3 files changed, 19 insertions, 1 deletions
diff --git a/error.c b/error.c
index 3635f0f..b1e74a1 100644
--- a/error.c
+++ b/error.c
@@ -278,6 +278,11 @@ static void do_error(int code, va_list ap) {
 	flags = FILEPOS;
 	sfree(sp);
 	break;
+      case err_emptypara:
+	fpos = *va_arg(ap, filepos *);
+	sprintf(error, "found no text in paragraph");
+	flags = FILEPOS;
+	break;
       case err_whatever:
 	sp = va_arg(ap, char *);
         vsprintf(error, sp, ap);
diff --git a/halibut.h b/halibut.h
index ed2a0da..99b9a0e 100644
--- a/halibut.h
+++ b/halibut.h
@@ -244,6 +244,7 @@ enum {
     err_text_codeline,		       /* \c line too long in text backend */
     err_htmlver,		       /* unrecognised HTML version keyword */
     err_charset,		       /* unrecognised character set name */
+    err_emptypara,		       /* paragraph contains no actual text */
     err_whatever                       /* random error of another type */
 };
 
diff --git a/input.c b/input.c
index 493449c..d8d44f9 100644
--- a/input.c
+++ b/input.c
@@ -1529,7 +1529,19 @@ static void read_file(paragraph ***ret, input *in, indexdata *idx,
 	}
 	stk_free(parsestk);
 	prev_para_type = par.type;
-	addpara(par, ret);
+	/*
+	 * Before we add the paragraph to the output list, we
+	 * should check that there was any text in it at all; there
+	 * might not be if (for example) the paragraph contained
+	 * nothing but an unrecognised command sequence, and if we
+	 * put an empty paragraph on the list it may confuse the
+	 * back ends later on.
+	 */
+	if (par.words) {
+	    addpara(par, ret);
+	} else {
+	    error(err_emptypara, &par.fpos);
+	}
 	if (t.type == tok_eof)
 	    already = TRUE;
     }