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edusperoni merged 2 commits into from
Nov 9, 2026
Merged

fix: convert callback results the return type can hold #2097

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074c27c
fix: convert JS callback results that the primitive return type can hold
edusperoni Nov 8, 2026
bf0f0b6
test: format float/double callback results the same on every Android …
edusperoni Nov 8, 2026
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50 changes: 26 additions & 24 deletions test-app/app/src/main/assets/app/tests/testPrimitiveCallbackReturns.js
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Original file line number Diff line number Diff line change
Expand Up @@ -49,41 +49,43 @@ describe("Primitive return values of JS callbacks", function () {
"{}": function () { return {}; }
};

// Captured from the boxed conversion; columns are z b c s i j f d.
// Columns are z b c s i j f d. A value converts only when the return type
// can hold it (whole numbers in range for integer types, float range for
// float, a one-character string for char); otherwise the binding throws.
var expected = {
"0": "ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ok:0 ok:0 ex:ClassCastException ex:ClassCastException",
"1": "ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ok:1 ok:1 ex:ClassCastException ex:ClassCastException",
"-1": "ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ok:-1 ok:-1 ex:ClassCastException ex:ClassCastException",
"-0": "ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ok:0 ok:0 ex:ClassCastException ex:ClassCastException",
"2^31": "ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ok:2147483648 ex:ClassCastException ex:ClassCastException",
"-2^31-1": "ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ok:-2147483649 ex:ClassCastException ex:ClassCastException",
"2^40": "ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ok:1099511627776 ex:ClassCastException ex:ClassCastException",
"2^60": "ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ok:1152921504606846976 ex:ClassCastException ex:ClassCastException",
"0": "ex:ClassCastException ok:0 ex:ClassCastException ok:0 ok:0 ok:0 ok:0 ok:0",
"1": "ex:ClassCastException ok:1 ex:ClassCastException ok:1 ok:1 ok:1 ok:1 ok:1",
"-1": "ex:ClassCastException ok:-1 ex:ClassCastException ok:-1 ok:-1 ok:-1 ok:-1 ok:-1",
"-0": "ex:ClassCastException ok:0 ex:ClassCastException ok:0 ok:0 ok:0 ok:0 ok:0",
"2^31": "ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ok:2147483648 ok:2.14748365E+9 ok:2147483648",
"-2^31-1": "ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ok:-2147483649 ok:-2.14748365E+9 ok:-2147483649",
"2^40": "ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ok:1099511627776 ok:1.09951163E+12 ok:1099511627776",
"2^60": "ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ok:1152921504606846976 ok:1.1529215E+18 ok:1.152921504606847E+18",
"1.5": "ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ok:1.5 ok:1.5",
"-1.5": "ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ok:-1.5",
"1e-40": "ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ok:1.0E-40",
"3.5e38": "ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ok:3.5E38",
"NaN": "ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ok:NaN",
"Infinity": "ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ok:Infinity",
"-Infinity": "ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ok:-Infinity",
"-2.5": "ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ok:-2.5",
"-1.5": "ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ok:-1.5 ok:-1.5",
"1e-40": "ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ok:9.9999999999999993E-41",
"3.5e38": "ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ok:3.5E+38",
"NaN": "ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ok:NaN ok:NaN",
"Infinity": "ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ok:Infinity ok:Infinity",
"-Infinity": "ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ok:-Infinity ok:-Infinity",
"-2.5": "ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ok:-2.5 ok:-2.5",
"true": "ok:true ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException",
"false": "ok:false ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException",
"'1'": "ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException",
"'a'": "ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException",
"null": "ok:false ok:0 ok:0 ok:0 ok:0 ok:0 ok:0.0 ok:0.0",
"undefined": "ok:false ok:0 ok:0 ok:0 ok:0 ok:0 ok:0.0 ok:0.0",
"Number(5)": "ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ok:5 ok:5 ex:ClassCastException ex:ClassCastException",
"'1'": "ex:ClassCastException ex:ClassCastException ok:49 ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException",
"'a'": "ex:ClassCastException ex:ClassCastException ok:97 ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException",
"null": "ok:false ok:0 ok:0 ok:0 ok:0 ok:0 ok:0 ok:0",
"undefined": "ok:false ok:0 ok:0 ok:0 ok:0 ok:0 ok:0 ok:0",
"Number(5)": "ex:ClassCastException ok:5 ex:ClassCastException ok:5 ok:5 ok:5 ok:5 ok:5",
"Number(2.5)": "ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ok:2.5 ok:2.5",
"Boolean(true)": "ok:true ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException",
"Boolean(false)": "ok:true ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException",
"Boolean(false)": "ok:false ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException",
"long(5)": "ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ok:5 ex:ClassCastException ex:ClassCastException",
"byte(2)": "ex:ClassCastException ok:2 ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException",
"short(3)": "ex:ClassCastException ex:ClassCastException ex:ClassCastException ok:3 ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException",
"char('a')": "ex:ClassCastException ex:ClassCastException ok:97 ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException",
"float(1.5)": "ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ok:1.5 ex:ClassCastException",
"double(2)": "ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ok:2.0",
"{}": "ok:false ok:0 ok:0 ok:0 ok:0 ok:0 ok:0.0 ok:0.0"
"double(2)": "ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ex:ClassCastException ok:2",
"{}": "ok:false ok:0 ok:0 ok:0 ok:0 ok:0 ok:0 ok:0"
};

var kinds = ["z", "b", "c", "s", "i", "j", "f", "d"];
Expand Down
16 changes: 14 additions & 2 deletions test-app/app/src/main/java/com/tns/tests/PrimitiveReturnTest.java
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Original file line number Diff line number Diff line change
@@ -1,5 +1,8 @@
package com.tns.tests;

import java.math.BigDecimal;
import java.math.MathContext;

/**
* Calls each primitive-returning method of a JS implementation and reports either the
* returned value or the class of what was thrown, so a spec can pin how JS return values
Expand All @@ -24,6 +27,15 @@ public interface Returns {
double d();
}

// Float.toString/Double.toString changed their shortest-digits algorithm
// across Android versions; BigDecimal rounding prints the same everywhere.
private static String format(double value, int digits) {
if (Double.isNaN(value) || Double.isInfinite(value)) {
return Double.toString(value);
}
return new BigDecimal(value).round(new MathContext(digits)).stripTrailingZeros().toString();
}

public static String call(Returns r, String kind) {
try {
switch (kind) {
Expand All @@ -40,9 +52,9 @@ public static String call(Returns r, String kind) {
case "j":
return "ok:" + r.j();
case "f":
return "ok:" + r.f();
return "ok:" + format(r.f(), 9);
case "d":
return "ok:" + r.d();
return "ok:" + format(r.d(), 17);
default:
throw new IllegalArgumentException(kind);
}
Expand Down
90 changes: 59 additions & 31 deletions test-app/runtime/src/main/cpp/Runtime.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -56,6 +56,7 @@

#include <cfloat>
#include <climits>
#include <cstdint>
#include <cmath>
#include <cstring>

Expand Down Expand Up @@ -503,10 +504,12 @@ jobject Runtime::RunScript(JNIEnv* _env, jobject obj, jstring scriptFile) {
}

/*
* The primitive-returning cases of JsArgToArrayConverter::ConvertArg that box
* into exactly the declared wrapper type, which is all the generated binding's
* cast accepts. Everything else keeps the boxed conversion, including the
* values it turns into a ClassCastException or a defaulted null.
* A JS callback result for a primitive Java return type, converted only when
* the declared type can hold it: whole numbers in range for the integer types,
* a value within float range (or 0, NaN, +-Infinity) for float, any number for
* double, a one-character string for char. Anything else keeps the boxed
* conversion, whose result the generated binding rejects with a
* ClassCastException.
*/
static bool TryGetPrimitiveReturnBits(Isolate* isolate,
const Local<Value>& value, Type type,
Expand All @@ -516,62 +519,87 @@ static bool TryGetPrimitiveReturnBits(Isolate* isolate,
}

if (type == Type::Boolean) {
if (!value->IsBoolean() && !value->IsBooleanObject()) {
return false;
if (value->IsBoolean()) {
bits = value->IsTrue() ? 1 : 0;
return true;
}
if (value->IsBooleanObject()) {
bits = value.As<BooleanObject>()->ValueOf() ? 1 : 0;
return true;
}
// ToBoolean, as the boxed path does: a Boolean object is always true.
bits = value->BooleanValue(isolate) ? 1 : 0;
return true;
}

// Number objects are left to the boxed path: reading one calls valueOf,
// which must not run twice if this path then declines.
if (!value->IsNumber()) {
return false;
}

if (type == Type::Int && value->IsInt32()) {
bits = value.As<Int32>()->Value();
if (type == Type::Char) {
Local<String> str;
if (value->IsString()) {
str = value.As<String>();
} else if (value->IsStringObject()) {
str = value.As<StringObject>()->ValueOf();
} else {
return false;
}
if (str->Length() != 1) {
return false;
}
uint16_t unit;
str->WriteV2(isolate, 0, 1, &unit);
bits = unit;
return true;
}

double d = value.As<Number>()->Value();
// Beyond int64 the boxed path's double -> int64 cast is undefined.
constexpr double kTwoPow63 = 9223372036854775808.0;
if (std::isfinite(d) && std::fabs(d) >= kTwoPow63) {
double d;
if (value->IsNumber()) {
d = value.As<Number>()->Value();
} else if (value->IsNumberObject()) {
d = value.As<NumberObject>()->ValueOf();
} else {
return false;
}
bool isWholeNumber =
std::isfinite(d) && d == static_cast<double>(static_cast<int64_t>(d));

bool isWhole = std::isfinite(d) && std::trunc(d) == d;
switch (type) {
case Type::Byte:
if (isWhole && d >= INT8_MIN && d <= INT8_MAX) {
bits = static_cast<jbyte>(d);
return true;
}
return false;
case Type::Short:
if (isWhole && d >= INT16_MIN && d <= INT16_MAX) {
bits = static_cast<jshort>(d);
return true;
}
return false;
case Type::Int:
if (isWholeNumber && INT_MIN <= d && d <= INT_MAX) {
if (isWhole && d >= INT32_MIN && d <= INT32_MAX) {
bits = static_cast<jint>(d);
return true;
}
return false;
case Type::Long:
if (isWholeNumber) {
// 2^63 itself is not representable; the boxed path's handling of it is
// undefined, so it is left there.
if (isWhole && std::fabs(d) < 9223372036854775808.0) {
bits = static_cast<jlong>(d);
return true;
}
return false;
case Type::Float:
if (!isWholeNumber && FLT_MIN <= d && d <= FLT_MAX) {
case Type::Float: {
double magnitude = std::fabs(d);
if (!std::isfinite(d) || d == 0 ||
(magnitude >= FLT_MIN && magnitude <= FLT_MAX)) {
float f = static_cast<jfloat>(d);
int32_t raw;
memcpy(&raw, &f, sizeof(raw));
bits = raw;
return true;
}
return false;
}
case Type::Double:
if (!isWholeNumber) {
memcpy(&bits, &d, sizeof(bits));
return true;
}
return false;
memcpy(&bits, &d, sizeof(bits));
return true;
default:
return false;
}
Expand Down
17 changes: 11 additions & 6 deletions test-app/runtime/src/main/java/com/tns/Runtime.java
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Original file line number Diff line number Diff line change
Expand Up @@ -1537,14 +1537,13 @@ private static Object discardCall(String methodName, Class<?> retType, String re
}

/*
* For return types the native side can hand back as raw bits instead of a
* boxed object: it writes {bits, 1} here and returns null, or leaves the
* array untouched and returns the boxed value as before.
* For primitive return types the native side hands the converted value back
* as raw bits: it writes {bits, 1} here and returns null, or leaves the
* array untouched and returns a boxed value from the generic conversion.
*/
private static long[] newPrimitiveResult(int returnType) {
boolean raw = returnType == TypeIDs.Boolean || returnType == TypeIDs.Int || returnType == TypeIDs.Long
|| returnType == TypeIDs.Float || returnType == TypeIDs.Double;
return raw ? new long[2] : null;
boolean primitive = returnType >= TypeIDs.Boolean && returnType <= TypeIDs.Double;
return primitive ? new long[2] : null;
}

private static Object takePrimitiveResult(Object nativeResult, int returnType, long[] primitiveResult) {
Expand All @@ -1555,6 +1554,12 @@ private static Object takePrimitiveResult(Object nativeResult, int returnType, l
long bits = primitiveResult[0];
if (returnType == TypeIDs.Boolean) {
return bits != 0;
} else if (returnType == TypeIDs.Char) {
return (char) bits;
} else if (returnType == TypeIDs.Byte) {
return (byte) bits;
} else if (returnType == TypeIDs.Short) {
return (short) bits;
} else if (returnType == TypeIDs.Int) {
return (int) bits;
} else if (returnType == TypeIDs.Long) {
Expand Down
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