sed: deal with peculiar behavior of '2d;2,1p' in GNU sed

function                                             old     new   delta
process_files                                       2173    2120     -53

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

2 files changed, 16 insertions, 12 deletions

diff --git a/editors/sed.c b/editors/sed.c
index 2127301d5..ed12e4336 100644
--- a/editors/sed.c
+++ b/editors/sed.c
@@ -894,12 +894,13 @@ static void process_files(void)
                         || (!sed_cmd->beg_line && !sed_cmd->end_line
                                 && !sed_cmd->beg_match && !sed_cmd->end_match)
                         /* Or did we match the start of a numerical range? */
-                        || (sed_cmd->beg_line > 0 && (sed_cmd->beg_line == linenum
-                                                        /* "shadowed beginning" case: "1d;1,ENDp" - p still matches at line 2
-                                                         * even though 1d skipped line 1 which is a start line for p */
-                                                        || (sed_cmd->end_line && sed_cmd->beg_line < linenum && sed_cmd->end_line >= linenum)
-                                                        || (sed_cmd->end_match && sed_cmd->beg_line < linenum)
-                                                )
+                        || (sed_cmd->beg_line > 0
+                            && (sed_cmd->beg_line == linenum
+                               /* GNU sed compat:
+                                * "shadowed beginning" case: "1d;1,ENDp" - p still matches at line 2
+                                * even though 1d skipped line 1 which is a start line for p */
+                               || (sed_cmd->beg_line < linenum && (sed_cmd->end_line > 0 || sed_cmd->end_match))
+                               )
                         )
                         /* Or does this line match our begin address regex? */
                         || (beg_match(sed_cmd, pattern_space))
@@ -928,12 +929,10 @@ static void process_files(void)
                                      && (regexec(sed_cmd->end_match,
                                                  pattern_space, 0, NULL, 0) == 0)
                                 );
-                                if (n && sed_cmd->beg_line > 0) {
-                                        /* Once matched, "n,regex" range is dead, disabling it */
-                                        regfree(sed_cmd->end_match);
-                                        free(sed_cmd->end_match);
-                                        sed_cmd->end_match = NULL;
-                                }
+                        }
+                        if (n && sed_cmd->beg_line > 0) {
+                                /* once matched, "n,xxx" range is dead, disabling it */
+                                sed_cmd->beg_line = -2;
                         }
                         sed_cmd->in_match = !n;
                 }
diff --git a/testsuite/sed.tests b/testsuite/sed.tests
index 8af156ae9..677303be1 100755
--- a/testsuite/sed.tests
+++ b/testsuite/sed.tests
@@ -220,4 +220,9 @@ testing "sed d does not break n,regex matching #2" \
         "second2\nthird2\n" "" \
         "first\nsecond\nthird\nfourth\n""first2\nsecond2\nthird2\nfourth2\n"
 
+testing "sed 2d;2,1p (gnu compat)" \
+        "sed -n '2d;2,1p'" \
+        "third\n" "" \
+        "first\nsecond\nthird\nfourth\n"
+
 exit $FAILCOUNT