[LLaDA2] address review findings from #13598

Fixes the six in-scope issues raised in the llada2 model/pipeline review:

1. Carry tokenizer `attention_mask` through `_prepare_input_ids` and add an
   `attention_mask` arg to `__call__` for pre-tokenized inputs. The runtime
   mask now reflects prompt padding and zeros out the block-aligned tail
   past `prompt_length + gen_length` instead of treating those positions
   as valid context.

2. Thread the per-call `block_length` into `BlockRefinementScheduler.set_timesteps`
   so the transfer schedule matches the requested block size (previously the
   scheduler only read its constructor default).

3. Drop `x0`/`x0_p`/`confidence` from `_callback_tensor_inputs` (never bound
   locals) and bind `sampled_tokens`, `sampled_probs`, `editing_transfer_index`,
   `active_block` so all advertised callback keys resolve.

4. Allow EOS exactly at index `prompt_length` (the first generated position)
   to mark a row finished.

5. Freeze rows that have already emitted EOS so subsequent block refinement
   doesn't extend them, and trim per-row at decode (previously gated on
   batch_size==1) so post-EOS positions don't leak into decoded text.

6. Stop calling `self.set_progress_bar_config(...)` from inside `__call__`;
   build a local config dict for the inner block bar so user-supplied flags
   (in particular `disable=True`) survive the call.

Adds regression tests pinning each of the six fixes.

Author: kashif

src/diffusers/pipelines/llada2/pipeline_llada2.py

@@ -71,7 +71,14 @@ class LLaDA2Pipeline(DiffusionPipeline):
     scheduler: BlockRefinementScheduler
     tokenizer: Any
 
-    _callback_tensor_inputs = ["block_x", "x0", "x0_p", "transfer_index", "confidence", "active_block"]
+    _callback_tensor_inputs = [
+        "block_x",
+        "transfer_index",
+        "editing_transfer_index",
+        "sampled_tokens",
+        "sampled_probs",
+        "active_block",
+    ]
 
     def __init__(
         self,
@@ -99,16 +106,28 @@ def _prepare_input_ids(
         use_chat_template: bool,
         add_generation_prompt: bool,
         chat_template_kwargs: dict[str, Any] | None,
-    ) -> torch.LongTensor:
-        """Convert prompt/messages/input_ids to a [batch, seq] LongTensor."""
+        attention_mask: torch.LongTensor | None = None,
+    ) -> tuple[torch.LongTensor, torch.LongTensor]:
+        """Convert prompt/messages/input_ids to `(input_ids, attention_mask)` tensors of shape `[batch, seq]`."""
         if input_ids is not None:
             if input_ids.ndim == 1:
                 input_ids = input_ids.unsqueeze(0)
             if input_ids.ndim != 2:
                 raise ValueError(f"`input_ids` must be 2D, got shape {tuple(input_ids.shape)}.")
             if input_ids.dtype != torch.long:
                 raise ValueError(f"`input_ids` must be int64 token IDs, got dtype={input_ids.dtype}.")
-            return input_ids
+            if attention_mask is None:
+                attention_mask = torch.ones_like(input_ids, dtype=torch.long)
+            else:
+                if attention_mask.ndim == 1:
+                    attention_mask = attention_mask.unsqueeze(0)
+                if attention_mask.shape != input_ids.shape:
+                    raise ValueError(
+                        f"`attention_mask` shape {tuple(attention_mask.shape)} must match `input_ids` shape "
+                        f"{tuple(input_ids.shape)}."
+                    )
+                attention_mask = attention_mask.to(dtype=torch.long)
+            return input_ids, attention_mask
 
         if self.tokenizer is None:
             raise ValueError("Tokenizer is required when `input_ids` is not provided.")
@@ -129,7 +148,11 @@ def _prepare_input_ids(
                 return_dict=True,
                 **chat_template_kwargs,
             )
-            return encoded["input_ids"]
+            ids = encoded["input_ids"]
+            mask = encoded.get("attention_mask")
+            if mask is None:
+                mask = torch.ones_like(ids, dtype=torch.long)
+            return ids, mask.to(dtype=torch.long)
 
         if use_chat_template and getattr(self.tokenizer, "chat_template", None):
             if isinstance(prompt, list):
@@ -142,10 +165,18 @@ def _prepare_input_ids(
                 return_dict=True,
                 **chat_template_kwargs,
             )
-            return encoded["input_ids"]
+            ids = encoded["input_ids"]
+            mask = encoded.get("attention_mask")
+            if mask is None:
+                mask = torch.ones_like(ids, dtype=torch.long)
+            return ids, mask.to(dtype=torch.long)
 
         encoded = self.tokenizer(prompt, return_tensors="pt", padding=isinstance(prompt, list))
-        return encoded["input_ids"]
+        ids = encoded["input_ids"]
+        mask = encoded.get("attention_mask")
+        if mask is None:
+            mask = torch.ones_like(ids, dtype=torch.long)
+        return ids, mask.to(dtype=torch.long)
 
     def check_inputs(
         self,
@@ -215,6 +246,7 @@ def __call__(
         prompt: str | list[str] | None = None,
         messages: list[dict[str, str]] | None = None,
         input_ids: torch.LongTensor | None = None,
+        attention_mask: torch.LongTensor | None = None,
         use_chat_template: bool = True,
         add_generation_prompt: bool = True,
         gen_length: int = 2048,
@@ -252,6 +284,11 @@ def __call__(
                 when provided. Requires a tokenizer with `apply_chat_template`.
             input_ids (`torch.LongTensor`, *optional*):
                 Pre-tokenized input IDs. Takes precedence over `prompt` and `messages`.
+            attention_mask (`torch.LongTensor`, *optional*):
+                Per-token mask (1 for valid prompt tokens, 0 for padding) matching the shape of `input_ids`. Only used
+                when `input_ids` is provided. When omitted (and `input_ids` is given), all positions are treated as
+                valid. When constructing inputs from `prompt` / `messages`, the tokenizer's mask is carried through
+                automatically.
             use_chat_template (`bool`, defaults to `True`):
                 Whether to wrap the prompt in a chat template.
             add_generation_prompt (`bool`, defaults to `True`):
@@ -299,8 +336,8 @@ def __call__(
                 Callback executed after each refinement step with signature `callback_on_step_end(self, step: int,
                 timestep: int, callback_kwargs: Dict)`.
             callback_on_step_end_tensor_inputs (`List[str]`, *optional*):
-                Tensor keys to pass to the callback. Allowed keys: `block_x`, `x0`, `x0_p`, `transfer_index`,
-                `confidence`, `active_block`.
+                Tensor keys to pass to the callback. Allowed keys: `block_x`, `transfer_index`,
+                `editing_transfer_index`, `sampled_tokens`, `sampled_probs`, `active_block`.
 
         Examples:
         """
@@ -328,10 +365,11 @@ def __call__(
         )
 
         # 2. Prepare input IDs from prompt/messages/input_ids
-        prompt_ids = self._prepare_input_ids(
+        prompt_ids, prompt_attention_mask = self._prepare_input_ids(
             prompt=prompt,
             messages=messages,
             input_ids=input_ids,
+            attention_mask=attention_mask,
             use_chat_template=use_chat_template,
             add_generation_prompt=add_generation_prompt,
             chat_template_kwargs=None,
@@ -342,6 +380,7 @@ def __call__(
         if prompt_ids.ndim == 1:
             prompt_ids = prompt_ids.unsqueeze(0)
         prompt_ids = prompt_ids.to(device=device)
+        prompt_attention_mask = prompt_attention_mask.to(device=device)
         batch_size, prompt_length = prompt_ids.shape
 
         if eos_token_id is None:
@@ -353,14 +392,18 @@ def __call__(
 
         num_inference_steps = min(num_inference_steps, gen_length // minimal_topk)
 
-        self.scheduler.set_timesteps(num_inference_steps, device=device)
+        self.scheduler.set_timesteps(num_inference_steps, device=device, block_length=block_length)
 
         # 3. Build attention mask and position IDs
         num_blocks = (prompt_length + gen_length + block_length - 1) // block_length
         total_length = num_blocks * block_length
 
-        # 2D attention mask (no padding) — the model handles backend-specific conversion internally.
-        attn_mask = torch.ones((batch_size, total_length), device=device, dtype=torch.long)
+        # 2D attention mask: prompt tokenizer mask + ones over generated positions + zeros over the
+        # block-aligned tail past `prompt_length + gen_length`. The model handles backend-specific
+        # conversion internally; this just tells it which positions are real context.
+        attn_mask = torch.zeros((batch_size, total_length), device=device, dtype=torch.long)
+        attn_mask[:, :prompt_length] = prompt_attention_mask
+        attn_mask[:, prompt_length : prompt_length + gen_length] = 1
 
         position_ids = torch.arange(total_length, device=device, dtype=torch.long).unsqueeze(0).expand(batch_size, -1)
 
@@ -377,9 +420,8 @@ def __call__(
         global_step = 0
 
         # 5. Block-wise refinement loop
-        block_progress_bar_config = getattr(self, "_progress_bar_config", {}).copy()
-        block_progress_bar_config["position"] = 0
-        block_progress_bar_config["desc"] = "Blocks"
+        outer_progress_bar_config = getattr(self, "_progress_bar_config", {}).copy()
+        block_progress_bar_config = {**outer_progress_bar_config, "position": 0, "desc": "Blocks"}
         for num_block in tqdm(range(prefill_blocks, num_blocks), **block_progress_bar_config):
             current_window_end = (num_block + 1) * block_length
             block_x = x[:, :current_window_end]
@@ -396,8 +438,13 @@ def __call__(
             post_steps = 0
             step_idx = 0
             should_continue = True
-            self.set_progress_bar_config(position=1, leave=False, desc=f"Block {num_block} Inference Steps")
-            progress_bar = self.progress_bar(total=num_inference_steps)
+            inner_progress_bar_config = {
+                **outer_progress_bar_config,
+                "position": 1,
+                "leave": False,
+                "desc": f"Block {num_block} Inference Steps",
+            }
+            progress_bar = tqdm(total=num_inference_steps, **inner_progress_bar_config)
 
             while should_continue:
                 block_tokens = block_x[:, -block_length:]
@@ -428,10 +475,19 @@ def __call__(
 
                 transfer_index = scheduler_output.transfer_index
                 editing_transfer_index = scheduler_output.editing_transfer_index
+                sampled_tokens = scheduler_output.sampled_tokens
+                sampled_probs = scheduler_output.sampled_probs
+                active_block = block_tokens == mask_token_id
                 final_transfer = transfer_index | editing_transfer_index
 
+                # Freeze rows that already emitted EOS so further blocks don't extend them.
+                if eos_early_stop and finished.any():
+                    final_transfer = final_transfer & ~finished[:, None]
+
                 if final_transfer.any():
-                    block_x[:, -block_length:] = scheduler_output.prev_sample
+                    block_x[:, -block_length:] = torch.where(
+                        final_transfer, scheduler_output.prev_sample, block_tokens
+                    )
 
                 if eos_early_stop and eos_token_id is not None:
                     finished = self.scheduler.check_eos_finished(
@@ -474,14 +530,21 @@ def __call__(
         # 6. Post-process output
         generated = x[:, : prompt_length + gen_length]
         sequences = generated[:, prompt_length:]
-        if eos_token_id is not None and batch_size == 1:
-            eos_positions = (sequences[0] == eos_token_id).nonzero(as_tuple=True)[0]
-            if len(eos_positions) > 0:
-                sequences = sequences[:, : int(eos_positions[0].item()) + 1]
+
+        # For decode, trim each row at the first EOS so post-EOS positions (which may still hold
+        # mask tokens or refined content for unfinished blocks) don't leak into the decoded text.
+        decode_sequences: list[torch.LongTensor] | torch.LongTensor = sequences
+        if eos_token_id is not None:
+            decode_sequences = [
+                seq[: int((seq == eos_token_id).nonzero(as_tuple=True)[0][0]) + 1]
+                if (seq == eos_token_id).any()
+                else seq
+                for seq in sequences
+            ]
 
         texts = None
         if output_type == "text" and self.tokenizer is not None:
-            texts = self.tokenizer.batch_decode(sequences, skip_special_tokens=True)
+            texts = self.tokenizer.batch_decode(decode_sequences, skip_special_tokens=True)
 
         if not return_dict:
             return sequences.to(device=device), texts

src/diffusers/schedulers/scheduling_block_refinement.py

@@ -75,12 +75,21 @@ def __init__(
         self.timesteps = torch.arange(self.num_inference_steps - 1, -1, -1, dtype=torch.long)
         self._transfer_schedule: torch.LongTensor | None = None
 
-    def set_timesteps(self, num_inference_steps: int, device: str | torch.device | None = None) -> None:
+    def set_timesteps(
+        self,
+        num_inference_steps: int,
+        device: str | torch.device | None = None,
+        block_length: int | None = None,
+    ) -> None:
         if num_inference_steps <= 0:
             raise ValueError(f"`num_inference_steps` must be > 0, got {num_inference_steps}.")
+        if block_length is None:
+            block_length = self.config.block_length
+        elif block_length <= 0:
+            raise ValueError(f"`block_length` must be > 0, got {block_length}.")
         self.num_inference_steps = num_inference_steps
         self.timesteps = torch.arange(self.num_inference_steps - 1, -1, -1, device=device, dtype=torch.long)
-        self._transfer_schedule = self.get_num_transfer_tokens(self.config.block_length, self.num_inference_steps).to(
+        self._transfer_schedule = self.get_num_transfer_tokens(block_length, self.num_inference_steps).to(
             device=device if device is not None else "cpu"
         )
 
@@ -343,7 +352,8 @@ def check_eos_finished(
             if len(eos_pos[0]) == 0:
                 continue
             eos_pos = int(eos_pos[0][0].item())
-            if prompt_length >= eos_pos:
+            # The first generated token sits at index `prompt_length`; allow EOS there.
+            if eos_pos < prompt_length:
                 continue
             if (cur_x[b, prompt_length:eos_pos] != mask_token_id).all().item():
                 finished[b] = True