Add crate_name attribute (#2118)

This PR adds `crate_name` attribute to `rust_proto_library` and
`rust_grpc_library` rules. This aligns with `crate_name` attribute
provided in other rules to allow custom crate name different from label
name.

Setting `--crate-name` flag to `rustc_flags` attribute is not an option
because `rustc` does not allow `--crate-name` flag to be set twice.

@UebelAndre Would you mind reviewing this PR when you have a chance?

---------

docs/flatten.md

@@ -598,7 +598,7 @@ Running `bazel test //hello_lib:hello_lib_doc_test` will run all documentation t
 ## rust_grpc_library
 
 <pre>
-rust_grpc_library(<a href="#rust_grpc_library-name">name</a>, <a href="#rust_grpc_library-deps">deps</a>, <a href="#rust_grpc_library-rust_deps">rust_deps</a>, <a href="#rust_grpc_library-rustc_flags">rustc_flags</a>)
+rust_grpc_library(<a href="#rust_grpc_library-name">name</a>, <a href="#rust_grpc_library-crate_name">crate_name</a>, <a href="#rust_grpc_library-deps">deps</a>, <a href="#rust_grpc_library-rust_deps">rust_deps</a>, <a href="#rust_grpc_library-rustc_flags">rustc_flags</a>)
 </pre>
 
 Builds a Rust library crate from a set of `proto_library`s suitable for gRPC.
@@ -632,6 +632,7 @@ rust_binary(
 | Name  | Description | Type | Mandatory | Default |
 | :------------- | :------------- | :------------- | :------------- | :------------- |
 | <a id="rust_grpc_library-name"></a>name |  A unique name for this target.   | <a href="https://bazel.build/concepts/labels#target-names">Name</a> | required |  |
+| <a id="rust_grpc_library-crate_name"></a>crate_name |  Crate name to use for this target.<br><br>                This must be a valid Rust identifier, i.e. it may contain only alphanumeric characters and underscores.                 Defaults to the target name, with any hyphens replaced by underscores.   | String | optional | <code>""</code> |
 | <a id="rust_grpc_library-deps"></a>deps |  List of proto_library dependencies that will be built. One crate for each proto_library will be created with the corresponding gRPC stubs.   | <a href="https://bazel.build/concepts/labels">List of labels</a> | required |  |
 | <a id="rust_grpc_library-rust_deps"></a>rust_deps |  The crates the generated library depends on.   | <a href="https://bazel.build/concepts/labels">List of labels</a> | optional | <code>[]</code> |
 | <a id="rust_grpc_library-rustc_flags"></a>rustc_flags |  List of compiler flags passed to <code>rustc</code>.<br><br>                These strings are subject to Make variable expansion for predefined                 source/output path variables like <code>$location</code>, <code>$execpath</code>, and                  <code>$rootpath</code>. This expansion is useful if you wish to pass a generated                 file of arguments to rustc: <code>@$(location //package:target)</code>.   | List of strings | optional | <code>[]</code> |
@@ -856,7 +857,7 @@ Rust Prost toolchain rule.
 ## rust_proto_library
 
 <pre>
-rust_proto_library(<a href="#rust_proto_library-name">name</a>, <a href="#rust_proto_library-deps">deps</a>, <a href="#rust_proto_library-rust_deps">rust_deps</a>, <a href="#rust_proto_library-rustc_flags">rustc_flags</a>)
+rust_proto_library(<a href="#rust_proto_library-name">name</a>, <a href="#rust_proto_library-crate_name">crate_name</a>, <a href="#rust_proto_library-deps">deps</a>, <a href="#rust_proto_library-rust_deps">rust_deps</a>, <a href="#rust_proto_library-rustc_flags">rustc_flags</a>)
 </pre>
 
 Builds a Rust library crate from a set of `proto_library`s.
@@ -890,6 +891,7 @@ rust_binary(
 | Name  | Description | Type | Mandatory | Default |
 | :------------- | :------------- | :------------- | :------------- | :------------- |
 | <a id="rust_proto_library-name"></a>name |  A unique name for this target.   | <a href="https://bazel.build/concepts/labels#target-names">Name</a> | required |  |
+| <a id="rust_proto_library-crate_name"></a>crate_name |  Crate name to use for this target.<br><br>                This must be a valid Rust identifier, i.e. it may contain only alphanumeric characters and underscores.                 Defaults to the target name, with any hyphens replaced by underscores.   | String | optional | <code>""</code> |
 | <a id="rust_proto_library-deps"></a>deps |  List of proto_library dependencies that will be built. One crate for each proto_library will be created with the corresponding stubs.   | <a href="https://bazel.build/concepts/labels">List of labels</a> | required |  |
 | <a id="rust_proto_library-rust_deps"></a>rust_deps |  The crates the generated library depends on.   | <a href="https://bazel.build/concepts/labels">List of labels</a> | optional | <code>[]</code> |
 | <a id="rust_proto_library-rustc_flags"></a>rustc_flags |  List of compiler flags passed to <code>rustc</code>.<br><br>                These strings are subject to Make variable expansion for predefined                 source/output path variables like <code>$location</code>, <code>$execpath</code>, and                  <code>$rootpath</code>. This expansion is useful if you wish to pass a generated                 file of arguments to rustc: <code>@$(location //package:target)</code>.   | List of strings | optional | <code>[]</code> |

docs/rust_proto.md

@@ -258,7 +258,7 @@ configuration.
 ## rust_grpc_library
 
 <pre>
-rust_grpc_library(<a href="#rust_grpc_library-name">name</a>, <a href="#rust_grpc_library-deps">deps</a>, <a href="#rust_grpc_library-rust_deps">rust_deps</a>, <a href="#rust_grpc_library-rustc_flags">rustc_flags</a>)
+rust_grpc_library(<a href="#rust_grpc_library-name">name</a>, <a href="#rust_grpc_library-crate_name">crate_name</a>, <a href="#rust_grpc_library-deps">deps</a>, <a href="#rust_grpc_library-rust_deps">rust_deps</a>, <a href="#rust_grpc_library-rustc_flags">rustc_flags</a>)
 </pre>
 
 Builds a Rust library crate from a set of `proto_library`s suitable for gRPC.
@@ -292,6 +292,7 @@ rust_binary(
 | Name  | Description | Type | Mandatory | Default |
 | :------------- | :------------- | :------------- | :------------- | :------------- |
 | <a id="rust_grpc_library-name"></a>name |  A unique name for this target.   | <a href="https://bazel.build/concepts/labels#target-names">Name</a> | required |  |
+| <a id="rust_grpc_library-crate_name"></a>crate_name |  Crate name to use for this target.<br><br>                This must be a valid Rust identifier, i.e. it may contain only alphanumeric characters and underscores.                 Defaults to the target name, with any hyphens replaced by underscores.   | String | optional | <code>""</code> |
 | <a id="rust_grpc_library-deps"></a>deps |  List of proto_library dependencies that will be built. One crate for each proto_library will be created with the corresponding gRPC stubs.   | <a href="https://bazel.build/concepts/labels">List of labels</a> | required |  |
 | <a id="rust_grpc_library-rust_deps"></a>rust_deps |  The crates the generated library depends on.   | <a href="https://bazel.build/concepts/labels">List of labels</a> | optional | <code>[]</code> |
 | <a id="rust_grpc_library-rustc_flags"></a>rustc_flags |  List of compiler flags passed to <code>rustc</code>.<br><br>                These strings are subject to Make variable expansion for predefined                 source/output path variables like <code>$location</code>, <code>$execpath</code>, and                  <code>$rootpath</code>. This expansion is useful if you wish to pass a generated                 file of arguments to rustc: <code>@$(location //package:target)</code>.   | List of strings | optional | <code>[]</code> |
@@ -331,7 +332,7 @@ Rust Prost toolchain rule.
 ## rust_proto_library
 
 <pre>
-rust_proto_library(<a href="#rust_proto_library-name">name</a>, <a href="#rust_proto_library-deps">deps</a>, <a href="#rust_proto_library-rust_deps">rust_deps</a>, <a href="#rust_proto_library-rustc_flags">rustc_flags</a>)
+rust_proto_library(<a href="#rust_proto_library-name">name</a>, <a href="#rust_proto_library-crate_name">crate_name</a>, <a href="#rust_proto_library-deps">deps</a>, <a href="#rust_proto_library-rust_deps">rust_deps</a>, <a href="#rust_proto_library-rustc_flags">rustc_flags</a>)
 </pre>
 
 Builds a Rust library crate from a set of `proto_library`s.
@@ -365,6 +366,7 @@ rust_binary(
 | Name  | Description | Type | Mandatory | Default |
 | :------------- | :------------- | :------------- | :------------- | :------------- |
 | <a id="rust_proto_library-name"></a>name |  A unique name for this target.   | <a href="https://bazel.build/concepts/labels#target-names">Name</a> | required |  |
+| <a id="rust_proto_library-crate_name"></a>crate_name |  Crate name to use for this target.<br><br>                This must be a valid Rust identifier, i.e. it may contain only alphanumeric characters and underscores.                 Defaults to the target name, with any hyphens replaced by underscores.   | String | optional | <code>""</code> |
 | <a id="rust_proto_library-deps"></a>deps |  List of proto_library dependencies that will be built. One crate for each proto_library will be created with the corresponding stubs.   | <a href="https://bazel.build/concepts/labels">List of labels</a> | required |  |
 | <a id="rust_proto_library-rust_deps"></a>rust_deps |  The crates the generated library depends on.   | <a href="https://bazel.build/concepts/labels">List of labels</a> | optional | <code>[]</code> |
 | <a id="rust_proto_library-rustc_flags"></a>rustc_flags |  List of compiler flags passed to <code>rustc</code>.<br><br>                These strings are subject to Make variable expansion for predefined                 source/output path variables like <code>$location</code>, <code>$execpath</code>, and                  <code>$rootpath</code>. This expansion is useful if you wish to pass a generated                 file of arguments to rustc: <code>@$(location //package:target)</code>.   | List of strings | optional | <code>[]</code> |

examples/proto/basic/BUILD.bazel

@@ -4,7 +4,8 @@ load("@rules_rust//rust:defs.bzl", "rust_binary", "rust_library")
 package(default_visibility = ["//proto:__subpackages__"])
 
 rust_proto_library(
-    name = "common_proto_rust",
+    name = "libcommon_proto_rust",
+    crate_name = "common_proto_rust",
     tags = ["manual"],
     deps = ["//proto:common"],
 )
@@ -13,7 +14,7 @@ rust_library(
     name = "common_lib",
     srcs = ["lib.rs"],
     tags = ["manual"],
-    deps = [":common_proto_rust"],
+    deps = [":libcommon_proto_rust"],
 )
 
 rust_binary(
@@ -22,6 +23,6 @@ rust_binary(
     tags = ["manual"],
     deps = [
         ":common_lib",
-        ":common_proto_rust",
+        ":libcommon_proto_rust",
     ],
 )

examples/proto/helloworld/BUILD.bazel

@@ -10,7 +10,8 @@ proto_library(
 )
 
 rust_grpc_library(
-    name = "helloworld_proto",
+    name = "libhelloworld_proto",
+    crate_name = "helloworld_proto",
     tags = ["manual"],
     visibility = ["//proto/helloworld:__subpackages__"],
     deps = [":helloworld"],

examples/proto/helloworld/greeter_client/BUILD.bazel

@@ -7,6 +7,6 @@ rust_binary(
     tags = ["manual"],
     visibility = ["//proto/helloworld:__subpackages__"],
     deps = [
-        "//proto/helloworld:helloworld_proto",
+        "//proto/helloworld:libhelloworld_proto",
     ] + GRPC_COMPILE_DEPS,
 )

proto/protobuf/proto.bzl

@@ -253,7 +253,7 @@ def _rust_protogrpc_library_impl(ctx, is_grpc):
     ]
 
     toolchain = find_toolchain(ctx)
-    crate_name = compute_crate_name(ctx.workspace_name, ctx.label, toolchain)
+    crate_name = compute_crate_name(ctx.workspace_name, ctx.label, toolchain, ctx.attr.crate_name)
 
     return _rust_proto_compile(
         protos = depset(transitive = transitive_sources),
@@ -280,6 +280,14 @@ def _rust_proto_library_impl(ctx):
 rust_proto_library = rule(
     implementation = _rust_proto_library_impl,
     attrs = {
+        "crate_name": attr.string(
+            doc = """\
+                Crate name to use for this target.
+
+                This must be a valid Rust identifier, i.e. it may contain only alphanumeric characters and underscores.
+                Defaults to the target name, with any hyphens replaced by underscores.
+            """,
+        ),
         "deps": attr.label_list(
             doc = (
                 "List of proto_library dependencies that will be built. " +
@@ -368,6 +376,14 @@ def _rust_grpc_library_impl(ctx):
 rust_grpc_library = rule(
     implementation = _rust_grpc_library_impl,
     attrs = {
+        "crate_name": attr.string(
+            doc = """\
+                Crate name to use for this target.
+
+                This must be a valid Rust identifier, i.e. it may contain only alphanumeric characters and underscores.
+                Defaults to the target name, with any hyphens replaced by underscores.
+            """,
+        ),
         "deps": attr.label_list(
             doc = (
                 "List of proto_library dependencies that will be built. " +