[Bug mi/28711] gdb closes when displaying structs with long field names in eclipse

["aburgess at redhat dot com" <sourceware-bugzilla@sourceware.org>]

https://sourceware.org/bugzilla/show_bug.cgi?id=28711

Andrew Burgess <aburgess at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |aburgess at redhat dot com
   Last reconfirmed|                            |2021-12-17
     Ever confirmed|0                           |1
             Status|UNCONFIRMED                 |NEW

--- Comment #1 from Andrew Burgess <aburgess at redhat dot com> ---
Was able to reproduce this without using Eclipse, with current HEAD.

First, I had to patch GDB to slow it down a little.  I observed, that when this
bug triggers in Eclipse the complete command is now read in the fist "read"
call.  When GDB issues the second "read" call, it gets, not only the remainder
of the first command, including the trailing \n, but it also gets the start of
the next command sent from eclipse.

When I tried to reproduce this in GDB without eclipse, I couldn't reproduce
this read pattern, even bulk pasting in the commands, at least for me, GDB
seemed to process things too quickly.

So I added this patch to GDB:

### START ####

diff --git a/gdb/event-top.c b/gdb/event-top.c
index 530ea298247..e12a87a7910 100644
--- a/gdb/event-top.c
+++ b/gdb/event-top.c
@@ -854,6 +874,7 @@ gdb_readline_no_editing_callback (gdb_client_data
client_data)

   buffer_grow_char (&line_buffer, '\0');
   result = buffer_finish (&line_buffer);
+  sleep (1);
   ui->input_handler (gdb::unique_xmalloc_ptr<char> (result));
 }


### END ###

And now I am able to reproduce the failure.

(1) Create a pseudo terminal to use as the MI terminal - in another shell I do
`tty ; tail -f /dev/null`, and copy the path to the pseudo terminal that is
printed, then

(2) Compile the test.c program from the original bug report,

(3) Start GDB: ./gdb/gdb --data-directory ./gdb/data-directory/ --interpreter
mi2 --nx -q --interpreter console -ex "new-ui mi /dev/pts/13" -ex "set
pagination off" -ex "show version" -ex "start" ./test.x
    Replace "/dev/pts/13" with the path copied in step #1.

(4) Now switch back to the terminal used in step #1, this should have started
up as an MI terminal.  Paste in the following commands.  These need to be
pasted in a single paste action, NOT one at a time:

### START ### 
-var-create --thread 1 --frame 0 - * var
-var-list-children var1
-var-info-path-expression
var1.aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
-var-info-path-expression
var1.aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa
### END ###

For me, GDB will then exit every time.  What I observe is that the call to
`fgetc` in gdb_readline_no_editing_callback returns EOF after it has read the
1024 long command - this is the first command where the \n appears in the next
read block.  I still don't understand why that call is returning EOF....

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