diff --git a/.github/workflows/mingw.yml b/.github/workflows/mingw.yml
index 8afa726334a90c..27e21e36389f77 100644
--- a/.github/workflows/mingw.yml
+++ b/.github/workflows/mingw.yml
@@ -44,7 +44,7 @@ jobs:
         ) }}
       MINGW_PACKAGE_PREFIX: >-
         mingw-w${{
-        endsWith(matrix.msystem, '64') && '64' || '32'
+        case(endsWith(matrix.msystem, '64'), '64', '32')
         }}-${{ case(
         startsWith(matrix.msystem, 'clang'), 'clang',
         startsWith(matrix.msystem, 'ucrt'), 'ucrt',
diff --git a/ext/zlib/zlib.c b/ext/zlib/zlib.c
index 7e319cae0de3cf..578ad108515d64 100644
--- a/ext/zlib/zlib.c
+++ b/ext/zlib/zlib.c
@@ -1094,8 +1094,9 @@ zstream_run_func(struct zstream_run_args *args)
             break;
         }
 
-        if (err != Z_OK && err != Z_BUF_ERROR)
+        if (err != Z_OK && err != Z_BUF_ERROR) {
             break;
+        }
 
         if (z->stream.avail_out > 0) {
             z->flags |= ZSTREAM_FLAG_IN_STREAM;
@@ -1170,12 +1171,17 @@ zstream_run_try(VALUE value_arg)
     /* retry if no exception is thrown */
     if (err == Z_OK && args->interrupt) {
        args->interrupt = 0;
-       goto loop;
+
+       /* Retry only if both avail_in > 0 (more input to process) and avail_out > 0
+        * (output buffer has space). If avail_out == 0, the buffer is full and should
+        * be consumed by the caller first. If avail_in == 0, there's nothing more to process. */
+       if (z->stream.avail_in > 0 && z->stream.avail_out > 0) {
+          goto loop;
+       }
     }
 
-    if (flush != Z_FINISH && err == Z_BUF_ERROR
-	    && z->stream.avail_out > 0) {
-	z->flags |= ZSTREAM_FLAG_IN_STREAM;
+    if (flush != Z_FINISH && err == Z_BUF_ERROR && z->stream.avail_out > 0) {
+        z->flags |= ZSTREAM_FLAG_IN_STREAM;
     }
 
     zstream_reset_input(z);
diff --git a/parse.y b/parse.y
index 6e0c610a7c4359..3a22c68d5df3eb 100644
--- a/parse.y
+++ b/parse.y
@@ -5008,12 +5008,6 @@ block_param	: f_arg ',' f_opt_arg(primary_value) ',' f_rest_arg opt_args_tail(bl
                         $$ = new_args(p, $1, 0, $3, 0, $4, &@$);
                     /*% ripper: params!($:1, Qnil, $:3, Qnil, *$:4[0..2]) %*/
                     }
-                | f_arg excessed_comma
-                    {
-                        $$ = new_args_tail(p, 0, 0, 0, &@2);
-                        $$ = new_args(p, $1, 0, $2, 0, $$, &@$);
-                    /*% ripper: params!($:1, Qnil, $:2, Qnil, Qnil, Qnil, Qnil) %*/
-                    }
                 | f_arg ',' f_rest_arg ',' f_arg opt_args_tail(block_args_tail)
                     {
                         $$ = new_args(p, $1, 0, $3, $5, $6, &@$);
@@ -5075,6 +5069,15 @@ block_param_def	: '|' opt_block_param opt_bv_decl '|'
                         $$ = $2;
                     /*% ripper: block_var!($:2, $:3) %*/
                     }
+                | '|' f_arg excessed_comma opt_bv_decl '|'
+                    {
+                        p->max_numparam = ORDINAL_PARAM;
+                        p->ctxt.in_argdef = 0;
+                        $$ = new_args_tail(p, 0, 0, 0, &@3);
+                        $$ = new_args(p, $2, 0, $3, 0, $$, &@$);
+                    /*% ripper: params!($:2, Qnil, $:3, Qnil, Qnil, Qnil, Qnil) %*/
+                    /*% ripper: block_var!($:$, $:4) %*/
+                    }
                 ;
 
 opt_block_param	: /* none */
diff --git a/test/zlib/test_zlib.rb b/test/zlib/test_zlib.rb
index bedf243b3e5919..5b0bf9c9807ce7 100644
--- a/test/zlib/test_zlib.rb
+++ b/test/zlib/test_zlib.rb
@@ -1266,6 +1266,36 @@ def test_gzfile_read_size_boundary
         end
       }
     end
+
+    # Test for signal interrupt bug: Z_BUF_ERROR with avail_out > 0
+    # This reproduces the issue where thread wakeup during GzipReader operations
+    # can cause Z_BUF_ERROR to be raised incorrectly
+    def test_thread_wakeup_interrupt
+      pend 'fails' if RUBY_ENGINE == 'truffleruby'
+      content = SecureRandom.base64(5000)
+      gzipped = Zlib.gzip(content)
+
+      1000.times do
+        thr = Thread.new do
+          loop do
+            Zlib::GzipReader.new(StringIO.new(gzipped)).read
+          end
+        end
+
+        # Wakeup the thread multiple times to trigger interrupts
+        10.times do
+          thr.wakeup
+          Thread.pass
+        end
+
+        # Give thread a moment to process
+        sleep 0.001
+
+        # Clean up
+        thr.kill
+        thr.join
+      end
+    end
   end
 
   class TestZlibGzipWriter < Test::Unit::TestCase
@@ -1534,5 +1564,36 @@ def test_gunzip_no_memory_leak
         10_000.times {Zlib.gunzip(d)}
       };
     end
+
+    # Test for signal interrupt bug: Z_BUF_ERROR with avail_out > 0
+    # This reproduces the issue where thread wakeup during GzipReader operations
+    # can cause Z_BUF_ERROR to be raised incorrectly
+    def test_thread_wakeup_interrupt
+      pend 'fails' if RUBY_ENGINE == 'truffleruby'
+
+      content = SecureRandom.base64(5000)
+      gzipped = Zlib.gzip(content)
+
+      1000.times do
+        thr = Thread.new do
+          loop do
+            Zlib::GzipReader.new(StringIO.new(gzipped)).read
+          end
+        end
+
+        # Wakeup the thread multiple times to trigger interrupts
+        10.times do
+          thr.wakeup
+          Thread.pass
+        end
+
+        # Give thread a moment to process
+        sleep 0.001
+
+        # Clean up
+        thr.kill
+        thr.join
+      end
+    end
   end
 end