fix: remove multithreaded buffer access in project_manager

Until we have proper multithreaded buffer lifetime management we should avoid
accessing buffers that may have been deleted already.

src/Project.zig

@@ -520,6 +520,7 @@ pub fn delete_task(self: *Self, command: []const u8) error{}!void {
 }
 
 pub fn did_open(self: *Self, file_path: []const u8, file_type: []const u8, language_server: []const u8, version: usize, text: []const u8) StartLspError!void {
+    defer std.heap.c_allocator.free(text);
     self.update_mru(file_path, 0, 0) catch {};
     const lsp = try self.get_or_start_language_server(file_path, language_server);
     const uri = try self.make_URI(file_path);
@@ -529,7 +530,10 @@ pub fn did_open(self: *Self, file_path: []const u8, file_type: []const u8, langu
     }) catch return error.LspFailed;
 }
 
-pub fn did_change(self: *Self, file_path: []const u8, version: usize, root_dst_addr: usize, root_src_addr: usize, eol_mode: Buffer.EolMode) LspError!void {
+pub fn did_change(self: *Self, file_path: []const u8, version: usize, text_dst: []const u8, text_src: []const u8, eol_mode: Buffer.EolMode) LspError!void {
+    _ = eol_mode;
+    defer std.heap.c_allocator.free(text_dst);
+    defer std.heap.c_allocator.free(text_src);
     const lsp = try self.get_language_server(file_path);
     const uri = try self.make_URI(file_path);
 
@@ -545,22 +549,11 @@ pub fn did_change(self: *Self, file_path: []const u8, version: usize, root_dst_a
             self.allocator.free(scratch);
     }
 
-    const root_dst: Buffer.Root = if (root_dst_addr == 0) return else @ptrFromInt(root_dst_addr);
-    const root_src: Buffer.Root = if (root_src_addr == 0) return else @ptrFromInt(root_src_addr);
-
     var dizzy_edits = std.ArrayListUnmanaged(dizzy.Edit){};
-    var dst = std.ArrayList(u8).init(arena);
-    var src = std.ArrayList(u8).init(arena);
     var edits_cb = std.ArrayList(u8).init(arena);
     const writer = edits_cb.writer();
 
-    {
+    const scratch_len = 4 * (text_dst.len + text_src.len) + 2;
-        const frame = tracy.initZone(@src(), .{ .name = "store" });
-        defer frame.deinit();
-        try root_dst.store(dst.writer(), eol_mode);
-        try root_src.store(src.writer(), eol_mode);
-    }
-    const scratch_len = 4 * (dst.items.len + src.items.len) + 2;
     const scratch = blk: {
         const frame = tracy.initZone(@src(), .{ .name = "scratch" });
         defer frame.deinit();
@@ -571,7 +564,7 @@ pub fn did_change(self: *Self, file_path: []const u8, version: usize, root_dst_a
     {
         const frame = tracy.initZone(@src(), .{ .name = "diff" });
         defer frame.deinit();
-        try dizzy.PrimitiveSliceDiffer(u8).diff(arena, &dizzy_edits, src.items, dst.items, scratch);
+        try dizzy.PrimitiveSliceDiffer(u8).diff(arena, &dizzy_edits, text_src, text_dst, scratch);
     }
     var lines_dst: usize = 0;
     var last_offset: usize = 0;
@@ -583,7 +576,7 @@ pub fn did_change(self: *Self, file_path: []const u8, version: usize, root_dst_a
         for (dizzy_edits.items) |dizzy_edit| {
             switch (dizzy_edit.kind) {
                 .equal => {
-                    scan_char(src.items[dizzy_edit.range.start..dizzy_edit.range.end], &lines_dst, '\n', &last_offset);
+                    scan_char(text_src[dizzy_edit.range.start..dizzy_edit.range.end], &lines_dst, '\n', &last_offset);
                 },
                 .insert => {
                     const line_start_dst: usize = lines_dst;
@@ -592,15 +585,15 @@ pub fn did_change(self: *Self, file_path: []const u8, version: usize, root_dst_a
                             .start = .{ .line = line_start_dst, .character = last_offset },
                             .end = .{ .line = line_start_dst, .character = last_offset },
                         },
-                        .text = dst.items[dizzy_edit.range.start..dizzy_edit.range.end],
+                        .text = text_dst[dizzy_edit.range.start..dizzy_edit.range.end],
                     });
                     edits_count += 1;
-                    scan_char(dst.items[dizzy_edit.range.start..dizzy_edit.range.end], &lines_dst, '\n', &last_offset);
+                    scan_char(text_dst[dizzy_edit.range.start..dizzy_edit.range.end], &lines_dst, '\n', &last_offset);
                 },
                 .delete => {
                     var line_end_dst: usize = lines_dst;
                     var offset_end_dst: usize = last_offset;
-                    scan_char(src.items[dizzy_edit.range.start..dizzy_edit.range.end], &line_end_dst, '\n', &offset_end_dst);
+                    scan_char(text_src[dizzy_edit.range.start..dizzy_edit.range.end], &line_end_dst, '\n', &offset_end_dst);
                     try cbor.writeValue(writer, .{
                         .range = .{
                             .start = .{ .line = lines_dst, .character = last_offset },

src/project_manager.zig

@@ -147,11 +147,13 @@ pub fn did_open(file_path: []const u8, file_type: *const FileType, version: usiz
     return send(.{ "did_open", project, file_path, file_type.name, language_server, version, text_ptr, text.len });
 }
 
-pub fn did_change(file_path: []const u8, version: usize, root_dst: usize, root_src: usize, eol_mode: Buffer.EolMode) (ProjectManagerError || ProjectError)!void {
+pub fn did_change(file_path: []const u8, version: usize, text_dst: []const u8, text_src: []const u8, eol_mode: Buffer.EolMode) (ProjectManagerError || ProjectError)!void {
     const project = tp.env.get().str("project");
     if (project.len == 0)
         return error.NoProject;
-    return send(.{ "did_change", project, file_path, version, root_dst, root_src, @intFromEnum(eol_mode) });
+    const text_dst_ptr: usize = if (text_dst.len > 0) @intFromPtr(text_dst.ptr) else 0;
+    const text_src_ptr: usize = if (text_src.len > 0) @intFromPtr(text_src.ptr) else 0;
+    return send(.{ "did_change", project, file_path, version, text_dst_ptr, text_dst.len, text_src_ptr, text_src.len, @intFromEnum(eol_mode) });
 }
 
 pub fn did_save(file_path: []const u8) (ProjectManagerError || ProjectError)!void {
@@ -322,12 +324,14 @@ const Process = struct {
         var version: usize = 0;
         var text_ptr: usize = 0;
         var text_len: usize = 0;
+        var text_dst_ptr: usize = 0;
+        var text_dst_len: usize = 0;
+        var text_src_ptr: usize = 0;
+        var text_src_len: usize = 0;
         var n: usize = 0;
         var task: []const u8 = undefined;
         var context: usize = undefined;
 
-        var root_dst: usize = 0;
-        var root_src: usize = 0;
         var eol_mode: Buffer.EolModeTag = @intFromEnum(Buffer.EolMode.lf);
 
         if (try cbor.match(m.buf, .{ "walk_tree_entry", tp.extract(&project_directory), tp.extract(&path), tp.extract(&high), tp.extract(&low) })) {
@@ -373,8 +377,10 @@ const Process = struct {
         } else if (try cbor.match(m.buf, .{ "did_open", tp.extract(&project_directory), tp.extract(&path), tp.extract(&file_type), tp.extract_cbor(&language_server), tp.extract(&version), tp.extract(&text_ptr), tp.extract(&text_len) })) {
             const text = if (text_len > 0) @as([*]const u8, @ptrFromInt(text_ptr))[0..text_len] else "";
             self.did_open(project_directory, path, file_type, language_server, version, text) catch |e| return from.forward_error(e, @errorReturnTrace()) catch error.ClientFailed;
-        } else if (try cbor.match(m.buf, .{ "did_change", tp.extract(&project_directory), tp.extract(&path), tp.extract(&version), tp.extract(&root_dst), tp.extract(&root_src), tp.extract(&eol_mode) })) {
+        } else if (try cbor.match(m.buf, .{ "did_change", tp.extract(&project_directory), tp.extract(&path), tp.extract(&version), tp.extract(&text_dst_ptr), tp.extract(&text_dst_len), tp.extract(&text_src_ptr), tp.extract(&text_src_len), tp.extract(&eol_mode) })) {
-            self.did_change(project_directory, path, version, root_dst, root_src, @enumFromInt(eol_mode)) catch |e| return from.forward_error(e, @errorReturnTrace()) catch error.ClientFailed;
+            const text_dst = if (text_dst_len > 0) @as([*]const u8, @ptrFromInt(text_dst_ptr))[0..text_dst_len] else "";
+            const text_src = if (text_src_len > 0) @as([*]const u8, @ptrFromInt(text_src_ptr))[0..text_src_len] else "";
+            self.did_change(project_directory, path, version, text_dst, text_src, @enumFromInt(eol_mode)) catch |e| return from.forward_error(e, @errorReturnTrace()) catch error.ClientFailed;
         } else if (try cbor.match(m.buf, .{ "did_save", tp.extract(&project_directory), tp.extract(&path) })) {
             self.did_save(project_directory, path) catch |e| return from.forward_error(e, @errorReturnTrace()) catch error.ClientFailed;
         } else if (try cbor.match(m.buf, .{ "did_close", tp.extract(&project_directory), tp.extract(&path) })) {
@@ -497,11 +503,11 @@ const Process = struct {
         return project.did_open(file_path, file_type, language_server, version, text);
     }
 
-    fn did_change(self: *Process, project_directory: []const u8, file_path: []const u8, version: usize, root_dst: usize, root_src: usize, eol_mode: Buffer.EolMode) (ProjectError || Project.LspError)!void {
+    fn did_change(self: *Process, project_directory: []const u8, file_path: []const u8, version: usize, text_dst: []const u8, text_src: []const u8, eol_mode: Buffer.EolMode) (ProjectError || Project.LspError)!void {
         const frame = tracy.initZone(@src(), .{ .name = module_name ++ ".did_change" });
         defer frame.deinit();
         const project = self.projects.get(project_directory) orelse return error.NoProject;
-        return project.did_change(file_path, version, root_dst, root_src, eol_mode);
+        return project.did_change(file_path, version, text_dst, text_src, eol_mode);
     }
 
     fn did_save(self: *Process, project_directory: []const u8, file_path: []const u8) (ProjectError || Project.LspError)!void {

src/tui/editor.zig

@@ -571,11 +571,11 @@ pub const Editor = struct {
         self.syntax = syntax: {
             const lang_override = file_type orelse tp.env.get().str("language");
             var content = std.ArrayListUnmanaged(u8).empty;
-            defer content.deinit(self.allocator);
+            defer content.deinit(std.heap.c_allocator);
             {
                 const frame_ = tracy.initZone(@src(), .{ .name = "store" });
                 defer frame_.deinit();
-                try new_buf.root.store(content.writer(self.allocator), new_buf.file_eol_mode);
+                try new_buf.root.store(content.writer(std.heap.c_allocator), new_buf.file_eol_mode);
             }
 
             const syn_file_type = blk: {
@@ -603,7 +603,7 @@ pub const Editor = struct {
                     file_path,
                     syn_.file_type,
                     self.lsp_version,
-                    try content.toOwnedSlice(self.allocator),
+                    try content.toOwnedSlice(std.heap.c_allocator),
                     new_buf.is_ephemeral(),
                 ) catch |e|
                     self.logger.print("project_manager.did_open failed: {any}", .{e});
@@ -1669,10 +1669,18 @@ pub const Editor = struct {
         return if (p) |p_| @intFromPtr(p_) else 0;
     }
 
+    fn text_from_root(root_: ?Buffer.Root, eol_mode: Buffer.EolMode) ![]const u8 {
+        const root = root_ orelse return &.{};
+        var text = std.ArrayList(u8).init(std.heap.c_allocator);
+        defer text.deinit();
+        try root.store(text.writer(), eol_mode);
+        return text.toOwnedSlice();
+    }
+
     fn send_editor_update(self: *const Self, old_root: ?Buffer.Root, new_root: ?Buffer.Root, eol_mode: Buffer.EolMode) !void {
         _ = try self.handlers.msg(.{ "E", "update", token_from(new_root), token_from(old_root), @intFromEnum(eol_mode) });
         if (self.syntax) |_| if (self.file_path) |file_path| if (old_root != null and new_root != null)
-            project_manager.did_change(file_path, self.lsp_version, token_from(new_root), token_from(old_root), eol_mode) catch {};
+            project_manager.did_change(file_path, self.lsp_version, try text_from_root(new_root, eol_mode), try text_from_root(old_root, eol_mode), eol_mode) catch {};
     }
 
     fn send_editor_eol_mode(self: *const Self, eol_mode: Buffer.EolMode, utf8_sanitized: bool) !void {
@@ -5809,16 +5817,16 @@ pub const Editor = struct {
 
         self.syntax = syntax: {
             var content = std.ArrayListUnmanaged(u8).empty;
-            defer content.deinit(self.allocator);
+            defer content.deinit(std.heap.c_allocator);
             const root = try self.buf_root();
-            try root.store(content.writer(self.allocator), try self.buf_eol_mode());
+            try root.store(content.writer(std.heap.c_allocator), try self.buf_eol_mode());
             const syn = syntax.create_file_type(self.allocator, file_type, tui.query_cache()) catch null;
             if (syn) |syn_| if (self.file_path) |file_path|
                 project_manager.did_open(
                     file_path,
                     syn_.file_type,
                     self.lsp_version,
-                    try content.toOwnedSlice(self.allocator),
+                    try content.toOwnedSlice(std.heap.c_allocator),
                     if (self.buffer) |p| p.is_ephemeral() else true,
                 ) catch |e|
                     self.logger.print("project_manager.did_open failed: {any}", .{e});