[Bashdb-devel] ugly code in install-data-hook

[Eric B. <eb...@by...>]

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The following code in Makefile.am's install-data-hook has a severe bug,
and I'm not sure how to work around it.  Furthermore, the code is tied to
GNU make, and is not portable to other make programs:

#
# This is ugly. Bash 3.0 requires things to be different than where
# many OS's would want to put bash debugger scripts or where a user
# may have asked for this to be put. It's wrong in the directory
# names it uses and for the name of the main include.
# So... using the place that configure determined bash
# wants this to be put, (BASHDB_MAIN), we try to remove any existing files
# before making a symbolic link to it. Also if was in a directory
# (containing perhaps old code), that gets removed and a symbolic link
# is added or relocated if there was another symbolic link. Finally
# the basename that bash wants to use is symlinked to the main name
# that this distribution uses dbg-main.inc, unless those are the same.
#
OLD_DIR :=$(dir @BASHDB_MAIN@)
OLD_MAIN:=$(notdir @BASHDB_MAIN@)
PARENT_DIR:=$(dir $(OLD_DIR))
install-data-hook:
	@if test -e @BASHDB_MAIN@ ; then \
	  if test $(OLD_MAIN) != dbg-main.inc ; then \
	    $(RM) @BASHDB_MAIN@ || true; \
          fi; fi
	@if test -d $(DESTDIR)$(OLD_DIR) ; then \
	     $(RM) -fr $(DESTDIR)$(OLD_DIR:/=) || true; \
	else if test -L $(DESTDIR)$(OLD_DIR:/=) ; then \
	     $(RM) -f $(DESTDIR)$(OLD_DIR:/=) || true; \
	fi; fi
	test -d $(DESTDIR)$(PKGDATADIR) || $(mkdir_p) $(DESTDIR)$(PKGDATADIR)
	$(LN_S) $(DESTDIR)$(PKGDATADIR) $(DESTDIR)$(PARENT_DIR:/=) || true
	@if test dbg-main.inc != $(OLD_MAIN) ; then \
	  ( if cd $(DESTDIR)$(pkgdatadir) ; then \
	     test -e $(OLD_MAIN) && $(RM) $(OLD_MAIN); \
	     $(LN_S) dbg-main.inc $(OLD_MAIN) || \
	     echo "WARNING: I'm having trouble letting bash know where the
debugger is. Use the bashdb script only." ; \
	  fi ) \
	fi


In the case where bash was configured with DEBUGGER_START_FILE set in the
environment to the same location as where I configured bashdb
- --with-bashdb-main, then OLDDIR and PKGDATADIR are the same directory, and
'make install' proceeds to install all the dbg-*.inc files, then calls the
hook which removes the directory containing all the newly installed
dbg-*.inc files, leaving a crippled installation.

This is the case on cygwin because I maintain both the bash and bashdb
packages, so I can coordinate the two configure runs to use the same
location for the debugger main entry point.

An informative trace from 'make install', where I manually replaced all
the instructions in install-data-local with echos of what would otherwise
run, shows:

...
 /usr/bin/install -c -m 644 '/tmp/bashdb-3.1-0.04/dbg-set-d-vars.inc'
'/tmp/bashdb-3.1-0.04/.inst/usr/share/bashdb/dbg-set-d-vars.inc'
make  install-data-hook
make[3]: Entering directory `/tmp/bashdb-3.1-0.04/.build'
if test -e /usr/share/bashdb/bashdb-main.inc ; then  if test
bashdb-main.inc != dbg-main.inc ; then  /usr/bin/rm
/usr/share/bashdb/bashdb-main.inc || true;  fi; fi
if test -d /tmp/bashdb-3.1-0.04/.inst/usr/share/bashdb/ ; then
/usr/bin/rm -fr /tmp/bashdb-3.1-0.04/.inst/usr/share/bashdb || true;  else
if test -L /tmp/bashdb-3.1-0.04/.inst/usr/share/bashdb ; then  /usr/bin/rm
- -f /tmp/bashdb-3.1-0.04/.inst/usr/share/bashdb || true;  fi; fi
echo 'test -d /tmp/bashdb-3.1-0.04/.inst/usr/share/bashdb || mkdir -p --
/tmp/bashdb-3.1-0.04/.inst/usr/share/bashdb'
test -d /tmp/bashdb-3.1-0.04/.inst/usr/share/bashdb || mkdir -p --
/tmp/bashdb-3.1-0.04/.inst/usr/share/bashdb
echo 'ln -s /tmp/bashdb-3.1-0.04/.inst/usr/share/bashdb
/tmp/bashdb-3.1-0.04/.inst/usr/share/bashdb || true'
ln -s /tmp/bashdb-3.1-0.04/.inst/usr/share/bashdb
/tmp/bashdb-3.1-0.04/.inst/usr/share/bashdb || true
if test dbg-main.inc != bashdb-main.inc ; then  ( if cd
/tmp/bashdb-3.1-0.04/.inst/usr/share/bashdb ; then  test -e
bashdb-main.inc && /usr/bin/rm bashdb-main.inc;  ln -s dbg-main.inc
bashdb-main.inc ||  echo "WARNING: Im having trouble letting bash know
where the debugger is. Use the bashdb script only." ;  fi )  fi

- --
Life is short - so eat dessert first!

Eric Blake             eb...@by...
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