Bug#309185: tetex-bin: FTBFS in experimental: Endless loop.
Hi,
Kurt Roeckx <kurt@roeckx.be> wrote:
> Your package is failing to build in experimental. It
> seems to be stuck in an endless loop doing this over and
> over again:
[...]
Here is my (partial) understanding of the problem:
debian/rules contains a rule that causes it to be remade (which is
explicitely supported by GNU Make) from debian/rules.in with eperl:
% :: %.in $(eperl_sourcefiles)
eperl -P -o $@ $<
However, in $(eperl_sourcefiles)'s expansion, we find
debian/common.variables debian/common.functions, which are real files
*but* are declared as .PHONY targets (it took me a while to spot the
.PHONY declarations and the end of debian/rules, explaining why the
files were being remade every time debian/rules was run...). I suppose
Frank declared them as .PHONY because he wanted them to be updated[1]
whenever possible.
So, debian/rules depends on .PHONY targets. Therefore, it should always
be remade, whenever Make runs it, explaining the endless loop. However,
on my system, and presumably on Frank's, the loop breaks (at least, when
I tried, it was remade "only" twice). That, I don't understand.
But in my opinion, having .PHONY targets being real files *and* being
depended on is not appropriate, and is causing the problem here (not to
mention headaches). Does it mean that targets depending on the .PHONY
targets should be remade every time, or only when the .PHONY target
files are newer? This sounds ambiguous to me.
I've tested the following patch to debian/rules.in, in order to fix this
problem. debian/common.variables and debian/common.functions are no
longer .PHONY targets. They are updated whenever Make decides to remake
debian/rules. debian/rules is automatically updated when one of its
sources (debian/rules.in and $(eperl_sourcefiles)) is newer.
With this patch, if debian/rules is up-to-date but you have updated the
master files in ../../tetex-common, they will not be copied in the
package build directory to cause debian/rules to be updated. This is
probably something Frank wanted to avoid, but I don't see any elegant
way to that. One way would be with a wrapper script, that checks whether
the master files are newer, updates them if this is the case, and then
runs make; another way would be with a .PHONY target listed as a
prerequesite of every legal top-level target of debian/rules (clean,
build, binary, binary-arch, etc.) that does this job. None of these is
elegant...
--- debian/rules.in.orig 2005-05-16 15:14:51.000000000 +0200
+++ debian/rules.in 2005-05-16 15:11:48.000000000 +0200
@@ -66,8 +66,49 @@
configure:
:
+# common.variables and common.functions are shared between the tetex-base and
+# tetex-bin source packages. If you want to use this mechanism, check out the
+# tetex-common tree and put it two directories above the package directory.
+# I use ~/src/Packages/tetex-common together with ~/src/Packages/tetex-base/tetex-base-$version/.
+define update-debian-common.variables
+ test -e $(real_common_variables) && \
+ test $(real_common_variables) -nt debian/common.variables && \
+ cp $(real_common_variables) debian/common.variables || true
+endef
+
+# $(real_common_variables):
+# # just do nothing if it does not exist
+# true
+
+define update-debian-common.functions
+ test -e $(real_common_functions) && \
+ test $(real_common_functions) -nt debian/common.functions.in && \
+ cp $(real_common_functions) debian/common.functions.in && \
+ eperl -P -o debian/common.functions debian/common.functions.in \
+ || true
+endef
+
+# $(real_common_functions):
+# # just do nothing if it does not exist
+# true
+
+debian/rules: debian/rules.in $(eperl_sourcefiles)
+ # Refresh debian/common.variables debian/common.functions every time
+ # the rules file is going to be regenerated
+ $(update-debian-common.variables)
+ $(update-debian-common.functions)
+ # Regenerate the rules file
+ eperl -P -o $@ $<
+
+# Override the general double-colon rule for generating files from their
+# .in eperl sources; otherwise, Make will complain that
+# debian/common.functions depends on itself, since it is in
+# $(eperl_sourcefiles).
+debian/common.functions: debian/common.functions.in debian/common.variables
+ eperl -P -o $@ $<
+
# Eperl is simply great: thanks, Davide!
-% :: %.in $(eperl_sourcefiles)
+% :: %.in $(eperl_sourcefiles)
eperl -P -o $@ $<
@@ -115,30 +156,6 @@
-make distclean
-# common.variables and common.functions are shared between the tetex-base and
-# tetex-bin source packages. If you want to use this mechanism, check out the
-# tetex-common tree and put it two directories above the package directory.
-# I use ~/src/Packages/tetex-common together with ~/src/Packages/tetex-base/tetex-base-$version/.
-debian/common.variables:
- test -e $(real_common_variables) && \
- test $(real_common_variables) -nt $@ && \
- cp $(real_common_variables) $@ || true
-
-# $(real_common_variables):
-# # just do nothing if it does not exist
-# true
-
-debian/common.functions:
- test -e $(real_common_functions) && \
- test $(real_common_functions) -nt $@.in && \
- cp $(real_common_functions) $@.in || true
- eperl -P -o $@ $@.in
-
-# $(real_common_functions):
-# # just do nothing if it does not exist
-# true
-
-
configure-stamp: $(stampdir) patch-stamp
# comment out the following line if you want to check the configure target
# in a CVS working copy
@@ -278,7 +295,6 @@
echo "dummy content for dpkg-source" > debian/sid-stamp
.PHONY: binary binary-arch binary-indep clean checkroot patchclean sarge sid
-.PHONY: debian/common.functions debian/common.variables
# Local variables:
[1] i.e., for common.variables, copied from
../../tetex-common/common.variables if this exists, and for
common.functions, regenerated from common.functions.in, itself
copied from ../../tetex-common/common.functions.in it this exists.
--
Florent
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