All settings

This section describes all available configuration settings available in Xdebug.

boolean xdebug.auto_trace = false #

When this setting is set to on, the tracing of function calls will be enabled just before the script is run. This makes it possible to trace code in the auto_prepend_file.

integer xdebug.cli_color = 0 #

Introduced in Xdebug >= 2.2

If this setting is 1, Xdebug will color var_dumps and stack traces output when in CLI mode and when the output is a tty. On Windows, the ANSICON tool needs to be installed.

If the setting is 2, then Xdebug will always color var_dumps and stack trace, no matter whether it's connected to a tty or whether ANSICON is installed. In this case, you might end up seeing escape codes.

See this article for some more information.

boolean xdebug.collect_assignments = false #

Introduced in Xdebug >= 2.1

This setting, defaulting to 0, controls whether Xdebug should add variable assignments to function traces. Assign-by-var (=&) assignments are included too.

boolean xdebug.collect_includes = true #

This setting, defaulting to 1, controls whether Xdebug should write the filename used in include(), include_once(), require() or require_once() to the trace files.

integer xdebug.collect_params = 0 #

This setting, defaulting to 0, controls whether Xdebug should collect the parameters passed to functions when a function call is recorded in either the function trace or the stack trace.

The setting defaults to 0 because for very large scripts it may use huge amounts of memory and therefore make it impossible for the huge script to run. You can most safely turn this setting on, but you can expect some problems in scripts with a lot of function calls and/or huge data structures as parameters. Xdebug 2 will not have this problem with increased memory usage, as it will never store this information in memory. Instead it will only be written to disk. This means that you need to have a look at the disk usage though.

This setting can have four different values. For each of the values a different amount of information is shown. Below you will see what information each of the values provides. See also the introduction of the feature Stack Traces for a few screenshots.

¹ in the CLI version of PHP it will not have the tool tip, nor in output files.

boolean xdebug.collect_return = false #

This setting, defaulting to 0, controls whether Xdebug should write the return value of function calls to the trace files.

boolean xdebug.collect_vars = false #

This setting tells Xdebug to gather information about which variables are used in a certain scope. This analysis can be quite slow as Xdebug has to reverse engineer PHP's opcode arrays. This setting will not record which values the different variables have, for that use xdebug.collect_params. This setting needs to be enabled only if you wish to use xdebug_get_declared_vars().

boolean xdebug.coverage_enable = true #

Introduced in Xdebug >= 2.2

If this setting is set to false, then Xdebug will not set-up internal structures to allow code coverage. This speeds up Xdebug quite a bit, but of course, Code Coverage Analysis won't work.

boolean xdebug.default_enable = true #

If this setting is 1, then stacktraces will be shown by default on an error event. You can disable showing stacktraces from your code with xdebug_disable(). As this is one of the basic functions of Xdebug, it is advisable to leave this setting set to 1.

string xdebug.dump.* = Empty #

* can be any of COOKIE, FILES, GET, POST, REQUEST, SERVER, SESSION. These seven settings control which data from the superglobals is shown when an error situation occurs.

Each of those php.ini setting can consist of a comma separated list of variables from this superglobal to dump, or * for all of them. Make sure you do not add spaces in this setting.

In order to dump the REMOTE_ADDR and the REQUEST_METHOD when an error occurs, and all GET parameters, add these settings:

xdebug.dump.SERVER = REMOTE_ADDR,REQUEST_METHOD
xdebug.dump.GET = *

boolean xdebug.dump_globals = true #

When this setting is set to true, Xdebug adds the values of the super globals as configured through the xdebug.dump.* to on-screen stack traces and the error log (if enabled).

boolean xdebug.dump_once = true #

Controls whether the values of the superglobals should be dumped on all error situations (set to 0) or only on the first (set to 1).

boolean xdebug.dump_undefined = false #

If you want to dump undefined values from the superglobals you should set this setting to 1, otherwise leave it set to 0.

integer xdebug.extended_info = 1 #

Available in Xdebug < 2.8

Controls whether Xdebug should enforce 'extended_info' mode for the PHP parser; this allows Xdebug to do file/line breakpoints with the remote debugger. When tracing or profiling scripts you generally want to turn off this option as PHP's generated oparrays will increase with about a third of the size slowing down your scripts. This setting can not be set in your scripts with ini_set(), but only in php.ini.

string xdebug.file_link_format = #

Introduced in Xdebug >= 2.1

This setting determines the format of the links that are made in the display of stack traces where file names are used. This allows IDEs to set up a link-protocol that makes it possible to go directly to a line and file by clicking on the filenames that Xdebug shows in stack traces. An example format might look like:

myide://%f@%l

The possible format specifiers are:

For various IDEs/OSses there are some instructions listed on how to make this work:

Firefox on Linux

• Open about:config
• Add a new boolean setting "network.protocol-handler.expose.xdebug" and set it to "false"
• Add the following into a shell script ~/bin/ff-xdebug.sh:

  #! /bin/sh
  
  f=`echo $1 | cut -d @ -f 1 | sed 's/xdebug:\/\///'`
  l=`echo $1 | cut -d @ -f 2`
  

  Add to that one of (depending whether you have komodo, gvim or netbeans):
  • komodo $f -l $l
  • gvim --remote-tab +$l $f
  • netbeans "$f:$l"
• Make the script executable with chmod +x ~/bin/ff-xdebug.sh
• Set the xdebug.file_link_format setting to xdebug://%f@%l

Windows and netbeans

• Create the file netbeans.bat and save it in your path (C:\Windows will work):

  @echo off
  setlocal enableextensions enabledelayedexpansion
  set NETBEANS=%1
  set FILE=%~2
  %NETBEANS% --nosplash --console suppress --open "%FILE:~19%"
  nircmd win activate process netbeans.exe
  

  Note: Remove the last line if you don't have nircmd.

• Save the following code as netbeans_protocol.reg:

  Windows Registry Editor Version 5.00
  
  [HKEY_CLASSES_ROOT\netbeans]
  "URL Protocol"=""
  @="URL:Netbeans Protocol"
  
  [HKEY_CLASSES_ROOT\netbeans\DefaultIcon]
  @="\"C:\\Program Files\\NetBeans 7.1.1\\bin\\netbeans.exe,1\""
  
  [HKEY_CLASSES_ROOT\netbeans\shell]
  
  [HKEY_CLASSES_ROOT\netbeans\shell\open]
  
  [HKEY_CLASSES_ROOT\netbeans\shell\open\command]
  @="\"C:\\Windows\\netbeans.bat\" \"C:\\Program Files\\NetBeans 7.1.1\\bin\\netbeans.exe\" \"%1\""
  

  Note: Make sure to change the path to Netbeans (twice), as well as the netbeans.bat batch file if you saved it somewhere else than C:\Windows\.

• Double click on the netbeans_protocol.reg file to import it into the registry.
• Set the xdebug.file_link_format setting to xdebug.file_link_format = "netbeans://open/?f=%f:%l"

string xdebug.filename_format = ...%s%n #

Introduced in Xdebug >= 2.6

This setting determines the format with which Xdebug renders filenames in HTML stack traces (default: ...%s%n) and location information through the overloaded xdebug_var_dump() (default: %f).

The possible format specifiers are listed in this table. The example output is rendered according to the full path /var/www/vendor/mail/transport/mta.php.

integer xdebug.force_display_errors = 0 #

Introduced in Xdebug >= 2.3

If this setting is set to 1 then errors will always be displayed, no matter what the setting of PHP's display_errors is.

integer xdebug.force_error_reporting = 0 #

Introduced in Xdebug >= 2.3

This setting is a bitmask, like error_reporting. This bitmask will be logically ORed with the bitmask represented by error_reporting to dermine which errors should be displayed. This setting can only be made in php.ini and allows you to force certain errors from being shown no matter what an application does with ini_set().

bool xdebug.gc_stats_enable = false #

Introduced in Xdebug >= 2.6

If this setting is enabled, then statistics for garbage collection runs are automatically collected into the given directory set with xdebug.gc_stats_output_dir and with an automatically generated name configured by xdebug.gc_stats_output_name.

string xdebug.gc_stats_output_dir = /tmp #

Introduced in Xdebug >= 2.6

string xdebug.gc_stats_output_name = gcstats.%p #

Introduced in Xdebug >= 2.6

This setting determines the name of the file that is used to dump garbage collection statistics into. The setting specifies the format with format specifiers, very similar to sprintf() and strftime(). There are several format specifiers that can be used to format the file name.

See the xdebug.trace_output_name documentation for the supported specifiers.

integer xdebug.halt_level = 0 #

Introduced in Xdebug >= 2.3

This setting allows you to configure a mask that determines whether, and which, notices and/or warnings get converted to errors. You can configure notices and warnings that are generated by PHP, and notices and warnings that you generate yourself (by means of trigger_error()). For example, to convert the warning of strlen() (without arguments) to an error, you would do:

ini_set('xdebug.halt_level', E_WARNING);
strlen();
echo "Hi!\n";

Which will then result in the showing of the error message, and the abortion of the script. echo "Hi!\n"; will not be executed.

The setting is a bit mask, so to convert all notices and warnings into errors for all applications, you can set this in php.ini:

xdebug.halt_level=E_WARNING|E_NOTICE|E_USER_WARNING|E_USER_NOTICE

The bitmask only supports the four level that are mentioned above.

string xdebug.idekey = *complex* #

Controls which IDE Key Xdebug should pass on to the debugging client or proxy. The IDE Key is only important for use with the DBGp Proxy Tool, although some IDEs are incorrectly picky as to what its value is.

The default is based on the DBGP_IDEKEY environment setting. If it is not present, the default falls back to an empty string.

If this setting is set to a non-empty string, it selects its value over DBGP_IDEKEY environment variable as default value.

The internal IDE Key also gets updated through debugging session management and overrides the value of this setting as is explained in the documentation.

string xdebug.manual_url = http://www.php.net #

Available in Xdebug < 2.2.1

This is the base url for the links from the function traces and error message to the manual pages of the function from the message. It is advisable to set this setting to use the closest mirror.

integer xdebug.max_nesting_level = 256 #

Controls the protection mechanism for infinite recursion protection. The value of this setting is the maximum level of nested functions that are allowed before the script will be aborted.

When the maximum nesting level is reached, an "Error" exception is thrown.

integer xdebug.max_stack_frames = -1 #

Introduced in Xdebug >= 2.3

Controls how many stack frames are shown in stack traces, both on the command line during PHP error stack traces, as well as in the browser for HTML traces.

integer xdebug.overload_var_dump = 2 #

Introduced in Xdebug > 2.1

By default Xdebug overloads var_dump() with its own improved version for displaying variables when the html_errors php.ini setting is set to true. In case you do not want that, you can set this setting to 0, but check first if it's not smarter to turn off html_errors.

New in Xdebug 2.3: You can also use 2 as value for this setting. Besides formatting the var_dump() output nicely, it will also add filename and line number to the output. The xdebug.file_link_format setting is also respected.

Before Xdebug 2.4: the default value of this setting was 1.

integer xdebug.profiler_aggregate = 0 #

Available in Xdebug < 2.9

When this setting is set to 1, a single profiler file will be written for multiple requests. One can surf to multiple pages or reload a page to get an average across all requests. The file will be named .cachegrind.aggregate. You will need to move this file to get another round of aggregate data.

integer xdebug.profiler_append = 0 #

When this setting is set to 1, profiler files will not be overwritten when a new request would map to the same file (depending on the xdebug.profiler_output_name setting. Instead the file will be appended to with the new profile.

integer xdebug.profiler_enable = 0 #

Enables Xdebug's profiler which creates files in the profile output directory. Those files can be read by KCacheGrind to visualize your data. This setting can not be set in your script with ini_set(). If you want to selectively enable the profiler, please set xdebug.profiler_enable_trigger to 1 instead of using this setting.

integer xdebug.profiler_enable_trigger = 0 #

When this setting is set to 1, you can trigger the generation of profiler files by using the XDEBUG_PROFILE GET/POST parameter, or set a cookie with the name XDEBUG_PROFILE. This will then write the profiler data to defined directory. In order to prevent the profiler to generate profile files for each request, you need to set xdebug.profiler_enable to 0. Access to the trigger itself can be configured through xdebug.profiler_enable_trigger_value.

string xdebug.profiler_enable_trigger_value = "" #

Introduced in Xdebug >= 2.3

This setting can be used to restrict who can make use of the XDEBUG_PROFILE functionality as outlined in xdebug.profiler_enable_trigger. When changed from its default value of an empty string, the value of the cookie, GET or POST argument needs to match the shared secret set with this setting in order for the profiler to start.

string xdebug.profiler_output_dir = /tmp #

The directory where the profiler output will be written to, make sure that the user who the PHP will be running as has write permissions to that directory. This setting can not be set in your script with ini_set().

string xdebug.profiler_output_name = cachegrind.out.%p #

This setting determines the name of the file that is used to dump traces into. The setting specifies the format with format specifiers, very similar to sprintf() and strftime(). There are several format specifiers that can be used to format the file name.

See the xdebug.trace_output_name documentation for the supported specifiers.

string xdebug.remote_addr_header = "" #

Introduced in Xdebug >= 2.4

If xdebug.remote_addr_header is configured to be a non-empty string, then the value is used as key in the $SERVER superglobal array to determine which header to use to find the IP address or hostname to use for 'connecting back to'. This setting is only used in combination with xdebug.remote_connect_back and is otherwise ignored.

boolean xdebug.remote_autostart = false #

Normally you need to use a specific HTTP GET/POST variable to start remote debugging (see Step Debugging). When this setting is set to 1, Xdebug will always attempt to start a remote debugging session and try to connect to a client, even if the GET/POST/COOKIE variable was not present.

boolean xdebug.remote_connect_back = false #

Introduced in Xdebug >= 2.1

If enabled, the xdebug.remote_host setting is ignored and Xdebug will try to connect to the client that made the HTTP request. It checks the $_SERVER['HTTP_X_FORWARDED_FOR'] and $_SERVER['REMOTE_ADDR'] variables to find out which IP address to use.

If xdebug.remote_addr_header is configured, then the $SERVER variable with the configured name will be checked before the $_SERVER['HTTP_X_FORWARDED_FOR'] and $_SERVER['REMOTE_ADDR'] variables.

This setting does not apply for debugging through the CLI, as the $SERVER header variables are not available there.

Please note that there is no filter available, and anybody who can connect to the webserver will then be able to start a debugging session, even if their address does not match xdebug.remote_host.

integer xdebug.remote_cookie_expire_time = 3600 #

Introduced in Xdebug >= 2.1

This setting can be used to increase (or decrease) the time that the remote debugging session stays alive via the session cookie.

boolean xdebug.remote_enable = false #

This switch controls whether Xdebug should try to contact a debug client which is listening on the host and port as set with the settings xdebug.remote_host and xdebug.remote_port. If a connection can not be established the script will just continue as if this setting was 0.

string xdebug.remote_handler = dbgp #

Available in Xdebug < 2.9

Can only be 'dbgp' to represent the debugger protocol. The DBGp protocol is the only supported protocol.

string xdebug.remote_host = localhost #

Selects the host where the debug client is running, you can either use a host name, IP address, or 'unix:///path/to/sock' for a Unix domain socket. This setting is ignored if xdebug.remote_connect_back is enabled.

Support for Unix domain sockets was introduced in Xdebug 2.6.

string xdebug.remote_log = #

Configures a file name to log all Step Debugging connection attempts, failures, and communication.

Enable this functionality by setting the value to a absolute path. Make sure that the system user that PHP runs at (such as www-data if you are running with Apache) can create and write to the file.

The file is opened in append-mode, and will therefore not be overwritten by default. There is no concurrency protection available.

When successfully enabled, the log file will include any attempt that Xdebug makes to connect to an IDE:

[1603325] Log opened at 2020-06-21 17:54:05
[1603325] I: Connecting to configured address/port: localhost:9000.
[1603325] W: Creating socket for 'localhost:9000', poll success, but error: Operation now in progress (29).
[1603325] I: Connected to client. :-)

It includes the opening time (2020-06-21 17:54:05), the IP/Hostname and port Xdebug is trying to connect to (localhost:9000), and whether it succeeded (Connected to client :-)). The number in brackets ([1603325]) is the Process ID.

It also logs the debugging communication itself, which starts with the <init XML element:

<init
    xmlns="urn:debugger_protocol_v1" xmlns:xdebug="https://xdebug.org/dbgp/xdebug"
    fileuri="file:///home/httpd/www.xdebug.org/html/router.php"
    language="PHP" xdebug:language_version="7.4.2-dev"
    protocol_version="1.0" appid="1603325" idekey="XDEBUG_ECLIPSE">
        <engine version="2.9.6-dev"><![CDATA[Xdebug]]></engine>
        <author><![CDATA[Derick Rethans]]></author>
        <url><![CDATA[https://xdebug.org]]></url>
        <copyright><![CDATA[Copyright (c) 2002-2020 by Derick Rethans]]></copyright>
</init>

The fileuri attribute lists the entry point of your application, which can be useful to compare to breakpoint_set commands to see if path mappings are set-up correctly.

Beyond the <init element, you will find the configuration of features:

<- feature_set -i 4 -n extended_properties -v 1
-> <response
       xmlns="urn:debugger_protocol_v1" xmlns:xdebug="https://xdebug.org/dbgp/xdebug"
       command="feature_set" transaction_id="4" feature="extended_properties" success="1">
   </response>

And continuation commands:

<- step_into -i 9
-> <response
       xmlns="urn:debugger_protocol_v1" xmlns:xdebug="https://xdebug.org/dbgp/xdebug"
       command="step_into" transaction_id="9"
       status="break" reason="ok">
           <xdebug:message filename="file:///home/httpd/www.xdebug.org/html/router.php" lineno="3">
           </xdebug:message>
   </response>

You can read about DBGP - A common debugger protocol specification at its dedicated documation page.

The xdebug.remote_log_level setting controls how much information is logged.

Note: Many Linux distributions now use systemd, which implements private tmp directories. This means that when PHP is run through a web server or as PHP-FPM, the /tmp directory is prefixed with something akin to:

/tmp/systemd-private-ea3cfa882b4e478993e1994033fc5feb-apache.service-FfWZRg

integer xdebug.remote_log_level = 7 #

Introduced in Xdebug >= 2.8

Configures which logging messages should be emitted by the Step Debugging.

The following levels are supported:

string xdebug.remote_mode = req #

Selects when a debug connection is initiated. This setting can have two different values:

req

Xdebug will try to connect to the debug client as soon as the script starts.

jit

Xdebug will only try to connect to the debug client as soon as an error condition occurs.

integer xdebug.remote_port = 9000 #

The port to which Xdebug tries to connect on the remote host. Port 9000 is the default for both Xdebug and the Command Line Debug Client. As many clients use this port number, it is best to leave this setting unchanged.

integer xdebug.remote_timeout = 200 #

Introduced in Xdebug >= 2.6

The amount of time in milliseconds that Xdebug will wait for on an IDE to acknowledge an incoming debugging connection. The default value of 200 ms should in most cases be enough. In case you often get dropped debugging requests, perhaps because you have a high latency network, or a development box far away from your IDE, or have a slow firewall, then you can should increase this value.

Please note that increasing this value might mean that your requests seem to 'hang' in case Xdebug tries to establish a connection, but your IDE is not listening.

boolean xdebug.scream = false #

Introduced in Xdebug >= 2.1

If this setting is 1, then Xdebug will disable the @ (shut-up) operator so that notices, warnings and errors are no longer hidden.

integer xdebug.show_error_trace = 0 #

Introduced in Xdebug >= 2.4

When this setting is set to 1, Xdebug will show a stack trace whenever an Error is raised - even if this Error is actually caught.

integer xdebug.show_exception_trace = 0 #

When this setting is set to 1, Xdebug will show a stack trace whenever an Exception or Error is raised - even if this Exception or Error is actually caught.

Error 'exceptions' were introduced in PHP 7.

integer xdebug.show_local_vars = 0 #

When this setting is set to something != 0 Xdebug's generated stack dumps in error situations will also show all variables in the top-most scope. Beware that this might generate a lot of information, and is therefore turned off by default.

integer xdebug.show_mem_delta = 0 #

When this setting is set to something != 0 Xdebug's human-readable generated trace files will show the difference in memory usage between function calls. If Xdebug is configured to generate computer-readable trace files then they will always show this information.

boolean xdebug.trace_enable_trigger = false #

Introduced in Xdebug >= 2.2

When this setting is set to 1, you can trigger the generation of trace files by using the XDEBUG_TRACE GET/POST parameter, or set a cookie with the name XDEBUG_TRACE. This will then write the trace data to defined directory. In order to prevent Xdebug to generate trace files for each request, you need to set xdebug.auto_trace to 0. Access to the trigger itself can be configured through xdebug.trace_enable_trigger_value.

string xdebug.trace_enable_trigger_value = "" #

Introduced in Xdebug >= 2.3

This setting can be used to restrict who can make use of the XDEBUG_TRACE functionality as outlined in xdebug.trace_enable_trigger. When changed from its default value of an empty string, the value of the cookie, GET or POST argument needs to match the shared secret set with this setting in order for the trace file to be generated.

integer xdebug.trace_format = 0 #

The format of the trace file.

Fields for the computerized format:

See the introduction of Function Trace for a few examples.

integer xdebug.trace_options = 0 #

When set to '1' the trace files will be appended to, instead of being overwritten in subsequent requests.

string xdebug.trace_output_dir = /tmp #

The directory where the tracing files will be written to, make sure that the user who the PHP will be running as has write permissions to that directory.

string xdebug.trace_output_name = trace.%c #

This setting determines the name of the file that is used to dump traces into. The setting specifies the format with format specifiers, very similar to sprintf() and strftime(). There are several format specifiers that can be used to format the file name. The '.xt' extension is always added automatically.

The possible format specifiers are:

² This one is only available for trace file names since Xdebug 2.6.

³ New in version 2.2. This one is set by Apache's mod_unique_id module

integer xdebug.var_display_max_children = 128 #

Controls the amount of array children and object's properties are shown when variables are displayed with either xdebug_var_dump(), xdebug.show_local_vars or through Function Trace.

To disable any limitation, use -1 as value.

This setting does not have any influence on the number of children that is send to the client through the Step Debugging feature.

integer xdebug.var_display_max_data = 512 #

Controls the maximum string length that is shown when variables are displayed with either xdebug_var_dump(), xdebug.show_local_vars or through Function Trace.

To disable any limitation, use -1 as value.

This setting does not have any influence on the number of children that is send to the client through the Step Debugging feature.

integer xdebug.var_display_max_depth = 3 #

Controls how many nested levels of array elements and object properties are when variables are displayed with either xdebug_var_dump(), xdebug.show_local_vars or through Function Trace.

The maximum value you can select is 1023. You can also use -1 as value to select this maximum number.

This setting does not have any influence on the number of children that is send to the client through the Step Debugging feature.