replace ArrayLists with bounded storage

1 files changed, 40 insertions, 10 deletions

diff --git a/test/e2e_harness.zig b/test/e2e_harness.zig
index eb4c7a2f..c188827e 100644
--- a/test/e2e_harness.zig
+++ b/test/e2e_harness.zig
@@ -22,6 +22,24 @@ pub fn nowMs() i64 {
     _ = libc.clock_gettime(.MONOTONIC, &ts);
     return @as(i64, @intCast(ts.sec)) * 1000 + @divFloor(@as(i64, @intCast(ts.nsec)), 1_000_000);
 }
+const raw_capture_max = 64 * 1024 * 1024;
+
+pub const RawCapture = struct {
+    bytes: [raw_capture_max]u8 = undefined,
+    items: []u8 = &.{},
+    full: bool = false,
+
+    fn appendSlice(self: *RawCapture, chunk: []const u8) error{CaptureFull}!void {
+        if (self.full) return error.CaptureFull;
+        if (chunk.len > self.bytes.len - self.items.len) {
+            self.full = true;
+            return error.CaptureFull;
+        }
+        const end = self.items.len + chunk.len;
+        @memcpy(self.bytes[self.items.len..end], chunk);
+        self.items = self.bytes[0..end];
+    }
+};
 
 /// E2E test harness: forks the app in a pty and parses its output with a
 /// ghostty terminal emulator. Tests read the 2D screen GRID (via plainString),
@@ -47,8 +65,9 @@ pub const Harness = struct {
     trace: bool = false,
     /// every raw byte the app has emitted (accumulated in pump). Lets tests assert
     /// on control sequences the emulator consumes and never renders (e.g. OSC 52
-    /// clipboard writes). gpa-owned; freed in deinit.
-    raw: std.ArrayList(u8) = .empty,
+    /// clipboard writes). Capture is bounded explicitly so a runaway child cannot
+    /// consume unbounded test-runner memory.
+    raw: *RawCapture,
 
     pub fn init(gpa: std.mem.Allocator, exe: [*:0]const u8, rows: u16, cols: u16) !Harness {
         return initArgs(gpa, exe, rows, cols, null);
@@ -63,14 +82,16 @@ pub const Harness = struct {
 
     /// Like init, but passes extra CLI args (e.g. "-l", "dump.zon").
     pub fn initArgv(gpa: std.mem.Allocator, exe: [*:0]const u8, rows: u16, cols: u16, args: []const ?[*:0]const u8) !Harness {
+        const argv = try gpa.allocSentinel(?[*:0]const u8, args.len + 1, null);
+        defer gpa.free(argv);
+        argv[0] = exe;
+        for (args, 0..) |a, i| argv[i + 1] = a;
+
         var master: c_int = undefined;
         const ws = posix.winsize{ .row = rows, .col = cols, .xpixel = 0, .ypixel = 0 };
         const pid = forkpty(&master, null, null, &ws);
         if (pid == 0) {
-            var argv: [8:null]?[*:0]const u8 = @splat(null);
-            argv[0] = exe;
-            for (args, 0..) |a, i| argv[i + 1] = a;
-            _ = execvp(exe, &argv);
+            _ = execvp(exe, argv.ptr);
             _exit(127);
         }
         const term = try gpa.create(ghostty_vt.Terminal);
@@ -84,6 +105,9 @@ pub const Harness = struct {
         // vtStream() captures a pointer to `term`; term is heap-allocated so the
         // pointer stays valid for the life of the harness.
         const stream = term.vtStream();
+        const raw = try gpa.create(RawCapture);
+        errdefer gpa.destroy(raw);
+        raw.* = .{};
         return .{
             .gpa = gpa,
             .master = master,
@@ -92,6 +116,7 @@ pub const Harness = struct {
             .stream = stream,
             .rows = rows,
             .cols = cols,
+            .raw = raw,
         };
     }
 
@@ -99,7 +124,7 @@ pub const Harness = struct {
         posix.kill(self.pid, posix.SIG.KILL) catch {};
         _ = libc.close(self.master);
         self.stream.deinit();
-        self.raw.deinit(self.gpa);
+        self.gpa.destroy(self.raw);
         self.term.deinit(self.gpa);
         self.gpa.destroy(self.term);
     }
@@ -128,7 +153,7 @@ pub const Harness = struct {
             if ((fds[0].revents & posix.POLL.IN) != 0) {
                 const n = posix.read(self.master, &buf) catch break;
                 if (n == 0) break;
-                self.raw.appendSlice(self.gpa, buf[0..n]) catch {};
+                self.recordRaw(buf[0..n]);
                 self.stream.nextSlice(buf[0..n]);
             }
         }
@@ -147,7 +172,7 @@ pub const Harness = struct {
         var buf: [4096]u8 = undefined;
         const n = posix.read(self.master, &buf) catch return false;
         if (n == 0) return false;
-        self.raw.appendSlice(self.gpa, buf[0..n]) catch {};
+        self.recordRaw(buf[0..n]);
         self.stream.nextSlice(buf[0..n]);
         return true;
     }
@@ -206,7 +231,7 @@ pub const Harness = struct {
             if ((fds[0].revents & posix.POLL.IN) != 0) {
                 const n = posix.read(self.master, &buf) catch break;
                 if (n == 0) break;
-                self.raw.appendSlice(self.gpa, buf[0..n]) catch {};
+                self.recordRaw(buf[0..n]);
                 self.stream.nextSlice(buf[0..n]);
             }
             const text = try self.screenText();
@@ -219,6 +244,11 @@ pub const Harness = struct {
         if (self.trace) self.traceScreen("waitFor miss");
         return false;
     }
+    fn recordRaw(self: *Harness, bytes: []const u8) void {
+        self.raw.appendSlice(bytes) catch |err| switch (err) {
+            error.CaptureFull => {},
+        };
+    }
 
     /// The visual cursor position (viewport coords): { x, y }.
     pub fn cursor(self: *Harness) struct { x: u16, y: u16 } {