Summary:	ASTERISK-30243: func_logic: IF function complains if both branches are empty
Reporter:	N A (InterLinked)	Labels:
Date Opened:	2022-09-21 17:56:07	Date Closed:	2022-09-26 12:16:07
Priority:	Minor	Regression?
Status:	Closed/Complete	Components:	Functions/func_logic
Versions:	18.14.0	Frequency of Occurrence	Constant
Related Issues:
Environment:		Attachments:
Description:	The IF function complains if both branches (true and false) are empty, e.g.: {noformat} [2022-09-21 22:45:01] WARNING[27353][C-00000275]: func_logic.c:190 acf_if: Syntax IF(<expr>?[<true>][:<false>])  (expr must be non-null, and either <true> or <false> must be non-null) [2022-09-21 22:45:01] WARNING[27353][C-00000275]: func_logic.c:191 acf_if:       In this case, <expr>='1', <true>='(null)', and <false>='(null)' {noformat} However, there is no actual rationale for this. It is not incorrect to have both empty branches, as it's not necessarily wrong for the IF() function to resolve to nothing (empty string). This happens often in my case and this is the correct/desired behavior. Everything works correctly: except warnings are thrown for no reason. For example: {noformat} ${IF(${EXISTS(${ARG3}?${ARG3}:${foobar})})} {noformat} The logic here is simple: if an ARG3 is provided, use ARG3. Otherwise, use the variable foobar instead. In many cases, both ARG3 and foobar could be empty. So much of the time, the whole function could evaluate to an empty string. Using the EXISTS and ISNULL function don't help, since the contents will still evaluate as empty and thus IF will complain, even though this is correct and intentional. This has been a problem for years, I just haven't bothered to report it until now, but at this point it's one of the most common false alarms in my error log. Unlike other conditional applications, e.g. GotoIf, there is no inherent reason that the contents of an IF() call cannot all be empty. Accordingly, these WARNINGs are changed to debug messages, since nothing is actually wrong.
Comments:	By: Asterisk Team (asteriskteam) 2022-09-21 17:56:13.949-0500 Thanks for creating a report! The issue has entered the triage process. That means the issue will wait in this status until a Bug Marshal has an opportunity to review the issue. Once the issue has been reviewed you will receive comments regarding the next steps towards resolution. Please note that log messages and other files should not be sent to the Sangoma Asterisk Team unless explicitly asked for. All files should be placed on this issue in a sanitized fashion as needed. A good first step is for you to review the [Asterisk Issue Guidelines|https://wiki.asterisk.org/wiki/display/AST/Asterisk+Issue+Guidelines] if you haven't already. The guidelines detail what is expected from an Asterisk issue report. Then, if you are submitting a patch, please review the [Patch Contribution Process|https://wiki.asterisk.org/wiki/display/AST/Patch+Contribution+Process]. Please note that once your issue enters an open state it has been accepted. As Asterisk is an open source project there is no guarantee or timeframe on when your issue will be looked into. If you need expedient resolution you will need to find and pay a suitable developer. Asking for an update on your issue will not yield any progress on it and will not result in a response. All updates are posted to the issue when they occur. Please note that by submitting data, code, or documentation to Sangoma through JIRA, you accept the Terms of Use present at [https://www.asterisk.org/terms-of-use/|https://www.asterisk.org/terms-of-use/]. By: Friendly Automation (friendly-automation) 2022-09-26 12:16:08.599-0500 Change 19307 merged by Friendly Automation: func_logic: Don't emit warning if both IF branches are empty. [https://gerrit.asterisk.org/c/asterisk/+/19307|https://gerrit.asterisk.org/c/asterisk/+/19307] By: Friendly Automation (friendly-automation) 2022-09-26 12:20:28.618-0500 Change 19352 merged by Friendly Automation: func_logic: Don't emit warning if both IF branches are empty. [https://gerrit.asterisk.org/c/asterisk/+/19352|https://gerrit.asterisk.org/c/asterisk/+/19352] By: Friendly Automation (friendly-automation) 2022-09-26 12:33:02.147-0500 Change 19349 merged by Friendly Automation: func_logic: Don't emit warning if both IF branches are empty. [https://gerrit.asterisk.org/c/asterisk/+/19349|https://gerrit.asterisk.org/c/asterisk/+/19349] By: Friendly Automation (friendly-automation) 2022-09-26 12:33:05.929-0500 Change 19351 merged by Friendly Automation: func_logic: Don't emit warning if both IF branches are empty. [https://gerrit.asterisk.org/c/asterisk/+/19351|https://gerrit.asterisk.org/c/asterisk/+/19351] By: Friendly Automation (friendly-automation) 2022-09-26 12:33:09.777-0500 Change 19350 merged by Friendly Automation: func_logic: Don't emit warning if both IF branches are empty. [https://gerrit.asterisk.org/c/asterisk/+/19350|https://gerrit.asterisk.org/c/asterisk/+/19350]