race condition due to install-file macro ?

[Erik Joelsson]

Hello,

Short answer is no, there has to be some other explanation, like a jar 
file actually is corrupt or it is missing from the dependency list 
$(JRE_LIB_TARGETS). The latter is the most probable cause I think. These 
errors can sometimes be very subtle and hard to find. If this could 
happen, make wouldn't be a very useful tool imho.

Longer version. The way make is said to work, barring bugs of course, 
the following happens. First the makefile is parsed, reading all the 
rules and setting up the dependency tree. For each rule, it is 
determined if the target needs to be built or not and what other targets 
need to be built before it. When all that is done, the execution phase 
begins. When execution begins, the targets and order is decided and will 
not change. (Except of course for parallel execution where targets not 
dependent on each other can execute in any order.) A target will not 
start executing before all it's dependents are done, and done means the 
full recipe having executed and succeeded, not just the file showing up.

/Erik

On 2013-01-03 08:05, David Holmes wrote:
> Given:
>
> $(JRE_IMAGE_DIR)/lib/meta-index: $(JRE_LIB_TARGETS)
>     $(ECHO) $(LOG_INFO) Generating $(patsubst $(OUTPUT_ROOT)/%,%,$@)
>     $(CD) $(@D)&& $(TOOL_BUILDMETAINDEX) -o meta-index `$(LS) *.jar | 
> $(SED) 's/JObjC\.jar//g'`
>
> where the JRE_LIB_TARGETS all involve copying a file from the build 
> output directory to the correct images directory ... a given jar file 
> will appear in the images directory once the copy commences. Can it be 
> that make will see the existence of that file as indicating a 
> satisfactory meeting of the prerequisite and commence the recipe for 
> creating the meta-index thus allowing the indexing tool to start 
> working on a jar file that is still in the process of being copied?
>
> I don't know in detail how the parallel aspects of make really work.
>
> It may be that the install-file macro needs to copy to a tmp name and 
> then rename to the final name once the cp is complete.
>
> I haven't encountered this myself but others experimenting with the 
> Profiles builds have run into an error from the indexing tool 
> indicating a jar file could not be opened/read - which is explainable 
> if the file was still being copied.
>
> Thoughts?
>
> David