Provide instructions on how to debug i3bar

[i3/i3] / docs / debugging

diff --git a/docs/debugging b/docs/debugging
index 35460847db49b7987abf604988b2d07b6a857b86..400a6b2b45d7bd0f9a5c56bc386338c9444e3284 100644 (file)
--- a/docs/debugging
+++ b/docs/debugging
@@ -1,82 +1,115 @@
 Debugging i3: How To
 ====================
 Michael Stapelberg <michael@i3wm.org>
 Debugging i3: How To
 ====================
 Michael Stapelberg <michael@i3wm.org>

-February 2012
+January 2014

 
 

-This document describes how to debug i3 suitably for sending us useful bug
-reports, even if you have no clue of C programming.
+This document describes how to debug i3 to send us useful bug
+reports, even if you have no knowledge of C programming.

 
 

-First of all: Thank you for being interested in debugging i3. It really means
+Thank you for being interested in debugging i3. It really means

 something to us to get your bug fixed. If you have any questions about the
 something to us to get your bug fixed. If you have any questions about the

-debugging and/or need further help, do not hesitate to contact us!
+process and/or need further help, do not hesitate to contact us!

 
 

-== Verify you are using the latest (development) version
+== Verify you are using i3 ≥ 4.7

 
 

-Please verify that you are using the latest version of i3:
+Only the latest major version of i3 is supported, i.e. version 4.7 currently.
+To verify which version you are running, use:

 
 ---------------
 
 ---------------

-$ i3 --version
-i3 version 4.1.2-248-g51728ba (2012-02-12, branch "next")
+$ i3 --moreversion 2>&- || i3 --version
+Binary i3 version:  4.7 (2013-12-22, branch "tags/4.7")
+Running i3 version: 4.7-84-gac74a63 (2014-01-01, branch "next") (pid 1995)

 ---------------
 
 Your version can look like this:
 
 ---------------
 
 Your version can look like this:
 

-4.1.2::
-You are using a release version. Please
-upgrade to a development version first, or read
-link:debugging-release-version[Debugging i3: How To (release version)].
+4.7 (release version)::
+You are using a release version. In many cases, bugs are already
+fixed in the development version of i3. Even if the bug is not a known fixed
+one, we will still ask you to reproduce your error with the most recent
+development version of i3. Therefore, please upgrade to a development version
+if you can.

 
 

-4.1.2-248-g51728ba::
-Your version is 248 commits newer than 4.1.2, and the git revision of your
-version is +51728ba+. Go to http://code.i3wm.org/i3/commit/?h=next and see if
+4.7-85-g9c15b95 (development version)::
+Your version is 85 commits newer than 4.7, and the git revision of your
+version is +9c15b95+. Go to http://code.i3wm.org/i3/commit/?h=next and see if

 the line "commit" starts with the same revision. If so, you are using the
 latest version.
 
 the line "commit" starts with the same revision. If so, you are using the
 latest version.
 

-Development versions of i3 have several properties which make debugging easier:
+Development versions of i3 have logging enabled by default and are compiled
+with debug symbols.

 
 

-1. Shared memory debug logging is enabled by default. You do not have to enable
-   logging explicitly.
-2. Core dumps are enabled by default.
-3. If you are using a version from the Debian/Ubuntu autobuilder, it is
-   compiled without optimization. Debug symbols are available in the i3-wm-dbg
-   package. When compiling i3 yourself, debug mode is the default.
+== Enabling logging
+
+If you are using a development version (see previous section), you don’t need
+to do anything -- skip to section 3.
+
+If you are using a release version with a custom +~/.xsession+ (or xinitrc)
+file, execute i3 with a line like this:
+
+----------------------------------
+# Use 25 MiB of RAM for debug logs
+exec i3 --shmlog-size=26214400
+----------------------------------
+
+If you are *NOT* using an +~/.xsession+ file but you just chose "i3" from the
+list of sessions in your desktop manager (gdm, lxdm, …), edit
++/usr/share/xsessions/i3.desktop+ and replace the +Exec=i3+ line with:
+
+------------------------------
+Exec=i3 --shmlog-size=26214400
+------------------------------
+
+If you cannot restart i3 for some reason, you can enable debug logging on the
+fly:
+
+---------------------------------------
+i3-msg 'debuglog on; shmlog on; reload'
+---------------------------------------

 
 == Obtaining the debug logfile
 
 No matter whether i3 misbehaved in some way without crashing or whether it just
 crashed, the logfile provides all information necessary to debug the problem.
 
 
 == Obtaining the debug logfile
 
 No matter whether i3 misbehaved in some way without crashing or whether it just
 crashed, the logfile provides all information necessary to debug the problem.
 

-To save a compressed version of the logfile (suitable for attaching it to a
-bugreport), use:
---------------------------------------------------------------------
-i3-dump-log | gzip -9c > /tmp/i3.log.gz
---------------------------------------------------------------------
+To upload a compressed version of the logfile (for a bugreport), use:
+------------------------------------------------------------------------------
+DISPLAY=:0 i3-dump-log | bzip2 -c | curl --data-binary @- http://logs.i3wm.org
+------------------------------------------------------------------------------

 
 

-This command does not depend on i3 (it also works when i3 currently displays
-the crash dialog), but it requires a working X11 connection. When running it
-from a virtual console (Ctrl-Alt-F1), use:
+This command does not depend on i3 (it also works while i3 displays
+the crash dialog), but it requires a working X11 connection.

 
 

---------------------------------------------------------------------
-DISPLAY=:0 i3-dump-log | gzip -9c > /tmp/i3.log.gz
---------------------------------------------------------------------
+After running it, you will get a URL to the logfile. Please include that URL in
+your bug report.

 
 

-== Obtaining a backtrace
+== On crashes: Obtaining a backtrace

 
 

-When i3 displays its crash dialog, do the following:
+When i3 crashes, it will display a dialog stating “i3 just crashed”, offering
+you to save a backtrace to a text file.

 
 

-1. Switch to a virtual console (Ctrl-Alt-F1) or login from a different computer
-2. Generate a backtrace (see below)
-3. Switch back to the crash dialog (Ctrl-Alt-F7)
-4. Restart i3 in-place (you will keep your session), continue working
+To actually get useful backtraces, you should make sure that your version of i3
+is compiled with debug symbols:

 
 

-This is how you get a backtrace from a running i3 process:
+------------------------------------------------------------------------------
+$ file `which i3`
+/usr/bin/i3: ELF 64-bit LSB executable, x86-64, version 1 (SYSV), dynamically
+linked (uses shared libs), for GNU/Linux 2.6.18, not stripped
+------------------------------------------------------------------------------

 
 

------------------
-I3PID=$(pidof i3)
-gdb /proc/$I3PID/exe $I3PID \
-    --batch --quiet \
-    --ex 'backtrace full' > /tmp/i3-backtrace.txt 2>&1
------------------
+Notice the +not stripped+, which is the important part. If you have a version
+which is stripped, please check whether your distribution provides debug
+symbols (package +i3-wm-dbg+ on Debian for example) or if you can turn off
+stripping. If nothing helps, please build i3 from source.
+
+Once you have made sure that your i3 is compiled with debug symbols and the C
+debugger +gdb+ is installed on your machine, you can let i3 generate a
+backtrace in the crash dialog.
+
+After pressing "b" in the crash dialog, you will get a file called
++/tmp/i3-backtrace.%d.%d.txt+ where the first +%d+ is replaced by i3’s process
+id (PID) and the second one is incremented each time you generate a backtrace,
+starting at 0.

 
 == Sending bug reports/debugging on IRC
 
 
 == Sending bug reports/debugging on IRC
 


@@ -88,3 +121,19 @@ When debugging with us in IRC, be prepared to use a so called nopaste service
 such as http://nopaste.info or http://pastebin.com because pasting large
 amounts of text in IRC sometimes leads to incomplete lines (servers have line
 length limitations) or flood kicks.
 such as http://nopaste.info or http://pastebin.com because pasting large
 amounts of text in IRC sometimes leads to incomplete lines (servers have line
 length limitations) or flood kicks.

+
+== Debugging i3bar
+
+To debug i3bar problems, add +verbose yes+ to all +bar {}+ blocks in your i3 config
+and then restart all i3bar instances like this:
+
+---------------------------------------------------------------------
+$ killall i3bar
+$ for c in $(i3-msg -t get_bar_config | python -c \
+      'import json,sys;print("\n".join(json.load(sys.stdin)))'); do \
+    (i3bar --bar_id=$c >i3bar.$c.log 2>&1) & \
+  done;
+---------------------------------------------------------------------
+
+There will now be +i3bar.*.log+ files in your current directory that you can provide
+in your bug report.