From 1727f7fe35a32302d9bdd2653f1c556263153406 Mon Sep 17 00:00:00 2001
From: Shaisolaris <66793913+Shaisolaris@users.noreply.github.com>
Date: Sun, 11 Oct 2026 22:51:51 -0700
Subject: [PATCH] Skip leading newlines before applying the limit in paragraph
 mode gets

---
 ext/java/org/jruby/ext/stringio/StringIO.java | 17 ++++++++++------
 ext/stringio/stringio.c                       | 19 +++++++++++-------
 test/stringio/test_stringio.rb                | 20 +++++++++++++++++++
 3 files changed, 43 insertions(+), 13 deletions(-)

diff --git a/ext/java/org/jruby/ext/stringio/StringIO.java b/ext/java/org/jruby/ext/stringio/StringIO.java
index 85bb955..72599e5 100644
--- a/ext/java/org/jruby/ext/stringio/StringIO.java
+++ b/ext/java/org/jruby/ext/stringio/StringIO.java
@@ -895,6 +895,17 @@ private IRubyObject getline(ThreadContext context, final IRubyObject rs, int lim
             int p;
             int w = 0;
 
+            if (rs != context.nil && ((RubyString) rs).size() == 0) {
+                // paragraph mode: skip leading newlines before applying the limit
+                p = s;
+                while (stringBytes[p] == '\n') {
+                    if (++p == e) {
+                        ptr.pos = e - begin;
+                        return context.nil;
+                    }
+                }
+                s = p;
+            }
             if (limit > 0 && s + limit < e) {
                 e = getEncoding().rightAdjustCharHead(stringBytes, s, s + limit, e);
             }
@@ -906,12 +917,6 @@ private IRubyObject getline(ThreadContext context, final IRubyObject rs, int lim
             } else if ((n = ((RubyString) rs).size()) == 0) {
                 int paragraph_end = 0;
                 p = s;
-                while (stringBytes[p] == '\n') {
-                    if (++p == e) {
-                        return context.nil;
-                    }
-                }
-                s = p;
                 while ((p = Helpers.memchr(stringBytes, p, '\n', e - p)) != -1 && (p != e)) {
                     p++;
                     if (!((p < e && stringBytes[p] == '\n') ||
diff --git a/ext/stringio/stringio.c b/ext/stringio/stringio.c
index a689e6e..da4d1f1 100644
--- a/ext/stringio/stringio.c
+++ b/ext/stringio/stringio.c
@@ -1411,6 +1411,18 @@ strio_getline(struct getline_arg *arg, struct StringIO *ptr)
     s = RSTRING_PTR(ptr->string);
     e = s + RSTRING_LEN(ptr->string);
     s += ptr->pos;
+    if (!NIL_P(str) && RSTRING_LEN(str) == 0) {
+	/* paragraph mode: skip leading newlines before applying the limit */
+	p = s;
+	while (p[(p + 1 < e) && (*p == '\r') && 0] == '\n') {
+	    p += *p == '\r';
+	    if (++p == e) {
+		ptr->pos = e - RSTRING_PTR(ptr->string);
+		return Qnil;
+	    }
+	}
+	s = p;
+    }
     if (limit > 0 && (size_t)limit < (size_t)(e - s)) {
 	e = rb_enc_right_char_head(s, s + limit, e, get_enc(ptr));
     }
@@ -1423,13 +1435,6 @@ strio_getline(struct getline_arg *arg, struct StringIO *ptr)
     else if ((n = RSTRING_LEN(str)) == 0) {
 	const char *paragraph_end = NULL;
 	p = s;
-	while (p[(p + 1 < e) && (*p == '\r') && 0] == '\n') {
-	    p += *p == '\r';
-	    if (++p == e) {
-		return Qnil;
-	    }
-	}
-	s = p;
 	while ((p = memchr(p, '\n', e - p)) && (p != e)) {
 	    p++;
 	    if (!((p < e && *p == '\n') ||
diff --git a/test/stringio/test_stringio.rb b/test/stringio/test_stringio.rb
index fd88de5..7c947e8 100644
--- a/test/stringio/test_stringio.rb
+++ b/test/stringio/test_stringio.rb
@@ -143,6 +143,26 @@ def test_gets
     assert_string("", Encoding::UTF_8, StringIO.new("foo").gets(0))
   end
 
+  def test_gets_paragraph_with_limit
+    stringio = StringIO.new("a\n\n\n\nb\n\n\nc")
+    assert_equal("a", stringio.gets("", 1))
+    assert_equal("b", stringio.gets("", 1))
+    assert_equal("c", stringio.gets("", 1))
+    assert_nil(stringio.gets("", 1))
+
+    stringio = StringIO.new("a\n\n\n\nb")
+    assert_equal("a\n\n", stringio.gets("", 3))
+    assert_equal("b", stringio.gets("", 3))
+    assert_nil(stringio.gets("", 3))
+  end
+
+  def test_gets_paragraph_only_newlines
+    stringio = StringIO.new("\n\n\n")
+    assert_nil(stringio.gets(""))
+    assert_equal(3, stringio.pos)
+    assert_predicate(stringio, :eof?)
+  end
+
   def test_gets_utf_16
     stringio = StringIO.new("line1\nline2\nline3\n".encode("utf-16le"))
     assert_equal("line1\n".encode("utf-16le"), stringio.gets)