Log "inputs_pruned.json" during parsing when debug logging is enabled

We already log "inputs.json", which includes *all* JS files passed to JSCompiler. Sometimes JSCompiler will prune unreachable input JS files. "inputs_pruned.json" prints only the JS files still present after pruning.

Also resolve TODO about using better JSON printing, now that we don't support compiling JSCompiler -> JS via J2CL.

PiperOrigin-RevId: 890454847

Author: lauraharker

src/com/google/javascript/jscomp/Compiler.java

@@ -41,6 +41,7 @@
 import com.google.errorprone.annotations.CanIgnoreReturnValue;
 import com.google.errorprone.annotations.FormatMethod;
 import com.google.errorprone.annotations.MustBeClosed;
+import com.google.gson.GsonBuilder;
 import com.google.javascript.jscomp.CodePrinter.LicenseTracker;
 import com.google.javascript.jscomp.CompilerInput.ModuleType;
 import com.google.javascript.jscomp.CompilerOptions.DevMode;
@@ -497,13 +498,9 @@ public void printConfig() {
     if (this.isDebugLoggingEnabled()) {
       // Log to separate files for convenience.
       logToFile("externs.log", externs::toString);
-      // To get a pretty-printed JSON chunk graph, change the string generation expression to
-      //
-      // new GsonBuilder().setPrettyPrinting().create().toJson(chunkGraph.toJson())
-      //
-      // TODO(bradfordcsmith): Come up with a JSON-printing version that will work when this code is
-      // compiled with J2CL, so we can permanently improve this.
-      logToFile("inputs.json", () -> Iterables.toString(chunkGraph.getAllInputs()));
+      logToFile(
+          "inputs.json",
+          new GsonBuilder().setPrettyPrinting().create().toJson(chunkGraph.toJson())::toString);
       logToFile("options.log", () -> options.toString());
       logToFile("warningsGuard.log", () -> warningsGuard.toString());
     } else {
@@ -512,21 +509,22 @@ public void printConfig() {
       err.println("==== Externs ====");
       err.println(externs);
       err.println("==== Inputs ====");
-      // To get a pretty-printed JSON chunk graph, change this line to
-      //
-      // err.println(
-      //     new GsonBuilder().setPrettyPrinting().create().toJson(chunkGraph.toJson()));
-      //
-      // TODO(bradfordcsmith): Come up with a JSON-printing version that will work when this code is
-      // compiled with J2CL, so we can permanently improve this.
-      err.println(Iterables.toString(chunkGraph.getAllInputs()));
+      err.println(new GsonBuilder().setPrettyPrinting().create().toJson(chunkGraph.toJson()));
       err.println("==== CompilerOptions ====");
       err.println(options);
       err.println("==== WarningsGuard ====");
       err.println(warningsGuard);
     }
   }
 
+  private void maybeLogPrunedInputs() {
+    if (this.isDebugLoggingEnabled()) {
+      logToFile(
+          "inputs_pruned.json",
+          new GsonBuilder().setPrettyPrinting().create().toJson(chunkGraph.toJson())::toString);
+    }
+  }
+
   private void logToFile(String logFileName, Supplier<String> logStringSupplier) {
     try (LogFile log = this.createOrReopenLog(this.getClass(), logFileName)) {
       log.log(logStringSupplier);
@@ -2290,6 +2288,7 @@ void orderInputs() {
     if (staleInputs) {
       repartitionInputs();
     }
+    maybeLogPrunedInputs();
   }
 
   /**

src/com/google/javascript/jscomp/JSChunkGraph.java

@@ -96,9 +96,9 @@ public final class JSChunkGraph implements Serializable {
    *
    * <p>If the cache returns null, then the entry hasn't been filled in for that chunk.
    *
-   * <p>NOTE: JSChunk has identity semantics so this map implementation is safe
+   * <p>NOTE: JSChunk has identity semantics so this map implementation is safe.
    */
-  private final LinkedIdentityHashMap<JSChunk, Set<JSChunk>> dependencyMap =
+  private final transient LinkedIdentityHashMap<JSChunk, Set<JSChunk>> dependencyMap =
       new LinkedIdentityHashMap<>();
 
   /** Creates a chunk graph from a list of chunks in dependency order. */