Bug Parse Date 1966-11-01

[mariofelesdossantosjunior]

Gson version

Version: 2.10.1

Java / Android version

Android target sdk 33

Used tools

• Maven; version:
• Gradle; version:
• ProGuard (attach the configuration file please); version:
• ...

Description

Failure in parse date '1966-11-01'

Expected behavior

Failed parsing '1966-11-01' as Date; at path $.birthday

If it's a day's difference from success

[fzanutto]

This error seems to be happening since Gson 2.9.1.
Downgrading to 2.9.0 the error does not happen and the test succeeds

Stack trace:

Failed parsing '1966-11-01' as Date; at path $.birthday
com.google.gson.JsonSyntaxException: Failed parsing '1966-11-01' as Date; at path $.birthday
	at com.google.gson.internal.bind.DefaultDateTypeAdapter.deserializeToDate(DefaultDateTypeAdapter.java:165)
	at com.google.gson.internal.bind.DefaultDateTypeAdapter.read(DefaultDateTypeAdapter.java:148)
	at com.google.gson.internal.bind.DefaultDateTypeAdapter.read(DefaultDateTypeAdapter.java:48)
	at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$1.read(ReflectiveTypeAdapterFactory.java:161)
	at com.google.gson.internal.bind.ReflectiveTypeAdapterFactory$Adapter.read(ReflectiveTypeAdapterFactory.java:266)
	at com.google.gson.Gson.fromJson(Gson.java:1058)
	at com.google.gson.Gson.fromJson(Gson.java:1016)
	at com.google.gson.Gson.fromJson(Gson.java:959)
	at com.google.gson.Gson.fromJson(Gson.java:927)

[Marcono1234]

The exception should have a cause ("Caused by: ..."), could you please include that part of the stack trace as well?

I assume #2134 might be responsible for this issue, but I could not reproduce it yet locally, for me no exception occurred.
For testing I used the following code, does that cause the exception for you as well¹?

Gson gson = new GsonBuilder().setDateFormat("yyyy-MM-dd'T'HH:mm:ss").create();
System.out.println(gson.fromJson("1966-11-01", Date.class));

Could you also please provide the output of this?

System.out.println(Locale.getDefault());
System.out.println(TimeZone.getDefault());

Maybe the default locale or timezone on your PC somehow affects the date parsing. Could be related to #1511, that your default timezone does not consider 1966-11-01 to be a valid date (?).

Footnotes

1. In the future please also include the reproduction code as text in the issue, not just as screenshot. That makes it easier to test it. ↩

[mariofelesdossantosjunior]

Hello, The problem only occurs when running on a device, or via Roboletric in tests.

Execute:

System.out.println(Locale.getDefault());
System.out.println(TimeZone.getDefault());

Result:

pt_BR
sun.util.calendar.ZoneInfo[id="America/Sao_Paulo",offset=-10800000,dstSavings=0,useDaylight=false,transitions=93,lastRule=null]

[Marcono1234]

Thanks! This seems to be caused indeed by your default timezone. If I add the following to the test code above

TimeZone.setDefault(TimeZone.getTimeZone("America/Sao_Paulo"));

It fails with:

Exception in thread "main" com.google.gson.JsonSyntaxException: Failed parsing '1966-11-01' as Date; at path $
	at com.google.gson.internal.bind.DefaultDateTypeAdapter.deserializeToDate(DefaultDateTypeAdapter.java:164)
	at com.google.gson.internal.bind.DefaultDateTypeAdapter.read(DefaultDateTypeAdapter.java:147)
	at com.google.gson.internal.bind.DefaultDateTypeAdapter.read(DefaultDateTypeAdapter.java:47)
	at com.google.gson.Gson.fromJson(Gson.java:1227)
	at com.google.gson.Gson.fromJson(Gson.java:1137)
	at com.google.gson.Gson.fromJson(Gson.java:1047)
	at com.google.gson.Gson.fromJson(Gson.java:982)
	at GsonTest4.main(GsonTest4.java:251)
Caused by: java.text.ParseException: Failed to parse date ["1966-11-01"]: HOUR_OF_DAY: 0 -> 1
	at com.google.gson.internal.bind.util.ISO8601Utils.parse(ISO8601Utils.java:279)
	at com.google.gson.internal.bind.DefaultDateTypeAdapter.deserializeToDate(DefaultDateTypeAdapter.java:162)
	... 7 more
Caused by: java.lang.IllegalArgumentException: HOUR_OF_DAY: 0 -> 1
	at java.base/java.util.GregorianCalendar.computeTime(GregorianCalendar.java:2790)
	at java.base/java.util.Calendar.updateTime(Calendar.java:3411)
	at java.base/java.util.Calendar.getTimeInMillis(Calendar.java:1805)
	at java.base/java.util.Calendar.getTime(Calendar.java:1776)
	at com.google.gson.internal.bind.util.ISO8601Utils.parse(ISO8601Utils.java:160)
	... 8 more

Not sure if this can be fixed in any way other than reverting #2134 ¹, which would mean Gson would fail to detect dates which are invalid for all timezones, or fixing #1511, which might negatively affect other users.

As pointed out in the discussion in #2480, it might be better if you switched from java.util.Date to java.time.LocalDate for parsing your date in yyyy-MM-dd format (and write a custom TypeAdapter for LocalDate because Gson has currently no built-in one).

@eamonnmcmanus, what do you think?

Footnotes

1. However, the question would be then if that malformed Date for 1966-11-01 with America/Sao_Paulo timezone behaves correctly, or if you will get incorrect results when trying to use it, since this does not represent a valid date apparently. ↩