_on_first_line: bool = false,
 
         dont_bundle_twice: bool = false,
         allow_commonjs: bool = false,
@@ -1302,6 +1303,7 @@ pub const Bundler = struct {
                 var opts = js_parser.Parser.Options.init(jsx, loader);
                 opts.legacy_transform_require_to_import = bundler.options.allow_runtime and !bundler.options.target.isBun();
                 opts.features.allow_runtime = bundler.options.allow_runtime;
+                opts.features.set_breakpoint_on_first_line = this_parse.set_breakpoint_on_first_line;
                 opts.features.trim_unused_imports = bundler.options.trim_unused_imports orelse loader.isTypeScript();
                 opts.features.should_fold_typescript_constant_expressions = loader.isTypeScript() or target.isBun() or bundler.options.minify_syntax;
                 opts.features.dynamic_require = target.isBun();
diff --git a/src/cli.zig b/src/cli.zig
index 88b6aa057..0fb618afc 100644
--- a/src/cli.zig
+++ b/src/cli.zig
@@ -161,7 +161,8 @@ pub const Arguments = struct {
         clap.parseParam("--no-macros                       Disable macros from being executed in the bundler, transpiler and runtime") catch unreachable,
         clap.parseParam("--target <STR>                    The intended execution environment for the bundle. \"browser\", \"bun\" or \"node\"") catch unreachable,
         clap.parseParam("--inspect <STR>?                  Activate Bun's Debugger") catch unreachable,
-        clap.parseParam("--inspect-wait <STR>?             Activate Bun's Debugger and wait for a connection before executing") catch unreachable,
+        clap.parseParam("--inspect-wait <STR>?             Activate Bun's Debugger, wait for a connection before executing") catch unreachable,
+        clap.parseParam("--inspect-brk <STR>?              Activate Bun's Debugger, set breakpoint on first line of code and wait") catch unreachable,
         clap.parseParam("<POS>...                          ") catch unreachable,
     };
 
@@ -530,6 +531,18 @@ pub const Arguments = struct {
                         .path_or_port = inspect_flag,
                         .wait_for_connection = true,
                     } };
+            } else if (args.option("--inspect-brk")) |inspect_flag| {
+                ctx.runtime_options.debugger = if (inspect_flag.len == 0)
+                    Command.Debugger{ .enable = .{
+                        .wait_for_connection = true,
+                        .set_breakpoint_on_first_line = true,
+                    } }
+                else
+                    Command.Debugger{ .enable = .{
+                        .path_or_port = inspect_flag,
+                        .wait_for_connection = true,
+                        .set_breakpoint_on_first_line = true,
+                    } };
             }
         }
 
@@ -969,6 +982,7 @@ pub const Command = struct {
         enable: struct {
             path_or_port: []const u8 = "",
             wait_for_connection: bool = false,
+            set_breakpoint_on_first_line: bool = false,
         },
     };
 
diff --git a/src/cli/test_command.zig b/src/cli/test_command.zig
index 5686659c8..5bf48d7d9 100644
--- a/src/cli/test_command.zig
+++ b/src/cli/test_command.zig
@@ -924,7 +924,6 @@ pub const TestCommand = struct {
         // https://docs.github.com/en/actions/using-workflows/workflow-commands-for-github-actions#grouping-log-lines
         const file_prefix = if (Output.is_github_action) "::group::" else "";
 
-        vm.main_hash = @as(u32, @truncate(bun.hash(file_path)));
         var repeat_count = reporter.repeat_count;
         var repeat_index: u32 = 0;
         while (repeat_index < repeat_count) : (repeat_index += 1) {
diff --git a/src/js_parser.zig b/src/js_parser.zig
index bb767d875..ebe2a01c9 100644
--- a/src/js_parser.zig
+++ b/src/js_parser.zig
@@ -2950,6 +2950,20 @@ pub const Parser = struct {
             before.deinit();
         }
 
+        // --inspect-brk
+        if (p.options.features.set_breakpoint_on_first_line) {
+            var debugger_stmts = try p.allocator.alloc(Stmt, 1);
+            debugger_stmts[0] = Stmt{
+                .data = .{ .s_debugger = .{} },
+                .loc = logger.Loc.Empty,
+            };
+            before.append(
+                js_ast.Part{
+                    .stmts = debugger_stmts,
+                },
+            ) catch unreachable;
+        }
+
         if (p.options.bundle) {
             // allocate an empty part for the bundle
             before.append(
diff --git a/src/runtime.zig b/src/runtime.zig
index 790f5b197..2c22f392e 100644
--- a/src/runtime.zig
+++ b/src/runtime.zig
@@ -290,6 +290,8 @@ pub const Runtime = struct {
         minify_syntax: bool = false,
         minify_identifiers: bool = false,
 
+        set_breakpoint_on_first_line: bool = false,
+
         /// Instead of jsx("div", {}, void 0)
         /// ->
         /// {