From ac4635f757b610ac082f2d4b968b331f90b2f555 Mon Sep 17 00:00:00 2001
From: "Benedicto Franco Jr." <bene@trendvidia.com>
Date: Fri, 30 Oct 2026 18:50:15 -0700
Subject: [PATCH] check_decode: mirror Tree's branches and tags

The corpus's Tree gained map<string, Tree> branches and
map<string, string> tags (protowire#449). check_decode's PB leg decodes
into a hand-written struct, so it skipped both as unknown and the
pb/deep-map-101 and pb/deep-scalar-map-101 rows failed for that reason
alone. With the fields added, every row passes: the decoders already
count a map's { and every PB map entry.

The Tree map holds unique_ptr so its value type is complete at the
member's declaration, as the standard requires.

Advances trendvidia/protowire#449
---
 CHANGELOG.md             | 8 ++++++++
 cmd/check_decode/main.cc | 9 ++++++++-
 2 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index c86ff8d..c827442 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -11,6 +11,14 @@ format changes.
 
 ## [Unreleased]
 
+### Fixed
+
+- **`check_decode`'s `Tree` has `branches` and `tags`** (protowire#449).
+  Without them the PB leg skipped both fields as unknown, so the corpus's
+  map-depth rows could not reach the decoder's map path. The decoders
+  needed no change: they already count a map's `{` and every PB map entry
+  toward `MaxNestingDepth`.
+
 ## [1.1.0] — 2026-09-11
 
 ### Added
diff --git a/cmd/check_decode/main.cc b/cmd/check_decode/main.cc
index b5a175b..7f65293 100644
--- a/cmd/check_decode/main.cc
+++ b/cmd/check_decode/main.cc
@@ -40,6 +40,7 @@
 #include <cstring>
 #include <filesystem>
 #include <fstream>
+#include <map>
 #include <memory>
 #include <span>
 #include <sstream>
@@ -111,10 +112,16 @@ struct Tree {
   std::unique_ptr<Tree> child;
   std::string label;
   std::vector<Tree> children;
+  // Held by pointer so the map's value type is complete here, where the
+  // standard requires it; the wire form is the same as map<string, Tree>.
+  std::map<std::string, std::unique_ptr<Tree>> branches;
+  std::map<std::string, std::string> tags;
   PROTOWIRE_FIELDS(Tree,
                    PROTOWIRE_FIELD(1, child),
                    PROTOWIRE_FIELD(2, label),
-                   PROTOWIRE_FIELD(3, children))
+                   PROTOWIRE_FIELD(3, children),
+                   PROTOWIRE_FIELD(4, branches),
+                   PROTOWIRE_FIELD(5, tags))
 };
 
 struct StringHolder {