Handle symlinks and root_symlinks in Runfiles

Fixes #18249.

Closes #18399.

PiperOrigin-RevId: 532767884
Change-Id: I7c50b2bea7b93072e601a192031c14d2c22a5713

src/main/java/com/google/devtools/build/lib/remote/RemoteOutputChecker.java

@@ -125,12 +125,27 @@ private void addRunfiles(ProviderCollection buildTarget) {
     if (runfilesSupport == null) {
       return;
     }
-    for (Artifact runfile : runfilesSupport.getRunfiles().getArtifacts().toList()) {
+    var runfiles = runfilesSupport.getRunfiles();
+    for (Artifact runfile : runfiles.getArtifacts().toList()) {
       if (runfile.isSourceArtifact()) {
         continue;
       }
       toplevelArtifactsToDownload.add(runfile);
     }
+    for (var symlink : runfiles.getSymlinks().toList()) {
+      var artifact = symlink.getArtifact();
+      if (artifact.isSourceArtifact()) {
+        continue;
+      }
+      toplevelArtifactsToDownload.add(artifact);
+    }
+    for (var symlink : runfiles.getRootSymlinks().toList()) {
+      var artifact = symlink.getArtifact();
+      if (artifact.isSourceArtifact()) {
+        continue;
+      }
+      toplevelArtifactsToDownload.add(artifact);
+    }
   }
 
   public void addInputToDownload(ActionInput file) {

src/test/shell/bazel/remote/build_without_the_bytes_test.sh

@@ -1778,4 +1778,96 @@ EOF
   expect_log "Found remote cache eviction error, retrying the build..."
 }
 
+function test_download_toplevel_symlinks_runfiles() {
+    cat > rules.bzl <<EOF
+def _symlink_rule_impl(ctx):
+    file = ctx.actions.declare_file("file.txt")
+    executable = ctx.actions.declare_file("executable")
+
+    ctx.actions.run_shell(
+        outputs = [file],
+        command = "echo 'Hello World!' > " + file.path,
+    )
+    ctx.actions.write(executable, "[[ -L symlink.txt ]] && cat symlink.txt")
+    return [DefaultInfo(
+        runfiles = ctx.runfiles(
+            symlinks = {"symlink.txt": file},
+        ),
+        executable = executable,
+    )]
+
+symlink_rule = rule(
+    implementation = _symlink_rule_impl,
+    executable = True,
+    attrs = {},
+)
+EOF
+  cat > BUILD <<EOF
+load(":rules.bzl", "symlink_rule")
+symlink_rule(name = "symlink")
+EOF
+
+  bazel run \
+    --remote_executor=grpc://localhost:${worker_port} \
+    --remote_download_toplevel \
+    //:symlink >& $TEST_log || fail "Failed to run //:symlink"
+
+  expect_log "Hello World"
+
+  rm bazel-bin/file.txt
+
+  bazel run \
+    --remote_executor=grpc://localhost:${worker_port} \
+    --remote_download_toplevel \
+    //:symlink >& $TEST_log || fail "Failed to run //:symlink"
+
+  expect_log "Hello World"
+}
+
+function test_download_toplevel_root_symlinks_runfiles() {
+    cat > rules.bzl <<EOF
+def _symlink_rule_impl(ctx):
+    file = ctx.actions.declare_file("file.txt")
+    executable = ctx.actions.declare_file("executable")
+
+    ctx.actions.run_shell(
+        outputs = [file],
+        command = "echo 'Hello World!' > " + file.path,
+    )
+    ctx.actions.write(executable, "[[ -L ../symlink.txt ]] && cat ../symlink.txt")
+    return [DefaultInfo(
+        runfiles = ctx.runfiles(
+            root_symlinks = {"symlink.txt": file},
+        ),
+        executable = executable,
+    )]
+
+symlink_rule = rule(
+    implementation = _symlink_rule_impl,
+    executable = True,
+    attrs = {},
+)
+EOF
+  cat > BUILD <<EOF
+load(":rules.bzl", "symlink_rule")
+symlink_rule(name = "symlink")
+EOF
+
+  bazel run \
+    --remote_executor=grpc://localhost:${worker_port} \
+    --remote_download_toplevel \
+    //:symlink >& $TEST_log || fail "Failed to run //:symlink"
+
+  expect_log "Hello World"
+
+  rm bazel-bin/file.txt
+
+  bazel run \
+    --remote_executor=grpc://localhost:${worker_port} \
+    --remote_download_toplevel \
+    //:symlink >& $TEST_log || fail "Failed to run //:symlink"
+
+  expect_log "Hello World"
+}
+
 run_suite "Build without the Bytes tests"