Include location in NumberFormatException thrown by JsonTreeReader

[dong0713]

Problem

JsonReader.nextDouble(), nextLong() and nextInt() already include the JSON path in the NumberFormatException thrown when a value cannot be parsed. This was added in #3000 as a fix for #1564.

However, the corresponding methods in JsonTreeReader were missing this handling. As a result, the two public deserialization entry points behave inconsistently:

class Model { int x; }

// Streaming path — already includes location (since #3000)
new Gson().fromJson("{\"x\":\"\"}", Model.class);
// -> JsonSyntaxException: ... Expected an int but was  at line 1 column 8 path $.x

// Tree path — no location information
JsonObject obj = new JsonObject();
obj.add("x", new JsonPrimitive(""));
new Gson().fromJson(obj, Model.class);
// -> JsonSyntaxException: ... NumberFormatException: For input string: ""

Both paths consume untrusted JSON and report parse failures to the caller, so they should report the same location information.

Fix

Mirror the existing JsonReader handling: wrap the JsonPrimitive conversion in nextDouble(), nextLong() and nextInt() with a try-catch, and rethrow a NumberFormatException containing the offending value and locationString(), preserving the original exception as the cause (via initCause(e)), exactly as the streaming JsonReader does.

Tests

Added three regression tests in JsonTreeReaderTest (testNextDouble/NextInt/NextLongNumberFormatExceptionContainsLocation), asserting the message contains the JSON path (path $.x / path $.y), paralleling the existing tests added for JsonReader in JsonReaderTest.

Full test suite: Tests run: 4607, Failures: 0, Errors: 0, Skipped: 20 — no regressions.

Notes

• This is the tree-path counterpart of fix: Include location info in NumberFormatException from JsonReader #3000; JsonTreeReader overrides the same JsonReader methods, so the omission is a direct symmetric gap.
• The outer Gson.fromJson only catches EOFException/IllegalStateException/IOException, so the bare NumberFormatException from the tree path reaches the caller unwrapped, making the missing location directly user-visible.

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[eamonnmcmanus]

Thanks for helping improve consistency here!

[eamonnmcmanus]

It's annoying that NumberFormatException doesn't have a constructor with a cause parameter!

Given that the code pattern here occurs three times, I think it would make sense to introduce a helper method, so you could write this:

throw numberFormatException("Expected a double " ..., e);

[dong0713]

Done — introduced a numberFormatException helper as suggested. Thanks!

[eamonnmcmanus]

Thanks again!