[homestar9]

Description

On Adobe ColdFusion, FileAppender and RollingFileAppender write queued lines several times:
N lines queued together end up N + (N-1) + … + 1 times in the file, and each one is also printed
to the console.

The log listener passes its queue to preProcessQueue() as an argument. Adobe ColdFusion passes
arrays by value, so FileAppender's queue.clear() empties a copy. The listener then takes one
line off the real queue, prints it to the console through the base processQueueElement(), and
the next pass writes everything left again. Lucee and BoxLang pass arrays by reference, so they
are not affected. Setting this.passArrayByReference = true on ACF 2023 also makes the unchanged
code write each line once, which confirms the cause.

Changes:

• AbstractAppender: a new private drainQueue() removes and returns the queued entries from
  the appender's own queue (variables.logListener.queue), so it works whichever way the engine
  passes arrays. It removes exactly the entries it read rather than calling clear(), so a line
  queued during the write is kept for the next pass. On every engine, that line could be lost
  before.
• FileAppender.preProcessQueue() writes drainQueue() and ignores the argument.
• FileAppender.processQueueElement() (new) writes a line the listener takes off the queue
  itself to the file instead of the console.
• The preProcessQueue, postProcessQueue and processQueueElement docblocks now say the
  queue argument may be a copy and should only be read.

Hook signatures are unchanged, so custom appenders that override them keep working. The fix does
not depend on this.passArrayByReference, which most applications don't set.

Jira Issues

https://ortussolutions.atlassian.net/browse/COLDBOX-1467

Type of change

• Bug Fix

Checklist

• My code follows the style guidelines of this project cfformat
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

Tests

New specs in FileAppenderTest.cfc, using a small test appender (QueueTestFileAppender.cfc)
that runs the listener in the test thread, so no sleeping is needed. The existing "can log
messages" spec now checks for an exact line count; before, it only checked that the text
appeared, which is why this was missed.

	ACF 2023	ACF 2025	Lucee 6	BoxLang (CFML compat)	BoxLang
New specs, before the fix	3 fail	3 fail	1 fails	1 fails	1 fails
All tests/specs/logging, after the fix	52 pass	52 pass	52 pass	52 pass	52 pass