mapscript java makefile dependency problem

[arkadi]

In mapserver/mapscript/java/Makefile.in:

all: interface mapscript_so mapscript_java mapscript_jar
mapscript_java::
        $(JAVAC) edu/umn/gis/mapscript/*.java
mapscript_jar::
        $(JAR) cf mapscript.jar edu

In case parallel build is performed or make is evaluating targets in unspecified order the JAR file might be created without all necessary .class files. Consider this simple proof:

lithium(/7)arkadi:~/tmp/m> cat Makefile
all: a b
a::
        @sleep 2
        @echo a
b::
        @echo b
lithium(/7)arkadi:~/tmp/m> make -j2
b
a
lithium(/7)arkadi:~/tmp/m> make
a
b
lithium(/7)arkadi:~/tmp/m>

[arkadi]

The issue is present in Mapserver 5.0 too.

[unicoletti]

Parallel build is in fact discouraged. Closing.

[arkadi]

Quite an interesting approach in the era of multi-core CPU. The typical 1U server has 4 or 8 CPU-s these days, I believe.

The real problem is: the build silently produce incorrect result. I assume the sane way of "discouraging" parallel compile would be enforcing -j1 for whatever reason you need the build serialized. Else it is troublesome to explain to the customers the Mapserver is commercial grade software in the light in can't be even properly compiled.

Maybe it is my fault, but I can't find anything in the documentation about "Parallel build is discouraged".

Yet it could be fixed with one-line patch.

Reopening the ticket. Please consider fixing or documenting this issue properly.

[unicoletti]

Patch are always *very* much welcome ;-)

[unicoletti]

This patch allows paralle compilation and in fact speeds things up a little

[unicoletti]

Arkadi, please try the patch and report your findings here so that I can commit to svn and close this ticket.

[arkadi]

Works for me.

Thank you.

[unicoletti]

Closing