Build warning message lazily

Author: bjfish

src/main/java/org/truffleruby/aot/ParserCache.java

@@ -67,7 +67,7 @@ private static RootParseNode parse(RubySource source) {
         if (!rubyWarnings.warnings.isEmpty()) {
             throw new RuntimeException("Core files should not emit warnings: " + String.join(
                     ", ",
-                    rubyWarnings.warnings.stream().map(w -> w.message).collect(Collectors.toList())));
+                    rubyWarnings.warnings.stream().map(w -> w.getWarningMessage()).collect(Collectors.toList())));
         }
         return rootParseNode;
     }

src/main/java/org/truffleruby/language/EmitWarningsNode.java

@@ -45,19 +45,19 @@ public void printWarnings(RubyContext context) {
     public static void printWarnings(RubyContext context, RubyDeferredWarnings warnings) {
         if (context == null) {
             for (RubyDeferredWarnings.WarningMessage warningMessage : warnings.warnings) {
-                System.err.println(warningMessage.message);
+                System.err.println(warningMessage.getWarningMessage());
             }
         } else {
             boolean isVerbose = context.getCoreLibrary().isVerbose();
             boolean warningsEnabled = context.getCoreLibrary().warningsEnabled();
             for (RubyDeferredWarnings.WarningMessage warningMessage : warnings.warnings) {
                 if (warningMessage.verbosity == RubyDeferredWarnings.Verbosity.VERBOSE) {
                     if (isVerbose) {
-                        printWarning(context, warningMessage.message);
+                        printWarning(context, warningMessage.getWarningMessage());
                     }
                 } else {
                     if (warningsEnabled) {
-                        printWarning(context, warningMessage.message);
+                        printWarning(context, warningMessage.getWarningMessage());
                     }
                 }
             }

src/main/java/org/truffleruby/parser/RubyDeferredWarnings.java

@@ -47,12 +47,31 @@ public enum Verbosity {
 
     public class WarningMessage {
         public final Verbosity verbosity;
-        public final String message;
+        private final String fileName;
+        private final Integer lineNumber;
+        private final String message;
 
-        public WarningMessage(Verbosity verbosity, String message) {
+        public WarningMessage(Verbosity verbosity, String fileName, Integer lineNumber, String message) {
             this.verbosity = verbosity;
+            this.fileName = fileName;
+            this.lineNumber = lineNumber;
             this.message = message;
         }
+
+        public String getWarningMessage() {
+            StringBuilder buffer = new StringBuilder(100);
+            if (fileName != null) {
+                buffer.append(fileName);
+                if (lineNumber != null) {
+                    buffer.append(':').append(lineNumber).append(": ");
+                } else {
+                    buffer.append(' ');
+                }
+            }
+            buffer.append("warning: ").append(message).append('\n');
+            return buffer.toString();
+        }
+
     }
 
     @Override
@@ -62,29 +81,22 @@ public void warn(String message) {
 
     /** Prints a warning, unless $VERBOSE is nil. */
     public void warn(String fileName, int lineNumber, String message) {
-        warnings.add(new WarningMessage(Verbosity.NON_VERBOSE, makeWarningMessage(fileName, lineNumber, message)));
+        warnings.add(new WarningMessage(Verbosity.NON_VERBOSE, fileName, lineNumber, message));
     }
 
     /** Prints a warning, unless $VERBOSE is nil. */
     public void warn(String fileName, String message) {
-        StringBuilder buffer = new StringBuilder(100);
-        if (fileName != null) {
-            buffer.append(fileName).append(' ');
-        }
-        buffer.append("warning: ").append(message).append('\n');
-        warnings.add(new WarningMessage(Verbosity.NON_VERBOSE, buffer.toString()));
-    }
-
-    private String makeWarningMessage(String fileName, int lineNumber, String message) {
-        StringBuilder buffer = new StringBuilder(100);
-        buffer.append(fileName).append(':').append(lineNumber).append(": ");
-        buffer.append("warning: ").append(message).append('\n');
-        return buffer.toString();
+        warnings.add(new WarningMessage(Verbosity.NON_VERBOSE, fileName, null, message));
     }
 
-    /** Prints a warning, only in verbose mode. */
+    /** Prints a warning, only if $VERBOSE is true. */
     public void warning(String fileName, int lineNumber, String message) {
-        warnings.add(new WarningMessage(Verbosity.VERBOSE, makeWarningMessage(fileName, lineNumber, message)));
+        warnings.add(
+                new WarningMessage(
+                        Verbosity.VERBOSE,
+                        fileName,
+                        lineNumber,
+                        message));
     }
 
 }

src/main/java/org/truffleruby/parser/RubyWarnings.java

@@ -91,7 +91,7 @@ public void warn(String fileName, String message) {
         printWarning(buffer.toString());
     }
 
-    /** Prints a warning, only in verbose mode. */
+    /** Prints a warning, only if $VERBOSE is true. */
     public void warning(String fileName, int lineNumber, String message) {
         if (!isVerbose()) {
             return;