Here are the guidelines for being an Emacs pretester. If you would like to do this, say so, and I'll add you to the pretest list. Information for Emacs Pretesters The purpose of Emacs pretesting is to verify that the new Emacs distribution, about to be released, works properly on your system *with no change whatever*, when installed following the precise recommendations that come with the Emacs distribution. Here are some guidelines on how to do pretesting so as to make it helpful. All of them follow from common sense together with the nature of the purpose and the situation. Please save this file, and reread it when a new series of pretests starts. * Get the pretest from gnu/emacs/emacs-MM.NN.tar.gz and gnu/emacs/leim-MM.NN.tar.gz on alpha.gnu.org. * After a few days of testing, if there are no problems, please report that Emacs works for you and what configuration you are testing it on. * If you want to communicate with other pretesters, send mail to emacs-pretesters@gnu.org. I don't use that mailing list when I send to you because I've found that mailing lists tend to amplify random noise into long discussions or even arguments, and that can waste a lot of time. But when you have a reason to ask other pretesters for help, you can do it that way. * It is absolutely vital that you tell me about even the smallest change or departure from the standard sources and procedure. Otherwise, you are not testing the same program that I asked you to test. Testing a different program is usually of no use whatever. It can even cause trouble if you fail to tell me that you tested some other program instead of what I am about to release. I might think that Emacs works, when in fact it has not even been tried, and might have a glaring fault. * Don't use a site-load.el file or a site-init.el file when you pretest. Using either of those files means you are not testing Emacs as a typical site would use it. Actually, it does no harm to test Emacs with such customizations *as well as* testing it "out of the box". Anything you do that could find a bug is useful, as long as you make sure I know exactly what you did. The important point is that testing with local changes is no substitute for testing Emacs exactly as it is distributed. * Even changing the compilation options counts as a change in the program. The Emacs sources specify which compilation options to use. Some of them are specified in makefiles, and some in machine-specific configuration files. They also give you ways to override this--but if you do, then you are not testing what ordinary users will do. Therefore, when pretesting, it is vital to test with the default compilation options. (Testing with a different set of options can be useful *in addition*, but not *instead of* the default options.) * The machine and system configuration files of Emacs are parts of Emacs. So when you test Emacs, you need to do it with the configuration files that come with Emacs. If Emacs does not come with configuration files for a certain machine, and you test it with configuration files that don't come with Emacs, this is effectively changing Emacs. Because the crucial fact about the planned release is that, without changes, it doesn't work on that machine. To make Emacs work on that machine, I would need to install new configuration files. That is not out of the question, since it is safe--it certainly won't break any other machines that already work. But you will have to rush me the legal papers to give the FSF permission to use such a large piece of text. * Look in the etc/MACHINES file. The etc/MACHINES file says which configuration files to use for your machine, so use the ones that are recommended. If you guess, you might guess wrong and encounter spurious difficulties. What's more, if you don't follow etc/MACHINES then you aren't helping to test that its recommendations are valid. The etc/MACHINES file may describe other things that you need to do to make Emacs work on your machine. If so, you should follow these recommendations also, for the same reason. * Send your problem reports to emacs-pretest-bug@gnu.org, not bug-gnu-emacs. Sometimes I won't know what to do about a system-dependent issue, and I may need people to tell me what happens if you try a certain thing on a certain system. When this happens, I'll send out a query. * Don't delay sending information. When you test on a system and encounter no problems, please tell me about it right away. That way, I will know that someone has tested Emacs on that kind of system. Please don't wait for several days "to see if it really works before you say anything." Tell me right away that Emacs seems basically to work; then, if you notice a problem a few days later, tell me immediately about that when you see it. It is okay if you double check things before reporting a problem, such as to see if you can easily fix it. But don't wait very long. A good rule to use in pretesting is always to tell me about every problem on the same day you encounter it, even if that means you can't find a solution before you report the problem. I'd much rather hear about a problem today and a solution tomorrow than get both of them tomorrow at the same time. * Make each bug report self-contained. If you refer back to another message, whether from you or from someone else, then it will be necessary for anyone who wants to investigate the bug to find the other message. This may be difficult, it is probably time-consuming. To help me save time, simply copy the relevant parts of any previous messages into your own bug report. In particular, if I ask you for more information because a bug report was incomplete, it is best to send me the *entire* collection of relevant information, all together. If you send just the additional information, that makes me do extra work. There is even a risk that I won't remember what question you are sending me the answer to. * When you encounter a bug that manifests itself as a Lisp error, try setting debug-on-error to t and making the bug happen again. Then you will get a Lisp backtrace. Including that in your bug report is very useful. * Debugging optimized code is possible, if you compile with GCC, but in some cases the optimized code can be confusing. If you are not accustomed to that, recompile Emacs without -O. One way to do this is make clean make CFLAGS=-g * If you use X windows, it is a good idea to run Emacs under GDB (or some other suitable debugger) *all the time*, at least while pretesting. Then, when Emacs crashes, you will be able to debug the live process, not just a core dump. The `pr' command defined in src/.gdbinit is very useful in this case for examining Lisp_Object values as they would appear in Lisp. If you can't use `pr' because Emacs has got a fault already, or because you have only a core dump, you can use `xtype' to look at the type of a value, and then choose one of the other commands `xsymbol', `xstring', `xcons', `xvector' and so on to examine the contents. I myself *always* run Emacs under GDB so that I can debug conveniently if the occasion arises. * To get Lisp-level backtrace information within GDB, look for stack frames that call Ffuncall. Select them one by one in GDB and type this: p *args pr This will print the name of the Lisp function called by that level of function calling. By printing the remaining elements of args, you can see the argument values. Here's how to print the first argument: p args[1] pr If you do not have a live process, you can use xtype and the other x... commands such as xsymbol to get such information, albeit less conveniently. * Even with a live process, these x... commands are useful for examining the fields in a buffer, window, process, frame or marker. Here's an example using concepts explained in the node "Value History" of the GDB manual to print the variable frame from this line in xmenu.c: buf.frame_or_window = Fcons (frame, prefix); First, use these commands: cd src gdb emacs b xmenu.c:1209 r -q Then type C-x 5 2 to create a new frame, and it hits the breakpoint: (gdb) p frame $1 = 1077872640 (gdb) xtype Lisp_Vectorlike PVEC_FRAME (gdb) xframe $2 = (struct frame *) 0x3f0800 (gdb) p *$ $3 = { size = 536871989, next = 0x366240, name = 809661752, [...] } (gdb) p $3->name $4 = 809661752 Now we can use `pr' to print the name of the frame: (gdb) pr "emacs@steenrod.math.nwu.edu" * The Emacs C code heavily uses macros defined in lisp.h. So suppose we want the address of the l-value expression near the bottom of `kbd_buffer_store_event' from keyboard.c: XVECTOR (kbd_buffer_frame_or_window)->contents[kbd_store_ptr - kbd_buffer] = event->frame_or_window); XVECTOR is a macro, and therefore GDB does not know about it. GDB cannot evaluate p XVECTOR (kbd_buffer_frame_or_window). However, you can use the xvector command in GDB to get the same result. Here is how: (gdb) p kbd_buffer_frame_or_window $1 = 1078005760 (gdb) xvector $2 = (struct Lisp_Vector *) 0x411000 0 (gdb) p $->contents[kbd_store_ptr - kbd_buffer] $3 = 1077872640 (gdb) p &$ $4 = (int *) 0x411008 * Here's a related example of macros and the GDB `define' command. There are many Lisp vectors such as `recent_keys', which contains the last 100 keystrokes. We can print this Lisp vector p recent_keys pr But this may be inconvenient, since `recent_keys' is much more verbose than `C-h l'. We might want to print only the last 10 elements of this vector. `recent_keys' is updated in keyboard.c by the command XVECTOR (recent_keys)->contents[recent_keys_index] = c; So we define a GDB command `xvector-elts', so the last 10 keystrokes are printed by xvector-elts recent_keys recent_keys_index 10 where you can define xvector-elts as follows: define xvector-elts set $i = 0 p $arg0 xvector set $foo = $ while $i < $arg2 p $foo->contents[$arg1-($i++)] pr end document xvector-elts Prints a range of elements of a Lisp vector. xvector-elts v n i prints `i' elements of the vector `v' ending at the index `n'. end * To debug what happens while preloading and dumping Emacs, do `gdb temacs' and start it with `r -batch -l loadup dump'. If temacs actually succeeds when running under GDB in this way, do not try to run the dumped Emacs, because it was dumped with the GDB breakpoints in it. * If you encounter X protocol errors, try evaluating (x-synchronize t). That puts Emacs into synchronous mode, where each Xlib call checks for errors before it returns. This mode is much slower, but when you get an error, you will see exactly which call really caused the error. * If the symptom of the bug is that Emacs fails to respond, don't assume Emacs is `hung'--it may instead be in an infinite loop. To find out which, make the problem happen under GDB and stop Emacs once it is not responding. (If Emacs is using X Windows directly, you can stop Emacs by typing C-z at the GDB job.) Then try stepping with `step'. If Emacs is hung, the `step' command won't return. If it is looping, `step' will return. If this shows Emacs is hung in a system call, stop it again and examine the arguments of the call. In your bug report, state exactly where in the source the system call is, and what the arguments are. If Emacs is in an infinite loop, please determine where the loop starts and ends. The easiest way to do this is to use the GDB command `finish'. Each time you use it, Emacs resumes execution until it exits one stack frame. Keep typing `finish' until it doesn't return--that means the infinite loop is in the stack frame which you just tried to finish. Stop Emacs again, and use `finish' repeatedly again until you get back to that frame. Then use `next' to step through that frame. By stepping, you will see where the loop starts and ends. Also please examine the data being used in the loop and try to determine why the loop does not exit when it should. Include all of this information in your bug report. * If certain operations in Emacs are slower than they used to be, here is some advice for how to find out why. Stop Emacs repeatedly during the slow operation, and make a backtrace each time. Compare the backtraces looking for a pattern--a specific function that shows up more often than you'd expect. If you don't see a pattern in the C backtraces, get some Lisp backtrace information by looking at Ffuncall frames (see above), and again look for a pattern. When using X, you can stop Emacs at any time by typing C-z at GDB. When not using X, you can do this with C-g. * Configure tries to figure out what kind of system you have by compiling and linking programs which calls various functions and looks at whether that succeeds. The file config.log contains any messages produced by compilers while running configure, to aid debugging if configure makes a mistake. But note that config.cache reads: # Giving --cache-file=/dev/null disables caching, for debugging configure. or more simply, rm config.cache ./configure * Always be precise when talking about changes you have made. Show things rather than describing them. Use exact filenames (relative to the main directory of the distribution), not partial ones. For example, say "I changed Makefile" rather than "I changed the makefile". Instead of saying "I defined the MUMBLE macro", send a diff. * Always use `diff -c' to make diffs. If you don't include context, it may be hard for me to figure out where you propose to make the changes. So I might have to ignore your patch. * When you write a fix, keep in mind that I can't install a change that *might* break other systems without the risk that it will fail to work and therefore require an additional cycle of pretesting. People often suggest fixing a problem by changing config.h or src/ymakefile or even src/Makefile to do something special that a particular system needs. Sometimes it is totally obvious that such changes would break Emacs for almost all users. I can't possibly make a change like that. All I can do is send it back to you and ask you to find a fix that is safe to install. Sometimes people send fixes that *might* be an improvement in general--but it is hard to be sure of this. I can install such changes some of the time, but not during pretest, when I am trying to get a new version to work reliably as quickly as possible. The safest changes for me to install are changes to the s- and m- files. At least I know those can't affect most systems. Another safe kind of change is one that uses a conditional to make sure it will apply only to a particular kind of system. Ordinarily, that is a bad way to solve a problem, and I would want to find a cleaner alternative. But the virtue of safety can make it superior at pretest time. * Don't try changing Emacs *in any way* unless it fails to work unchanged. * Don't even suggest changes to add features or make something cleaner. Every change I install could introduce a bug, so I won't install a change during pretest unless I see it is *necessary*. * If you would like to suggest changes for purposes other than fixing user-visible bugs, don't wait till pretest time. Instead, send them after I have made a release that proves to be stable. Then I can give your suggestions proper consideration. If you send them at pretest time, I will have to defer them till later, and that might mean I forget all about them. * In some cases, if you don't follow these guidelines, your information might still be useful, but I might have to do more work to make use of it. Unfortunately, I am so far behind in my work that I just can't keep up unless you help me to do it efficiently. Some suggestions for debugging on MS Windows: Marc Fleischeuers, Geoff Voelker and Andrew Innes To debug emacs with Microsoft Visual C++, you either start emacs from the debugger or attach the debugger to a running emacs process. To start emacs from the debugger, you can use the file bin/debug.bat. The Microsoft Developer studio will start and under Project, Settings, Debug, General you can set the command-line arguments and emacs' startup directory. Set breakpoints (Edit, Breakpoints) at Fsignal and other functions that you want to examine. Run the program (Build, Start debug). Emacs will start and the debugger will take control as soon as a breakpoint is hit. You can also attach the debugger to an already running emacs process. To do this, start up the Microsoft Developer studio and select Build, Start debug, Attach to process. Choose the emacs process from the list. Send a break to the running process (Debug, Break) and you will find that execution is halted somewhere in user32.dll. Open the stack trace window and go up the stack to w32_msg_pump. Now you can set breakpoints in emacs (Edit, Breakpoints). Continue the running emacs process (Debug, Step out) and control will return to emacs, until a breakpoint is hit. To examine the contents of a lisp variable, you can use the function 'debug_print'. Right-click on a variable, select QuickWatch, and place 'debug_print(' and ')' around the expression. Press 'Recalculate' and the output is sent to the 'Debug' pane in the Output window. If emacs was started from the debugger, a console window was opened at emacs' startup; this console window also shows the output of 'debug_print'. It is also possible to keep appropriately masked and typecast lisp symbols in the Watch window, this is more convenient when steeping though the code. For instance, on entering apply_lambda, you can watch (struct Lisp_Symbol *) (0xfffffff & args[0]). Local Variables: mode: text End: