tsort: diagnose errors reading the input

* src/tsort.c (tsort): Check for errors after readtoken().
* NEWS: Mention the bug fix.

2 files changed, 8 insertions, 1 deletions

diff --git a/NEWS b/NEWS
index a8db32246..2c68b1735 100644
--- a/NEWS
+++ b/NEWS
@@ -11,6 +11,9 @@ GNU coreutils NEWS                                    -*- outline -*-
   Previously such file names would have caused the strip process to fail.
   [This bug was present in "the beginning".]
 
+  tsort now diagnoses read errors on the input.
+  [This bug was present in "the beginning".]
+
 
 * Noteworthy changes in release 9.3 (2023-04-18) [stable]
 
diff --git a/src/tsort.c b/src/tsort.c
index 0032cb5d0..2775fb39e 100644
--- a/src/tsort.c
+++ b/src/tsort.c
@@ -453,7 +453,11 @@ tsort (char const *file)
       /* T2. Next Relation.  */
       size_t len = readtoken (stdin, DELIM, sizeof (DELIM) - 1, &tokenbuffer);
       if (len == (size_t) -1)
-        break;
+        {
+          if (ferror (stdin))
+            die (EXIT_FAILURE, errno, _("%s: read error"), quotef (file));
+          break;
+        }
 
       assert (len != 0);