From 07930c5ee74b8d2645fc55465833ab84e2f4444a Mon Sep 17 00:00:00 2001
From: Sergey Poznyakoff <gray@gnu.org>
Date: Mon, 13 May 2019 14:24:58 +0300
Subject: wordsplit: return single empty string on empty input in WRDSF_NOSPLIT
 mode

* src/wordsplit.c (wordsplit_finish): Make sure at one non-null
argument is always returned in WRDSF_NOSPLIT mode.
* tests/wordsplit.at: Add new test.
---
 src/wordsplit.c    | 39 +++++++++++++++++++++++++--------------
 tests/wordsplit.at | 13 +++++++++++--
 2 files changed, 36 insertions(+), 16 deletions(-)

diff --git a/src/wordsplit.c b/src/wordsplit.c
index f94015a..e979f27 100644
--- a/src/wordsplit.c
+++ b/src/wordsplit.c
@@ -805,25 +805,35 @@ wordsplit_finish (struct wordsplit *wsp)
       n++;
     }
 
-  if (n == 0 && (wsp->ws_flags & WRDSF_INCREMENTAL))
+  if (n == 0)
     {
-      /* The loop above have eliminated all nodes. Restart the
-	 processing, if there's any input left. */
-      if (wsp->ws_endp < wsp->ws_len)
+      /* The loop above have eliminated all nodes. */
+      if (wsp->ws_flags & WRDSF_INCREMENTAL)
 	{
-	  int rc;
-	  if (wsp->ws_flags & WRDSF_SHOWDBG)
-	    wsp->ws_debug (_("Restarting"));
-	  rc = wordsplit_process_list (wsp, skip_delim (wsp));
-	  if (rc)
-	    return rc;
+	  /* Restart the processing, if there's any input left. */
+	  if (wsp->ws_endp < wsp->ws_len)
+	    {
+	      int rc;
+	      if (wsp->ws_flags & WRDSF_SHOWDBG)
+		wsp->ws_debug (_("Restarting"));
+	      rc = wordsplit_process_list (wsp, skip_delim (wsp));
+	      if (rc)
+		return rc;
+	    }
+	  else
+	    {
+	      wsp->ws_error = WRDSE_EOF;
+	      return WRDSE_EOF;
+	    }
+	  goto again;
 	}
-      else
+
+      if (wsp->ws_flags & WRDSF_NOSPLIT)
 	{
-	  wsp->ws_error = WRDSE_EOF;
-	  return WRDSE_EOF;
+	  if (wordsplit_add_segm (wsp, 0, 0, _WSNF_EMPTYOK))
+	    return wsp->ws_errno;
+	  n = 1;
 	}
-      goto again;
     }
 
   if (alloc_space (wsp, n + 1))
@@ -2412,6 +2422,7 @@ wordsplit_process_list (struct wordsplit *wsp, size_t start)
 	    }
 	}
     }
+
   return wsp->ws_errno;
 }
 
diff --git a/tests/wordsplit.at b/tests/wordsplit.at
index 631d939..e3af703 100644
--- a/tests/wordsplit.at
+++ b/tests/wordsplit.at
@@ -262,7 +262,7 @@ TOTAL: 2
 [],
 [FOO=bar BAZ=qux])
 
-TESTWSP([nosplit with expansion],[wsp-var-nosplit],[nosplit],
+TESTWSP([nosplit with variable expansion],[wsp-var-nosplit],[nosplit],
 [a $FOO test],
 [NF: 1
 0: "a variable expansion test\n"
@@ -271,7 +271,7 @@ TOTAL: 1
 [],
 [FOO="variable expansion"])
 
-TESTWSP([nosplit without expansion],[],[nosplit novar],
+TESTWSP([nosplit without variable expansion],[],[nosplit novar],
 [a $FOO test],
 [NF: 1
 0: "a $FOO test\n"
@@ -280,6 +280,15 @@ TOTAL: 1
 [],
 [FOO="variable expansion"])
 
+TESTWSP([nosplit: empty expansion],[],[nosplit trimnl],
+[$FOO],
+[NF: 1
+0: ""
+TOTAL: 1
+],
+[],
+[FOO=""])
+
 TESTWSP([default value (defined)],[],[],
 [${FOO:-bar}],
 [NF: 1
-- 
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