Improve MaskOutput dimension consistency (#7591)

## Summary

This PR fixes an issue with mask dimension consistency. Prior to this
change, the following workflow would fail with `tuple out of range`
error:

<img width="1072" alt="image"
src="https://github.com/user-attachments/assets/d0a9e658-1d64-4db4-adee-973bbdaca745"
/>

### Before this PR

Dimension compatibility for invocations that take a mask input:
- `ApplyMaskTensorToImageInvocation`: 2 or 3
- `MaskTensorToImageInvocation`: 2 or 3
- `InvertTensorMaskInvocation`: 3

Mask dimension for invocations that produce a MaskOutput:
- `RectangleMaskInvocation`: 3
- `AlphaMaskToTensorInvocation`: 3
- `InvertTensorMaskInvocation`: 3
- `ImageMaskToTensorInvocation`: 3
- `SegmentAnythingInvocation`: 2

### After this PR (changes in bold)

Dimension compatibility for invocations that take a mask input:
- `ApplyMaskTensorToImageInvocation`: 2 or 3
- `MaskTensorToImageInvocation`: 2 or 3
- `InvertTensorMaskInvocation`: **2 or 3** <----------------

Mask dimension for invocations that produce a MaskOutput:
- `RectangleMaskInvocation`: 3
- `AlphaMaskToTensorInvocation`: 3
- `InvertTensorMaskInvocation`: 3
- `ImageMaskToTensorInvocation`: 3
- `SegmentAnythingInvocation`: **3** <-------------------


## QA Instructions

I tested the workflow in the PR description and this workflow:
<img width="872" alt="image"
src="https://github.com/user-attachments/assets/20496860-ce81-47c0-a46a-a611b73faa22"
/>


## Merge Plan

No special instructions.

## Checklist

- [x] _The PR has a short but descriptive title, suitable for a
changelog_
- [x] _Tests added / updated (if applicable)_
- [x] _Documentation added / updated (if applicable)_
- [ ] _Updated `What's New` copy (if doing a release after this PR)_

invokeai/app/invocations/mask.py

@@ -86,7 +86,7 @@ def invoke(self, context: InvocationContext) -> MaskOutput:
     title="Invert Tensor Mask",
     tags=["conditioning"],
     category="conditioning",
-    version="1.0.0",
+    version="1.1.0",
     classification=Classification.Beta,
 )
 class InvertTensorMaskInvocation(BaseInvocation):
@@ -96,6 +96,15 @@ class InvertTensorMaskInvocation(BaseInvocation):
 
     def invoke(self, context: InvocationContext) -> MaskOutput:
         mask = context.tensors.load(self.mask.tensor_name)
+
+        # Verify dtype and shape.
+        assert mask.dtype == torch.bool
+        assert mask.dim() in [2, 3]
+
+        # Unsqueeze the channel dimension if it is missing. The MaskOutput type expects a single channel.
+        if mask.dim() == 2:
+            mask = mask.unsqueeze(0)
+
         inverted = ~mask
 
         return MaskOutput(

invokeai/app/invocations/primitives.py

@@ -416,6 +416,7 @@ def invoke(self, context: InvocationContext) -> ColorOutput:
 class MaskOutput(BaseInvocationOutput):
     """A torch mask tensor."""
 
+    # shape: [1, H, W], dtype: bool
     mask: TensorField = OutputField(description="The mask.")
     width: int = OutputField(description="The width of the mask in pixels.")
     height: int = OutputField(description="The height of the mask in pixels.")

invokeai/app/invocations/segment_anything.py

@@ -49,7 +49,7 @@ def to_list(self) -> list[list[int]]:
     title="Segment Anything",
     tags=["prompt", "segmentation"],
     category="segmentation",
-    version="1.1.0",
+    version="1.2.0",
 )
 class SegmentAnythingInvocation(BaseInvocation):
     """Runs a Segment Anything Model."""
@@ -96,8 +96,10 @@ def invoke(self, context: InvocationContext) -> MaskOutput:
             # masks contains bool values, so we merge them via max-reduce.
             combined_mask, _ = torch.stack(masks).max(dim=0)
 
+        # Unsqueeze the channel dimension.
+        combined_mask = combined_mask.unsqueeze(0)
         mask_tensor_name = context.tensors.save(combined_mask)
-        height, width = combined_mask.shape
+        _, height, width = combined_mask.shape
         return MaskOutput(mask=TensorField(tensor_name=mask_tensor_name), width=width, height=height)
 
     @staticmethod

invokeai/frontend/web/src/services/api/schema.ts

@@ -7716,11 +7716,6 @@ export type components = {
          * @description Gets the bounding box of the given mask image.
          */
         GetMaskBoundingBoxInvocation: {
-            /**
-             * @description Optional metadata to be saved with the image
-             * @default null
-             */
-            metadata?: components["schemas"]["MetadataField"] | null;
             /**
              * Id
              * @description The id of this instance of an invocation. Must be unique among all instances of invocations.