write the settings reference page

docs/reference/settings.md

@@ -0,0 +1,315 @@
+---
+title: Settings
+---
+
+Every setting PHP Debugger supports, in alphabetical order.
+
+Each setting says where it can be set:
+
+- **Anywhere** — `php.ini`, a `conf.d` file, per-directory config, or at runtime
+  with `ini_set()`.
+- **System and per-directory** — `php.ini` and per-directory config such as
+  `.htaccess` or a vhost, but not at runtime.
+- **`php.ini` only** — read once at startup, so changing it later has no effect.
+
+## `php_debugger.client_discovery_header`
+
+| Type | Default | Set in |
+| --- | --- | --- |
+| String | `HTTP_X_FORWARDED_FOR,REMOTE_ADDR` | Anywhere |
+
+The request headers consulted, in order, when
+[`discover_client_host`](#php_debuggerdiscover_client_host) is on. The first one
+present supplies the address; if it holds a comma-separated list, the first entry
+is used.
+
+```ini
+php_debugger.client_discovery_header=HTTP_X_REAL_IP,REMOTE_ADDR
+```
+
+## `php_debugger.client_host`
+
+| Type | Default | Set in |
+| --- | --- | --- |
+| String | `localhost` | Anywhere |
+
+The machine the debugger connects out to. The default works when your editor and
+your code run on the same machine; from inside a container it needs an address that
+reaches your host.
+
+```ini
+php_debugger.client_host=host.docker.internal
+```
+
+## `php_debugger.client_port`
+
+| Type | Default | Set in |
+| --- | --- | --- |
+| Integer | `9003` | Anywhere |
+
+The port your editor is listening on. Change it only if something else already has
+`9003`, and make your editor match.
+
+```ini
+php_debugger.client_port=9004
+```
+
+## `php_debugger.cloud_id`
+
+| Type | Default | Set in |
+| --- | --- | --- |
+| String | empty | `php.ini` only |
+
+Relays the session through Xdebug Cloud rather than connecting directly, for when
+the debugger cannot reach your machine at all. Setting it takes priority over
+`client_host`. See the [Xdebug Cloud documentation](https://xdebug.org/docs/cloud).
+
+```ini
+php_debugger.cloud_id=your-id-here
+```
+
+## `php_debugger.connect_timeout_ms`
+
+| Type | Default | Set in |
+| --- | --- | --- |
+| Integer | `200` | Anywhere |
+
+How long, in milliseconds, a single connection attempt may take. Every attempt that
+finds nothing listening costs the request this much, which is why the default is
+small.
+
+```ini
+php_debugger.connect_timeout_ms=500
+```
+
+## `php_debugger.control_socket`
+
+| Type | Default | Set in |
+| --- | --- | --- |
+| String | `default` | Anywhere. Linux only |
+
+Opens a per-process socket that lets an external tool inspect a running request or
+pause it. `default` and `time` both poll every 25ms; `no` turns it off. On a system
+without a usable TSC clock, `default` disables itself and `time` falls back to
+100ms.
+
+```ini
+php_debugger.control_socket=no
+```
+
+## `php_debugger.discover_client_host`
+
+| Type | Default | Set in |
+| --- | --- | --- |
+| Boolean | `0` | Anywhere |
+
+Works the client address out from the incoming HTTP request instead of using
+`client_host`. Only the host is discovered — the port is always `client_port` — and
+`client_host` is still used as a fallback.
+
+Because the headers it reads are supplied by the request, only enable this behind a
+proxy you control.
+
+```ini
+php_debugger.discover_client_host=1
+```
+
+## `php_debugger.idekey`
+
+| Type | Default | Set in |
+| --- | --- | --- |
+| String | empty | Anywhere |
+
+An identifier sent to your editor when the session opens, so a client handling
+several sessions can tell them apart. Most setups never need it.
+
+```ini
+php_debugger.idekey=my-project
+```
+
+## `php_debugger.log`
+
+| Type | Default | Set in |
+| --- | --- | --- |
+| String | empty | Anywhere |
+
+The file where the debugger writes its own log. Appended to rather than truncated,
+and flushed line by line, so a crash does not cost you the last entry. Leave it
+unset outside of debugging: it grows without limit and records paths, trigger
+values and protocol traffic.
+
+```ini
+php_debugger.log=/tmp/php-debugger.log
+```
+
+## `php_debugger.log_level`
+
+| Type | Default | Set in |
+| --- | --- | --- |
+| Integer | `7` | Anywhere |
+
+How much is written to the log. A threshold — everything at or below the number is
+recorded.
+
+| Value | Records |
+| --- | --- |
+| `0` | Critical failures only. |
+| `1` | Errors as well. |
+| `3` | Warnings as well. |
+| `5` | Every protocol message in both directions. |
+| `7` | Connections, sessions and breakpoint resolution. The default. |
+| `10` | Everything, including each trigger check and configuration decision. |
+
+```ini
+php_debugger.log_level=10
+```
+
+## `php_debugger.mode`
+
+| Type | Default | Set in |
+| --- | --- | --- |
+| String | `debug` | `php.ini` only |
+
+Whether the debugger does anything at all. Two values are accepted: `debug`, and
+`off` for no overhead rather than very little. Any other value is ignored: a
+message is logged and the mode stays `debug`.
+
+```ini
+php_debugger.mode=off
+```
+
+## `php_debugger.on_demand_debugging_enabled`
+
+| Type | Default | Set in |
+| --- | --- | --- |
+| Boolean | `0` | `php.ini` only |
+
+Allows the debugger to attach part-way through a request, which is what makes
+`php_debugger_break()` and `php_debugger_connect_to_client()` work when no session
+is running.
+
+The cost is high: every request must be compiled with debugging instrumentation
+whether or not it ends up being debugged, which gives away roughly half of the
+near-zero overhead you would otherwise have. Leave it off unless you need it.
+
+```ini
+php_debugger.on_demand_debugging_enabled=1
+```
+
+## `php_debugger.path_mapping`
+
+| Type | Default | Set in |
+| --- | --- | --- |
+| Boolean | `0` | Anywhere |
+
+Enables server-side translation between the paths the running machine sees and the
+paths your editor knows. With it off, paths are passed through unchanged.
+
+Most setups do not need this — mapping is normally configured in the editor, which
+is where to look first if breakpoints in a container are being ignored.
+
+```ini
+php_debugger.path_mapping=1
+```
+
+## `php_debugger.start_upon_error`
+
+| Type | Default | Set in |
+| --- | --- | --- |
+| String | `default` | System and per-directory |
+
+Whether an error should start a debugging session when none is running. Only `yes`
+enables it; `default` and `no` both leave it off. It also needs
+[`on_demand_debugging_enabled`](#php_debuggeron_demand_debugging_enabled), since
+starting mid-request is exactly what that setting permits.
+
+```ini
+php_debugger.start_upon_error=yes
+```
+
+## `php_debugger.start_with_request`
+
+| Type | Default | Set in |
+| --- | --- | --- |
+| String | `yes` | System and per-directory |
+
+When a session begins.
+
+| Value | Meaning |
+| --- | --- |
+| `yes` | Every request starts one. The default. |
+| `no` | Never. |
+| `trigger` | Only when a trigger is present in the request. |
+
+`yes` is the right choice here. `trigger` exists to keep a heavyweight debugger out
+of the way, which is not a problem this one has.
+
+```ini
+php_debugger.start_with_request=trigger
+```
+
+## `php_debugger.trigger_value`
+
+| Type | Default | Set in |
+| --- | --- | --- |
+| String | empty | System and per-directory |
+
+Turns the trigger into a shared secret: with a value set, a trigger only counts if
+it matches, and one that does not is refused and logged. Several secrets can be
+accepted at once by separating them with commas.
+
+Only relevant when `start_with_request` is `trigger`.
+
+```ini
+php_debugger.trigger_value=letmein,alsofine
+```
+
+## `php_debugger.var_display_max_children`
+
+| Type | Default | Set in |
+| --- | --- | --- |
+| Integer | `128` | Anywhere |
+
+How many elements of an array or object are sent in one go. Your editor can raise
+this for its own session, and usually does, in which case its value wins.
+
+```ini
+php_debugger.var_display_max_children=256
+```
+
+## `php_debugger.var_display_max_data`
+
+| Type | Default | Set in |
+| --- | --- | --- |
+| Integer | `512` | Anywhere |
+
+How many bytes of a string are sent before it is truncated. Also overridable by
+your editor.
+
+```ini
+php_debugger.var_display_max_data=2048
+```
+
+## `php_debugger.var_display_max_depth`
+
+| Type | Default | Set in |
+| --- | --- | --- |
+| Integer | `3` | Anywhere |
+
+How many levels deep into a nested structure are sent in one go. Expanding a node
+in your editor fetches the next layer, so this is a batch size rather than a limit
+on what you can reach. Also overridable by your editor.
+
+```ini
+php_debugger.var_display_max_depth=5
+```
+
+:::info[The `xdebug.` prefix also works]
+
+Every setting on this page can also be written with an `xdebug.` prefix instead of
+`php_debugger.`. The two names share a single value, so either spelling has the
+same effect, and where both are set explicitly `php_debugger.` wins.
+
+This is what lets an existing configuration carry on working untouched.
+
+:::

sidebars.js

@@ -47,9 +47,9 @@ const sidebars = {
       label: 'Reference',
       collapsed: false,
       items: [
+        'reference/settings',
         'reference/cli-options',
         'reference/environment-variables',
-        'reference/configuration-file',
         'reference/debug-protocol',
       ],
     },