14 files changed, 85 insertions, 21 deletions
diff --git a/.github/workflows/check_misc.yml b/.github/workflows/check_misc.yml
index 543c54a3c9..2d73e1771a 100644
--- a/.github/workflows/check_misc.yml
+++ b/.github/workflows/check_misc.yml
@@ -37,10 +37,10 @@ jobs:
           EMAIL: [email protected]
           GIT_AUTHOR_NAME: git
           GIT_COMMITTER_NAME: git
-          GITHUB_OLD_SHA: ${{ startsWith(github.event_name, 'pull') && github.event.pull_request.base.sha || github.event.before }}
-          GITHUB_NEW_SHA: ${{ startsWith(github.event_name, 'pull') && github.event.pull_request.merge_commit_sha || github.event.after }}
+          GITHUB_OLD_SHA: ${{ github.event.pull_request.base.sha }}
+          GITHUB_NEW_SHA: ${{ github.event.pull_request.merge_commit_sha }}
           PUSH_REF: ${{ github.ref == 'refs/heads/master' && github.ref || '' }}
-        if: ${{ github.repository == 'ruby/ruby' }}
+        if: ${{ github.repository == 'ruby/ruby' && startsWith(github.event_name, 'pull') }}
 
       - name: Check if C-sources are US-ASCII
         run: |
diff --git a/compile.c b/compile.c
index cbde124516..6bcfcd3398 100644
--- a/compile.c
+++ b/compile.c
@@ -13384,7 +13384,8 @@ outer_variable_cmp(const void *a, const void *b, void *arg)
 
     if (!ap->name) {
         return -1;
-    } else if (!bp->name) {
+    }
+    else if (!bp->name) {
         return 1;
     }
 
diff --git a/gc.c b/gc.c
index e920348a12..f0189294bd 100644
--- a/gc.c
+++ b/gc.c
@@ -3060,7 +3060,6 @@ rb_gc_mark_roots(void *objspace, const char **categoryp)
 
     MARK_CHECKPOINT("vm");
     rb_vm_mark(vm);
-    if (vm->self) gc_mark_internal(vm->self);
 
     MARK_CHECKPOINT("end_proc");
     rb_mark_end_proc();
diff --git a/hash.c b/hash.c
index be26e0eb3f..379dac814b 100644
--- a/hash.c
+++ b/hash.c
@@ -3872,7 +3872,6 @@ rb_hash_values(VALUE hash)
         }
         rb_ary_set_len(values, size);
     }
-
     else {
         rb_hash_foreach(hash, values_i, values);
     }
diff --git a/io_buffer.c b/io_buffer.c
index 40c12ef5c1..190b67d8ac 100644
--- a/io_buffer.c
+++ b/io_buffer.c
@@ -496,7 +496,9 @@ io_buffer_for_yield_instance(VALUE _arguments)
 
     arguments->instance = io_buffer_for_make_instance(arguments->klass, arguments->string, arguments->flags);
 
-    rb_str_locktmp(arguments->string);
+    if (!RB_OBJ_FROZEN(arguments->string)) {
+        rb_str_locktmp(arguments->string);
+    }
 
     return rb_yield(arguments->instance);
 }
@@ -510,7 +512,9 @@ io_buffer_for_yield_instance_ensure(VALUE _arguments)
         rb_io_buffer_free(arguments->instance);
     }
 
-    rb_str_unlocktmp(arguments->string);
+    if (!RB_OBJ_FROZEN(arguments->string)) {
+        rb_str_unlocktmp(arguments->string);
+    }
 
     return Qnil;
 }
diff --git a/proc.c b/proc.c
index 98aa10d59f..8543110476 100644
--- a/proc.c
+++ b/proc.c
@@ -1562,7 +1562,8 @@ rb_sym_to_proc(VALUE sym)
         RARRAY_ASET(sym_proc_cache, index, procval);
 
         return RB_GC_GUARD(procval);
-    } else {
+    }
+    else {
         return sym_proc_new(rb_cProc, sym);
     }
 }
diff --git a/re.c b/re.c
index e666a7c3d4..b47538d594 100644
--- a/re.c
+++ b/re.c
@@ -3507,7 +3507,8 @@ rb_reg_regcomp(VALUE str)
             return reg_cache;
 
         return reg_cache = rb_reg_new_str(str, 0);
-    } else {
+    }
+    else {
         return rb_reg_new_str(str, 0);
     }
 }
diff --git a/test/ruby/test_io_buffer.rb b/test/ruby/test_io_buffer.rb
index 55296c1f23..70c5ef061d 100644
--- a/test/ruby/test_io_buffer.rb
+++ b/test/ruby/test_io_buffer.rb
@@ -121,6 +121,16 @@ class TestIOBuffer < Test::Unit::TestCase
     end
   end
 
+  def test_string_mapped_buffer_frozen
+    string = "Hello World".freeze
+    IO::Buffer.for(string) do |buffer|
+      assert_raise IO::Buffer::AccessError, "Buffer is not writable!" do
+        buffer.set_string("abc")
+      end
+      assert_equal "H".ord, buffer.get_value(:U8, 0)
+    end
+  end
+
   def test_non_string
     not_string = Object.new
 
diff --git a/test/ruby/test_zjit.rb b/test/ruby/test_zjit.rb
index 7b582df2f5..d7249053e5 100644
--- a/test/ruby/test_zjit.rb
+++ b/test/ruby/test_zjit.rb
@@ -31,6 +31,20 @@ class TestZJIT < Test::Unit::TestCase
     }
   end
 
+  def test_putstring
+    assert_compiles '""', %q{
+      def test = "#{""}"
+      test
+    }, insns: [:putstring]
+  end
+
+  def test_putchilldedstring
+    assert_compiles '""', %q{
+      def test = ""
+      test
+    }, insns: [:putchilledstring]
+  end
+
   def test_leave_param
     assert_compiles '5', %q{
       def test(n) = n
diff --git a/thread.c b/thread.c
index 41bd6c9ec6..5575157728 100644
--- a/thread.c
+++ b/thread.c
@@ -6229,7 +6229,8 @@ threadptr_interrupt_exec_exec(rb_thread_t *th)
         if (task) {
             if (task->flags & rb_interrupt_exec_flag_new_thread) {
                 rb_thread_create(task->func, task->data);
-            } else {
+            }
+            else {
                 (*task->func)(task->data);
             }
             ruby_xfree(task);
diff --git a/tool/auto-style.rb b/tool/auto-style.rb
index d2b007bd51..25055ace7d 100644..100755
--- a/tool/auto-style.rb
+++ b/tool/auto-style.rb
@@ -69,7 +69,7 @@ class Git
   def git(*args)
     cmd = ['git', *args].shelljoin
     puts "+ #{cmd}"
-    unless with_clean_env { system(cmd) }
+    unless with_clean_env { system('git', *args) }
       abort "Failed to run: #{cmd}"
     end
   end
@@ -173,6 +173,10 @@ IGNORED_FILES = [
   %r{\Asample/trick[^/]*/},
 ]
 
+DIFFERENT_STYLE_FILES = %w[
+  addr2line.c io_buffer.c prism*.c scheduler.c
+]
+
 oldrev, newrev, pushref = ARGV
 unless dry_run = pushref.empty?
   branch = IO.popen(['git', 'rev-parse', '--symbolic', '--abbrev-ref', pushref], &:read).strip
@@ -194,7 +198,7 @@ if files.empty?
   exit
 end
 
-trailing = eofnewline = expandtab = false
+trailing = eofnewline = expandtab = indent = false
 
 edited_files = files.select do |f|
   src = File.binread(f) rescue next
@@ -202,6 +206,8 @@ edited_files = files.select do |f|
 
   trailing0 = false
   expandtab0 = false
+  indent0 = false
+
   src.gsub!(/^.*$/).with_index do |line, lineno|
     trailing = trailing0 = true if line.sub!(/[ \t]+$/, '')
     line
@@ -225,7 +231,15 @@ edited_files = files.select do |f|
     end
   end
 
-  if trailing0 or eofnewline0 or expandtab0
+  if File.fnmatch?("*.[ch]", f, File::FNM_PATHNAME) &&
+     !DIFFERENT_STYLE_FILES.any? {|pat| File.fnmatch?(pat, f, File::FNM_PATHNAME)}
+    src.gsub!(/^\w+\([^(\n)]*?\)\K[ \t]*(?=\{$)/, "\n")
+    src.gsub!(/^([ \t]*)\}\K[ \t]*(?=else\b)/, "\n" '\1')
+    src.gsub!(/^[ \t]*\}\n\K\n+(?=[ \t]*else\b)/, '')
+    indent = indent0 = true
+  end
+
+  if trailing0 or eofnewline0 or expandtab0 or indent0
     File.binwrite(f, src)
     true
   end
@@ -236,6 +250,7 @@ else
   msg = [('remove trailing spaces' if trailing),
          ('append newline at EOF' if eofnewline),
          ('expand tabs' if expandtab),
+         ('adjust indents' if indent),
         ].compact
   message = "* #{msg.join(', ')}. [ci skip]"
   if expandtab
diff --git a/vm.c b/vm.c
index 6f20d43ee4..7b0775fbb3 100644
--- a/vm.c
+++ b/vm.c
@@ -2982,6 +2982,7 @@ rb_vm_update_references(void *ptr)
     if (ptr) {
         rb_vm_t *vm = ptr;
 
+        vm->self = rb_gc_location(vm->self);
         vm->mark_object_ary = rb_gc_location(vm->mark_object_ary);
         vm->load_path = rb_gc_location(vm->load_path);
         vm->load_path_snapshot = rb_gc_location(vm->load_path_snapshot);
@@ -3068,6 +3069,8 @@ rb_vm_mark(void *ptr)
             rb_gc_mark_maybe(*list->varptr);
         }
 
+        rb_gc_mark_movable(vm->self);
+
         if (vm->main_namespace) {
             rb_namespace_entry_mark((void *)vm->main_namespace);
         }
diff --git a/zjit/src/codegen.rs b/zjit/src/codegen.rs
index 32ea9e1c15..286f3f39b4 100644
--- a/zjit/src/codegen.rs
+++ b/zjit/src/codegen.rs
@@ -252,6 +252,7 @@ fn gen_insn(cb: &mut CodeBlock, jit: &mut JITState, asm: &mut Assembler, functio
         Insn::NewArray { elements, state } => gen_new_array(jit, asm, elements, &function.frame_state(*state)),
         Insn::NewRange { low, high, flag, state } => gen_new_range(asm, opnd!(low), opnd!(high), *flag, &function.frame_state(*state)),
         Insn::ArrayDup { val, state } => gen_array_dup(asm, opnd!(val), &function.frame_state(*state)),
+        Insn::StringCopy { val, chilled } => gen_string_copy(asm, opnd!(val), *chilled),
         Insn::Param { idx } => unreachable!("block.insns should not have Insn::Param({idx})"),
         Insn::Snapshot { .. } => return Some(()), // we don't need to do anything for this instruction at the moment
         Insn::Jump(branch) => return gen_jump(jit, asm, branch),
@@ -611,6 +612,17 @@ fn gen_send_without_block_direct(
     Some(ret)
 }
 
+/// Compile a string resurrection
+fn gen_string_copy(asm: &mut Assembler, recv: Opnd, chilled: bool) -> Opnd {
+    asm_comment!(asm, "call rb_ec_str_resurrect");
+    // TODO: split rb_ec_str_resurrect into separate functions
+    let chilled = if chilled { Opnd::Imm(1) } else { Opnd::Imm(0) };
+    asm.ccall(
+        rb_ec_str_resurrect as *const u8,
+        vec![EC, recv, chilled],
+    )
+}
+
 /// Compile an array duplication instruction
 fn gen_array_dup(
     asm: &mut Assembler,
diff --git a/zjit/src/hir.rs b/zjit/src/hir.rs
index 17b4aad6cf..c67f25451a 100644
--- a/zjit/src/hir.rs
+++ b/zjit/src/hir.rs
@@ -396,7 +396,7 @@ pub enum Insn {
     /// SSA block parameter. Also used for function parameters in the function's entry block.
     Param { idx: usize },
 
-    StringCopy { val: InsnId },
+    StringCopy { val: InsnId, chilled: bool },
     StringIntern { val: InsnId },
 
     /// Put special object (VMCORE, CBASE, etc.) based on value_type
@@ -602,7 +602,7 @@ impl<'a> std::fmt::Display for InsnPrinter<'a> {
             Insn::ArraySet { array, idx, val } => { write!(f, "ArraySet {array}, {idx}, {val}") }
             Insn::ArrayDup { val, .. } => { write!(f, "ArrayDup {val}") }
             Insn::HashDup { val, .. } => { write!(f, "HashDup {val}") }
-            Insn::StringCopy { val } => { write!(f, "StringCopy {val}") }
+            Insn::StringCopy { val, .. } => { write!(f, "StringCopy {val}") }
             Insn::Test { val } => { write!(f, "Test {val}") }
             Insn::IsNil { val } => { write!(f, "IsNil {val}") }
             Insn::Jump(target) => { write!(f, "Jump {target}") }
@@ -978,7 +978,7 @@ impl Function {
                     }
                 },
             Return { val } => Return { val: find!(*val) },
-            StringCopy { val } => StringCopy { val: find!(*val) },
+            StringCopy { val, chilled } => StringCopy { val: find!(*val), chilled: *chilled },
             StringIntern { val } => StringIntern { val: find!(*val) },
             Test { val } => Test { val: find!(*val) },
             &IsNil { val } => IsNil { val: find!(val) },
@@ -1623,7 +1623,7 @@ impl Function {
                     worklist.push_back(high);
                     worklist.push_back(state);
                 }
-                Insn::StringCopy { val }
+                Insn::StringCopy { val, .. }
                 | Insn::StringIntern { val }
                 | Insn::Return { val }
                 | Insn::Defined { v: val, .. }
@@ -2142,10 +2142,14 @@ pub fn iseq_to_hir(iseq: *const rb_iseq_t) -> Result<Function, ParseError> {
                     let value_type = SpecialObjectType::from(get_arg(pc, 0).as_u32());
                     state.stack_push(fun.push_insn(block, Insn::PutSpecialObject { value_type }));
                 }
-                YARVINSN_putstring | YARVINSN_putchilledstring => {
-                    // TODO(max): Do something different for chilled string
+                YARVINSN_putstring => {
                     let val = fun.push_insn(block, Insn::Const { val: Const::Value(get_arg(pc, 0)) });
-                    let insn_id = fun.push_insn(block, Insn::StringCopy { val });
+                    let insn_id = fun.push_insn(block, Insn::StringCopy { val, chilled: false });
+                    state.stack_push(insn_id);
+                }
+                YARVINSN_putchilledstring => {
+                    let val = fun.push_insn(block, Insn::Const { val: Const::Value(get_arg(pc, 0)) });
+                    let insn_id = fun.push_insn(block, Insn::StringCopy { val, chilled: true });
                     state.stack_push(insn_id);
                 }
                 YARVINSN_putself => { state.stack_push(self_param); }