proc.c: assume rb_iseq_location_t::first_lineno is always availablewip-topic/thread-fix-start-with-empty-iseq

rb_iseq_location_t::first_lineno (typically referenced as
iseq->body->location.first_lineno, where iseq is an rb_iseq_t *) can
always be assumed to contain a Fixnum regardless of whether struct
rb_iseq_constant_body::line_info_table (likewise,
iseq->body->line_info_table) is NULL or non-NULL.

This fixes TypeError on starting a new thread with an empty Proc with
trace instructions disabled. The TypeError comes from thread_pthread.c,
in native_set_thread_name(), where it expects the line number returned
from rb_proc_location(). The number can be nil if the line_info_table is
NULL. The check seems to be the remains from the days before the
dedicated 'first_lineno' field was introduced. So remove it.

This also modifies two other places, Proc#to_s and method redefinition
code, in the same way.

2 files changed, 7 insertions, 14 deletions

diff --git a/proc.c b/proc.c
index d72e1a9254..1cc36a083c 100644
--- a/proc.c
+++ b/proc.c
@@ -1076,12 +1076,8 @@ iseq_location(const rb_iseq_t *iseq)
     if (!iseq) return Qnil;
     rb_iseq_check(iseq);
     loc[0] = iseq->body->location.path;
-    if (iseq->body->line_info_table) {
-	loc[1] = rb_iseq_first_lineno(iseq);
-    }
-    else {
-	loc[1] = Qnil;
-    }
+    loc[1] = iseq->body->location.first_lineno;
+
     return rb_ary_new4(2, loc);
 }
 
@@ -1234,12 +1230,9 @@ proc_to_s_(VALUE self, const rb_proc_t *proc)
       case block_type_iseq:
 	{
 	    const rb_iseq_t *iseq = rb_iseq_check(block->as.captured.code.iseq);
-	    int first_lineno = 0;
-	    if (iseq->body->line_info_table) {
-		first_lineno = FIX2INT(rb_iseq_first_lineno(iseq));
-	    }
 	    str = rb_sprintf("#<%s:%p@%"PRIsVALUE":%d%s>", cname, (void *)self,
-			     iseq->body->location.path, first_lineno, is_lambda);
+			     iseq->body->location.path,
+			     FIX2INT(iseq->body->location.first_lineno), is_lambda);
 	}
 	break;
       case block_type_symbol:
diff --git a/vm_method.c b/vm_method.c
index 33e90cf9f1..8aea9b54cc 100644
--- a/vm_method.c
+++ b/vm_method.c
@@ -563,9 +563,9 @@ rb_method_entry_make(VALUE klass, ID mid, VALUE defined_class, rb_method_visibil
 	      default:
 		break;
 	    }
-	    if (iseq && !NIL_P(iseq->body->location.path)) {
-		int line = iseq->body->line_info_table ? FIX2INT(rb_iseq_first_lineno(iseq)) : 0;
-		rb_compile_warning(RSTRING_PTR(iseq->body->location.path), line,
+	    if (iseq) {
+		rb_compile_warning(RSTRING_PTR(iseq->body->location.path),
+				   FIX2INT(iseq->body->location.first_lineno),
 				   "previous definition of %"PRIsVALUE" was here",
 				   rb_id2str(old_def->original_id));
 	    }