Fix createFromFormat to respect setTestNow for missing components

src/Chronos.php

@@ -660,9 +660,96 @@ public static function createFromFormat(
             throw new InvalidArgumentException($message);
         }
 
+        $testNow = static::getTestNow();
+        if ($testNow !== null) {
+            $dateTime = static::applyTestNowToMissingComponents($dateTime, $format, $testNow);
+        }
+
         return $dateTime;
     }
 
+    /**
+     * Apply testNow values to date/time components that weren't in the format string.
+     *
+     * @param static $dateTime The parsed datetime instance.
+     * @param string $format The format string used for parsing.
+     * @param \Cake\Chronos\Chronos $testNow The test now instance.
+     * @return static
+     */
+    protected static function applyTestNowToMissingComponents(
+        self $dateTime,
+        string $format,
+        Chronos $testNow,
+    ): static {
+        // Parse format string to find which characters are actual format specifiers (not escaped)
+        $formatChars = static::getFormatCharacters($format);
+
+        // Check which components are present in the format
+        $hasYear = (bool)array_intersect($formatChars, ['Y', 'y', 'o', 'X', 'x']);
+        $hasMonth = (bool)array_intersect($formatChars, ['m', 'n', 'M', 'F']);
+        $hasDay = (bool)array_intersect($formatChars, ['d', 'j', 'D', 'l', 'N', 'z', 'w', 'W', 'S']);
+        $hasHour = (bool)array_intersect($formatChars, ['H', 'G', 'h', 'g']);
+        $hasMinute = (bool)array_intersect($formatChars, ['i']);
+        $hasSecond = (bool)array_intersect($formatChars, ['s']);
+        $hasMicro = (bool)array_intersect($formatChars, ['u', 'v']);
+
+        // If the format includes '!' or '|', PHP resets unspecified components to Unix epoch or zero
+        // In that case, we should not override with testNow
+        $hasReset = in_array('!', $formatChars, true) || in_array('|', $formatChars, true);
+        if ($hasReset) {
+            return $dateTime;
+        }
+
+        // Replace missing components with testNow values
+        $year = $hasYear ? $dateTime->year : $testNow->year;
+        $month = $hasMonth ? $dateTime->month : $testNow->month;
+        $day = $hasDay ? $dateTime->day : $testNow->day;
+        $hour = $hasHour ? $dateTime->hour : $testNow->hour;
+        $minute = $hasMinute ? $dateTime->minute : $testNow->minute;
+        $second = $hasSecond ? $dateTime->second : $testNow->second;
+        $micro = $hasMicro ? $dateTime->micro : $testNow->micro;
+
+        // Only modify if something needs to change
+        if (
+            !$hasYear || !$hasMonth || !$hasDay ||
+            !$hasHour || !$hasMinute || !$hasSecond || !$hasMicro
+        ) {
+            return $dateTime
+                ->setDate($year, $month, $day)
+                ->setTime($hour, $minute, $second, $micro);
+        }
+
+        return $dateTime;
+    }
+
+    /**
+     * Extract format characters from a format string, handling escapes.
+     *
+     * @param string $format The format string.
+     * @return array<string> Array of format characters.
+     */
+    protected static function getFormatCharacters(string $format): array
+    {
+        $chars = [];
+        $length = strlen($format);
+        $i = 0;
+
+        while ($i < $length) {
+            $char = $format[$i];
+
+            // Backslash escapes the next character
+            if ($char === '\\' && $i + 1 < $length) {
+                $i += 2;
+                continue;
+            }
+
+            $chars[] = $char;
+            $i++;
+        }
+
+        return $chars;
+    }
+
     /**
      * Returns parse warnings and errors from the last ``createFromFormat()``
      * call.

tests/TestCase/DateTime/CreateFromFormatTest.php

@@ -29,6 +29,88 @@ public function testCreateFromFormatReturnsInstance()
         $this->assertTrue($d instanceof Chronos);
     }
 
+    public function testCreateFromFormatWithTestNowMissingYear()
+    {
+        Chronos::setTestNow(new Chronos('2020-12-01 14:30:45'));
+        $d = Chronos::createFromFormat('m-d H:i:s', '10-05 09:15:30');
+        $this->assertDateTime($d, 2020, 10, 5, 9, 15, 30);
+    }
+
+    public function testCreateFromFormatWithTestNowMissingDate()
+    {
+        Chronos::setTestNow(new Chronos('2020-12-01 14:30:45'));
+        $d = Chronos::createFromFormat('H:i:s', '09:15:30');
+        $this->assertDateTime($d, 2020, 12, 1, 9, 15, 30);
+    }
+
+    public function testCreateFromFormatWithTestNowMissingTime()
+    {
+        Chronos::setTestNow(new Chronos('2020-12-01 14:30:45'));
+        $d = Chronos::createFromFormat('Y-m-d', '2021-06-15');
+        $this->assertDateTime($d, 2021, 6, 15, 14, 30, 45);
+    }
+
+    public function testCreateFromFormatWithTestNowPartialDate()
+    {
+        Chronos::setTestNow(new Chronos('2020-12-01 00:00:00'));
+        $d = Chronos::createFromFormat('m-d', '10-05');
+        $this->assertDateTime($d, 2020, 10, 5, 0, 0, 0);
+    }
+
+    public function testCreateFromFormatWithTestNowDayOnly()
+    {
+        Chronos::setTestNow(new Chronos('2020-12-01 00:00:00'));
+        $d = Chronos::createFromFormat('d', '05');
+        $this->assertDateTime($d, 2020, 12, 5, 0, 0, 0);
+    }
+
+    public function testCreateFromFormatWithTestNowComplete()
+    {
+        // When format is complete, testNow should not affect the result
+        Chronos::setTestNow(new Chronos('2020-12-01 14:30:45'));
+        $d = Chronos::createFromFormat('Y-m-d H:i:s', '1975-05-21 22:32:11');
+        $this->assertDateTime($d, 1975, 5, 21, 22, 32, 11);
+    }
+
+    public function testCreateFromFormatWithTestNowResetModifier()
+    {
+        // The '!' modifier resets to Unix epoch, should not use testNow
+        Chronos::setTestNow(new Chronos('2020-12-01 14:30:45'));
+        $d = Chronos::createFromFormat('!Y-m-d', '2021-06-15');
+        $this->assertDateTime($d, 2021, 6, 15, 0, 0, 0);
+    }
+
+    public function testCreateFromFormatWithTestNowPipeModifier()
+    {
+        // The '|' modifier resets unspecified components to zero, should not use testNow
+        Chronos::setTestNow(new Chronos('2020-12-01 14:30:45'));
+        $d = Chronos::createFromFormat('Y-m-d|', '2021-06-15');
+        $this->assertDateTime($d, 2021, 6, 15, 0, 0, 0);
+    }
+
+    public function testCreateFromFormatWithoutTestNow()
+    {
+        // Without testNow set, behavior should use real current time for missing components
+        Chronos::setTestNow(null);
+        $d = Chronos::createFromFormat('Y-m-d H:i:s', '1975-05-21 22:32:11');
+        $this->assertDateTime($d, 1975, 5, 21, 22, 32, 11);
+    }
+
+    public function testCreateFromFormatWithTestNowEscapedCharacters()
+    {
+        // Escaped format characters should not be treated as format specifiers
+        Chronos::setTestNow(new Chronos('2020-12-01 14:30:45'));
+        $d = Chronos::createFromFormat('\Y\-m-d', 'Y-10-05');
+        $this->assertDateTime($d, 2020, 10, 5, 14, 30, 45);
+    }
+
+    public function testCreateFromFormatWithTestNowMicroseconds()
+    {
+        Chronos::setTestNow(new Chronos('2020-12-01 14:30:45.123456'));
+        $d = Chronos::createFromFormat('Y-m-d H:i:s', '2021-06-15 09:15:30');
+        $this->assertSame(123456, $d->micro);
+    }
+
     public function testCreateFromFormatWithTimezoneString()
     {
         $d = Chronos::createFromFormat('Y-m-d H:i:s', '1975-05-21 22:32:11', 'Europe/London');