Use -C link-arg= instead of link-args to handle nested spaces

rust/private/rustc.bzl

@@ -1018,7 +1018,10 @@ def construct_arguments(
 
             env.update(link_env)
             rustc_flags.add(ld, format = "--codegen=linker=%s")
-            rustc_flags.add_joined("--codegen", link_args, join_with = " ", format_joined = "link-args=%s")
+
+            # Split link args into individual "--codegen=link-arg=" flags to handle nested spaces.
+            # Additional context: https://github.com/rust-lang/rust/pull/36574
+            rustc_flags.add_all(link_args, format_each = "--codegen=link-arg=%s")
 
         _add_native_link_flags(rustc_flags, dep_info, linkstamp_outs, ambiguous_libs, crate_info.type, toolchain, cc_toolchain, feature_configuration, compilation_mode)
 

test/unit/native_deps/native_deps_test.bzl

@@ -113,13 +113,17 @@ def _bin_has_native_libs_test_impl(ctx):
     return analysistest.end(env)
 
 def _extract_linker_args(argv):
-    return [a for a in argv if (
-        a.startswith("link-arg=") or
-        a.startswith("link-args=") or
-        a.startswith("-l") or
-        a.endswith(".lo") or
-        a.endswith(".o")
-    )]
+    return [
+        a.removeprefix("--codegen=link-arg=").removeprefix("--codegen=link-args=")
+        for a in argv
+        if (
+            a.startswith("--codegen=link-arg=") or
+            a.startswith("--codegen=link-args=") or
+            a.startswith("-l") or
+            a.endswith(".lo") or
+            a.endswith(".o")
+        )
+    ]
 
 def _bin_has_native_dep_and_alwayslink_test_impl(ctx):
     env = analysistest.begin(ctx)
@@ -171,8 +175,7 @@ def _cdylib_has_native_dep_and_alwayslink_test_impl(ctx):
     tut = analysistest.target_under_test(env)
     action = tut.actions[0]
 
-    # skipping first link-arg since it contains unrelated linker flags
-    linker_args = _extract_linker_args(action.argv)[1:]
+    linker_args = _extract_linker_args(action.argv)
 
     toolchain = _get_toolchain(ctx)
     compilation_mode = ctx.var["COMPILATION_MODE"]
@@ -204,7 +207,7 @@ def _cdylib_has_native_dep_and_alwayslink_test_impl(ctx):
             "link-arg=bazel-out/k8-{}/bin/{}test/unit/native_deps/libalwayslink{}.lo".format(compilation_mode, workspace_prefix, pic_suffix),
             "link-arg=-Wl,--no-whole-archive",
         ]
-    asserts.equals(env, want, linker_args)
+    assert_list_contains_adjacent_elements(env, linker_args, want)
     return analysistest.end(env)
 
 def _get_pic_suffix(ctx, compilation_mode):
@@ -334,11 +337,8 @@ def _linkopts_propagate_test_impl(ctx):
     # Consistently with cc rules, dependency linkopts take precedence over
     # dependent linkopts (i.e. dependency linkopts appear later in the command
     # line).
-    linkopt_args = [
-        arg
-        for arg in _extract_linker_args(action.argv)
-        if arg.startswith("link-args")
-    ][0].split(" ")
+
+    linkopt_args = _extract_linker_args(action.argv)
     assert_list_contains_adjacent_elements(
         env,
         linkopt_args,