fatal error if Flex and Bison is not configured

fatal error if Flex and Bison is not configured

[zhihao wang]

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Hi all,

I try to build xen 4.2( revision number: 25161) on Ubuntu 11.10_amd64, Mac
pro. After running ./configure and make. I got the following fatal error:

*libxlu_cfg_y.y:22:26: fatal error: libxlu_cfg_l.h: No such file or
directory compilation terminated.*

So the original libxlu_cfg_l.h is deleted when making, and should be
regenerated but it is not.  I find the path of flex and bison is not set.
When I add the correct path of flex and bison in tools.mk manually, This
error is fixed.

So, Is there anything in build scripts to modify to avoid this error ?

Regards

Wangzhihao

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Re: fatal error if Flex and Bison is not configured

[Ian Campbell]

On Thu, 2012-04-12 at 12:12 +0100, zhihao wang wrote:
> Hi all,
> 
> I try to build xen 4.2( revision number: 25161) on Ubuntu 11.10_amd64,
> Mac pro. After running ./configure and make. I got the following fatal
> error:
> 
> libxlu_cfg_y.y:22:26: fatal error: libxlu_cfg_l.h: No such file or
> directory compilation terminated.
> 
> 
> So the original libxlu_cfg_l.h is deleted when making, and should be
> regenerated but it is not.

Actually it should never have been deleted in the first place, unless
you have been modifying the flex source.

Please can you enumerate the exact steps you took, starting from the
initial clone of the repo, which caused the file to be deleted?

> I find the path of flex and bison is not set.  When I add the correct
> path of flex and bison in tools.mk manually, This error is fixed. 

Those tools should be optional since the generated files are checked in.
However perhaps configure should detect and provide the paths but behave
in a non-fatal manner if they aren't available? Roger, what do you
think?

Ian.

Re : fatal error if Flex and Bison is not configured

[David TECHER]

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BISON=$(which bison) FLEX=$(which flex) CURL=$(which curl-config) XML=$(which xml2-config) ./configure


________________________________
 De : zhihao wang <accept.acm@gmail.com>
À : xen-devel@lists.xen.org 
Cc : Ian.Campbell@citrix.com 
Envoyé le : Jeudi 12 avril 2012 13h12
Objet : [Xen-devel] fatal error if Flex and Bison is not configured
 

Hi all,

I try to build xen 4.2( revision number: 	25161)


	
	
	
	on Ubuntu 11.10_amd64, Mac pro. After running ./configure and make. I got the following fatal error:


libxlu_cfg_y.y:22:26: fatal error: libxlu_cfg_l.h: No such file or directory compilation terminated.

So the original libxlu_cfg_l.h is deleted when making, and should be regenerated but it is not.  I find the path of flex and bison is not set.  When I add the correct path of flex and bison in tools.mk manually, This error is fixed. 

So, Is there anything in build scripts to modify to avoid this error ? 

Regards

Wangzhihao





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Re: fatal error if Flex and Bison is not configured

[George Dunlap]

On Thu, Apr 12, 2012 at 12:24 PM, Ian Campbell <Ian.Campbell@citrix.com> wrote:
> On Thu, 2012-04-12 at 12:12 +0100, zhihao wang wrote:
>> Hi all,
>>
>> I try to build xen 4.2( revision number: 25161) on Ubuntu 11.10_amd64,
>> Mac pro. After running ./configure and make. I got the following fatal
>> error:
>>
>> libxlu_cfg_y.y:22:26: fatal error: libxlu_cfg_l.h: No such file or
>> directory compilation terminated.
>>
>>
>> So the original libxlu_cfg_l.h is deleted when making, and should be
>> regenerated but it is not.
>
> Actually it should never have been deleted in the first place, unless
> you have been modifying the flex source.
>
> Please can you enumerate the exact steps you took, starting from the
> initial clone of the repo, which caused the file to be deleted?
>
>> I find the path of flex and bison is not set.  When I add the correct
>> path of flex and bison in tools.mk manually, This error is fixed.
>
> Those tools should be optional since the generated files are checked in.
> However perhaps configure should detect and provide the paths but behave
> in a non-fatal manner if they aren't available? Roger, what do you
> think?

FWIW, I managed to get into a state where I ran into this error too;
after a sequence of fairly random steps, it went away, and I wasn't
able to reproduce it again.  I have no idea what I did to get there in
the first place, nor what I did to fix it.

Zhihao: I think if you make a clean copy of the repo and run
./configure again, the problem will probably go away.

 -George

Re: fatal error if Flex and Bison is not configured

[Ian Campbell]

On Thu, 2012-04-12 at 14:28 +0100, George Dunlap wrote:
> On Thu, Apr 12, 2012 at 12:24 PM, Ian Campbell <Ian.Campbell@citrix.com> wrote:
> > On Thu, 2012-04-12 at 12:12 +0100, zhihao wang wrote:
> >> Hi all,
> >>
> >> I try to build xen 4.2( revision number: 25161) on Ubuntu 11.10_amd64,
> >> Mac pro. After running ./configure and make. I got the following fatal
> >> error:
> >>
> >> libxlu_cfg_y.y:22:26: fatal error: libxlu_cfg_l.h: No such file or
> >> directory compilation terminated.
> >>
> >>
> >> So the original libxlu_cfg_l.h is deleted when making, and should be
> >> regenerated but it is not.
> >
> > Actually it should never have been deleted in the first place, unless
> > you have been modifying the flex source.
> >
> > Please can you enumerate the exact steps you took, starting from the
> > initial clone of the repo, which caused the file to be deleted?
> >
> >> I find the path of flex and bison is not set.  When I add the correct
> >> path of flex and bison in tools.mk manually, This error is fixed.
> >
> > Those tools should be optional since the generated files are checked in.
> > However perhaps configure should detect and provide the paths but behave
> > in a non-fatal manner if they aren't available? Roger, what do you
> > think?
> 
> FWIW, I managed to get into a state where I ran into this error too;
> after a sequence of fairly random steps, it went away, and I wasn't
> able to reproduce it again.  I have no idea what I did to get there in
> the first place, nor what I did to fix it.

I wonder if this is to do with timestamp skew or something like that
cause false reruns of bison? Those would then fail (no bison) which in
turn would cause make to delete the target.

Perhaps we need to disable the flex and bison rules unless some magic
flag is set (by those who are modifying the relevant sources)?

CCing IanJ on the assumption he knows what's going on here..

> Zhihao: I think if you make a clean copy of the repo and run
> ./configure again, the problem will probably go away.

"hg revert <paths>" would probably do the job too.

Ian.

Re: fatal error if Flex and Bison is not configured

[Ian Jackson]

Ian Campbell writes ("Re: [Xen-devel] fatal error if Flex and Bison is not configured"):
> I wonder if this is to do with timestamp skew or something like that
> cause false reruns of bison? Those would then fail (no bison) which in
> turn would cause make to delete the target.

Timestamp skew could certainly cause this.

Is NFS involved ?  Does the computer you're using have a stable,
synchronised, clock ?  Are you copying working trees about ?  Are you
using a tree actually cloned with hg ?

It's also possible, I guess, that hg takes no special care with
mtimes, in which case just "hg pull" might, if you were unlucky,
update the files in different seconds and in the wrong order.

> Perhaps we need to disable the flex and bison rules unless some magic
> flag is set (by those who are modifying the relevant sources)?

Well, we have configure now.  We could enable those rules iff
(suitably recent[1]) bison and flex were found.

[1] The original reason why we checked these files into the tree was
that shipped versions of Centos and RHEL had truly prehistoric
versions which didn't support making properly reentrant
scanners/parsers.

Ian.

Re: fatal error if Flex and Bison is not configured

[Dario Faggioli]

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On Thu, 2012-04-12 at 14:28 +0100, George Dunlap wrote: 
> > Those tools should be optional since the generated files are checked in.
> > However perhaps configure should detect and provide the paths but behave
> > in a non-fatal manner if they aren't available? Roger, what do you
> > think?
> 
> FWIW, I managed to get into a state where I ran into this error too;
> after a sequence of fairly random steps, it went away, and I wasn't
> able to reproduce it again.  
>
Same here, it occurred to me last week or something like that.

> I have no idea what I did to get there in
> the first place, nor what I did to fix it.
> 
Me neither... AFAICR (as I was on an `hg clone'-ed repo) I checked out
the original files that went missing by hand. :-(

Sorry of not being able to help more.

Dario

-- 
<<This happens because I choose it to happen!>> (Raistlin Majere)
-----------------------------------------------------------------
Dario Faggioli, Ph.D, http://retis.sssup.it/people/faggioli
Senior Software Engineer, Citrix Systems R&D Ltd., Cambridge (UK)



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Re: fatal error if Flex and Bison is not configured

[Roger Pau Monne]

El 12/04/2012, a las 12:24, Ian Campbell escribió:
> On Thu, 2012-04-12 at 12:12 +0100, zhihao wang wrote:
>> Hi all,
>> 
>> I try to build xen 4.2( revision number: 25161) on Ubuntu 11.10_amd64,
>> Mac pro. After running ./configure and make. I got the following fatal
>> error:
>> 
>> libxlu_cfg_y.y:22:26: fatal error: libxlu_cfg_l.h: No such file or
>> directory compilation terminated.
>> 
>> 
>> So the original libxlu_cfg_l.h is deleted when making, and should be
>> regenerated but it is not.
> 
> Actually it should never have been deleted in the first place, unless
> you have been modifying the flex source.
> 
> Please can you enumerate the exact steps you took, starting from the
> initial clone of the repo, which caused the file to be deleted?
> 
>> I find the path of flex and bison is not set.  When I add the correct
>> path of flex and bison in tools.mk manually, This error is fixed. 
> 
> Those tools should be optional since the generated files are checked in.
> However perhaps configure should detect and provide the paths but behave
> in a non-fatal manner if they aren't available? Roger, what do you
> think?


We stopped checking for bison and flex, but we left the variables, so if the user sets BISON and FLEX in their environment everything should be ok. Since this seems to be a common problem one possible solution is to check for BISON and FLEX on the libxl Makefile when needed (and in configure in a non fatal manner), and if not found, print an error message telling the user to rerun configure, instead of just failing ungracefully. I've just send a patch that I think fixes this issue.

> 
> Ian.
> 
> 
> 
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