perl-5.11.2 breaks NYTProf savesrc option (Lexer API suspected)

Tim Bunce wrote:
>The primary issue is the off-by-one error in the array indexing.

There's a bit more to it than that.  The indexing was off-by-one for
*some* places that process a new line, but correct for others, so the
saved source as a whole was mangled rather than simply offset.  Also,
there were some redundant calls to update_debugger_info(), so some lines
got saved twice, in some cases off-by-one for one saving and not for
the other.  The saved source is, therefore, hopelessly broken in 5.11.2.

Attached patch fixes the source saving.  Includes a new test, which works
through all reachable places that source lines get saved.  This should
close RT #70804.

-zefram

2 files changed, 51 insertions, 0 deletions

diff --git a/t/comp/line_debug.t b/t/comp/line_debug.t
new file mode 100644
index 0000000000..175c71a65e
--- /dev/null
+++ b/t/comp/line_debug.t
@@ -0,0 +1,31 @@
+#!./perl
+
+chdir 't' if -d 't';
+
+sub ok {
+    my($test,$ok) = @_;
+    print "not " unless $ok;
+    print "ok $test\n";
+}
+
+# The auxiliary file contains a bunch of code that systematically exercises
+# every place that can call lex_next_chunk() (except for the one that's not
+# used by the main Perl parser).
+open AUX, "<", "comp/line_debug_0.aux" or die $!;
+my @lines = <AUX>;
+close AUX;
+my $nlines = @lines;
+
+print "1..", 2+$nlines, "\n";
+
+$^P = 0x2;
+do "comp/line_debug_0.aux";
+
+ok 1, scalar(@{"_<comp/line_debug_0.aux"}) == 1+$nlines;
+ok 2, !defined(${"_<comp/line_debug_0.aux"}[0]);
+
+for(1..$nlines) {
+	ok 2+$_, ${"_<comp/line_debug_0.aux"}[$_] eq $lines[$_-1];
+}
+
+1;
diff --git a/t/comp/line_debug_0.aux b/t/comp/line_debug_0.aux
new file mode 100644
index 0000000000..2d31d747aa
--- /dev/null
+++ b/t/comp/line_debug_0.aux
@@ -0,0 +1,20 @@
+$z = 'line one';
+$z
+    =
+    'multiline statement';
+$z = 'line five';
+$z = '
+    multiline
+    string
+';
+$z = 'line ten';
+$z = <<EOS;
+    multiline
+    heredoc
+EOS
+$z = 'line fifteen';
+format Z =
+    @<<<< multiline format
+    $z
+.
+$z = 'line twenty';