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-rw-r--r--editors/awk.c33
-rwxr-xr-xtestsuite/awk.tests7
2 files changed, 32 insertions, 8 deletions
diff --git a/editors/awk.c b/editors/awk.c
index d56d6330d..2c15f9e4e 100644
--- a/editors/awk.c
+++ b/editors/awk.c
@@ -1763,6 +1763,29 @@ static void fsrealloc(int size)
nfields = size;
}
+static int regexec1_nonempty(const regex_t *preg, const char *s, regmatch_t pmatch[])
+{
+ int r = regexec(preg, s, 1, pmatch, 0);
+ if (r == 0 && pmatch[0].rm_eo == 0) {
+ /* For example, happens when FS can match
+ * an empty string (awk -F ' *'). Logically,
+ * this should split into one-char fields.
+ * However, gawk 5.0.1 searches for first
+ * _non-empty_ separator string match:
+ */
+ size_t ofs = 0;
+ do {
+ ofs++;
+ if (!s[ofs])
+ return REG_NOMATCH;
+ regexec(preg, s + ofs, 1, pmatch, 0);
+ } while (pmatch[0].rm_eo == 0);
+ pmatch[0].rm_so += ofs;
+ pmatch[0].rm_eo += ofs;
+ }
+ return r;
+}
+
static int awk_split(const char *s, node *spl, char **slist)
{
int n;
@@ -1788,17 +1811,11 @@ static int awk_split(const char *s, node *spl, char **slist)
regmatch_t pmatch[2]; // TODO: why [2]? [1] is enough...
l = strcspn(s, c+2); /* len till next NUL or \n */
- if (regexec(icase ? spl->r.ire : spl->l.re, s, 1, pmatch, 0) == 0
+ if (regexec1_nonempty(icase ? spl->r.ire : spl->l.re, s, pmatch) == 0
&& pmatch[0].rm_so <= l
) {
+ /* if (pmatch[0].rm_eo == 0) ... - impossible */
l = pmatch[0].rm_so;
- if (pmatch[0].rm_eo == 0) {
- /* For example, happens when FS can match
- * an empthy string (awk -F ' *')
- */
- l++;
- pmatch[0].rm_eo++;
- }
n++; /* we saw yet another delimiter */
} else {
pmatch[0].rm_eo = l;
diff --git a/testsuite/awk.tests b/testsuite/awk.tests
index 87f6b5007..06a531d96 100755
--- a/testsuite/awk.tests
+++ b/testsuite/awk.tests
@@ -398,5 +398,12 @@ testing 'awk do not allow "str"++' \
'' \
'anything'
+#gawk compat: FS regex matches only non-empty separators:
+#with -*, the splitting is NOT f o o b a r, but foo bar:
+testing 'awk FS regex which can match empty string' \
+ "awk -F '-*' '{print \$1 \"-\" \$2 \"=\" \$3 \"*\" \$4}'" \
+ "foo-bar=*\n" \
+ '' \
+ 'foo--bar'
exit $FAILCOUNT