Handle +/-inf in protos (#7256)

* Handle +/-inf in protos

* Check for digit in 4th pos

src/idl_parser.cpp

@@ -489,10 +489,21 @@ CheckedError Parser::Next() {
         }
 
         const auto has_sign = (c == '+') || (c == '-');
-        if (has_sign && IsIdentifierStart(*cursor_)) {
+        if (has_sign) {
-          // '-'/'+' and following identifier - it could be a predefined
+          // Check for +/-inf which is considered a float constant.
-          // constant. Return the sign in token_, see ParseSingleValue.
+          if (strncmp(cursor_, "inf", 3) == 0 &&
-          return NoError();
+              !(IsIdentifierStart(cursor_[4]) || is_digit(cursor_[4]))) {
+            attribute_.assign(cursor_ - 1, cursor_ + 3);
+            token_ = kTokenFloatConstant;
+            cursor_ += 3;
+            return NoError();
+          }
+
+          if (IsIdentifierStart(*cursor_)) {
+            // '-'/'+' and following identifier - it could be a predefined
+            // constant. Return the sign in token_, see ParseSingleValue.
+            return NoError();
+          }
         }
 
         auto dot_lvl =
@@ -2178,8 +2189,12 @@ template<typename T> void EnumDef::ChangeEnumValue(EnumVal *ev, T new_value) {
 }
 
 namespace EnumHelper {
-template<BaseType E> struct EnumValType { typedef int64_t type; };
+template<BaseType E> struct EnumValType {
-template<> struct EnumValType<BASE_TYPE_ULONG> { typedef uint64_t type; };
+  typedef int64_t type;
+};
+template<> struct EnumValType<BASE_TYPE_ULONG> {
+  typedef uint64_t type;
+};
 }  // namespace EnumHelper
 
 struct EnumValBuilder {
@@ -2885,8 +2900,11 @@ CheckedError Parser::ParseProtoFields(StructDef *struct_def, bool isextend,
           if (key == "default") {
             // Temp: skip non-numeric and non-boolean defaults (enums).
             auto numeric = strpbrk(val.c_str(), "0123456789-+.");
-            if (IsScalar(type.base_type) &&
+            if (IsFloat(type.base_type) &&
-                (numeric == val.c_str() || val == "inf" || val == "-inf")) {
+                (val == "inf" || val == "+inf" || val == "-inf")) {
+              // Prefer to be explicit with +inf.
+              field->value.constant = val == "inf" ? "+inf" : val;
+            } else if (IsScalar(type.base_type) && numeric == val.c_str()) {
               field->value.constant = val;
             } else if (val == "true") {
               field->value.constant = val;

tests/prototest/test.golden

@@ -51,6 +51,9 @@ table ProtoMessage {
   /// doc comment for r.
   r:proto.test.ProtoMessage_.Anonymous0;
   outer_enum:proto.test.ProtoEnum;
+  u:float = +inf;
+  v:float = +inf;
+  w:float = -inf;
 }
 
 namespace proto.test.ProtoMessage_;

tests/prototest/test.proto

@@ -67,4 +67,8 @@ message ProtoMessage {
     OtherMessage t = 18;
   }
   optional ProtoEnum outer_enum = 33;
+  // Tests that `inf` and `+/-inf` can be parsed in proto options.
+  optional float u = 34 [default = inf];
+  optional float v = 35 [default = +inf];
+  optional float w = 36 [default = -inf];
 }

tests/prototest/test_include.golden

@@ -49,6 +49,9 @@ table ProtoMessage {
   /// doc comment for r.
   r:proto.test.ProtoMessage_.Anonymous0;
   outer_enum:proto.test.ProtoEnum;
+  u:float = +inf;
+  v:float = +inf;
+  w:float = -inf;
 }
 
 namespace proto.test.ProtoMessage_;

tests/prototest/test_suffix.golden

@@ -51,6 +51,9 @@ table ProtoMessage {
   /// doc comment for r.
   r:proto.test.test_namespace_suffix.ProtoMessage_.Anonymous0;
   outer_enum:proto.test.test_namespace_suffix.ProtoEnum;
+  u:float = +inf;
+  v:float = +inf;
+  w:float = -inf;
 }
 
 namespace proto.test.test_namespace_suffix.ProtoMessage_;

tests/prototest/test_union.golden

@@ -61,6 +61,9 @@ table ProtoMessage {
   /// doc comment for r.
   r:proto.test.ProtoMessage_.RUnion;
   outer_enum:proto.test.ProtoEnum;
+  u:float = +inf;
+  v:float = +inf;
+  w:float = -inf;
 }
 
 namespace proto.test.ProtoMessage_;

tests/prototest/test_union_include.golden

@@ -59,6 +59,9 @@ table ProtoMessage {
   /// doc comment for r.
   r:proto.test.ProtoMessage_.RUnion;
   outer_enum:proto.test.ProtoEnum;
+  u:float = +inf;
+  v:float = +inf;
+  w:float = -inf;
 }
 
 namespace proto.test.ProtoMessage_;

tests/prototest/test_union_suffix.golden

@@ -61,6 +61,9 @@ table ProtoMessage {
   /// doc comment for r.
   r:proto.test.test_namespace_suffix.ProtoMessage_.RUnion;
   outer_enum:proto.test.test_namespace_suffix.ProtoEnum;
+  u:float = +inf;
+  v:float = +inf;
+  w:float = -inf;
 }
 
 namespace proto.test.test_namespace_suffix.ProtoMessage_;