Implementation:AUTOMATIC1111 Stable diffusion webui CheckpointInfo

Knowledge Sources	stable-diffusion-webui
Domains	Model Management, Checkpoint Merging, Reproducibility
Last Updated	2026-02-08 00:00 GMT

Overview

Concrete tool for representing and identifying model checkpoints provided by stable-diffusion-webui.

Description

The CheckpointInfo class encapsulates all identifying information about a Stable Diffusion model checkpoint file. Upon construction, it computes a legacy hash, reads SHA-256 from cache, derives a 10-character shorthash, resolves the display name relative to the model directory, extracts safetensors metadata, and registers the checkpoint under all of its aliases in the global checkpoints_list and checkpoint_aliases dictionaries. The companion function get_closet_checkpoint_match resolves a user-provided search string to a CheckpointInfo instance through exact alias lookup followed by substring matching.

Usage

Use CheckpointInfo when loading or referencing model checkpoints prior to merging. Use get_closet_checkpoint_match to resolve user-provided model identifiers (from UI dropdowns or API calls) to their corresponding checkpoint objects.

Code Reference

Source Location

• Repository: stable-diffusion-webui
• File: modules/sd_models.py
• Lines: L56-128 (CheckpointInfo class), L153-177 (list_models), L183-200 (get_closet_checkpoint_match)

Signature

class CheckpointInfo:
    def __init__(self, filename):
        ...

    def register(self):
        ...

    def calculate_shorthash(self):
        ...

def get_closet_checkpoint_match(search_string):
    ...

Import

from modules import sd_models
# or directly:
from modules.sd_models import CheckpointInfo, get_closet_checkpoint_match

I/O Contract

Inputs

CheckpointInfo.__init__:

Name	Type	Required	Description
filename	str	Yes	Absolute or relative path to the checkpoint file (.ckpt or .safetensors)

get_closet_checkpoint_match:

Name	Type	Required	Description
search_string	str	Yes	A model identifier: name, title, hash, shorthash, or substring of title

Outputs

CheckpointInfo.__init__:

Name	Type	Description
(instance)	CheckpointInfo	Object with properties: filename, name, name_for_extra, model_name, hash, sha256, shorthash, title, short_title, ids, metadata, is_safetensors

get_closet_checkpoint_match:

Name	Type	Description
return	CheckpointInfo or None	The matching checkpoint info, or None if no match found

Properties

Property	Type	Description
filename	str	Original filename passed to the constructor
name	str	Relative name within the model directory (e.g., v1-5-pruned.safetensors)
name_for_extra	str	Base filename without extension for display purposes
model_name	str	Sanitized name with path separators replaced by underscores, without extension
hash	str	Legacy model hash (partial file hash)
sha256	str or None	Full SHA-256 hex digest from cache, or None if not yet computed
shorthash	str or None	First 10 characters of sha256, or None
title	str	Display title: "name [shorthash]" or just name if shorthash is unavailable
short_title	str	Short display title using name_for_extra
ids	list[str]	All aliases under which this checkpoint is registered
metadata	dict	Metadata extracted from safetensors header (empty dict for .ckpt files)
is_safetensors	bool	Whether the file uses safetensors format

Usage Examples

Basic Usage

from modules.sd_models import CheckpointInfo, get_closet_checkpoint_match

# Create a CheckpointInfo from a file path
info = CheckpointInfo("/models/Stable-diffusion/v1-5-pruned-emaonly.safetensors")
print(info.title)       # "v1-5-pruned-emaonly.safetensors [6ce0161689]"
print(info.shorthash)   # "6ce0161689"
print(info.sha256)      # full SHA-256 hex string
info.register()         # adds to global checkpoints_list and checkpoint_aliases

# Look up a checkpoint by search string
match = get_closet_checkpoint_match("v1-5-pruned")
if match:
    print(match.filename)

Lookup Priority

# 1. Exact alias match (O(1) dict lookup)
match = get_closet_checkpoint_match("6ce0161689")  # by shorthash

# 2. Substring match on title (sorted by title length)
match = get_closet_checkpoint_match("v1-5")

# 3. Substring match after stripping checksum bracket suffix
match = get_closet_checkpoint_match("v1-5-pruned [abc123]")

Related Pages

Implements Principle

• Principle:AUTOMATIC1111_Stable_diffusion_webui_Checkpoint_model_selection