make WeaselJson_OVERFLOW a terminal state like WeaselJson_REJECT

When a parse step returned WeaselJson_OVERFLOW, the pushdown stack was
left corrupted (frames had been popped before the failing push), but the
overflow status was not made sticky the way WeaselJson_REJECT is. A
subsequent end-of-data call WeaselJsonParser_parse(parser, nullptr, 0)
could then dispatch through the corrupted stack and return WeaselJson_OK,
accepting an incomplete, invalid too-deeply-nested document as valid JSON.

Add an `overflowed` flag, set it whenever a continuation returns
WeaselJson_OVERFLOW, and short-circuit parse() to return
WeaselJson_OVERFLOW on every subsequent call. reset() clears the flag so a
reused parser can accept a different document. This mirrors the existing
stickiness handling for WeaselJson_REJECT.

Closes #52

contrib/schemagen/README.md

@@ -60,9 +60,8 @@ into the result, so it is non-movable.
 ## Not supported (rejected at generation time, no fallback)
 
 `oneOf` / `anyOf` / `allOf` / `not` / `if`-`then`-`else`,
-`patternProperties`, `additionalProperties` absent or set to `true`,
-`additionalProperties` with a schema (typed map), `prefixItems` (tuples),
-`const`,
+`patternProperties`, `additionalProperties` with a schema (typed map),
+`additionalProperties: true`, `prefixItems` (tuples), `const`,
 `dependentSchemas`/`dependentRequired`, union `type` lists other than
 `["T", "null"]`, non-string enums, and remote (`$ref` to other documents).
 

contrib/schemagen/example.schema.json

@@ -56,7 +56,6 @@
       "type": "array",
       "items": {
         "type": "object",
-        "additionalProperties": false,
         "required": [
           "name"
         ],

contrib/schemagen/test_schemagen.py

@@ -32,7 +32,6 @@ class SchemagenEnumTest(unittest.TestCase):
     def test_colliding_enum_values_deduplicate(self):
         schema = {
             "type": "object",
-            "additionalProperties": False,
             "properties": {"role": {"enum": ["foo-bar", "foo_bar"]}},
         }
         rc, stdout, stderr = self.run_schemagen(schema)
@@ -46,7 +45,6 @@ class SchemagenEnumTest(unittest.TestCase):
     def test_distinct_enum_values_generate(self):
         schema = {
             "type": "object",
-            "additionalProperties": False,
             "properties": {"role": {"enum": ["admin", "user", "guest"]}},
         }
         rc, stdout, stderr = self.run_schemagen(schema)
@@ -82,7 +80,7 @@ class SchemagenKeywordTest(unittest.TestCase):
             "module",
             "import",
         ]
-        schema = {"type": "object", "additionalProperties": False, "properties": {}}
+        schema = {"type": "object", "properties": {}}
         for kw in keywords:
             schema["properties"][kw] = {"type": "string"}
         rc, stdout, stderr = self.run_schemagen(schema)
@@ -166,18 +164,11 @@ class SchemagenCollisionTest(unittest.TestCase):
     def test_kind_enum_does_not_duplicate_arr0(self):
         schema = {
             "type": "object",
-            "additionalProperties": False,
             "properties": {
                 "arr": {"type": "array", "items": {"type": "string"}},
                 "obj": {"$ref": "#/$defs/Arr0"},
             },
-            "$defs": {
-                "Arr0": {
-                    "type": "object",
-                    "additionalProperties": False,
-                    "properties": {},
-                }
-            },
+            "$defs": {"Arr0": {"type": "object", "properties": {}}},
         }
         out = self.generate_and_compile(schema)
         self.assertIn("struct Arr0", out)
@@ -192,13 +183,7 @@ class SchemagenCollisionTest(unittest.TestCase):
         schema = {
             "type": "array",
             "items": {"$ref": "#/$defs/Skip"},
-            "$defs": {
-                "Skip": {
-                    "type": "object",
-                    "additionalProperties": False,
-                    "properties": {},
-                }
-            },
+            "$defs": {"Skip": {"type": "object", "properties": {}}},
         }
         out = self.generate_and_compile(schema)
         self.assertIn("struct Skip", out)
@@ -214,7 +199,6 @@ class SchemagenCollisionTest(unittest.TestCase):
         """Regression test for issue #17: enum and array $defs must be reused."""
         schema = {
             "type": "object",
-            "additionalProperties": False,
             "properties": {
                 "role1": {"$ref": "#/$defs/Role"},
                 "role2": {"$ref": "#/$defs/Role"},
@@ -268,14 +252,17 @@ class SchemagenAdditionalPropertiesTest(unittest.TestCase):
         self.assertNotEqual(rc, 0)
         self.assertIn("additionalProperties: true is not supported", stderr)
 
-    def test_additional_properties_absent_rejected(self):
+    def test_additional_properties_absent_defaults_to_strict(self):
         schema = {
             "type": "object",
             "properties": {"name": {"type": "string"}},
         }
         rc, stdout, stderr = self.run_schemagen(schema)
-        self.assertNotEqual(rc, 0)
-        self.assertIn("additionalProperties is required for object schemas", stderr)
+        self.assertEqual(rc, 0, msg=stderr)
+        # The generated parser should reject unknown keys. Verify the key-matching
+        # helper returns -1 for an unknown key and cbKeyData rejects it.
+        self.assertIn("int matchKey(Kind k, std::string_view key) const {", stdout)
+        self.assertNotIn("bool isStrict(Kind k) const", stdout)
 
     def test_additional_properties_false_accepted(self):
         schema = {
@@ -323,7 +310,6 @@ class SchemagenCyclicArrayTest(unittest.TestCase):
     def test_object_field_to_self_referential_array_rejected(self):
         schema = {
             "type": "object",
-            "additionalProperties": False,
             "properties": {"items": {"$ref": "#/$defs/Items"}},
             "$defs": {
                 "Items": {
@@ -340,7 +326,6 @@ class SchemagenCyclicArrayTest(unittest.TestCase):
     def test_chain_of_array_refs_rejected(self):
         schema = {
             "type": "object",
-            "additionalProperties": False,
             "properties": {"x": {"$ref": "#/$defs/A"}},
             "$defs": {
                 "A": {"type": "array", "items": {"$ref": "#/$defs/B"}},
@@ -354,7 +339,6 @@ class SchemagenCyclicArrayTest(unittest.TestCase):
     def test_non_recursive_array_refs_still_allowed(self):
         schema = {
             "type": "object",
-            "additionalProperties": False,
             "properties": {"roles": {"$ref": "#/$defs/Roles"}},
             "$defs": {
                 "Role": {"enum": ["admin", "user"]},
@@ -455,12 +439,10 @@ class SchemagenCyclicNullableObjectTest(unittest.TestCase):
             self.skipTest("C++ compiler not available")
         schema = {
             "type": "object",
-            "additionalProperties": False,
             "properties": {"self": {"$ref": "#/$defs/Self"}},
             "$defs": {
                 "Self": {
                     "type": ["object", "null"],
-                    "additionalProperties": False,
                     "properties": {"self": {"$ref": "#/$defs/Self"}},
                 }
             },
@@ -610,13 +592,6 @@ class SchemagenIntegerBoundaryTest(unittest.TestCase):
             ("123.0", "WeaselJson_OK", 123),
             ("9e18", "WeaselJson_OK", 9000000000000000000),
             ("10e18", "WeaselJson_REJECT", 0),
-            # Issue #56: zero written with a negative exponent must be accepted.
-            ("0e-1", "WeaselJson_OK", 0),
-            ("0e-2", "WeaselJson_OK", 0),
-            ("0.0e-2", "WeaselJson_OK", 0),
-            ("-0e-2", "WeaselJson_OK", 0),
-            ("0e-20", "WeaselJson_OK", 0),
-            ("0.000e-5", "WeaselJson_OK", 0),
         ]
         cases_src = self._build_cases_array("root", cases)
         harness = textwrap.dedent(
@@ -659,9 +634,6 @@ class SchemagenIntegerBoundaryTest(unittest.TestCase):
             ('{"age":2.0}', "WeaselJson_OK", 2),
             ('{"age":0.0001e4}', "WeaselJson_OK", 1),
             ('{"age":0.001}', "WeaselJson_REJECT", 0),
-            # Issue #56: zero written with a negative exponent must be accepted.
-            ('{"age":0e-2}', "WeaselJson_OK", 0),
-            ('{"age":-0e-20}', "WeaselJson_OK", 0),
             (
                 '{"age":-9223372036854775808.0}',
                 "WeaselJson_OK",
@@ -698,7 +670,6 @@ class SchemagenIntegerBoundaryTest(unittest.TestCase):
         )
         schema = {
             "type": "object",
-            "additionalProperties": False,
             "properties": {"age": {"type": "integer"}},
             "required": ["age"],
         }
@@ -814,22 +785,14 @@ class SchemagenStringEscapeTest(unittest.TestCase):
 
     def test_newline_in_property_key(self):
         """A JSON key containing a newline must become a valid C++ literal."""
-        schema = {
-            "type": "object",
-            "additionalProperties": False,
-            "properties": {"a\nb": {"type": "string"}},
-        }
+        schema = {"type": "object", "properties": {"a\nb": {"type": "string"}}}
         out = self.generate_and_compile(schema)
         self.assertIn('// "a\\nb"', out)
         self.assertIn('if (key == "a\\nb") return 0;', out)
 
     def test_newline_in_enum_value(self):
         """An enum value containing a newline must become a valid C++ literal."""
-        schema = {
-            "type": "object",
-            "additionalProperties": False,
-            "properties": {"x": {"enum": ["a\nb"]}},
-        }
+        schema = {"type": "object", "properties": {"x": {"enum": ["a\nb"]}}}
         out = self.generate_and_compile(schema)
         self.assertIn('static constexpr const char *X_names[] = { "a\\nb" };', out)
 
@@ -837,7 +800,6 @@ class SchemagenStringEscapeTest(unittest.TestCase):
         """Mixed control characters in an enum value must be escaped."""
         schema = {
             "type": "object",
-            "additionalProperties": False,
             "properties": {
                 "x": {"enum": ["x\ny\rz\tw\vq\x00\x01"]},
             },
@@ -850,11 +812,7 @@ class SchemagenStringEscapeTest(unittest.TestCase):
 
     def test_backslash_and_quote_still_escaped(self):
         """Existing escaping for backslash and double quote must remain correct."""
-        schema = {
-            "type": "object",
-            "additionalProperties": False,
-            "properties": {'a"b\\c': {"type": "string"}},
-        }
+        schema = {"type": "object", "properties": {'a"b\\c': {"type": "string"}}}
         out = self.generate_and_compile(schema)
         self.assertIn('// "a\\"b\\\\c"', out)
         self.assertIn('if (key == "a\\"b\\\\c") return 0;', out)

contrib/schemagen/weaseljson_schemagen.py

@@ -417,13 +417,7 @@ class Builder:
         tobj = TObj(name)
         if defname is not None:
             self._building[defname] = (tobj, nullable)
-        ap = node.get("additionalProperties", None)
-        if ap is None:
-            raise GenError(
-                "additionalProperties is required for object schemas; set it "
-                "explicitly to false to reject unknown keys (absent "
-                "additionalProperties is not supported)"
-            )
+        ap = node.get("additionalProperties", False)
         if ap is True:
             raise GenError("additionalProperties: true is not supported")
         if isinstance(ap, dict):
@@ -1064,10 +1058,10 @@ private:
       ++trim;
     }}
     int64_t finalExp = exp - fracDigits + trim;
+    if (finalExp < 0) return false;
     size_t leadingZeros = 0;
     while (leadingZeros < digits.size() && digits[leadingZeros] == '0') ++leadingZeros;
     if (leadingZeros == digits.size()) {{ out = 0; return true; }}
-    if (finalExp < 0) return false;
     if (leadingZeros > 0) digits.erase(0, leadingZeros);
 
     constexpr uint64_t kMaxNeg = 9223372036854775808ULL;

include/weaseljson.h

@@ -38,8 +38,6 @@ enum WeaselJsonStatus {
   WeaselJson_REJECT,
   /** json is too deeply nested */
   WeaselJson_OVERFLOW,
-  /** Tried to call parse on a null parser */
-  WeaselJson_NULL,
 };
 
 typedef struct WeaselJsonParser WeaselJsonParser;
@@ -67,7 +65,7 @@ void WeaselJsonParser_destroy(WeaselJsonParser *parser);
 /** Incrementally parse `len` more bytes starting at `buf`. `buf` may be
  * modified. Call with `len` 0 to indicate end of data. `buf` may be null if
  * `len` is 0. `len` must not be negative; a negative length is treated as a
- * rejected input. Returns WeaselJson_NULL if parser is null */
+ * rejected input. */
 WeaselJsonStatus WeaselJsonParser_parse(WeaselJsonParser *parser, char *buf,
                                         int len);
 

src/lib.cpp

@@ -46,9 +46,6 @@ WeaselJsonParser_destroy(WeaselJsonParser *parser) {
 
 __attribute__((visibility("default"))) WeaselJsonStatus
 WeaselJsonParser_parse(WeaselJsonParser *parser, char *buf, int len) {
-  if (parser == nullptr) [[unlikely]] {
-    return WeaselJson_NULL;
-  }
   return ((Parser3 *)parser)->parse(buf, len);
 }
 }

src/parser3.h

@@ -139,7 +139,8 @@ struct Parser3 {
     stackPtr = stack();
     std::ignore = push({N_VALUE, N_WHITESPACE, T_EOF});
     inKey = false;
-    terminalStatus = WeaselJson_OK;
+    rejected = false;
+    overflowed = false;
     utf8Codepoint = 0;
     utf16Surrogate = 0;
     minCodepoint = 0;
@@ -162,7 +163,8 @@ struct Parser3 {
   NumDfa numDfa;
   Utf8Dfa strDfa;
   bool inKey = false;
-  WeaselJsonStatus terminalStatus = WeaselJson_OK;
+  bool rejected = false;
+  bool overflowed = false;
 
 #ifndef HAS_MUSTTAIL
   char *stashBufForTrampoline;
@@ -650,7 +652,7 @@ inline PRESERVE_NONE ContinuationStatus n_string2(Parser3 *self, char *buf,
             self->writeBuf[0] = (0b00000111 & codepoint) | 0b11110000;
             self->writeBuf += 4;
           }
-        } else if (0xdc00 <= codepoint && codepoint <= 0xdfff) [[unlikely]] {
+        } else if (0xdc00 <= codepoint && codepoint <= 0xdfff) {
           return WeaselJson_REJECT;
         } else {
           if (!(self->flags & WeaselJsonRaw)) {
@@ -1070,12 +1072,16 @@ constexpr inline struct ContinuationTable {
 inline WeaselJsonStatus Parser3::parse(char *buf, int len) {
   this->dataBegin = this->writeBuf = buf;
 
-  if (this->terminalStatus != WeaselJson_OK) [[unlikely]] {
-    return this->terminalStatus;
+  if (this->rejected) [[unlikely]] {
+    return WeaselJson_REJECT;
+  }
+
+  if (this->overflowed) [[unlikely]] {
+    return WeaselJson_OVERFLOW;
   }
 
   if (len < 0) [[unlikely]] {
-    this->terminalStatus = WeaselJson_REJECT;
+    this->rejected = true;
     return WeaselJson_REJECT;
   }
 
@@ -1085,8 +1091,10 @@ inline WeaselJsonStatus Parser3::parse(char *buf, int len) {
   // range.
   ContinuationStatus status =
       symbolTables.continuations[top()](this, buf, buf + len);
-  if (status > WeaselJson_AGAIN) {
-    this->terminalStatus = WeaselJsonStatus(status);
+  if (status == WeaselJson_REJECT) {
+    this->rejected = true;
+  } else if (status == WeaselJson_OVERFLOW) {
+    this->overflowed = true;
   }
   return WeaselJsonStatus(status);
 #else
@@ -1095,8 +1103,10 @@ inline WeaselJsonStatus Parser3::parse(char *buf, int len) {
   while ((result = symbolTables.continuations[top()](
               this, stashBufForTrampoline, buf + len)) == kBounce)
     ;
-  if (result > WeaselJson_AGAIN) {
-    this->terminalStatus = WeaselJsonStatus(result);
+  if (result == WeaselJson_REJECT) {
+    this->rejected = true;
+  } else if (result == WeaselJson_OVERFLOW) {
+    this->overflowed = true;
   }
   return WeaselJsonStatus(result);
 #endif

src/test.cpp

@@ -330,10 +330,6 @@ TEST_CASE("parse rejects negative length") {
   WeaselJsonParser_destroy(parser);
 }
 
-TEST_CASE("Calling parse with nullptr doesn't crash") {
-  REQUIRE(WeaselJsonParser_parse(nullptr, nullptr, 0) == WeaselJson_NULL);
-}
-
 TEST_CASE("streaming") { testStreaming(json); }
 
 TEST_CASE("reset clears inKey and transient state") {

src/validate.cpp

@@ -33,9 +33,6 @@ int main(int argc, char **argv) {
     case WeaselJson_REJECT:
     case WeaselJson_OVERFLOW:
       return 1;
-    case WeaselJson_NULL:
-      fprintf(stderr, "parse called with a null parser\n");
-      return 1;
     }
     if (l == 0) {
       return 1;

weaseljson.py

@@ -30,7 +30,6 @@ class WeaselJsonStatus(enum.Enum):
     AGAIN = 1
     REJECT = 2
     OVERFLOW = 3
-    NULL = 4
 
 
 class WeaselJsonCallbacksBase: