Merge pull request #1033 from netfs/r1.9

Fix erroneous formatting of numbers that are larger than 6 digits.

Author: netfs

tensorflow_serving/util/json_tensor.cc

@@ -700,12 +700,16 @@ bool WriteDecimal(RapidJsonWriter* writer, dtype val) {
   string decimal_str;
   if (std::isfinite(val)) {
     decimal_str = absl::StrCat(val);
-    // Add trailing '.0' for whole numbers. StrCat() formats whole numbers
-    // without one. This can lead to lists containing mix of decimal and
-    // whole numbers -- making it difficult for consumers to pick the
-    // correct type to store these numbers (note, JSON does not have
-    // metadata to describe types. These are inferred from the tokens).
-    if (decimal_str.find('.') == string::npos) {
+    // Add trailing '.0' for whole numbers and those not in scientific notation.
+    // StrCat() formats numbers in six-digit (printf "%g"), numbers like 9000000
+    // and .00003 get written as 9e+06 and 3e-05 (scientific notation).
+    //
+    // Not adding '.0' can lead to lists containing mix of decimal and whole
+    // numbers -- making it difficult for consumers to pick the correct type to
+    // store these numbers (note, JSON does not have metadata to describe types.
+    // These are inferred from the tokens).
+    if (decimal_str.find('.') == string::npos &&
+        decimal_str.find('e') == string::npos) {
       absl::StrAppend(&decimal_str, ".0");
     }
   } else if (std::isnan(val)) {

tensorflow_serving/util/json_tensor_test.cc

@@ -546,6 +546,32 @@ TEST(JsontensorTest, FromJsonSingleBytesTensor) {
     ]})"));
 }
 
+// Tests StrCat() six-digit precision float output is correctly
+// represented in the final (output) JSON string.
+TEST(JsontensorTest, FromJsonSingleFloatTensorSixDigitPrecision) {
+  TensorMap tensormap;
+  ASSERT_TRUE(TextFormat::ParseFromString(R"(
+    dtype: DT_FLOAT
+    tensor_shape {
+      dim { size: 2 }
+      dim { size: 2 }
+    }
+    float_val: 9000000
+    float_val: 999999
+    float_val: .0003
+    float_val: .00003
+    )",
+                                          &tensormap["float_tensor"]));
+
+  string json;
+  TF_EXPECT_OK(MakeJsonFromTensors(tensormap, &json));
+  TF_EXPECT_OK(CompareJsonAllValuesAsStrings(json, R"({
+    "predictions": [
+      [9e+06, 999999.0],
+      [0.0003, 3e-05]
+    ]})"));
+}
+
 TEST(JsontensorTest, FromJsonSingleFloatTensorNonFinite) {
   TensorMap tensormap;
   ASSERT_TRUE(TextFormat::ParseFromString(R"(