Re: emacs-win-builder

[Eli Zaretskii]

> From: Nikolay Kudryavtsev <address@hidden>
> Date: Tue, 30 Aug 2016 22:47:48 +0300
> 
> Ladies and gentlemen, presenting emacs-win-builder, an Elisp script for 
> building Emacs on Windows. Currently I published it here.
> 
> The general idea is very simple. You start with only wget installed and Emacs 
> sources, run a single function and get a new version of Emacs built for you. 
> This installs the appropriate toolchain(MinGW and Msys2 are both supported), 
> then goes through the whole autogen -> configure -> make -> make install 
> cycle.
> 
> I believe this would save some time, both for maintainers of Emacs on Windows 
> and general users. This also allows Emacs developers to keep the build 
> procedure as complex as required, without having to worry about making it too 
> hard for users to follow. Also, this lowers the dependency on any toolchain, 
> since we can always add some of our own patches or non standard versions of 
> packages into the process(MinGW build already uses quite few of them). People 
> who want to hack around the build process would always have a working place 
> to start from. Also users would be able to test bug fixes immediately without 
> having to wait for a third party or the next RC.
> 
> Currently there are a few hacky pats, some parts should be better documented, 
> but the main build procedure works for every currently possible build. Out of 
> optional things, for MinGW only gnutls is currently built, but this is 
> solvable. Also, I'm not so sure on the versions of MinGW libraries, this 
> needs review from someone with better knowledge. I haven't thoroughly tested 
> the resulting builds, but since this script does not do any magic, any 
> possible problems with them seem solvable.

Thanks.  I have no problem with offering this in nt/ as an alternative
build method, provided that it is mentioned in nt/INSTALL and
nt/INSTALL.W64.

I have a few comments to the script and its concept:

 . It invokes MSYS programs from a (presumably) native Emacs,
   something that might not necessarily work, depending on the
   end-user setup.  E.g., on my systems, MSYS can only work when
   invoked from the MSYS Bash window.  Caveat emptor!

 . Your function that invokes the various commands ignores the return
   value of process-file-shell-command, so if some part of the build
   fails, the script will happily continue invoking the rest of the
   build commands regardless.  Also, it looks like the output of the
   build commands is not shown as the build proceeds, which means the
   user is building blind and cannot interrupt a runaway build.
   Wouldn't it be better to use start-file-process instead?

 . The list of dependencies to download should IMO be on a separate
   file and in a format that can be easily changed by someone who is
   not too proficient in Lisp, because the dependencies change and
   their versions change even more frequently.  The repeated portions
   of the URLs of the download sites could also be specified only
   once in that separate file.

 . Various versions of 7z are not Free Software, so I think we'd
   prefer to use bsdtar from libarchive instead.  As a bonus, users
   will be saved from the UAC elevation prompts when installing the
   package (at least with libarchive available from the ezwinports
   site).

 . This comment:

   (process-file-shell-command (concat "\"" (ewb-get-wget) "\" 
--no-check-certificate " file
                                       ;; ezwinports version of wget needs -O 
flag
                                       ;; otherwise it saves files as "download"
                                        " -O" file-name) nil "ewb")

    made me raise my brow: I use that version of wget all the time,
    and it certainly does NOT save files as "download".  So some other
    factor is at work here, most probably the download URLs that all
    end in "/download".  A better URL is something like this:

     http://downloads.sourceforge.net/project/ezwinports/FILE

    where FILE is the file you want to download, like
    zlib-1.2.8-2-w32-bin.zip.

  . Last but not least: AFAIK, Windows will not allow you to install
    executables and DLLs that overwrite running modules.  So, for
    example, running "make install" from an Emacs that lives in the
    same directory as where "make install" will copy the newly-built
    executable will fail, and I think likewise with DLLs that are in
    use by the running Emacs process.  Users should be aware of that
    caveat, and maybe the script should install in some staging area,
    leaving it to the user to copy to the final destination after
    exiting Emacs.

Thanks again for working on this.  I urge people here to try your
script and return feedback.