The completely unofficial Xdebug.ini

There are just a couple of minor annoyances with the Xdebug PHP debugger really, the first one being the absence of a proper documentation package to be downloaded and read offline.

I find well-commented ini files, in the Apache httpd.conf style, the best complement to user manuals and technical references: when you are editing the forgotten config of that vetust server that has no web access or even ssh whatsoever, awkwardly sitting on an unstable pile of extinguished hardware in the darkest corner of the server room, they will save you dozens of round trips to go googling for information.

Unfortunately the Xdebug distribution contains no such thing: no comments, no list of ini directives, no ini file at all. But since I am a nice chap, after having carved out such precious jewel, I thought it might be of interest to the community, and without further ado here it is:



[xdebug]

;;;;;;;;;;;;;;;;;;;
; About this file ;
;;;;;;;;;;;;;;;;;;;
;
; built by G. Giunta as a verbatim copy of info from xedbug website on 2007/11/08

; You must uncomment one (and only one) line from the following to load
; the xdebug extension.
zend_extension="/usr/lib/php4/xdebug.so"
;zend_extension_ts="/usr/lib/php4/xdebug.so"
;zend_extension_ts="c:\php4\xdebug.dll"
;zend_extension="c:\php4\xdebug.dll"

; 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.
xdebug.auto_trace=Off

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

; 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 Off 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.
; Value Argument Information Shown
; 0 None.
; 1 Type and number of elements (f.e. string(6), array(8)).
; 2 Type and number of elements, with a tool tip for the full information.
; 3 Full variable contents (with the limits respected as set by
; xdebug.var_display_max_children, xdebug.var_display_max_data and
; xdebug.var_display_max_depth.
; 4 Full variable contents and variable name.
xdebug.collect_params=0

; This setting, defaulting to Off, controls whether Xdebug should write the
; return value of function calls to the trace files.
xdebug.collect_return=On

; 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().
xdebug.collect_vars=Off

; If this setting is On 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 'On'.
xdebug.default_enable=On

; These seven settings control which data from the superglobals is shown when an
; error situation occurs. Each php.ini setting can consist of a comma seperated
; list of variables from this superglobal to dump, but 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, add this setting: xdebug.dump.SERVER = REMOTE_ADDR,REQUEST_METHOD
xdebug.dump.COOKIE=
xdebug.dump.FILES=
xdebug.dump.GET=
xdebug.dump.POST=
xdebug.dump.REQUEST=
xdebug.dump.SERVER=
xdebug.dump.SESSION=

; Controls whether the values of the superglobals as defined by the xdebug.dump.*
; settings whould be shown or not.
xdebug.dump_globals=On

; Controls whether the values of the superglobals should be dumped on all error
; situations (set to Off) or only on the first (set to On).
xdebug.dump_once=On

; If you want to dump undefined values from the superglobals you should set this
; setting to On, otherwise leave it set to Off.
xdebug.dump_undefined=Off

; 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.
xdebug.extended_info=1

; 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://%[email protected]%l
; The possible format specifiers are:
; %f the filename
; %l the line number
xdebug.file_link_format=

; Controls which IDE Key Xdebug should pass on to the DBGp debugger handler.
; The default is based on environment settings. First the environment setting
; DBGP_IDEKEY is consulted, then USER and as last USERNAME. The default is set
; to the first environment variable that is found. If none could be found the
; setting has as default ''.
xdebug.idekey=

; 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.
xdebug.manual_url=http://www.php.net

; 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.
xdebug.max_nesting_level=100

; 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 1. 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.
xdebug.overload_var_dump=On

; When this setting is set to 1, profiler files will not be overwritten when a
; new request would map to the same file (depnding on the xdebug.profiler_output_name setting.
; Instead the file will be appended to with the new profile.
xdebug.profiler_append=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().
xdebug.profiler_enable=0

; When this setting is set to 1, you can trigger the generation of profiler
; files by using the XDEBUG_PROFILE GET/POST parameter. This will then write
; the profiler data to defined directory.
xdebug.profiler_enable_trigger=0

; 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().
xdebug.profiler_output_dir=/tmp

; 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.
xdebug.profiler_output_name=cachegrind.out.%p

; Normally you need to use a specific HTTP GET/POST variable to start remote debugging.
; When this setting is set to 'On' 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.
xdebug.remote_autostart=Off

; 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 Off.
xdebug.remote_enable=Off

; Can be either 'php3' which selects the old PHP 3 style debugger output, 'gdb'
; which enables the GDB like debugger interface or 'dbgp' - the brand new debugger
; protocol. The DBGp protocol is more widely supported by clients. See more
; information in the introduction for Remote Debugging.
xdebug.remote_handler=dbgp

; Selects the host where the debug client is running, you can either use a host
; name or an IP address.
xdebug.remote_host=localhost

; If set to a value, it is used as filename to a file to which all remote debugger
; communications are logged. The file is always opened in append-mode, and will
; therefore not be overwritten by default. There is no concurrency protection
; available.
xdebug.remote_log=

; 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.
; hit Xdebug will only try to connect to the debug client as soon as an error condition occurs.
xdebug.remote_mode=req

; The port to which Xdebug tries to connect on the remote host. Port 9000 is the
; default for both the client and the bundled debugclient. As many clients use
; this port number, it is best to leave this setting unchanged.
xdebug.remote_port=9000

; When this setting is set to 1, Xdebug will show a stack trace whenever an
; exception is raised - even if this exception is actually caught.
xdebug.show_exception_trace=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.
xdebug.show_local_vars=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.
xdebug.show_mem_delta=0

; The format of the trace file.
; 0 shows a human readable indented trace file with: time index, memory usage,
; memory delta (if the setting xdebug.show_mem_delta is enabled), level,
; function name, function parameters (if the setting xdebug.collect_params
; is enabled, filename and line number.
; 1 writes a computer readable format which has two different records. There
; are different records for entering a stack frame, and leaving a stack frame
xdebug.trace_format=0

; When set to '1' the trace files will be appended to, instead of being overwritten
; in subsequent requests.
xdebug.trace_options=0

; 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.
xdebug.trace_output_dir=/tmp

; 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:
; %c crc32 of the current working directory trace.%c trace.1258863198.xt
; %p pid trace.%p trace.5174.xt
; %r random number trace.%r trace.072db0.xt
; %s script name cachegrind.out.%s cachegrind.out._home_httpd_html_test_xdebug_test_php
; %t timestamp (seconds) trace.%t trace.1179434742.xt
; %u timestamp (microseconds) trace.%u trace.1179434749_642382.xt
; %H $_SERVER['HTTP_HOST'] trace.%H trace.kossu.xt
; %R $_SERVER['REQUEST_URI'] trace.%R trace._test_xdebug_test_php_var=1_var2=2.xt
; %S session_id (from $_COOKIE if set) trace.%S trace.c70c1ec2375af58f74b390bbdd2a679d.xt
; %% literal % trace.%% trace.%%.xt
xdebug.trace_output_name=trace.%c

; 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 Traces. This setting does not have any influence on the
; number of children that is send to the client through the Remote Debugging feature.
xdebug.var_display_max_children=128

; Controls the maximum string length that is shown when variables are displayed
; with either xdebug_var_dump(), xdebug.show_local_vars or through Function Traces.
; This setting does not have any influence on the amount of data that is send to
; the client through the Remote Debugging feature.
xdebug.var_display_max_data=512

; 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 Traces. This setting does not have
; any influence on the depth of children that is send to the client through the
; Remote Debugging feature.
xdebug.var_display_max_depth=3

For installation, just copy and paste it at the end of your php.ini file (or, if you’re on Debian or similarly configured distros, you can save it as separate file in the php ini directory).

Note1: the zend_extension lines at the top of the file are tailored for a php4 install. Make sure to change them to fit your environment.

Note2: I know, for having asked him, that Derick (for those of you living under a Rock, the Xdebug author, and second-to-best dutch hacker I have ever had the pleasure to meet) does not officially endorse this, because, being a very competent hacker, he:

  • prefers to keep his ini files uncluttered, only adding in there directives that have different values from the default
  • is trying to set up an automated generator that would produce the ini file out of the source code
  • You have been warned!

5 thoughts on “The completely unofficial Xdebug.ini

  1. Brilliant! … I just started using xdebug and its such a pain spending time online to figure out what each directive does.
    Thanks so much for this.

  2. If php is compiled with debug the zend_extention line has to include this. So it has to be either zend_extention_debug og zend_extention_debug_ts respectively.

  3. My xdebug used to create a unique file each time, but now just uses the same filename, and whatever I set xdebug.profiler_output_name to it doesn’t seem to make a difference. Any ideas?

  4. @james: no idea, sorry

    Did you recently set up the xdebug.ini I provided whereas you had none before? Or did you change something else?
    What is your platform (os/webserver/php/xdebug)?

    A common cause of trouble with php.ini is editing one version of the file while actually using another one

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