Improvements to better support cxx (#2192)

* Support adding to `deps` from annotations in Cargo.toml files
* Default `extra_aliased_targets` and `gen_binaries` to `None` rather
than empty collections, because the rust code has explicit handling for
`None` vs empty when merging.

crate_universe/private/crate.bzl

@@ -85,8 +85,8 @@ def _annotation(
         data = None,
         data_glob = None,
         deps = None,
-        extra_aliased_targets = {},
-        gen_binaries = [],
+        extra_aliased_targets = None,
+        gen_binaries = None,
         disable_pipelining = False,
         gen_build_script = None,
         patch_args = None,

crate_universe/src/config.rs

@@ -368,6 +368,7 @@ pub struct AnnotationsProvidedByPackage {
     pub gen_build_script: Option<bool>,
     pub data: Option<BTreeSet<String>>,
     pub data_glob: Option<BTreeSet<String>>,
+    pub deps: Option<BTreeSet<StringOrSelect>>,
     pub compile_data: Option<BTreeSet<String>>,
     pub compile_data_glob: Option<BTreeSet<String>>,
     pub rustc_env: Option<BTreeMap<String, String>>,
@@ -387,6 +388,7 @@ impl CrateAnnotations {
             gen_build_script,
             data,
             data_glob,
+            deps,
             compile_data,
             compile_data_glob,
             rustc_env,
@@ -417,6 +419,7 @@ impl CrateAnnotations {
         default(&mut self.gen_build_script, gen_build_script);
         default(&mut self.data, data);
         default(&mut self.data_glob, data_glob);
+        default(&mut self.deps, deps);
         default(&mut self.compile_data, compile_data);
         default(&mut self.compile_data_glob, compile_data_glob);
         default(&mut self.rustc_env, rustc_env);

crate_universe/src/metadata/metadata_annotation.rs

@@ -391,7 +391,7 @@ impl Annotations {
                         // Mark that an annotation has been consumed
                         unused_extra_annotations.remove(id);
 
-                        // Fitler out the annotation
+                        // Filter out the annotation
                         extra
                     })
                     .cloned()

docs/crate_universe.md

@@ -637,8 +637,8 @@ A collection of extra attributes and settings for a particular crate
 | <a id="crate.annotation-data"></a>data |  A list of labels to add to a crate's <code>rust_library::data</code> attribute.   |  `None` |
 | <a id="crate.annotation-data_glob"></a>data_glob |  A list of glob patterns to add to a crate's <code>rust_library::data</code> attribute.   |  `None` |
 | <a id="crate.annotation-deps"></a>deps |  A list of labels to add to a crate's <code>rust_library::deps</code> attribute.   |  `None` |
-| <a id="crate.annotation-extra_aliased_targets"></a>extra_aliased_targets |  A list of targets to add to the generated aliases in the root crate_universe repository.   |  `{}` |
-| <a id="crate.annotation-gen_binaries"></a>gen_binaries |  As a list, the subset of the crate's bins that should get <code>rust_binary</code> targets produced. Or <code>True</code> to generate all, <code>False</code> to generate none.   |  `[]` |
+| <a id="crate.annotation-extra_aliased_targets"></a>extra_aliased_targets |  A list of targets to add to the generated aliases in the root crate_universe repository.   |  `None` |
+| <a id="crate.annotation-gen_binaries"></a>gen_binaries |  As a list, the subset of the crate's bins that should get <code>rust_binary</code> targets produced. Or <code>True</code> to generate all, <code>False</code> to generate none.   |  `None` |
 | <a id="crate.annotation-disable_pipelining"></a>disable_pipelining |  If True, disables pipelining for library targets for this crate.   |  `False` |
 | <a id="crate.annotation-gen_build_script"></a>gen_build_script |  An authorative flag to determine whether or not to produce <code>cargo_build_script</code> targets for the current crate.   |  `None` |
 | <a id="crate.annotation-patch_args"></a>patch_args |  The <code>patch_args</code> attribute of a Bazel repository rule. See [http_archive.patch_args](https://docs.bazel.build/versions/main/repo/http.html#http_archive-patch_args)   |  `None` |

examples/crate_universe/WORKSPACE.bazel

@@ -277,6 +277,14 @@ no_cargo_crate_repositories()
 
 crates_repository(
     name = "using_cxx",
+    annotations = {
+        "cxx": [
+            crate.annotation(
+                # Until https://github.com/dtolnay/cxx/pull/1257#issuecomment-1755816850 gets resolved.
+                deps = [":cxx_cc"],
+            ),
+        ],
+    },
     cargo_lockfile = "//using_cxx:Cargo.Bazel.lock",
     # `generator` is not necessary in official releases.
     # See load satement for `cargo_bazel_bootstrap`.