awk: fix FS assignment behavior. Closes 5108

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 12 insertions, 0 deletions

diff --git a/editors/awk.c b/editors/awk.c
index d69720d64..42f6ef866 100644
--- a/editors/awk.c
+++ b/editors/awk.c
@@ -1812,6 +1812,18 @@ static void handle_special(var *v)
                 is_f0_split = FALSE;
 
         } else if (v == intvar[FS]) {
+                /*
+                 * The POSIX-2008 standard says that changing FS should have no effect on the
+                 * current input line, but only on the next one. The language is:
+                 *
+                 * > Before the first reference to a field in the record is evaluated, the record
+                 * > shall be split into fields, according to the rules in Regular Expressions,
+                 * > using the value of FS that was current at the time the record was read.
+                 *
+                 * So, split up current line before assignment to FS:
+                 */
+                split_f0();
+
                 mk_splitter(getvar_s(v), &fsplitter);
 
         } else if (v == intvar[RS]) {