Re: [PATCH] Testsuite: Ensure changing directory does not break the log file

[Alan Hayward <Alan.Hayward@arm.com>]

> On 21 Feb 2019, at 22:40, Tom Tromey <tom@tromey.com> wrote:
> 
>>>>>> "Alan" == Alan Hayward <Alan.Hayward@arm.com> writes:
> 
> Alan> get_compiler_info switches to a new log file before checking the compiler
> Alan> to ensure the checks are not logged.
> 
> Haha, that seems pretty gross.

It was quite a fun issue to track down :)

> 
> Alan> The simpler and safer solution is to override the builtin cd function. The
> Alan> new function checks the current log file and if the path is relative, then
> Alan> it resets the logging using an absolute path. Finally it calls the builtin
> Alan> cd.  This ensures get_compiler_info (and any other code) can correctly
> Alan> backup and restore the current log file.
> 
> Makes sense to me.
> 
> Alan> +    if { [regexp "^-a \[^/\]" $saved_log match] } {
> 
> It may be better here to just extract the file name and either use "file normalize"
> (could be done unconditionally) or look at it with "file pathtype".
> See https://www.tcl.tk/man/tcl8.4/TclCmd/file.htm
> 
> Tom

Re-written using normalize and I also made the checking better.  With this version
it will be safe regardless of the arguments used for log_file.

This version ok?



diff --git a/gdb/testsuite/lib/gdb.exp b/gdb/testsuite/lib/gdb.exp
index d05854329d..f052bd2f3d 100644
--- a/gdb/testsuite/lib/gdb.exp
+++ b/gdb/testsuite/lib/gdb.exp
@@ -6284,5 +6284,37 @@ proc gdb_define_cmd {command command_list} {
     }
 }

+# Safe version of cd that ensures the log file is not stopped.
+
+rename cd builtin_cd
+
+proc cd { dir } {
+
+    # Get the existing log file flags.
+    set log_file_info [log_file -info]
+
+    # Split the flags into args and file name.
+    set log_file_flags ""
+    set log_file_file ""
+    foreach arg [ split "$log_file_info" " "] {
+       if [string match "-*" $arg] {
+           lappend log_file_flags $arg
+       } else {
+           lappend log_file_file $arg
+       }
+    }
+
+    # If there was an existing file, ensure it is an absolute path, and then
+    # reset logging.
+    if { $log_file_file != "" } {
+       set log_file_file [file normalize $log_file_file]
+       log_file
+       log_file $log_file_flags "$log_file_file"
+    }
+
+    # Call the builtin version of cd.
+    builtin_cd $dir
+}
+
 # Always load compatibility stuff.
 load_lib future.exp