Hi Gary,
I'm a bit unclear on one point. According to your description, should we
be seeing two prompts for commands like "cont", and "step"? When you say
we are expecting:
"Breakpoint hit:" <location>
<prompt>
Isn't it really:
<prompt>
"Breakpoint hit:" <location>
<prompt>
I figure this must be the case, because your fix removes the printing of
a prompt, and we still need one prompt, so there must have been two to
start with. I think in the above the last <prompt> is being produced
sequentially right after the "Breakpoint hit:" output, so is never an
issue. The first <prompt> comes from the printPrompt() call after
issuing the "cont" command, and it's possible to hit the breakpoint and
start producing more output before printPrompt() has completed, thus
causing the problem you are seeing.
There seems to be some purpose to printing this first prompt and I'm not
so sure eliminating it is the right thing to do. I think it might be
there to indicate that the command has been initiated, because there
could be some delay before the breakpoint is hit. So the issue then is
how to make sure this prompt appears in the input stream before any of
the "Step completed:" or "Breakpoint hit:" output. Possibly event
processing should be blocked until executeCommand() completes.
thanks,
Chris
On 5/26/18 3:50 AM, gary.ad...@oracle.com wrote:
This is a review request for a previously closed test bug.
The test was recently moved to the open repos, and the
proposed fix is in the open code.
Webrev: http://cr.openjdk.java.net/~gadams/8169718/webrev/
-------- Forwarded Message --------
Subject: RFR: JDK-8169718: nsk/jdb/locals/locals002: ERROR: Cannot
find boolVar with expected value: false
Date: Fri, 25 May 2018 11:35:10 -0400
From: Gary Adams <gary.ad...@oracle.com>
Reply-To: gary.ad...@oracle.com
The jdb tests use stdin to send commands to a jdb process
and parses the stdout to determine if a command was
successful and when the process is prompting for new commands
to be sent.
Some commands are synchronous, so when the command is completed
a new prompt is sent back immediately.
Some commands are asynchronous, so there could be a delay
until a breakpoint is reached. The event handler then sends a prompt
when the application thread is stopped and new jdb commands can be sent.
The problem causing the intermittent failures was a corruption in the
output stream when prompts were being sent at the wrong times.
Instead of receiving
"Breakpoint hit:" <location>
<prompt>
the log contained
"Breakpoint hit:" <prompt> <location>
Once out of sync, jdb commands were being sent prematurely
and the wrong values were being compared against expected behavior.
The simple fix proposed here recognizes that commands like "cont",
"step" and "next" are asynchronous commands and should not send back
a prompt immediately. Instead. the event handler will deliver the next prompt
when the next "Breakpoint hit:" or "Step completed:" state change occurs.
The bulk of the testing was done on windows-x64-debug builds where the
intermittent failures were observed in ~5 in 1000 testruns. The fix has
also been tested on linux-x64-debug, solaris-sparcv9-debug,
and macosx-x64-debug, even though the failures have never been reported
against those platforms.
Failures have been observed in many of the nsk/jdb tests with similar corrupted
output streams, but never directly associated with this issue before.
redefine001, caught_exception002, locals002, eval001, next001,
stop_at003, step002, print002, trace001, step_up001, read001,
clear004, kill001, set001
