Allow overriding crate universe packages to local packages

crate_universe/private/crate.bzl

@@ -113,7 +113,8 @@ def _annotation(
         rustc_env = None,
         rustc_env_files = None,
         rustc_flags = None,
-        shallow_since = None):
+        shallow_since = None,
+        override_targets = None):
     """A collection of extra attributes and settings for a particular crate
 
     Args:
@@ -166,6 +167,8 @@ def _annotation(
         rustc_flags (list, optional): A list of strings to set on a crate's `rust_library::rustc_flags` attribute.
         shallow_since (str, optional): An optional timestamp used for crates originating from a git repository
             instead of a crate registry. This flag optimizes fetching the source code.
+        override_targets (dict, optional): A dictionary of alternate tagets to use when something depends on this crate to allow
+            the parent repo to provide its own version of this dependency. Keys can be `proc_marco`, `build_script`, `lib`, `bin`.
 
     Returns:
         string: A json encoded string containing the specified version and separately all other inputs.
@@ -209,6 +212,7 @@ def _annotation(
             rustc_env_files = _stringify_list(rustc_env_files),
             rustc_flags = rustc_flags,
             shallow_since = shallow_since,
+            override_targets = override_targets,
         ),
     ))
 

crate_universe/src/config.rs

@@ -338,6 +338,9 @@ pub(crate) struct CrateAnnotations {
 
     /// Transition rule to use instead of `native.alias()`.
     pub(crate) alias_rule: Option<AliasRule>,
+
+    /// The crates to use instead of the generated one.
+    pub(crate) override_targets: Option<BTreeMap<String, Label>>,
 }
 
 macro_rules! joined_extra_member {
@@ -410,6 +413,7 @@ impl Add for CrateAnnotations {
             patches: joined_extra_member!(self.patches, rhs.patches, BTreeSet::new, BTreeSet::extend),
             extra_aliased_targets: joined_extra_member!(self.extra_aliased_targets, rhs.extra_aliased_targets, BTreeMap::new, BTreeMap::extend),
             alias_rule: self.alias_rule.or(rhs.alias_rule),
+            override_targets: self.override_targets.or(rhs.override_targets),
         };
 
         output

crate_universe/src/context/crate_context.rs

@@ -61,6 +61,28 @@ pub(crate) enum Rule {
     BuildScript(TargetAttributes),
 }
 
+impl Rule {
+    /// The keys that can be used in override_targets to override these Rule sources.
+    /// These intentionally match the accepted `Target.kind`s returned by cargo-metadata.
+    pub(crate) fn override_target_key(&self) -> &'static str {
+        match self {
+            Self::Library(..) => "lib",
+            Self::ProcMacro(..) => "proc-macro",
+            Self::Binary(..) => "bin",
+            Self::BuildScript(..) => "custom-build",
+        }
+    }
+
+    pub(crate) fn crate_name(&self) -> &str {
+        match self {
+            Self::Library(attrs)
+            | Self::ProcMacro(attrs)
+            | Self::Binary(attrs)
+            | Self::BuildScript(attrs) => &attrs.crate_name,
+        }
+    }
+}
+
 /// A set of attributes common to most `rust_library`, `rust_proc_macro`, and other
 /// [core rules of `rules_rust`](https://bazelbuild.github.io/rules_rust/defs.html).
 #[derive(Debug, Clone, PartialEq, Eq, Serialize, Deserialize)]
@@ -312,6 +334,11 @@ pub(crate) struct CrateContext {
     #[serde(skip_serializing_if = "Option::is_none")]
     #[serde(default)]
     pub(crate) alias_rule: Option<AliasRule>,
+
+    /// Targets to use instead of the default target for the crate.
+    #[serde(skip_serializing_if = "BTreeMap::is_empty")]
+    #[serde(default)]
+    pub(crate) override_targets: BTreeMap<String, Label>,
 }
 
 impl CrateContext {
@@ -497,6 +524,7 @@ impl CrateContext {
             disable_pipelining: false,
             extra_aliased_targets: BTreeMap::new(),
             alias_rule: None,
+            override_targets: BTreeMap::new(),
         }
         .with_overrides(extras)
     }
@@ -668,6 +696,10 @@ impl CrateContext {
                     }
                 }
             }
+
+            if let Some(override_targets) = &crate_extra.override_targets {
+                self.override_targets.extend(override_targets.clone());
+            }
         }
 
         self

crate_universe/src/context/platforms.rs

@@ -158,6 +158,7 @@ mod test {
             disable_pipelining: false,
             extra_aliased_targets: BTreeMap::default(),
             alias_rule: None,
+            override_targets: BTreeMap::default(),
         };
 
         let configurations =
@@ -215,6 +216,7 @@ mod test {
             disable_pipelining: false,
             extra_aliased_targets: BTreeMap::default(),
             alias_rule: None,
+            override_targets: BTreeMap::default(),
         }
     }
 
@@ -300,6 +302,7 @@ mod test {
             disable_pipelining: false,
             extra_aliased_targets: BTreeMap::default(),
             alias_rule: None,
+            override_targets: BTreeMap::default(),
         };
 
         let configurations =
@@ -365,6 +368,7 @@ mod test {
             disable_pipelining: false,
             extra_aliased_targets: BTreeMap::default(),
             alias_rule: None,
+            override_targets: BTreeMap::default(),
         };
 
         let configurations =

crate_universe/src/lockfile.rs

@@ -286,7 +286,7 @@ mod test {
         );
 
         assert_eq!(
-            Digest("4148d6b336e574a67417f77fb4727e9c1b014a0b5ab90771f57285f96bca0fee".to_owned()),
+            Digest("610cbb406b7452d32ae31c45ec82cd3b3b1fb184c3411ef613c948d88492441b".to_owned()),
             digest,
         );
     }

crate_universe/src/rendering.rs

@@ -371,33 +371,43 @@ impl Renderer {
         }
 
         for rule in &krate.targets {
-            match rule {
-                Rule::BuildScript(target) => {
-                    load("@rules_rust//cargo:defs.bzl", "cargo_build_script");
-                    let cargo_build_script =
-                        self.make_cargo_build_script(platforms, krate, target)?;
-                    starlark.push(Starlark::CargoBuildScript(cargo_build_script));
-                    starlark.push(Starlark::Alias(Alias {
-                        rule: AliasRule::default().rule(),
-                        name: target.crate_name.clone(),
-                        actual: Label::from_str("_bs").unwrap(),
-                        tags: BTreeSet::from(["manual".to_owned()]),
-                    }));
-                }
-                Rule::ProcMacro(target) => {
-                    load("@rules_rust//rust:defs.bzl", "rust_proc_macro");
-                    let rust_proc_macro = self.make_rust_proc_macro(platforms, krate, target)?;
-                    starlark.push(Starlark::RustProcMacro(rust_proc_macro));
-                }
-                Rule::Library(target) => {
-                    load("@rules_rust//rust:defs.bzl", "rust_library");
-                    let rust_library = self.make_rust_library(platforms, krate, target)?;
-                    starlark.push(Starlark::RustLibrary(rust_library));
-                }
-                Rule::Binary(target) => {
-                    load("@rules_rust//rust:defs.bzl", "rust_binary");
-                    let rust_binary = self.make_rust_binary(platforms, krate, target)?;
-                    starlark.push(Starlark::RustBinary(rust_binary));
+            if let Some(override_target) = krate.override_targets.get(rule.override_target_key()) {
+                starlark.push(Starlark::Alias(Alias {
+                    rule: AliasRule::default().rule(),
+                    name: rule.crate_name().to_owned(),
+                    actual: override_target.clone(),
+                    tags: BTreeSet::from(["manual".to_owned()]),
+                }));
+            } else {
+                match rule {
+                    Rule::BuildScript(target) => {
+                        load("@rules_rust//cargo:defs.bzl", "cargo_build_script");
+                        let cargo_build_script =
+                            self.make_cargo_build_script(platforms, krate, target)?;
+                        starlark.push(Starlark::CargoBuildScript(cargo_build_script));
+                        starlark.push(Starlark::Alias(Alias {
+                            rule: AliasRule::default().rule(),
+                            name: target.crate_name.clone(),
+                            actual: Label::from_str("_bs").unwrap(),
+                            tags: BTreeSet::from(["manual".to_owned()]),
+                        }));
+                    }
+                    Rule::ProcMacro(target) => {
+                        load("@rules_rust//rust:defs.bzl", "rust_proc_macro");
+                        let rust_proc_macro =
+                            self.make_rust_proc_macro(platforms, krate, target)?;
+                        starlark.push(Starlark::RustProcMacro(rust_proc_macro));
+                    }
+                    Rule::Library(target) => {
+                        load("@rules_rust//rust:defs.bzl", "rust_library");
+                        let rust_library = self.make_rust_library(platforms, krate, target)?;
+                        starlark.push(Starlark::RustLibrary(rust_library));
+                    }
+                    Rule::Binary(target) => {
+                        load("@rules_rust//rust:defs.bzl", "rust_binary");
+                        let rust_binary = self.make_rust_binary(platforms, krate, target)?;
+                        starlark.push(Starlark::RustBinary(rust_binary));
+                    }
                 }
             }
         }
@@ -967,6 +977,7 @@ mod test {
                 disable_pipelining: false,
                 extra_aliased_targets: BTreeMap::default(),
                 alias_rule: None,
+                override_targets: BTreeMap::default(),
             },
         );
 
@@ -1004,6 +1015,7 @@ mod test {
                 disable_pipelining: true,
                 extra_aliased_targets: BTreeMap::default(),
                 alias_rule: None,
+                override_targets: BTreeMap::default(),
             },
         );
 
@@ -1044,6 +1056,7 @@ mod test {
                 disable_pipelining: false,
                 extra_aliased_targets: BTreeMap::default(),
                 alias_rule: None,
+                override_targets: BTreeMap::default(),
             },
         );
 
@@ -1084,6 +1097,7 @@ mod test {
                 disable_pipelining: false,
                 extra_aliased_targets: BTreeMap::default(),
                 alias_rule: None,
+                override_targets: BTreeMap::default(),
             },
         );
 
@@ -1121,6 +1135,7 @@ mod test {
                 disable_pipelining: false,
                 extra_aliased_targets: BTreeMap::default(),
                 alias_rule: None,
+                override_targets: BTreeMap::default(),
             },
         );
 
@@ -1160,6 +1175,7 @@ mod test {
                 disable_pipelining: false,
                 extra_aliased_targets: BTreeMap::default(),
                 alias_rule: None,
+                override_targets: BTreeMap::default(),
             },
         );
 
@@ -1214,6 +1230,7 @@ mod test {
                 disable_pipelining: false,
                 extra_aliased_targets: BTreeMap::default(),
                 alias_rule: None,
+                override_targets: BTreeMap::default(),
             },
         );
 
@@ -1247,6 +1264,7 @@ mod test {
                 disable_pipelining: false,
                 extra_aliased_targets: BTreeMap::default(),
                 alias_rule: None,
+                override_targets: BTreeMap::default(),
             },
         );
 
@@ -1286,6 +1304,7 @@ mod test {
                 disable_pipelining: false,
                 extra_aliased_targets: BTreeMap::default(),
                 alias_rule: None,
+                override_targets: BTreeMap::default(),
             },
         );
 
@@ -1337,6 +1356,7 @@ mod test {
                 disable_pipelining: false,
                 extra_aliased_targets: BTreeMap::default(),
                 alias_rule: None,
+                override_targets: BTreeMap::default(),
             },
         );
 
@@ -1447,6 +1467,7 @@ mod test {
                 disable_pipelining: false,
                 extra_aliased_targets: BTreeMap::default(),
                 alias_rule: None,
+                override_targets: BTreeMap::default(),
             },
         );
 
@@ -1493,6 +1514,7 @@ mod test {
                 disable_pipelining: false,
                 extra_aliased_targets: BTreeMap::default(),
                 alias_rule: None,
+                override_targets: BTreeMap::default(),
             },
         );
 
@@ -1545,6 +1567,7 @@ mod test {
                 repository: None,
                 license: None,
                 alias_rule: None,
+                override_targets: BTreeMap::default(),
             },
         );
 
@@ -1608,6 +1631,7 @@ mod test {
                 repository: None,
                 license: None,
                 alias_rule: None,
+                override_targets: BTreeMap::default(),
             },
         );
 
@@ -1678,6 +1702,7 @@ mod test {
                 disable_pipelining: false,
                 extra_aliased_targets: BTreeMap::default(),
                 alias_rule: None,
+                override_targets: BTreeMap::default(),
             },
         );
 

docs/crate_universe.md

@@ -644,7 +644,8 @@ crate.annotation(<a href="#crate.annotation-version">version</a>, <a href="#crat
                  <a href="#crate.annotation-build_script_rustc_env">build_script_rustc_env</a>, <a href="#crate.annotation-build_script_toolchains">build_script_toolchains</a>, <a href="#crate.annotation-compile_data">compile_data</a>, <a href="#crate.annotation-compile_data_glob">compile_data_glob</a>,
                  <a href="#crate.annotation-crate_features">crate_features</a>, <a href="#crate.annotation-data">data</a>, <a href="#crate.annotation-data_glob">data_glob</a>, <a href="#crate.annotation-deps">deps</a>, <a href="#crate.annotation-extra_aliased_targets">extra_aliased_targets</a>, <a href="#crate.annotation-gen_binaries">gen_binaries</a>,
                  <a href="#crate.annotation-disable_pipelining">disable_pipelining</a>, <a href="#crate.annotation-gen_build_script">gen_build_script</a>, <a href="#crate.annotation-patch_args">patch_args</a>, <a href="#crate.annotation-patch_tool">patch_tool</a>, <a href="#crate.annotation-patches">patches</a>,
-                 <a href="#crate.annotation-proc_macro_deps">proc_macro_deps</a>, <a href="#crate.annotation-rustc_env">rustc_env</a>, <a href="#crate.annotation-rustc_env_files">rustc_env_files</a>, <a href="#crate.annotation-rustc_flags">rustc_flags</a>, <a href="#crate.annotation-shallow_since">shallow_since</a>)
+                 <a href="#crate.annotation-proc_macro_deps">proc_macro_deps</a>, <a href="#crate.annotation-rustc_env">rustc_env</a>, <a href="#crate.annotation-rustc_env_files">rustc_env_files</a>, <a href="#crate.annotation-rustc_flags">rustc_flags</a>, <a href="#crate.annotation-shallow_since">shallow_since</a>,
+                 <a href="#crate.annotation-override_targets">override_targets</a>)
 </pre>
 
 A collection of extra attributes and settings for a particular crate
@@ -685,6 +686,7 @@ A collection of extra attributes and settings for a particular crate
 | <a id="crate.annotation-rustc_env_files"></a>rustc_env_files |  A list of labels to set on a crate's <code>rust_library::rustc_env_files</code> attribute.   |  `None` |
 | <a id="crate.annotation-rustc_flags"></a>rustc_flags |  A list of strings to set on a crate's <code>rust_library::rustc_flags</code> attribute.   |  `None` |
 | <a id="crate.annotation-shallow_since"></a>shallow_since |  An optional timestamp used for crates originating from a git repository instead of a crate registry. This flag optimizes fetching the source code.   |  `None` |
+| <a id="crate.annotation-override_targets"></a>override_targets |  A dictionary of alternate tagets to use when something depends on this crate to allow the parent repo to provide its own version of this dependency. Keys can be <code>proc_marco</code>, <code>build_script</code>, <code>lib</code>, <code>bin</code>.   |  `None` |
 
 **RETURNS**
 

examples/crate_universe/WORKSPACE.bazel

@@ -718,6 +718,39 @@ load(
 
 complicated_dependencies_crate_repositories()
 
+###############################################################################
+# O V E R R I D E  T A R G E T
+###############################################################################
+
+crates_repository(
+    name = "override_target",
+    annotations = {
+        "foo": [crate.annotation(
+            override_targets = {"lib": "@//override_target:foo"},
+        )],
+    },
+    cargo_lockfile = "//override_target:Cargo.Bazel.lock",
+    # `generator` is not necessary in official releases.
+    # See load satement for `cargo_bazel_bootstrap`.
+    generator = "@cargo_bazel_bootstrap//:cargo-bazel",
+    lockfile = "//override_target:cargo-bazel-lock.json",
+    packages = {
+        "foo": crate.spec(
+            version = "0.0.0",
+        ),
+    },
+    splicing_config = splicing_config(
+        resolver_version = "2",
+    ),
+)
+
+load(
+    "@override_target//:defs.bzl",
+    override_target_crate_repositories = "crate_repositories",
+)
+
+override_target_crate_repositories()
+
 ###############################################################################
 
 # Used for Bazel CI