php - Xdebug: [Step Debug] Could not connect to debugging client. Tried: localhost:9003 (fallback through xdebug.client_host/xdebug.client_port) :-(

Question

What is the workaround of this message for xdebug ang php?

Xdebug: [Step Debug] Could not connect to debugging client. Tried: localhost:9003 (fallback through xdebug.client_host/xdebug.client_port) :-(

This message showup when I run composer update on WSL2 installed with UBUNTU 20.01.

My current php version is php8 and xdebug3

Update:

This is the x-debug section

xdebug

__   __   _      _
  / /  | |    | |
  V / __| | ___| |__  _   _  __ _
  > < / _` |/ _  '_ | | | |/ _` |
 / .  (_| |  __/ |_) | |_| | (_| |
/_/ \_\__,_|\___|_.__/ \__,_|\__, |
                              __/ |
                             |___/

Version => 3.0.1
Support Xdebug on Patreon, GitHub, or as a business: https://xdebug.org/support

Feature => Enabled/Disabled
Development Aids => ? disabled
Coverage => ? disabled
GC Stats => ? disabled
Profiler => ? disabled
Step Debugger => ? enabled
Tracing => ? disabled

Debugger => enabled
IDE Key =>

Directive => Local Value => Master Value
xdebug.auto_trace => This setting has been changed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#changed-"xdebug.auto_trace" => This setting has been changed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#changed-"xdebug.auto_trace"
xdebug.cli_color => 0 => 0
xdebug.client_discovery_header => no value => no value
xdebug.client_host => localhost => localhost
xdebug.client_port => 9003 => 9003
xdebug.cloud_id => no value => no value
xdebug.collect_assignments => Off => Off
xdebug.collect_includes => This setting has been removed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#removed-"xdebug.collect_includes" => This setting has been removed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#removed-"xdebug.collect_includes"
xdebug.collect_params => 0 => 0
xdebug.collect_return => Off => Off
xdebug.collect_vars => This setting has been removed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#removed-"xdebug.collect_vars" => This setting has been removed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#removed-"xdebug.collect_vars"
xdebug.connect_timeout_ms => 200 => 200
xdebug.coverage_enable => This setting has been changed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#changed-"xdebug.coverage_enable" => This setting has been changed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#changed-"xdebug.coverage_enable"
xdebug.default_enable => This setting has been changed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#changed-"xdebug.default_enable" => This setting has been changed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#changed-"xdebug.default_enable"
xdebug.discover_client_host => On => On
xdebug.dump.COOKIE => no value => no value
xdebug.dump.ENV => no value => no value
xdebug.dump.FILES => no value => no value
xdebug.dump.GET => no value => no value
xdebug.dump.POST => no value => no value
xdebug.dump.REQUEST => no value => no value
xdebug.dump.SERVER => no value => no value
xdebug.dump.SESSION => no value => no value
xdebug.dump_globals => On => On
xdebug.dump_once => On => On
xdebug.dump_undefined => Off => Off
xdebug.file_link_format => no value => no value
xdebug.filename_format => no value => no value
xdebug.force_display_errors => Off => Off
xdebug.force_error_reporting => 0 => 0
xdebug.gc_stats_enable => This setting has been changed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#changed-"xdebug.gc_stats_enable" => This setting has been changed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#changed-"xdebug.gc_stats_enable"
xdebug.gc_stats_output_dir => This setting has been changed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#changed-"xdebug.gc_stats_output_dir" => This setting has been changed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#changed-"xdebug.gc_stats_output_dir"
xdebug.gc_stats_output_name => gcstats.%p => gcstats.%p
xdebug.halt_level => 0 => 0
xdebug.idekey => no value => no value
xdebug.log => no value => no value
xdebug.log_level => 7 => 7
xdebug.max_nesting_level => 256 => 256
xdebug.max_stack_frames => -1 => -1
xdebug.mode => debug => debug
xdebug.output_dir => /mnt/c/www/traces => /mnt/c/www/traces
xdebug.overload_var_dump => This setting has been removed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#removed-"xdebug.overload_var_dump" => This setting has been removed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#removed-"xdebug.overload_var_dump"
xdebug.profiler_append => Off => Off
xdebug.profiler_enable => This setting has been changed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#changed-"xdebug.profiler_enable" => This setting has been changed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#changed-"xdebug.profiler_enable"
xdebug.profiler_enable_trigger => This setting has been changed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#changed-"xdebug.profiler_enable_trigger" => This setting has been changed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#changed-"xdebug.profiler_enable_trigger"
xdebug.profiler_enable_trigger_value => This setting has been changed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#changed-"xdebug.profiler_enable_trigger_value" => This setting has been changed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#changed-"xdebug.profiler_enable_trigger_value"
xdebug.profiler_output_dir => This setting has been changed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#changed-"xdebug.profiler_output_dir" => This setting has been changed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#changed-"xdebug.profiler_output_dir"
xdebug.profiler_output_name => cachegrind.out.%p => cachegrind.out.%p
xdebug.remote_autostart => This setting has been changed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#changed-"xdebug.remote_autostart" => This setting has been changed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#changed-"xdebug.remote_autostart"
xdebug.remote_connect_back => This setting has been changed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#changed-"xdebug.remote_connect_back" => This setting has been changed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#changed-"xdebug.remote_connect_back"
xdebug.remote_enable => This setting has been changed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#changed-"xdebug.remote_enable" => This setting has been changed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#changed-"xdebug.remote_enable"
xdebug.remote_host => This setting has been changed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#changed-"xdebug.remote_host" => This setting has been changed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#changed-"xdebug.remote_host"
xdebug.remote_log => This setting has been changed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#changed-"xdebug.remote_log" => This setting has been changed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#changed-"xdebug.remote_log"
xdebug.remote_log_level => This setting has been changed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#changed-"xdebug.remote_log_level" => This setting has been changed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#changed-"xdebug.remote_log_level"
xdebug.remote_mode => This setting has been changed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#changed-"xdebug.remote_mode" => This setting has been changed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#changed-"xdebug.remote_mode"
xdebug.remote_port => This setting has been changed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#changed-"xdebug.remote_port" => This setting has been changed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#changed-"xdebug.remote_port"
xdebug.remote_timeout => This setting has been changed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#changed-"xdebug.remote_timeout" => This setting has been changed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#changed-"xdebug.remote_timeout"
xdebug.scream => Off => Off
xdebug.show_error_trace => Off => Off
xdebug.show_exception_trace => Off => Off
xdebug.show_local_vars => Off => Off
xdebug.show_mem_delta => This setting has been removed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#removed-"xdebug.show_mem_delta" => This setting has been removed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#removed-"xdebug.show_mem_delta"
xdebug.start_upon_error => default => default
xdebug.start_with_request => 1 => 1
xdebug.trace_enable_trigger => This setting has been changed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#changed-"xdebug.trace_enable_trigger" => This setting has been changed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#changed-"xdebug.trace_enable_trigger"
xdebug.trace_enable_trigger_value => This setting has been changed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#changed-"xdebug.trace_enable_trigger_value" => This setting has been changed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#changed-"xdebug.trace_enable_trigger_value"
xdebug.trace_format => 0 => 0
xdebug.trace_options => 0 => 0
xdebug.trace_output_dir => This setting has been changed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#changed-"xdebug.trace_output_dir" => This setting has been changed, see the upgrading guide at https://xdebug.org/docs/upgrade_guide#changed-"xdebug.trace_output_dir"
xdebug.trace_output_name => trace.%c => trace.%c
xdebug.trigger_value => no value => no value
xdebug.var_display_max_children => 128 => 128
xdebug.var_display_max_data => 512 => 512
xdebug.var_display_max_depth => 3 => 3

Answer 1

What causes that message in the first place:

You have xdebug.start_with_request = yes (which is the same as xdebug.remote_autostart = yes for Xdebug v2). This option tells Xdebug to try to debug every single request/script regardless of the "debug me" flag.

If Xdebug fails to connect to the debug client (values from xdebug.client_host & xdebug.client_port .. or autodetected host if xdebug.discover_client_host is enabled) then it notifies you about that.

How to prevent it from appearing on my screen/in the output:

Xdebug uses standard PHP routines to write such warnings (e.g. standard PHP error_log() function). Normally such a message will be written to the standard PHP's error log. Looks like you do not have it configured at all in your php.ini (empty value) therefore PHP sends it to your standard output instead (so you still can have a chance to see it, as it might be important).

The solution is to point PHP's error_log ini setting to some valid location so you can read it when needed (path depends on your OS & distro, e.g. error_log = /var/log/php_error.log would be very common). If you do not need such log at all (have other logging system in place) -- use /dev/null or something similar instead.

---

You can also try xdebug.log_level = 0 but this should prevent Xdebug from logging anything, even if you specify xdebug.log.