Why does configure's --with-swig option require the directory instead of the binary itself?

[dbankieris]

@alexlin0

Under Ubuntu 20.04, apt-get install swig installs SWIG 4.0 at /usr/bin/swig4.0 and links /usr/bin/swig to it. Trick is incompatible with SWIG 4.0 (#768), and installing SWIG 3.0 yields /usr/bin/swig3.0. I have no idea what's going on in autoconf, but configure's --with-swig option uses SWIG 4.0 no matter what I give it. Can we not require specification of the binary instead of its directory?

[spfennell]

@dbankieris you can set the SWIG environment variable to /usr/bin/swig3.0 and configure will use that one instead. I can easily update --with-swig to be a path to the executable as well if you want me to make that change, or I can add a new option to preserve other people's swig configurations

[spfennell]

@dbankieris you wrote the code that uses the SWIG directory instead of the executable by the way, so maybe you can answer your own question...
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@alexlin0 @jmpenn

[spfennell]

@dbankieris you wrote the code that uses the SWIG directory instead of the executable by the way, so maybe you can answer your own question...
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@alexlin0 @jmpenn

Well, I wrote it, but then you updated it. It was a team effort. I'm looking at the code I wrote 2 years ago and rolling my eyes.

[dbankieris]

Ah, yes. We now use AX_PKG_SWIG, which uses AC_PATH_PROGS to search paths for swig, swig3.0, or swig2.0 and allows us to specify a minimum version. Maybe we could hack our own AX_PKG_SWIG, but it's probably not worth it.

I'm going to slowly back away and pretend I never created this issue...

[spfennell]

It's not that hard to hack. Just have --with-swig set SWIG in configure's environment. Then AX_PKG_SWIG will use SWIG instead of PATH