Clarification request: AC_PREFIX_DEFAULT([.]) and AC_CONFIG_SUBDIRS collide.

[Thomas Jahns]

Hello,

I noticed having a default prefix of . causes AC_CONFIG_SUBDIRS to fail.

Is this a bug in AC_PREFIX_DEFAULT (or its documentation) or in AC_CONFIG_SUBDIRS?

Regards, Thomas

P.S.: the failure looks like this

....
config.status: executing depfiles commands
=== configuring in yaxt (/path/to/package_top/directory_sub)
configure: running /bin/sh ./configure --disable-option-checking '--prefix=.'
--cache-file=/dev/null --srcdir=.
configure: error: expected an absolute directory name for --prefix: .
configure: error: ./configure failed for directory_sub

[Václav Zeman]

Post by Thomas Jahns
Hello,
I noticed having a default prefix of . causes AC_CONFIG_SUBDIRS to fail.
Is this a bug in AC_PREFIX_DEFAULT (or its documentation) or in AC_CONFIG_SUBDIRS?
Regards, Thomas
P.S.: the failure looks like this
....
config.status: executing depfiles commands
=== configuring in yaxt (/path/to/package_top/directory_sub)
configure: running /bin/sh ./configure --disable-option-checking
'--prefix=.' --cache-file=/dev/null --srcdir=.
configure: error: expected an absolute directory name for --prefix: .
configure: error: ./configure failed for directory_sub

I do not know the internals but this does look like a deliberate foot
shooting preventive measure rather than bug.

[Eric Blake]

Post by Václav Zeman

Post by Thomas Jahns
Hello,
I noticed having a default prefix of . causes AC_CONFIG_SUBDIRS to fail.
Is this a bug in AC_PREFIX_DEFAULT (or its documentation) or in AC_CONFIG_SUBDIRS?
configure: error: expected an absolute directory name for --prefix: .
configure: error: ./configure failed for directory_sub

I do not know the internals but this does look like a deliberate foot
shooting preventive measure rather than bug.

install.texi (and therefore INSTALL) documents that --prefix MUST be
absolute. Using AC_PREFIX_DEFAULT with a non-absolute location is
therefore unwise. That said, we either need a doc patch to mention this
about AC_PREFIX_DEFAULT, or it may be possible to refactor
AC_PREFIX_DEFAULT to canonicalize the default to be absolute to match
that --prefix must be absolute. Would you care to write the patch?