1.21.1 - 1.2.0

Brings the rule editor up to date with 26.1.2 - 1.4.1.

Rule Editor

• Added client.config.RuleFormat — how a config line maps to the fields of a RuleType. RuleFormat.PIPE is the previous positional format; mods can now edit other syntaxes (prefixes, key=value pairs, lines saved in an older layout) and provide their own cross-field checks and row summaries.
• Added the field kinds BLOCK, CUSTOM (a picker whose options the mod provides by Field.source()), CHOICE and TOGGLE (buttons instead of text inputs).
• Added client.config.RegistrySuggestionSource — a RuleSuggestionSource backed by RegistryCandidates, which mods extend for their CUSTOM fields.
• Added Field.asInline() — a field shares a row with the field before it when there's room, instead of always getting its own row.
• Added Field.withFallback(String) — an empty value shows (and summarizes as) the fallback instead of blank.
• Added Field.withIcon(ResourceLocation) — a TOGGLE field can be a small icon button without its own label.
• Added Field.withRowLabel(String) — labels the row with a different field.<name> translation, for fields (e.g. several icon toggles) that share one label.
• RuleEditScreen rows now sit in a scrolling list, so a rule can have any number of fields.
• Added Copy and Paste buttons that round-trip a rule line through the clipboard; pasted text is validated before it replaces the open rule's values.
• Number inputs and buttons are sized to fit their largest value; pickers share what's left of the row.
• A picker's resolved name shows inline at the end of its input when it fits.
• RuleListScreen can take an EntryPicker to add several entries at once next to the Add button.
• RuleListScreen.withDefaults adds a Reset button.
• RuleListScreen rows wrap long summaries and rule lines instead of cutting them off, show the raw saved line as a hover tooltip, and the list sizes itself to the widest entry (between 308px and 560px).
• RuleSuggestionSource.Option can have an icon, shown in the suggestion list.
• Long explanations under the screen titles are cut off with the full text on hover.
• Fixed a crash in RuleType.validate when a min/max field pair was optional and left empty, and ATTRIBUTE_VALUE fields assuming the attribute is the line's second field.

Differences from 26.1.2

• 1.21.1 lists can't size rows individually, so all RuleListScreen rows are as tall as the tallest entry needs, and RuleEditScreen rows all get room for a note when any field is an ATTRIBUTE_VALUE.
• RuleListScreen.subtitle takes the Screen that shows the tooltip as its first parameter.

Breaking Changes

• RuleSuggestionSource now takes the RuleType.Field (and the line's current values where they matter) instead of a Kind and a context string.

1.21.1 - 1.1.0

New Utilities

• Added util.ModCompat.isLoaded(String modId) — a one-line check for whether another mod is loaded, replacing hand-rolled per-mod loader enums.
• Added util.RomanNumeralUtil.generate(int) — converts an int to a Roman numeral string.

New Client Rendering Helpers

• Added client.util.PoseStackHelper.translateAndScale/rotateItem — common PoseStack transforms for drawing an ItemStack at an offset inside a block entity renderer.
• Added client.util.RenderingUtils.swing/flap/bob/walk — limb-animation math for ModelParts.

New Config/GUI Helpers

• Added client.config.RegistryCandidates — turns a built-in or datapack registry (entities, items, blocks, attributes, enchantments, biomes) into a searchable candidate list for EntryPickerScreen, including a fallback for datapack-driven registries (biomes, enchantments) when no world is loaded, e.g. editing config from the title screen.
• Added a second, heavier config-list editor for pipe-delimited, multi-field config rows: client.config.RuleType (field schema with per-field validation), RuleSuggestionSource (caller-supplied id lookups), RuleListContext (translation key prefixes), RuleListScreen and RuleEditScreen. This complements the existing append-only PickerListScreen for config lists that need several validated fields per row, edited in place.
• Added ConfigHelper.getOrDefault/ConfigHolder.getOrDefault — a guard that returns a fallback instead of throwing IllegalStateException when a config value is read before its spec is loaded (e.g. datagen or other contexts where no config file is ever loaded, such as a block's isEnabled(FeatureFlagSet) check running under the loot table provider).

Internal Cleanup

• No breaking changes to existing public APIs.