Generateheaders task should recieve only the module definition file as input

[rosadam]

Let's say we have these modules:

Module "A" looks like this:

src
└── main
    ├── spaghetti
    │   └── A.module
    └── ts
        └── A.ts

Module "B" looks like this:

src
└── main
    ├── spaghetti
    │   └── B.module
    └── ts
        └── B.ts

Module A depends on module B.

The problem: if I change B.ts, module A will be rebuilt. Why? because the input of A's generateHeaders task is not only the B.module file, but the whole compiled module. Also generateHeaders will never create the same output twice, because the generated files contain a timestamp.

So the order of execution looks like this now:

• change B.ts
• module B recompiles
• module A's generateHeaders is triggered
• module A's compileJs is triggered

[lptr]

The problematic execution now looks like this:

• change B.ts
• module B recompiles and gets packaged into its bundle ZIP
• because :a:generateHeaders's input has changed (the ZIP from module B), the ZIP is re-extracted, and :a:generateHeaders is re-executed
• because it generates different output (the timestamp has changed), the rest of module A is rebuilt, and the changes cascade to further modules

Possible solutions:

1. exclude the timestamp from generated headers

• change B.ts
• module B recompiles and gets packaged into its bundle ZIP
• because :a:generateHeaders's input has changed (the ZIP from module B), the ZIP is re-extracted, and :a:generateHeaders is re-executed
• because it generates the SAME output (no timestamp), module A is NOT rebuilt, and the changes DO NOT cascade to further modules

2. use a separate task to extract definition files from dependent modules

• change B.ts
• module B recompiles and gets packaged into its bundle ZIP
• the inputs of :a:extractDefinitions have changed (the ZIP from module B), the ZIP is re-extracted by :a:extractDefinitions
• the inputs of :a:generateHeaders HAVE NOT changed (they are the same files as before, extracted by :a:extractDefinitions), the task is NOT re-executed, and changes DO NOT cascade to further modules

Option 1) is easier to implement, as it requires only the removal of the timestamp in the header. However, option 2) would be a more complete solution, but require additional tasks, and the re-wiring of how generateHeaders is configured (i.e. now it uses the dependentModules property, just as all the other Spaghetti tasks, to find its dependent modules; after the change this task would receive a list of definition files instead of a list of bundle ZIPs).

[lptr]

It's also an option to introduce a switch in generateHeaders to disable timestamp generation. E.g. Javadoc uses a similar approach with generated content.

[lptr]

Another option is to:

3. publish the module definition file on a separate configuration hierarchy (modulesDef, perhaps, to match the already existing similar modulesObf configuration hierarchy). This way generateHeaders could take as input only the modulesDef configuration.

This would also make it possible to use a dependency module's definition, even if the module doesn't yet compile. This can be useful when working on two modules at the same time, trying to figure out how to change the API of the dependency module.

[lptr]

See PR #181