In ExpectFailure, never generate "value of" lines based on bytecode.

The immediate motivation here is to prevent cl/801287069 and similar changes from affecting "value of" lines seen by users who are testing their own `Subject` implementations. But this is something that we've wanted before, including to make behavior consistent between the JVM (under which we can read bytecode) and other platforms (under which we can't/don't).

RELNOTES=Changed `ExpectFailure` to never generate "value of" lines based on bytecode. This slightly simplifies writing new tests with `ExpectFailure` and prevents future behavior changes in some `ExpectFailure` tests that already exist. However, it may also require changes to other existing `ExpectFailure` tests to remove or change any assertions about the "value of" line.
PiperOrigin-RevId: 802995279

Author: cpovirk

core/pom.xml

@@ -136,10 +136,6 @@
                 <exclude>**/ActualValueInferenceTest.java</exclude>
                 <exclude>**/*GwtTest.java</exclude>
               </excludes>
-              <systemPropertyVariables>
-                <!-- Avoid automatically generating "value of" lines based on bytecode: We use one set of tests across multiple environments in our testing inside Google, and most of those environments (e.g., Android, J2CL) don't support "value of" lines. Thus, our tests are simplest if we disable "value of" lines altogether. -->
-                <com.google.common.truth.disable_infer_description>true</com.google.common.truth.disable_infer_description>
-              </systemPropertyVariables>
             </configuration>
           </execution>
           <execution>
@@ -148,6 +144,9 @@
               <includes>
                 <include>**/ActualValueInferenceTest.java</include>
               </includes>
+              <systemPropertyVariables>
+                <com.google.common.truth.enable_infer_description_for_expect_failure>true</com.google.common.truth.enable_infer_description_for_expect_failure>
+              </systemPropertyVariables>
             </configuration>
             <goals>
               <goal>test</goal>

core/src/main/java/com/google/common/truth/ExpectFailure.java

@@ -64,9 +64,21 @@
  * href="https://junit.org/junit4/javadoc/latest/org/junit/Assert.html#assertThrows%28java.lang.Class,%20org.junit.function.ThrowingRunnable%29">JUnit
  * 4</a>, <a
  * href="https://docs.junit.org/current/api/org.junit.jupiter.api/org/junit/jupiter/api/Assertions.html#assertThrows(java.lang.Class,org.junit.jupiter.api.function.Executable)">JUnit
- * 5</a>). We recommend it over {@code assertThrows} when you're testing a Truth subject because it
- * also checks that the assertion you're testing uses the supplied {@link FailureStrategy} and calls
- * {@link FailureStrategy#fail} only once.
+ * 5</a>). We recommend it over {@code assertThrows} when you're testing a Truth subject because:
+ *
+ * <ul>
+ *   <li>It performs additional checks:
+ *       <ul>
+ *         <li>It checks that the assertion you're testing uses the supplied {@link
+ *             FailureStrategy}.
+ *         <li>It checks that the assertion you're testing calls {@link FailureStrategy#fail} only
+ *             once.
+ *       </ul>
+ *   <li>It instructs Truth to generate failure messages <i>without</i> adding lines like "value of:
+ *       foo()" for {@code assertThat(foo())....} calls that it detects in the test bytecode. Truth
+ *       doesn't provide guarantees for when such lines will be generated, so tests become more
+ *       resilient without them.
+ * </ul>
  */
 public final class ExpectFailure implements Platform.JUnitTestRule {
   private boolean inRuleContext = false;
@@ -97,9 +109,16 @@ public StandardSubjectBuilder whenTesting() {
           "ExpectFailure.whenTesting() called previously, but did not capture a failure.");
     }
     failureExpected = true;
-    return StandardSubjectBuilder.forCustomFailureStrategy(this::captureFailure);
+    return StandardSubjectBuilder.forCustomFailureStrategy(
+        (ExpectFailureFailureStrategy) this::captureFailure);
   }
 
+  /**
+   * Marker interface that we check for so that we can automatically disable "value of" lines during
+   * {@link ExpectFailure} assertions.
+   */
+  interface ExpectFailureFailureStrategy extends FailureStrategy {}
+
   /**
    * Enters rule context to be ready to capture failures.
    *

core/src/main/java/com/google/common/truth/FailureMetadata.java

@@ -25,12 +25,14 @@
 import static com.google.common.truth.LazyMessage.evaluateAll;
 import static com.google.common.truth.Platform.cleanStackTrace;
 import static com.google.common.truth.Platform.inferDescription;
+import static com.google.common.truth.Platform.isInferDescriptionEnabledForExpectFailure;
 import static com.google.common.truth.Platform.makeComparisonFailure;
 import static com.google.common.truth.SubjectUtils.append;
 import static com.google.common.truth.SubjectUtils.concat;
 
 import com.google.common.base.Function;
 import com.google.common.collect.ImmutableList;
+import com.google.common.truth.ExpectFailure.ExpectFailureFailureStrategy;
 import org.jspecify.annotations.Nullable;
 
 /**
@@ -243,7 +245,11 @@ private ImmutableList<Fact> description() {
 
   /** Overload of {@link #description()} that allows passing a custom key for the fact. */
   private ImmutableList<Fact> description(String factKey) {
-    String description = inferDescription();
+    String description =
+        strategy instanceof ExpectFailureFailureStrategy
+                && !isInferDescriptionEnabledForExpectFailure()
+            ? null
+            : inferDescription();
     boolean descriptionIsInteresting = description != null;
     for (Step step : steps) {
       if (step.isCheckCall()) {

core/src/main/java/com/google/common/truth/Platform.java

@@ -242,6 +242,16 @@ private static boolean isInferDescriptionDisabled() {
     }
   }
 
+  static boolean isInferDescriptionEnabledForExpectFailure() {
+    try {
+      return Boolean.parseBoolean(
+          System.getProperty(
+              "com.google.common.truth.enable_infer_description_for_expect_failure"));
+    } catch (SecurityException e) {
+      return false;
+    }
+  }
+
   static AssertionError makeComparisonFailure(
       List<String> messages,
       List<Fact> facts,

core/src/main/java/com/google/common/truth/super/com/google/common/truth/Platform.java

@@ -24,15 +24,13 @@
 import jsinterop.annotations.JsMethod;
 import jsinterop.annotations.JsProperty;
 import jsinterop.annotations.JsType;
-import org.jspecify.annotations.NullMarked;
 import org.jspecify.annotations.Nullable;
 
 
 /**
  * Extracted routines that need to be swapped in for GWT, to allow for minimal deltas between the
  * GWT and non-GWT version.
  */
-@NullMarked
 final class Platform {
   private Platform() {}
 
@@ -182,6 +180,10 @@ static String expectFailureWarningIfWeb() {
         + " verifying that the expected failure occurred.)";
   }
 
+  static boolean isInferDescriptionEnabledForExpectFailure() {
+    return false; // irrelevant because we can infer descriptions only under the JVM
+  }
+
   // TODO(user): Move this logic to a common location.
   private static NativeRegExp compile(String pattern) {
     return new NativeRegExp(pattern);