[repro] module maps created for or on objc_library do not propagate to transitive objc_library #1532
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…o transitive objc_library this is a repro of an issue i've identified while trying to move to `mixed_language_library` from our custom macro. Regardless of how `module_map` is hinted in `swift_interop_info`, generated, or otherwise attached to an `objc_library`, out-of-the-box these module maps are not propagated to downstream `objc_library` in a `objc -> swift -> objc` arrangement. this is especially problematic in scenarios where PrintAsClang, going by its own uncontrollable heuristics, inserts an `@import` line for the upstream objc library in a generated header. this is something that needs to change in either `swift_clang_module_aspect` or `objc_library` to discover or otherwise propagate the upstream module maps, as this simple example does not work without customization of the rules or introducing manual dependencies on modulemaps (which isn't possible if relying on the generated modulemaps from the aspect).
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i think this is related to #1174 |
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My understanding is that this is "working as intended" from the point of view of Bazel core -- module maps are only used for importing clang modules into Swift. Even if you had I'm trying to use this intermediate rule (which pulls out the aspect-generated module map and kind of misuses
I would support fixing this in |
this is a repro of an issue i've identified while trying to move to
mixed_language_libraryfrom our custom macro. Regardless of howmodule_mapis hinted inswift_interop_info, generated, or otherwise attached to anobjc_library, out-of-the-box these module maps are not propagated to downstreamobjc_libraryin aobjc -> swift -> objcarrangement. this is especially problematic in scenarios where PrintAsClang, going by its own uncontrollable heuristics (in this case, the addition of a lightweight generic in a public-facing objc type), inserts an@importline for the upstream objc library in a generated header.this is something that needs to change in either
swift_clang_module_aspectorobjc_libraryto discover or otherwise propagate the upstream module maps, as this simple example does not work without customization of the rules or introducing manual dependencies on modulemaps (which isn't possible if relying on the generated modulemaps from the aspect).