RFR: JDK-8195689 Remove generated-configure.sh and instead use autoconf

[Magnus Ihse Bursie]

On 2018-01-18 19:37, Erik Joelsson wrote:
> Hello Magnus,
>
> Nice to see this finally happening!
Thanks!

>
> In building.md, when getting autoconf for Cygwin, I believe you also 
> need the autoconf wrapper scripts package. 
Hm, well, no, it's the other way around. "autoconf" is the name of the 
cygwin "autoconf wrapper scripts" package. It depends on "m4", 
"autoconf2.69" (or whatever), etc. I have verified that just installing 
"autoconf" will be enough, and will pull in all needed dependencies.

> Perhaps it's also worth mentioning that you can download the autoconf 
> src and build/install from there?
Well, I'm already giving a link to http://www.gnu.org/software/autoconf 
in the build readme. I'm not sure if it's helpful for anyone to download 
the autoconf source by themselves. Most users will have it available 
prebuilt. And if not, you'll also most likely need to pull down and 
build m4, and that's trickier. The reason why we used to download 
autoconf and build it from source was to make sure that we got the 
exactly right version, but that only made sense when we checked in the 
generated-configure.sh. (And this worked fine for us, since we had m4...)

> In jib-profiles.js, you need to use build_platform instead of 
> target_platform when creating the module name for the dependency. 
Good point. Fixed.

> I would also like if you added the dependency on the other main 
> profiles as well. At least linux-x86, linux-arm64 and windows-x86 are 
> still possible to build and should work fine with this. For 
> solaris-x64 you would need to generate the package for it to work.
Sure.
>
> The TMPDIR logic looks weird. Are you unconditionally setting it to 
> /cygdrive/t/...? That's a valid dir in our build farm, but not on my 
> local windows box:
>
> mkdir: cannot create directory ‘/cygdrive/t’: No such file or directory
> autom4te: cannot create 
> /cygdrive/t/workspace/.build/tmpdir/am4t7009.7040: No such file or 
> directory
>  at 
> /cygdrive/c/cygwin64/var/tmp/jib-erik/install/jpg/infra/builddeps/autoconf-windows_x64/2.69+1.0.1/autoconf-windows_x64-2.69+1.0.1.tar.gz/usr/bin/autom4te 
> line 954.
> Error: Failed to generate runnable configure script
Yeah, that was broken by design. :-(

Some offline discussion later, it turned out that the reason for the 
trouble was mismatch between cygwin-32 and cygwin-64. I've solved this 
by generating two different packages, for cygwin-32 and cygwin-64. I've 
also made some other minor fixes to the build script, e.g. using perl 
instead of sed due to the braindead sed being available on solaris. :(

Updated webrev:
http://cr.openjdk.java.net/~ihse/JDK-8195689-remove-generated-configure/webrev.02/

/Magnus


>
> /Erik
>
>
> On 2018-01-18 05:28, Magnus Ihse Bursie wrote:
>> Currently, we require all developers who modify the configure script 
>> to run autoconf locally, to update the generated-configure.sh script, 
>> which is then checked in. This is the only instance of checked in 
>> "compiled" code in OpenJDK, and this has brought along several problems:
>>
>> * Only a specific version of autoconf, 2.69, can be used, to avoid 
>> large code changes in the generated file. Unfortunately, Ubuntu ships 
>> a version of autoconf that claims to be 2.69 but is actually heavily 
>> patched. This requires all Ubuntu users to compiler their own 
>> autoconf from source.
>>
>> * The Oracle JDK closed sources has a closed version that needs to be 
>> updated. In practice, this has meant that all non-Oracle developers, 
>> need an Oracle sponsor for patches modifying the configure script.
>>
>> * If the configure script is not properly updated, the build will 
>> fail. The same happens on the Oracle side if the closed version is 
>> not in sync with the open version. It is easy to miss re-generating 
>> the script after the last fix of a typo in the comments in an .m4 
>> file...
>>
>> * Merging between two changes containing configure modifications is 
>> almost impossible. In practice, the entire generated-configure.sh 
>> needs to be thrown away and regenerated.
>>
>> The entire benefit of having the file in the repo is to save 
>> first-time developers the hassle of installing autoconf. On most 
>> platforms, this is a no-brainer (like "apt install autoconf"), and 
>> the requirement is similar to other open source projects using 
>> autoconf and "./configure". It's just not worth it.
>>
>> Bug: https://bugs.openjdk.java.net/browse/JDK-8195689
>> WebRev: 
>> http://cr.openjdk.java.net/~ihse/JDK-8195689-remove-generated-configure/webrev.01
>>
>> /Magnus
>