Add LSP diagnostics panel

src/tui.zig

@@ -150,6 +150,8 @@ pub const Client = struct {
         if (std.mem.eql(u8, line, "terminal_exit")) return self.closeTerminalPanel();
         if (std.mem.startsWith(u8, line, "syntax_spans ")) return self.openSyntaxSpans(line[13..]);
         if (std.mem.startsWith(u8, line, "lsp_sync ")) return self.openLspSync(line[9..]);
+        if (std.mem.startsWith(u8, line, "lsp_diagnostics ")) return self.openLspDiagnostics(line[16..]);
+        if (std.mem.eql(u8, line, "lsp_diagnostics_open_selected")) return self.openSelectedLspDiagnostic();
         if (std.mem.startsWith(u8, line, "panel_open ")) return self.applyProtocolCommand(line);
         if (std.mem.startsWith(u8, line, "list_open ")) return self.applyProtocolCommand(line);
         if (std.mem.startsWith(u8, line, "list_filter ")) return self.applyProtocolCommand(line);
@@ -439,6 +441,25 @@ pub const Client = struct {
         self.message = null;
     }
 
+    fn openLspDiagnostics(self: *Client, payload: []const u8) !void {
+        const rows = lsp_mod.diagnosticRowsAlloc(self.allocator, payload) catch return Error.ProtocolRejected;
+        defer freeOwnedRows(self.allocator, rows);
+        try self.session.openListPanel("lsp-diagnostics", rows);
+        self.message = null;
+    }
+
+    fn openSelectedLspDiagnostic(self: *Client) !void {
+        const selected = self.session.selectListPanel() catch return Error.ProtocolRejected;
+        const location = lsp_mod.diagnosticLocationFromRow(selected) catch return Error.ProtocolRejected;
+        const snap = try self.session.snapshot();
+        const bytes = try self.allocator.dupe(u8, snap.bytes);
+        defer self.allocator.free(bytes);
+        const offset = lsp_mod.byteOffsetForLineColumn(bytes, location.line, location.character) catch return Error.ProtocolRejected;
+        try self.session.openFixtureAt(bytes, offset);
+        try self.session.closePanel();
+        self.message = null;
+    }
+
     fn openStaticJobRow(self: *Client, title: []const u8, row: []const u8) !void {
         try self.session.openListPanel(title, &.{row});
         self.message = null;
@@ -1590,3 +1611,45 @@ test "adversarial: lsp sync rejection does not corrupt current buffer" {
     const snap = try client.session.snapshot();
     try std.testing.expectEqualStrings("safe", snap.bytes);
 }
+
+test "regular: lsp diagnostics panel renders rows and jumps to diagnostic" {
+    var client = try Client.init(std.testing.allocator, .{ .width = 96, .height = 7 });
+    defer client.deinit();
+
+    try client.handleTraceLine("open one\\nabcdTARGET");
+    const payload =
+        \\{"jsonrpc":"2.0","method":"textDocument/publishDiagnostics","params":{"uri":"file:///tmp/main.zig","diagnostics":[{"range":{"start":{"line":0,"character":4},"end":{"line":1,"character":5}},"severity":1,"message":"expected semicolon"}]}}
+    ;
+    const command = try std.fmt.allocPrint(std.testing.allocator, "lsp_diagnostics {s}", .{payload});
+    defer std.testing.allocator.free(command);
+    try client.handleTraceLine(command);
+    {
+        const frame = try client.render(std.testing.allocator);
+        defer std.testing.allocator.free(frame);
+        try std.testing.expect(std.mem.indexOf(u8, frame, "lsp-diagnostics") != null);
+        try std.testing.expect(std.mem.indexOf(u8, frame, "lsp:diagnostics:count_1") != null);
+        try std.testing.expect(std.mem.indexOf(u8, frame, "lsp:diag:error:1:5:file_///tmp/main.zig:expected_semicolon") != null);
+    }
+
+    try client.handleTraceLine("list_down");
+    try client.handleTraceLine("lsp_diagnostics_open_selected");
+    const snap = try client.session.snapshot();
+    try std.testing.expectEqual(@as(usize, 4), snap.cursor_byte);
+}
+
+test "adversarial: malformed diagnostics and unselected summary row do not corrupt buffer" {
+    var client = try Client.init(std.testing.allocator, .{ .width = 72, .height = 5 });
+    defer client.deinit();
+
+    try client.handleTraceLine("open safe");
+    try std.testing.expectError(Error.ProtocolRejected, client.handleTraceLine("lsp_diagnostics not-json"));
+    const payload =
+        \\{"jsonrpc":"2.0","method":"textDocument/publishDiagnostics","params":{"uri":"file:///tmp/main.zig","diagnostics":[{"range":{"start":{"line":0,"character":0},"end":{"line":0,"character":1}},"severity":2,"message":"warn"}]}}
+    ;
+    const command = try std.fmt.allocPrint(std.testing.allocator, "lsp_diagnostics {s}", .{payload});
+    defer std.testing.allocator.free(command);
+    try client.handleTraceLine(command);
+    try std.testing.expectError(Error.ProtocolRejected, client.handleTraceLine("lsp_diagnostics_open_selected"));
+    const snap = try client.session.snapshot();
+    try std.testing.expectEqualStrings("safe", snap.bytes);
+}