From 446a4d09413fa0b7ec8244c070a5adbb5d8daf22 Mon Sep 17 00:00:00 2001
From: Juan Cruz Viotti <jv@jviotti.com>
Date: Tue, 13 Aug 2024 17:14:45 -0400
Subject: [PATCH] Improve error message when compiling a `$ref` inside an
 unknown keyword (#148)

Signed-off-by: Juan Cruz Viotti <jv@jviotti.com>
---
 DEPENDENCIES                                  |  2 +-
 test/CMakeLists.txt                           |  1 +
 test/compile/fail_ref_from_unknown_keyword.sh | 35 +++++++++++++++++++
 .../src/jsonschema/default_compiler_draft4.h  |  8 ++++-
 4 files changed, 44 insertions(+), 2 deletions(-)
 create mode 100755 test/compile/fail_ref_from_unknown_keyword.sh

diff --git a/DEPENDENCIES b/DEPENDENCIES
index 967ea8de..3639ee0b 100644
--- a/DEPENDENCIES
+++ b/DEPENDENCIES
@@ -1,4 +1,4 @@
 vendorpull https://github.com/sourcemeta/vendorpull dea311b5bfb53b6926a4140267959ae334d3ecf4
 noa https://github.com/sourcemeta/noa 7e26abce7a4e31e86a16ef2851702a56773ca527
-jsontoolkit https://github.com/sourcemeta/jsontoolkit 2b44aee9b2be18a03b375c0b1f15c7623db8b922
+jsontoolkit https://github.com/sourcemeta/jsontoolkit e7a8f35b0b85cd87b5fa587b2ae767ed939a0b4d
 hydra https://github.com/sourcemeta/hydra 3c53d3fdef79e9ba603d48470a508cc45472a0dc
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index af021265..a6402635 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -140,6 +140,7 @@ add_jsonschema_test_unix(compile/pass_2)
 add_jsonschema_test_unix(compile/fail_no_schema)
 add_jsonschema_test_unix(compile/fail_schema_invalid_json)
 add_jsonschema_test_unix(compile/fail_unknown_metaschema)
+add_jsonschema_test_unix(compile/fail_ref_from_unknown_keyword)
 
 # Identify
 add_jsonschema_test_unix(identify/fail_resolve_from_no_match)
diff --git a/test/compile/fail_ref_from_unknown_keyword.sh b/test/compile/fail_ref_from_unknown_keyword.sh
new file mode 100755
index 00000000..9442b1bd
--- /dev/null
+++ b/test/compile/fail_ref_from_unknown_keyword.sh
@@ -0,0 +1,35 @@
+#!/bin/sh
+
+set -o errexit
+set -o nounset
+
+TMP="$(mktemp -d)"
+clean() { rm -rf "$TMP"; }
+trap clean EXIT
+
+cat << 'EOF' > "$TMP/schema.json"
+{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "properties": {
+    "foo": { "$ref": "#/$defs/bar" },
+    "baz": { "type": "string" }
+  },
+  "$defs": {
+    "bar": {
+      "$ref": "#/properties/baz"
+    }
+  }
+}
+EOF
+
+"$1" compile "$TMP/schema.json" 2>"$TMP/stderr.txt" \
+  && CODE="$?" || CODE="$?"
+test "$CODE" = "1" || exit 1
+
+cat << 'EOF' > "$TMP/expected.txt"
+error: The schema location is inside of an unknown keyword
+  #/properties/baz
+    at schema location "/$defs/bar/$ref"
+EOF
+
+diff "$TMP/stderr.txt" "$TMP/expected.txt"
diff --git a/vendor/jsontoolkit/src/jsonschema/default_compiler_draft4.h b/vendor/jsontoolkit/src/jsonschema/default_compiler_draft4.h
index f804ac4d..fb251e62 100644
--- a/vendor/jsontoolkit/src/jsonschema/default_compiler_draft4.h
+++ b/vendor/jsontoolkit/src/jsonschema/default_compiler_draft4.h
@@ -23,7 +23,13 @@ auto compiler_draft4_core_ref(const SchemaCompilerContext &context,
   const auto current{keyword_location(schema_context)};
   assert(context.frame.contains({type, current}));
   const auto &entry{context.frame.at({type, current})};
-  assert(context.references.contains({type, entry.pointer}));
+  if (!context.references.contains({type, entry.pointer})) {
+    assert(schema_context.schema.at(dynamic_context.keyword).is_string());
+    throw SchemaReferenceError(
+        schema_context.schema.at(dynamic_context.keyword).to_string(),
+        entry.pointer, "The schema location is inside of an unknown keyword");
+  }
+
   const auto &reference{context.references.at({type, entry.pointer})};
   const auto label{std::hash<std::string>{}(reference.destination)};