Add visible v1 diagnostics guardrails

src/tui.zig

@@ -1,5 +1,6 @@
 const std = @import("std");
 const context_mod = @import("context.zig");
+const diagnostics_mod = @import("diagnostics.zig");
 const input = @import("input.zig");
 const job_mod = @import("job.zig");
 const leader_mod = @import("leader.zig");
@@ -327,8 +328,20 @@ pub const Client = struct {
     }
 
     fn addRepoFile(self: *Client, payload: []const u8) !void {
-        const separator = std.mem.indexOfScalar(u8, payload, '=') orelse return repo_mod.Error.InvalidPath;
-        try self.repo.addFile(payload[0..separator], payload[separator + 1 ..]);
+        const separator = std.mem.indexOfScalar(u8, payload, '=') orelse {
+            self.message = "diagnostic:unsupported_file:invalid_repo_file_payload";
+            return repo_mod.Error.InvalidPath;
+        };
+        const file_bytes = payload[separator + 1 ..];
+        if (file_bytes.len > diagnostics_mod.max_file_bytes) {
+            self.message = "diagnostic:file_too_large";
+            return Error.ProtocolRejected;
+        }
+        self.repo.addFile(payload[0..separator], file_bytes) catch |err| {
+            self.message = "diagnostic:unsupported_file";
+            return err;
+        };
+        self.message = null;
     }
 
     fn openRepoList(self: *Client, title: []const u8, tree: bool, include_ignored: bool) !void {
@@ -355,8 +368,9 @@ pub const Client = struct {
             for (rows) |row| self.allocator.free(row);
             self.allocator.free(rows);
         }
+        const truncated = rowsContain(rows, "diagnostic:search_truncated");
         try self.session.openListPanel("search", rows);
-        self.message = null;
+        self.message = if (truncated) "diagnostic:search_truncated" else null;
     }
 
     fn openSelectedSearchResult(self: *Client) !void {
@@ -669,6 +683,10 @@ pub const Client = struct {
 
     fn save(self: *Client) !void {
         const snap = try self.session.snapshot();
+        if (snap.bytes.len > diagnostics_mod.max_file_bytes) {
+            self.message = "diagnostic:save_failed:file_too_large";
+            return Error.ProtocolRejected;
+        }
         const copy = try self.allocator.dupe(u8, snap.bytes);
         if (self.saved_bytes) |old| self.allocator.free(old);
         self.saved_bytes = copy;
@@ -807,6 +825,13 @@ fn assertLinesFit(frame: []const u8, width: usize) !void {
     }
 }
 
+fn rowsContain(rows: []const []const u8, needle: []const u8) bool {
+    for (rows) |row| {
+        if (std.mem.indexOf(u8, row, needle) != null) return true;
+    }
+    return false;
+}
+
 fn freeOwnedRows(allocator: std.mem.Allocator, rows: []const []const u8) void {
     for (rows) |row| allocator.free(row);
     allocator.free(rows);