`IntlDateFormatter` returns wrong output for 1940 date in Amsterdam timezone
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Description
Description
The following code:
<?php
$timezone = new DateTimeZone("Europe/Amsterdam");
$date = new DateTime("1940-01-01 00:00:00", $timezone);
var_dump($date);
$formatter = new IntlDateFormatter("en-US");
var_dump($formatter->format($date));
Resulted in this output:
object(DateTime)#2 (3) {
["date"]=>
string(26) "1940-01-01 00:00:00.000000"
["timezone_type"]=>
int(3)
["timezone"]=>
string(16) "Europe/Amsterdam"
}
string(69) "Sunday, December 31, 1939 at 11:40:00 PM Coordinated Universal Time"
But I expected this output instead:
object(DateTime)#2 (3) {
["date"]=>
string(26) "1940-01-01 00:00:00.000000"
["timezone_type"]=>
int(3)
["timezone"]=>
string(16) "Europe/Amsterdam"
}
string(48) "Monday, January 1, 1940 at 12:00:00 AM GMT+00:20"
Additional details
Until 16 May 1940, The Netherlands used UTC+00:20 as timezone. It looks like IntlDateFormatter is not aware of the UTC+00:20 timezone, so it outputs the date in UTC.
The occurrence of the problem seems related to the version of the ICU library:
| Environment | Source | PHP version | ICU version | Output |
|---|---|---|---|---|
| 3v4l.org | https://3v4l.org/UoVSs | 8.2.4 | 57.1 | ✅ As expected |
| Docker + Debian libicu | Dockerfile | 8.2.4 | 67.1 | ❌ Wrong |
| Docker + latest libicu | Dockerfile | 8.2.4 | 72.1 | ❌ Wrong |
I am not familiar enough with the ICU library to assess whether the problem originates there. Since the wrong output is present in PHP when using the latest versions (of PHP and the ICU library), I am submitting the bug here.
PHP Version
8.2.4
Operating System
No response
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start by reproducing the IntlDateFormatter example for Europe/Amsterdam and compare the ICU versions listed in the issue, using the referenced Debian and latest-ICU Dockerfiles. Trace whether the incorrect historical offset comes from PHP or ICU; done means the formatter returns the expected 1940 UTC+00:20 result or the issue is documented as an upstream ICU limitation.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- php
- Domain
- internationalization
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Mostly clear
- Newbie friendliness
- 38/100