CustomCommandLine: add emptiness checks

This is a semantic roll-forward of https://github.com/bazelbuild/bazel/commit/a76c94be7c56b93fc5a2f9ececfba7ac1f61f69c
which was rolled back in https://github.com/bazelbuild/bazel/commit/33cd68e18f554b98194b4ce924580d3333ab9217 due to
memory regressions.

In this commit:
- add @Nullable annotations to
  CustomCommandLine.Builder.add* methods where it
  makes sense
- add Preconditions.checkNotNull for non-nullable
  arguments
- add emptiness checks for Iterables in
  add(String, Iterable) style methods, to avoid
  adding the argument when the Iterable is empty
  and so the argument would not be followed by any
  values

RELNOTES: none
PiperOrigin-RevId: 162349842

1 files changed, 98 insertions, 7 deletions

diff --git a/src/test/java/com/google/devtools/build/lib/actions/CustomCommandLineTest.java b/src/test/java/com/google/devtools/build/lib/actions/CustomCommandLineTest.java
index ea061beb2d..d0eb08e2c1 100644
--- a/src/test/java/com/google/devtools/build/lib/actions/CustomCommandLineTest.java
+++ b/src/test/java/com/google/devtools/build/lib/actions/CustomCommandLineTest.java
@@ -18,6 +18,7 @@ import static org.junit.Assert.fail;
 
 import com.google.common.base.Function;
 import com.google.common.collect.ImmutableList;
+import com.google.common.testing.NullPointerTester;
 import com.google.devtools.build.lib.actions.Artifact.ArtifactExpander;
 import com.google.devtools.build.lib.actions.Artifact.SpecialArtifact;
 import com.google.devtools.build.lib.actions.Artifact.SpecialArtifactType;
@@ -187,13 +188,103 @@ public class CustomCommandLineTest {
   }
 
   @Test
-  public void testAddNulls() {
-    CustomCommandLine cl = CustomCommandLine.builder()
-        .add("--args", null)
-        .addExecPaths(null, ImmutableList.of(artifact1))
-        .addExecPath(null, null)
-        .build();
-    assertThat(cl.arguments()).isEqualTo(ImmutableList.of());
+  public void testAddNulls() throws Exception {
+    Artifact treeArtifact = createTreeArtifact("myTreeArtifact");
+    assertThat(treeArtifact).isNotNull();
+
+    CustomCommandLine cl =
+        CustomCommandLine.builder()
+            .add((CharSequence) null)
+            .add((Label) null)
+            .add("foo", null)
+            .add("foo", ImmutableList.of())
+            .add((Iterable<String>) null)
+            .add(ImmutableList.<String>of())
+            .addExecPath("foo", null)
+            .addExecPaths("foo", (Iterable<Artifact>) null)
+            .addExecPaths("foo", ImmutableList.<Artifact>of())
+            .addExecPaths(null)
+            .addExecPaths(ImmutableList.of())
+            .addPlaceholderTreeArtifactExecPath("foo", null)
+            .addJoinStrings("foo", "bar", null)
+            .addJoinStrings("foo", "bar", ImmutableList.of())
+            .addJoinValues("foo", "bar", null, String::toString)
+            .addJoinValues("foo", "bar", ImmutableList.of(), String::toString)
+            .addJoinExecPaths("foo", "bar", null)
+            .addJoinExecPaths("foo", "bar", ImmutableList.of())
+            .addPath(null)
+            .addPlaceholderTreeArtifactFormattedExecPath("foo", null)
+            .addJoinPaths("foo", null)
+            .addJoinPaths("foo", ImmutableList.of())
+            .addBeforeEachPath("foo", null)
+            .addBeforeEachPath("foo", ImmutableList.of())
+            .addBeforeEach("foo", null)
+            .addBeforeEach("foo", ImmutableList.of())
+            .addBeforeEachExecPath("foo", null)
+            .addBeforeEachExecPath("foo", ImmutableList.of())
+            .addFormatEach("%s", null)
+            .addFormatEach("%s", ImmutableList.of())
+            .add((CustomArgv) null)
+            .add((CustomMultiArgv) null)
+            .build();
+    assertThat(cl.arguments()).isEmpty();
+
+    assertThat(
+            CustomCommandLine.builder()
+                .addPaths("foo")
+                .addPaths("bar", (PathFragment[]) null)
+                .addPaths("baz", new PathFragment[0])
+                .build()
+                .arguments())
+        .containsExactly("foo", "baz")
+        .inOrder();
+
+    CustomCommandLine.Builder obj = CustomCommandLine.builder();
+    Class<CustomCommandLine.Builder> clazz = CustomCommandLine.Builder.class;
+    NullPointerTester npt =
+        new NullPointerTester()
+            .setDefault(Artifact.class, artifact1)
+            .setDefault(String.class, "foo")
+            .setDefault(PathFragment[].class, new PathFragment[] {PathFragment.create("foo")});
+
+    npt.testMethod(obj, clazz.getMethod("add", String.class, Iterable.class));
+    npt.testMethod(obj, clazz.getMethod("addExecPath", String.class, Artifact.class));
+    npt.testMethod(obj, clazz.getMethod("addExecPaths", String.class, Iterable.class));
+    npt.testMethod(
+        obj, clazz.getMethod("addPlaceholderTreeArtifactExecPath", String.class, Artifact.class));
+    npt.testMethod(
+        obj,
+        clazz.getMethod(
+            "addPlaceholderTreeArtifactFormattedExecPath", String.class, Artifact.class));
+    npt.testMethod(obj, clazz.getMethod("addParamFile", String.class, Artifact.class));
+    npt.testMethod(obj, clazz.getMethod("addPaths", String.class, PathFragment[].class));
+    npt.testMethod(
+        obj, clazz.getMethod("addJoinExpandedTreeArtifactExecPath", String.class, Artifact.class));
+    npt.testMethod(obj, clazz.getMethod("addExpandedTreeArtifactExecPaths", Artifact.class));
+
+    npt.setDefault(Iterable.class, ImmutableList.of("foo"));
+    npt.testMethod(
+        obj, clazz.getMethod("addJoinStrings", String.class, String.class, Iterable.class));
+    npt.testMethod(
+        obj,
+        clazz.getMethod(
+            "addJoinValues", String.class, String.class, Iterable.class, Function.class));
+    npt.testMethod(obj, clazz.getMethod("addBeforeEach", String.class, Iterable.class));
+    npt.testMethod(obj, clazz.getMethod("addFormatEach", String.class, Iterable.class));
+
+    npt.setDefault(Iterable.class, ImmutableList.of(artifact1));
+    npt.testMethod(
+        obj, clazz.getMethod("addJoinExecPaths", String.class, String.class, Iterable.class));
+    npt.testMethod(obj, clazz.getMethod("addBeforeEachExecPath", String.class, Iterable.class));
+
+    npt.setDefault(Iterable.class, ImmutableList.of(PathFragment.create("foo")));
+    npt.testMethod(obj, clazz.getMethod("addJoinPaths", String.class, Iterable.class));
+    npt.testMethod(obj, clazz.getMethod("addBeforeEachPath", String.class, Iterable.class));
+
+    npt.setDefault(Artifact.class, treeArtifact);
+    npt.testMethod(
+        obj, clazz.getMethod("addJoinExpandedTreeArtifactExecPath", String.class, Artifact.class));
+    npt.testMethod(obj, clazz.getMethod("addExpandedTreeArtifactExecPaths", Artifact.class));
   }
 
   @Test