Fix an NPE in StringConcatToTextBlock

The linemap isn't available if debug info is disabled, so just skip findings in that case.

PiperOrigin-RevId: 738668315

Author: cushon

core/src/main/java/com/google/errorprone/bugpatterns/StringConcatToTextBlock.java

@@ -173,6 +173,9 @@ private Description match(
                 (s, orig) -> s + " ".repeat(orig.length() - SPACE.trimTrailingFrom(orig).length()))
             .collect(toImmutableList());
     LineMap lineMap = state.getPath().getCompilationUnit().getLineMap();
+    if (lineMap == null) {
+      return NO_MATCH;
+    }
     String indent = " ".repeat((int) lineMap.getColumnNumber(replaceFrom) - 1);
     String suffix = trailingNewline ? "" : "\\";
     String replacement =

core/src/test/java/com/google/errorprone/bugpatterns/StringConcatToTextBlockTest.java

@@ -271,4 +271,19 @@ record Test(@SuppressWarnings("foo") @Anno int foo) {}
         .expectUnchanged()
         .doTest(TEXT_MATCH);
   }
+
+  @Test
+  public void noDebug() {
+    refactoringHelper
+        .addInputLines(
+            "Test.java",
+            """
+            class Test {
+              String s = "hello\\n" + "world\\n";
+            }
+            """)
+        .expectUnchanged()
+        .setArgs("-g:none")
+        .doTest(TEXT_MATCH);
+  }
 }