Revert "Build rust_test targets using a crate name different from the…

… underlying lib" (#2815)

This reverts commit b4ccc97.

That commit makes a behavior change, and thus should have been protected
by a feature flag. This will be done in a future PR.

docs/defs.md

@@ -567,7 +567,9 @@ rust_test(
 )
 ```
 
-Run the test with `bazel test //hello_lib:hello_lib_test`.
+Run the test with `bazel test //hello_lib:hello_lib_test`. The crate
+will be built using the same crate name as the underlying ":hello_lib"
+crate.
 
 ### Example: `test` directory
 

docs/flatten.md

@@ -1050,7 +1050,9 @@ rust_test(
 )
 ```
 
-Run the test with `bazel test //hello_lib:hello_lib_test`.
+Run the test with `bazel test //hello_lib:hello_lib_test`. The crate
+will be built using the same crate name as the underlying ":hello_lib"
+crate.
 
 ### Example: `test` directory
 

rust/private/rust.bzl

@@ -296,7 +296,6 @@ def _rust_test_impl(ctx):
 
     toolchain = find_toolchain(ctx)
 
-    crate_name = compute_crate_name(ctx.workspace_name, ctx.label, toolchain, ctx.attr.crate_name)
     crate_type = "bin"
     deps = transform_deps(ctx.attr.deps)
     proc_macro_deps = transform_deps(ctx.attr.proc_macro_deps + get_import_macro_deps(ctx))
@@ -310,8 +309,13 @@ def _rust_test_impl(ctx):
         # Target is building the crate in `test` config
         crate = ctx.attr.crate[rust_common.crate_info] if rust_common.crate_info in ctx.attr.crate else ctx.attr.crate[rust_common.test_crate_info].crate
 
+        output_hash = determine_output_hash(crate.root, ctx.label)
         output = ctx.actions.declare_file(
-            ctx.label.name + toolchain.binary_ext,
+            "test-%s/%s%s" % (
+                output_hash,
+                ctx.label.name,
+                toolchain.binary_ext,
+            ),
         )
 
         srcs, crate_root = transform_sources(ctx, ctx.files.srcs, getattr(ctx.file, "crate_root", None))
@@ -338,7 +342,7 @@ def _rust_test_impl(ctx):
 
         # Build the test binary using the dependency's srcs.
         crate_info_dict = dict(
-            name = crate_name,
+            name = crate.name,
             type = crate_type,
             root = crate.root,
             srcs = depset(srcs, transitive = [crate.srcs]),
@@ -364,8 +368,13 @@ def _rust_test_impl(ctx):
             crate_root = crate_root_src(ctx.attr.name, ctx.files.srcs, crate_root_type)
         srcs, crate_root = transform_sources(ctx, ctx.files.srcs, crate_root)
 
+        output_hash = determine_output_hash(crate_root, ctx.label)
         output = ctx.actions.declare_file(
-            ctx.label.name + toolchain.binary_ext,
+            "test-%s/%s%s" % (
+                output_hash,
+                ctx.label.name,
+                toolchain.binary_ext,
+            ),
         )
 
         data_paths = depset(direct = getattr(ctx.attr, "data", [])).to_list()
@@ -377,7 +386,7 @@ def _rust_test_impl(ctx):
 
         # Target is a standalone crate. Build the test binary as its own crate.
         crate_info_dict = dict(
-            name = crate_name,
+            name = compute_crate_name(ctx.workspace_name, ctx.label, toolchain, ctx.attr.crate_name),
             type = crate_type,
             root = crate_root,
             srcs = depset(srcs),
@@ -1339,7 +1348,9 @@ rust_test = rule(
         )
         ```
 
-        Run the test with `bazel test //hello_lib:hello_lib_test`.
+        Run the test with `bazel test //hello_lib:hello_lib_test`. The crate
+        will be built using the same crate name as the underlying ":hello_lib"
+        crate.
 
         ### Example: `test` directory
 

test/rust/src/lib.rs

@@ -12,4 +12,5 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
+#![crate_name = "hello_lib"]
 pub mod greeter;

test/unit/linkstamps/linkstamps_test.bzl

@@ -2,7 +2,7 @@
 
 load("@bazel_skylib//lib:unittest.bzl", "analysistest", "asserts")
 load("@rules_cc//cc:defs.bzl", "cc_library")
-load("//rust:defs.bzl", "rust_binary", "rust_library", "rust_test")
+load("//rust:defs.bzl", "rust_binary", "rust_common", "rust_library", "rust_test")
 load("//test/unit:common.bzl", "assert_action_mnemonic")
 
 def _is_running_on_linux(ctx):
@@ -20,9 +20,13 @@ def _supports_linkstamps_test(ctx):
     linkstamp_out = linkstamp_action.outputs.to_list()[0]
     asserts.equals(env, linkstamp_out.basename, "linkstamp.o")
     tut_out = tut.files.to_list()[0]
+    is_test = tut[rust_common.crate_info].is_test
     workspace_prefix = "" if ctx.workspace_name == "rules_rust" else "/external/rules_rust"
 
-    expected_linkstamp_path = tut_out.dirname + "/_objs/" + tut_out.basename + workspace_prefix + "/test/unit/linkstamps/linkstamp.o"
+    # Rust compilation outputs coming from a test are put in test-{hash} directory
+    # which we need to remove in order to obtain the linkstamp file path.
+    dirname = "/".join(tut_out.dirname.split("/")[:-1]) if is_test else tut_out.dirname
+    expected_linkstamp_path = dirname + "/_objs/" + tut_out.basename + workspace_prefix + "/test/unit/linkstamps/linkstamp.o"
     asserts.equals(
         env,
         linkstamp_out.path,

test/unit/rust_test_outputs_are_in_subdirectory/BUILD.bazel

@@ -0,0 +1,4 @@
+load(":rust_test_outputs.bzl", "rust_test_outputs_test_suite")
+
+############################ UNIT TESTS #############################
+rust_test_outputs_test_suite(name = "rust_test_outputs_test_suite")

test/unit/rust_test_outputs_are_in_subdirectory/foo.rs

@@ -0,0 +1 @@
+pub fn main() {}

test/unit/rust_test_outputs_are_in_subdirectory/rust_test_outputs.bzl

@@ -0,0 +1,64 @@
+"""Tests for rust_test outputs directory."""
+
+load("@bazel_skylib//lib:unittest.bzl", "analysistest", "asserts")
+load("//rust:defs.bzl", "rust_binary", "rust_common", "rust_test")
+
+def _rust_test_outputs_test(ctx):
+    env = analysistest.begin(ctx)
+    tut = analysistest.target_under_test(env)
+
+    output = tut[rust_common.crate_info].output
+
+    asserts.true(env, output.dirname.split("/")[-1].startswith("test-"))
+
+    return analysistest.end(env)
+
+rust_test_outputs_test = analysistest.make(
+    _rust_test_outputs_test,
+)
+
+def _rust_test_outputs_targets():
+    rust_binary(
+        name = "bin_outputs",
+        srcs = ["foo.rs"],
+        edition = "2018",
+    )
+
+    rust_test(
+        name = "test_outputs_with_srcs",
+        srcs = ["foo.rs"],
+        edition = "2018",
+    )
+
+    rust_test_outputs_test(
+        name = "rust_test_outputs_using_srcs_attr",
+        target_under_test = ":test_outputs_with_srcs",
+    )
+
+    rust_test(
+        name = "test_outputs_with_crate",
+        crate = "bin_outputs",
+        edition = "2018",
+    )
+
+    rust_test_outputs_test(
+        name = "rust_test_outputs_using_crate_attr",
+        target_under_test = ":test_outputs_with_crate",
+    )
+
+def rust_test_outputs_test_suite(name):
+    """Entry-point macro called from the BUILD file.
+
+    Args:
+        name: Name of the macro.
+    """
+
+    _rust_test_outputs_targets()
+
+    native.test_suite(
+        name = name,
+        tests = [
+            ":rust_test_outputs_using_srcs_attr",
+            ":rust_test_outputs_using_crate_attr",
+        ],
+    )