Feature Request

Add a first-class trace() convenience method (and corresponding TRACE constant / level name) to Phalcon\Logger\Logger, Phalcon\Logger\LoggerInterface, and Phalcon\Logger\AbstractLogger.

Current Behaviour

AbstractLogger exposes a CUSTOM = 8 constant and maps it to the level name "custom" in getLevels(). No named trace() method exists on Logger or LoggerInterface. Consumers who need trace-level logging must either:

• Subclass Logger, add a TRACE constant, override getLevels() to rename 8 → "trace", and add the trace() method themselves; or
• Call $logger->log(8, $message) with a magic integer and receive log entries labelled "custom" rather than "trace".

Both workarounds are friction the framework should absorb.

Expected Behaviour

// Constant available on AbstractLogger
AbstractLogger::TRACE; // = 8

// Level name returned as "trace", not "custom"
$logger->trace('Detailed wire-level response', ['body' => $body]);
// → level name in output: "trace"

Proposed Changes

phalcon/Logger/AbstractLogger.zep

1. Rename (or alias) CUSTOM → TRACE:

   const TRACE  = 8;  // rename; keep CUSTOM as a deprecated alias if needed for BC

2. Update getLevels() to map 8 → "trace":

   self::TRACE : "trace"

3. Update setLogLevel() fallback (self::CUSTOM → self::TRACE) and logLevel default comment.

phalcon/Logger/Logger.zep

Add the convenience method:

/**
 * Extra-verbose diagnostic output.
 *
 * Use for high-frequency, fine-grained events such as raw socket frames,
 * HTTP response bodies, or internal state transitions that are too noisy
 * for DEBUG.
 *
 * @param string $message
 * @param array  $context
 *
 * @return void
 * @throws Exception
 * @throws LoggerException
 */
public function trace(string message, array context = []) -> void
{
    this->addMessage(self::TRACE, message, context);
}

phalcon/Logger/LoggerInterface.zep

Add the corresponding interface method:

/**
 * Extra-verbose diagnostic output.
 *
 * @param string $message
 * @param array  $context
 *
 * @return void
 */
public function trace(string message, array context = []) -> void;

Motivation

• Trace is a well-established level. Log4j, SLF4J, Monolog, and most mature logging frameworks reserve a level below DEBUG for extra-verbose output (raw frames, full HTTP bodies, tight-loop state). CUSTOM with no semantic name is not a substitute.
• "custom" is not a usable level name in production. Structured log aggregators (e.g. Loki, ELK) filter by level string. "custom" cannot be mapped to any known severity in those systems; "trace" can.
• Subclassing just to rename a level is unnecessary friction. The workaround requires overriding both getLevels() (to rename the label) and adding the trace() method, despite the underlying integer slot already existing in the framework.

Real-World Reference

The following is the exact override currently required in downstream projects (TwistersFury\Phalcon\Shared\Logger\Logger) to work around the missing native support:

class Logger extends PhalconLogger
{
    const TRACE = 8; // CUSTOM

    private levels = [
        2 : "alert",
        1 : "critical",
        7 : "debug",
        0 : "emergency",
        3 : "error",
        6 : "info",
        5 : "notice",
        4 : "warning",
        8 : "trace"    // rename CUSTOM → trace
    ];

    public function trace(string message, array context = []) -> void
    {
        this->addMessage(self::CUSTOM, message, context);
    }

    protected function getLevels() -> array
    {
        return this->levels;
    }
}

This override would become unnecessary if the three changes above were made to the framework.

Backwards Compatibility

Keeping CUSTOM = 8 as a deprecated alias alongside TRACE = 8 (both pointing to the same integer) avoids breaking any existing code that references AbstractLogger::CUSTOM. The only observable change in output is the level label in log entries changing from "custom" to "trace" — applications that currently rely on the literal string "custom" in log output would need to update their log-parsing rules, but that is expected for a meaningful rename.