dualfroz
08305c1b95
ChronosTime::parseString() passed the fractional-seconds digits straight to (int), so a short fraction such as .5 was read as 5 microseconds instead of 500000 (half a second), diverging from DateTime. Right-pad the fractional digits to microseconds before converting.
67 lines
2.1 KiB
Markdown
67 lines
2.1 KiB
Markdown
# fix: parse fractional seconds in ChronosTime as a fraction of a second
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## Problem
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`ChronosTime` misinterprets a time string whose fractional-seconds part has fewer
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than six digits. The fractional part is treated as a literal microsecond count
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instead of a fraction of a second:
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```php
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(new Cake\Chronos\ChronosTime('12:00:00.5'))->format('H:i:s.u');
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// "12:00:00.000005" (5 microseconds)
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// expected "12:00:00.500000" (half a second, matching DateTime)
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(new DateTime('12:00:00.5'))->format('u'); // "500000"
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```
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So `12:00:00.5` becomes 5 microseconds rather than 500000, diverging from PHP's
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own `DateTime` and from the round-trip used when constructing a `ChronosTime`
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from a `DateTimeInterface` (which formats to six digits).
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## Root cause
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`src/ChronosTime.php`, `parseString()`:
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```php
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$microseconds = (int)substr($matches[4] ?? '', 0, 6);
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```
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`$matches[4]` is the digit run after the decimal point. Passing it straight to
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`(int)` reads `"5"` as `5`, ignoring that these are the most-significant digits of
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a fractional second. Only six-digit input (for example `.500000`) happened to
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work, which is why the issue was not caught: every existing test uses a full
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six-digit fraction (or a seven-digit one that is truncated to six).
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## The fix
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Right-pad the (at most six) fractional digits to microseconds before converting:
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```php
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$microseconds = (int)str_pad(substr($matches[4] ?? '', 0, 6), 6, '0', STR_PAD_RIGHT);
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```
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- `.5` -> `500000`
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- `.05` -> `50000`
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- `.500000` -> `500000` (unchanged)
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- `.000005` -> `5` (unchanged)
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- `.9999991`-> truncated to `999999` (unchanged; existing behaviour preserved)
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This matches how `DateTime` interprets fractional seconds.
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## Test
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Added `ChronosTimeTest::testConstructFromStringWithFractionalSeconds`, asserting
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that `12:00:00.5`, `12:00:00.05` and `12:00:00.000005` produce
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`500000`, `50000` and `5` microseconds respectively.
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## Gate
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```
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composer install && vendor/bin/phpunit
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```
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Result: exit code `0` - `OK (981 tests, 2496 assertions)`.
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Counterfactual: reverting `parseString()` to `(int)substr(...)` makes the new test
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fail - `12:00:00.5` yields `12:00:00.000005` instead of `12:00:00.500000`.
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