Preserve Writer failures when a template starts at column zero

handlebars/src/main/java/com/github/jknack/handlebars/internal/BaseTemplate.java

@@ -100,10 +100,11 @@ public void apply(final Context context, final Writer writer) throws IOException
     } catch (Exception ex) {
       String evidence = toString();
       String reason = ex.toString();
-      String message = filename + ":" + line + ":" + column + ": " + reason + "\n";
+      int errorColumn = Math.max(1, column);
+      String message = filename + ":" + line + ":" + errorColumn + ": " + reason + "\n";
       message += "    " + join(split(evidence, "\n"), "\n    ");
       HandlebarsError error =
-          new HandlebarsError(filename, line, column, reason, evidence, message);
+          new HandlebarsError(filename, line, errorColumn, reason, evidence, message);
       HandlebarsException hex = new HandlebarsException(error, ex);
       // Override the stack-trace
       hex.setStackTrace(ex.getStackTrace());

handlebars/src/test/java/com/github/jknack/handlebars/internal/TemplateTest.java

@@ -6,8 +6,13 @@
 package com.github.jknack.handlebars.internal;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertSame;
+import static org.junit.jupiter.api.Assertions.assertThrows;
 
+import java.io.FilterWriter;
 import java.io.IOException;
+import java.io.StringWriter;
+import java.io.Writer;
 import java.util.Arrays;
 import java.util.HashSet;
 import java.util.List;
@@ -17,6 +22,7 @@
 
 import com.github.jknack.handlebars.AbstractTest;
 import com.github.jknack.handlebars.Handlebars;
+import com.github.jknack.handlebars.HandlebarsException;
 import com.github.jknack.handlebars.TagType;
 import com.github.jknack.handlebars.Template;
 
@@ -28,6 +34,25 @@
  */
 public class TemplateTest extends AbstractTest {
 
+  @Test
+  public void preservesWriterFailureAtStartOfLine() throws IOException {
+    IOException failure = new IOException("Unable to write template output");
+    Writer writer =
+        new FilterWriter(new StringWriter()) {
+          @Override
+          public void write(String text, int offset, int length) throws IOException {
+            throw failure;
+          }
+        };
+    Template template = newHandlebars().compileInline("Hello {{user}}.");
+
+    HandlebarsException error =
+        assertThrows(HandlebarsException.class, () -> template.apply("", writer));
+
+    assertSame(failure, error.getCause());
+    assertEquals(1, error.getError().column);
+  }
+
   @Test
   public void simpleVarTests() throws IOException {
     assertVariables("{{v1}}", Arrays.asList("v1"));