"SourceType" should not be used to version the transforms

Currently, the transform creates the equivalent of a static record, with sourceType member: https://github.com/Agoric/transform-module/blob/master/src/index.js#L87

This is needs to be equal to “module”, “script”, or “expression”: https://github.com/Agoric/transform-module/blob/master/src/index.js#L211 https://github.com/Agoric/transform-module/blob/master/src/index.js#L224

And is wired to derive which transforms to enable: https://github.com/Agoric/transform-module/blob/master/src/babelPlugin.js#L469

In other words, sourceType is really about the type of the source.

However, changes in Babel or in how our Babel plugin work could introduce incompatible changes that need to be detected by the consumers. If sourceType is used, then we would need to include then we would need to include three versions for every change, “module-v2”, “script-v3”, AND “expression-v3” because changes will most likely impact all three types at the same time.

It would be much better to keep version orthogonal to type, so a new version affects all types at the same time.

@michaelfig, following our discussion today, does this clarifies my position?

@erights @warner

[jfparadis]

Hmm, I don’t think that cuts it.

• That URL refers to a separate package, agoric-sdk
• agoric-sdk has no dependency on transform-module

In other words, there is no relation between those two packages: moduleFormat isn’t part of the importer system.

In addition:

• Module format is used to pivot around cjs or not. https://github.com/Agoric/agoric-sdk/blob/master/packages/bundle-source/src/index.js#L29
• The default is getExport. https://github.com/Agoric/agoric-sdk/blob/master/packages/bundle-source/src/index.js#L48

Basically, module format used to decide whether or not to put a wrapper around a module. Its use is completely internal to agoric-sdk.

Bottom-line:

• sourceType: do we have a module, a script, an expression.
• moduleFormat: do we have a cjs module, or an agoric functor.
• version: which version of the functor do we have.

All three values need to evolve independently. The version needs to be tied to the output of the module transform, and needs to take into account the type of functor, etc. The importer then must decide what to do with a given version. Most likely agoric-sdk doesn’t need to be aware in involved with the version.

[michaelfig]

No longer relevant.