From 3befe3f3d3905daba1d82b76f806dc84a48f9877 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Raphael=20R=C3=B6sch?= <raphael.roesch@1und1.de>
Date: Mon, 5 Aug 2024 12:52:37 +0200
Subject: [PATCH] AVRO-2032: Add support for NaN, Infinity and -Infinity in
 JsonDecoder

JsonEncoder uses special string values to represent NaN, Infinity and
-Infinity values for float and double values, but JsonDecoder does not
accept these string values. This change adds support for these special
values to JsonDecoder.
---
 .../java/org/apache/avro/io/JsonDecoder.java  | 44 +++++++++++++++++++
 .../org/apache/avro/io/TestJsonDecoder.java   | 22 ++++++++++
 2 files changed, 66 insertions(+)

diff --git a/lang/java/avro/src/main/java/org/apache/avro/io/JsonDecoder.java b/lang/java/avro/src/main/java/org/apache/avro/io/JsonDecoder.java
index 2ad496a5b87..a546c6c3c06 100644
--- a/lang/java/avro/src/main/java/org/apache/avro/io/JsonDecoder.java
+++ b/lang/java/avro/src/main/java/org/apache/avro/io/JsonDecoder.java
@@ -199,6 +199,19 @@ public float readFloat() throws IOException {
       float result = in.getFloatValue();
       in.nextToken();
       return result;
+    } else if (in.getCurrentToken() == JsonToken.VALUE_STRING) {
+      String stringValue = in.getText();
+      in.nextToken();
+      if (isNaNString(stringValue)) {
+        return Float.NaN;
+      }
+      if (isNegativeInfinityString(stringValue)) {
+        return Float.NEGATIVE_INFINITY;
+      }
+      if (isPositiveInfinityString(stringValue)) {
+        return Float.POSITIVE_INFINITY;
+      }
+      throw error("float");
     } else {
       throw error("float");
     }
@@ -211,11 +224,42 @@ public double readDouble() throws IOException {
       double result = in.getDoubleValue();
       in.nextToken();
       return result;
+    } else if (in.getCurrentToken() == JsonToken.VALUE_STRING) {
+      String stringValue = in.getText();
+      in.nextToken();
+      if (isNaNString(stringValue)) {
+        return Double.NaN;
+      }
+      if (isNegativeInfinityString(stringValue)) {
+        return Double.NEGATIVE_INFINITY;
+      }
+      if (isPositiveInfinityString(stringValue)) {
+        return Double.POSITIVE_INFINITY;
+      }
+      throw error("double");
     } else {
       throw error("double");
     }
   }
 
+  // check whether the given string represents an IEEE 754 'NaN' string value as
+  // serialized by Jackson
+  private static boolean isNaNString(String value) {
+    return "NaN".equals(value);
+  }
+
+  // check whether the given string represents an IEEE 754 'Infinity' string value
+  // as serialized by Jackson
+  private static boolean isPositiveInfinityString(String value) {
+    return "Infinity".equals(value) || "INF".equals(value);
+  }
+
+  // check whether the given string represents an IEEE 754 '-Infinity' string
+  // value as serialized by Jackson
+  private static boolean isNegativeInfinityString(String value) {
+    return "-Infinity".equals(value) || "-INF".equals(value);
+  }
+
   @Override
   public Utf8 readString(Utf8 old) throws IOException {
     return new Utf8(readString());
diff --git a/lang/java/avro/src/test/java/org/apache/avro/io/TestJsonDecoder.java b/lang/java/avro/src/test/java/org/apache/avro/io/TestJsonDecoder.java
index 1f44344e3aa..03b79f8a5f3 100644
--- a/lang/java/avro/src/test/java/org/apache/avro/io/TestJsonDecoder.java
+++ b/lang/java/avro/src/test/java/org/apache/avro/io/TestJsonDecoder.java
@@ -118,4 +118,26 @@ void testIntWithError() throws IOException {
     JsonDecoder decoder = DecoderFactory.get().jsonDecoder(schema, record);
     Assertions.assertThrows(AvroTypeException.class, () -> reader.read(null, decoder));
   }
+
+  @Test
+  void testIeee754SpecialCases() throws IOException {
+    String def = "{\"type\":\"record\",\"name\":\"X\",\"fields\": [" + "{\"type\":\"float\",\"name\":\"nanFloat\"},"
+        + "{\"type\":\"float\",\"name\":\"infinityFloat\"},"
+        + "{\"type\":\"float\",\"name\":\"negativeInfinityFloat\"}," + "{\"type\":\"double\",\"name\":\"nanDouble\"},"
+        + "{\"type\":\"double\",\"name\":\"infinityDouble\"},"
+        + "{\"type\":\"double\",\"name\":\"negativeInfinityDouble\"}" + "]}";
+    Schema schema = new Schema.Parser().parse(def);
+    DatumReader<GenericRecord> reader = new GenericDatumReader<>(schema);
+
+    String record = "{\"nanFloat\":\"NaN\", \"infinityFloat\":\"Infinity\", \"negativeInfinityFloat\":\"-Infinity\", "
+        + "\"nanDouble\":\"NaN\", \"infinityDouble\":\"Infinity\", \"negativeInfinityDouble\":\"-Infinity\"}";
+    Decoder decoder = DecoderFactory.get().jsonDecoder(schema, record);
+    GenericRecord r = reader.read(null, decoder);
+    assertEquals(Float.NaN, r.get("nanFloat"));
+    assertEquals(Float.POSITIVE_INFINITY, r.get("infinityFloat"));
+    assertEquals(Float.NEGATIVE_INFINITY, r.get("negativeInfinityFloat"));
+    assertEquals(Double.NaN, r.get("nanDouble"));
+    assertEquals(Double.POSITIVE_INFINITY, r.get("infinityDouble"));
+    assertEquals(Double.NEGATIVE_INFINITY, r.get("negativeInfinityDouble"));
+  }
 }