race condition due to install-file macro ?

[David Holmes]

Thanks Erik.

Well the jar files exist AFAICS.

I should mention that there is sometimes a similar failure in the Hudson 
builds where the rt.jar recipe give a Zip error opening rt.jar for 
update when the previous line of the recipe created rt.jar.

I can not explain either of the failures. They certainly seem like 
timing issues though.

David
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On 3/01/2013 6:11 PM, Erik Joelsson wrote:
> 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