docs: Mention debug key

This already existed in 2.19 but was not documented.

Author: jtojnar

NEWS.md

@@ -34,6 +34,7 @@
 - Spouts can fetch item contents lazily by passing a function as `content` to `Item`. ([#1413](https://github.com/fossar/selfoss/pull/1413))
 - Spouts’ `name`, `description` and `params` properties now require a type hint. ([#1425](https://github.com/fossar/selfoss/pull/1425))
 - All classes other than spouts were made final. ([#1546](https://github.com/fossar/selfoss/pull/1546))
+- The debugging level (in selfoss ≤ 2.18 set by modifying `src/common.php`) can be changed in the `config.ini` using `debug` key. ([#1298](https://github.com/fossar/selfoss/pull/1298))
 
 ### Other changes
 - `tidy` PHP extension is now required if you want to use “Content extractor” spout. ([#1392](https://github.com/fossar/selfoss/pull/1392))

docs/content/docs/administration/options.md

@@ -59,6 +59,16 @@ Port for database connections. By default `3306` will be used for MySQL and `543
 A UNIX domain socket used for connecting to the MySQL database server. Usually, you want to use `db_host=localhost`, which should use the default socket path (typically `/run/mysqld/mysqld.sock` for MySQL or `/run/postgresql` for PostgreSQL) but if you need to specify a different location, you can. This is orthogonal to `db_host` option.
 </div>
 
+### `debug`
+<div class="config-option">
+
+Level of detail for diagnostics. Enable this for debug traces if you encounter selfoss internal errors or are developing selfoss.
+
+* `0` (default) – Debugging is disabled, errors will only be [logged](#logger-level).
+* `1` – Debugging is enabled, any error or warning will terminate the application and cause debugging information to be printed into the web browser.
+* `2` – Same as `1` but additional information (HTTP requests) will be logged when fetching feed content.
+</div>
+
 ### `logger_destination`
 <div class="config-option">
 

src/helpers/Configuration.php

@@ -49,9 +49,6 @@ final class Configuration {
 
     // Internal but overridable values.
 
-    /** Debugging level @internal */
-    public int $debug = 0;
-
     /** @internal */
     public string $datadir = __DIR__ . '/../../data';
 
@@ -63,6 +60,9 @@ final class Configuration {
 
     // Rest of the values.
 
+    /** Debugging level */
+    public int $debug = 0;
+
     public string $dbType = 'sqlite';
 
     public string $dbFile = '%datadir%/sqlite/selfoss.db';