Add support for forwarding symbol graph

[luispadron]

rules_swift has support for symbol_graph in SwiftInfo: bazelbuild/rules_swift#838

The framework target should forward that as well

[jerrymarino]

Is there a reason that the symbol graph shouldn't be part of inputs and outputs / adjacent to the other components? The existing compiler artifacts are collected onto these struct(s) / follow this pattern and would suggest to keep the .symbolgraph similar to how we process .swiftmodule output

[luispadron]

The symbol graphs are added as extra outputs. They don't seem to be available in the rule last I checked

[luispadron]

Is there a way to access extra outputs from the rule? What you suggest is what I tried originally but the symbol graph wasn't in the list the rule gets.

If there's a way to query the extra output groups though that would work

[luispadron]

Updated this to use dep.output_groups, in there it will have a swift_symbol_graph if the --features=swift.emit_symbol_graph is provided (which the .docc rule transitions on)

[jerrymarino]

Changes LGTM 👍 .

Seems like plumbing in the .symbolgraph here good enough to get it correctly propagating end to end for you?

[luispadron]

Yep this worked in testing, it correctly forwards the libraries symbol graphs (if they were requested)

[thiagohmcruz]

Looks like this is not backwards compatible:

Traceback (most recent call last):
        File "/private/var/tmp/_bazel_thiago/90ec49cd0a280be0e29f918d4d51c649/external/build_bazel_rules_ios/rules/framework.bzl", line 1042, column 40, in _apple_framework_packaging_impl
                swift_info = _get_merged_swift_info(ctx, framework_files, transitive_deps)
        File "/private/var/tmp/_bazel_thiago/90ec49cd0a280be0e29f918d4d51c649/external/build_bazel_rules_ios/rules/framework.bzl", line 566, column 57, in _get_merged_swift_info
                swift_info_fields["modules"] = _copy_swiftmodule(ctx, framework_files)
        File "/private/var/tmp/_bazel_thiago/90ec49cd0a280be0e29f918d4d51c649/external/build_bazel_rules_ios/rules/framework.bzl", line 537, column 52, in _copy_swiftmodule
                swift_module = swift_common.create_swift_module(
        File "/private/var/tmp/_bazel_thiago/90ec49cd0a280be0e29f918d4d51c649/external/build_bazel_rules_swift/swift/internal/providers.bzl", line 357, column 5, in create_swift_module
                def create_swift_module(
Error: create_swift_module() got unexpected keyword argument: symbol_graph

Was that intentional? We can bump rules_swift internally but curious if there's any suggestion on how to bump rules_ios with this change. I can also look into how to make this optional in rules_ios if that's what we want.

[thiagohmcruz]

Looks like this is not backwards compatible:

Traceback (most recent call last):
        File "/private/var/tmp/_bazel_thiago/90ec49cd0a280be0e29f918d4d51c649/external/build_bazel_rules_ios/rules/framework.bzl", line 1042, column 40, in _apple_framework_packaging_impl
                swift_info = _get_merged_swift_info(ctx, framework_files, transitive_deps)
        File "/private/var/tmp/_bazel_thiago/90ec49cd0a280be0e29f918d4d51c649/external/build_bazel_rules_ios/rules/framework.bzl", line 566, column 57, in _get_merged_swift_info
                swift_info_fields["modules"] = _copy_swiftmodule(ctx, framework_files)
        File "/private/var/tmp/_bazel_thiago/90ec49cd0a280be0e29f918d4d51c649/external/build_bazel_rules_ios/rules/framework.bzl", line 537, column 52, in _copy_swiftmodule
                swift_module = swift_common.create_swift_module(
        File "/private/var/tmp/_bazel_thiago/90ec49cd0a280be0e29f918d4d51c649/external/build_bazel_rules_swift/swift/internal/providers.bzl", line 357, column 5, in create_swift_module
                def create_swift_module(
Error: create_swift_module() got unexpected keyword argument: symbol_graph

Was that intentional? We can bump rules_swift internally but curious if there's any suggestion on how to bump rules_ios with this change. I can also look into how to make this optional in rules_ios if that's what we want.

Nvm, we're internally using an old version of rules_swift overriding the version rules_ios uses so that's on us and I'll take a look!