Move `SpawnInputUtils` to open source.

Clean up methods to never return `null` - all callers expect a matching input to be found. This removes a lot of `checkNotNull` calls.

PiperOrigin-RevId: 454740106
Change-Id: I49c84e36c93e71e659662580a6197b6f2325c8ac
diff --git a/src/test/java/com/google/devtools/build/lib/testutil/BUILD b/src/test/java/com/google/devtools/build/lib/testutil/BUILD
index 1109da3..031ea9b 100644
--- a/src/test/java/com/google/devtools/build/lib/testutil/BUILD
+++ b/src/test/java/com/google/devtools/build/lib/testutil/BUILD
@@ -125,6 +125,19 @@
 )
 
 java_library(
+    name = "spawn_input_utils",
+    srcs = ["SpawnInputUtils.java"],
+    deps = [
+        "//src/main/java/com/google/devtools/build/lib/actions",
+        "//src/main/java/com/google/devtools/build/lib/actions:action_input_helper",
+        "//src/main/java/com/google/devtools/build/lib/actions:artifacts",
+        "//src/main/java/com/google/devtools/build/lib/actions:fileset_output_symlink",
+        "//src/main/java/com/google/devtools/build/lib/vfs",
+        "//third_party:guava",
+    ],
+)
+
+java_library(
     name = "test_interrupting_bug_reporter",
     srcs = ["TestInterruptingBugReporter.java"],
     deps = [
diff --git a/src/test/java/com/google/devtools/build/lib/testutil/SpawnInputUtils.java b/src/test/java/com/google/devtools/build/lib/testutil/SpawnInputUtils.java
new file mode 100644
index 0000000..4ebcd35
--- /dev/null
+++ b/src/test/java/com/google/devtools/build/lib/testutil/SpawnInputUtils.java
@@ -0,0 +1,128 @@
+// Copyright 2022 The Bazel Authors. All rights reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//    http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+package com.google.devtools.build.lib.testutil;
+
+import static com.google.common.base.MoreObjects.firstNonNull;
+import static com.google.common.base.Preconditions.checkState;
+
+import com.google.common.collect.ImmutableList;
+import com.google.devtools.build.lib.actions.ActionExecutionContext;
+import com.google.devtools.build.lib.actions.ActionExecutionMetadata;
+import com.google.devtools.build.lib.actions.ActionInput;
+import com.google.devtools.build.lib.actions.ActionInputHelper;
+import com.google.devtools.build.lib.actions.Artifact;
+import com.google.devtools.build.lib.actions.Artifact.MissingExpansionException;
+import com.google.devtools.build.lib.actions.Artifact.SpecialArtifact;
+import com.google.devtools.build.lib.actions.FilesetOutputSymlink;
+import com.google.devtools.build.lib.actions.Spawn;
+import com.google.devtools.build.lib.vfs.Path;
+import java.util.ArrayList;
+import java.util.Map;
+import java.util.NoSuchElementException;
+
+/** Utilities for finding {@link ActionInput} instances within a {@link Spawn}. */
+public final class SpawnInputUtils {
+
+  public static ActionInput getInputWithName(Spawn spawn, String name) {
+    return spawn.getInputFiles().toList().stream()
+        .filter(input -> input.getExecPathString().contains(name))
+        .findFirst()
+        .orElseThrow(() -> noSuchInput("spawn input", name, spawn));
+  }
+
+  public static Artifact getFilesetArtifactWithName(Spawn spawn, String name) {
+    return spawn.getFilesetMappings().keySet().stream()
+        .filter(filesetArtifact -> filesetArtifact.getExecPathString().contains(name))
+        .findFirst()
+        .orElseThrow(() -> noSuchInput("fileset artifact", name, spawn));
+  }
+
+  public static ActionInput getFilesetInputWithName(
+      Spawn spawn, ActionExecutionContext context, String artifactName, String inputName) {
+    Path execRoot = context.getExecRoot();
+    for (Map.Entry<Artifact, ImmutableList<FilesetOutputSymlink>> entry :
+        spawn.getFilesetMappings().entrySet()) {
+      Artifact filesetArtifact = entry.getKey();
+      if (!filesetArtifact.getExecPathString().contains(artifactName)) {
+        continue;
+      }
+      for (FilesetOutputSymlink filesetOutputSymlink : entry.getValue()) {
+        if (filesetOutputSymlink.getTargetPath().toString().contains(inputName)) {
+          Path inputPath = execRoot.getRelative(filesetOutputSymlink.getTargetPath());
+          return ActionInputHelper.fromPath(inputPath.asFragment());
+        }
+      }
+    }
+    throw noSuchInput("fileset input in " + artifactName, inputName, spawn);
+  }
+
+  public static ActionInput getRunfilesFilesetInputWithName(
+      Spawn spawn, ActionExecutionContext context, String artifactName, String inputName) {
+    Artifact filesetArtifact = getRunfilesArtifactWithName(spawn, artifactName);
+    checkState(filesetArtifact.isFileset(), filesetArtifact);
+
+    ImmutableList<FilesetOutputSymlink> filesetLinks;
+    try {
+      filesetLinks = context.getArtifactExpander().getFileset(filesetArtifact);
+    } catch (MissingExpansionException e) {
+      throw new IllegalStateException(e);
+    }
+    for (FilesetOutputSymlink filesetOutputSymlink : filesetLinks) {
+      if (filesetOutputSymlink.getTargetPath().toString().contains(inputName)) {
+        Path inputPath = context.getExecRoot().getRelative(filesetOutputSymlink.getTargetPath());
+        return ActionInputHelper.fromPath(inputPath.asFragment());
+      }
+    }
+    throw noSuchInput("runfiles fileset in " + filesetArtifact, inputName, spawn);
+  }
+
+  public static SpecialArtifact getTreeArtifactWithName(Spawn spawn, String name) {
+    ActionInput input = getInputWithName(spawn, name);
+    checkState(
+        input instanceof SpecialArtifact && ((SpecialArtifact) input).isTreeArtifact(),
+        "Expected spawn %s to have tree artifact input with name %s, but it is: %s",
+        spawn.getResourceOwner().describe(),
+        name,
+        input);
+    return (SpecialArtifact) input;
+  }
+
+  public static Artifact getExpandedToArtifact(
+      String name, Artifact expandableArtifact, Spawn spawn, ActionExecutionContext context) {
+    ArrayList<Artifact> expansion = new ArrayList<>();
+    context.getArtifactExpander().expand(expandableArtifact, expansion);
+    return expansion.stream()
+        .filter(artifact -> artifact.getExecPathString().contains(name))
+        .findFirst()
+        .orElseThrow(
+            () -> noSuchInput("artifact expanded from " + expandableArtifact, name, spawn));
+  }
+
+  public static Artifact getRunfilesArtifactWithName(Spawn spawn, String name) {
+    return spawn.getRunfilesSupplier().getArtifacts().toList().stream()
+        .filter(artifact -> artifact.getExecPathString().contains(name))
+        .findFirst()
+        .orElseThrow(() -> noSuchInput("runfiles artifact", name, spawn));
+  }
+
+  private static NoSuchElementException noSuchInput(String inputType, String name, Spawn spawn) {
+    ActionExecutionMetadata action = spawn.getResourceOwner();
+    return new NoSuchElementException(
+        String.format(
+            "No %s named %s in %s",
+            inputType, name, firstNonNull(action.getProgressMessage(), action.prettyPrint())));
+  }
+
+  private SpawnInputUtils() {}
+}