fix: have inputs construct connections (#7116)

* fix: have inputs construct connections

* chore: fix build hopefully

* fix: PR comments

core/block.ts

@@ -1568,13 +1568,7 @@ export class Block implements IASTNodeLocation, IDeletable {
    * @returns The input object created.
    */
   appendValueInput(name: string): Input {
-    return this.appendInput(
-      new ValueInput(
-        name,
-        this,
-        this.makeConnection_(ConnectionType.INPUT_VALUE)
-      )
-    );
+    return this.appendInput(new ValueInput(name, this));
   }
 
   /**
@@ -1586,13 +1580,7 @@ export class Block implements IASTNodeLocation, IDeletable {
    */
   appendStatementInput(name: string): Input {
     this.statementInputCount++;
-    return this.appendInput(
-      new StatementInput(
-        name,
-        this,
-        this.makeConnection_(ConnectionType.NEXT_STATEMENT)
-      )
-    );
+    return this.appendInput(new StatementInput(name, this));
   }
 
   /**
@@ -1632,7 +1620,7 @@ export class Block implements IASTNodeLocation, IDeletable {
       false
     );
     if (!inputConstructor) return null;
-    return this.appendInput(new inputConstructor(name, this, null));
+    return this.appendInput(new inputConstructor(name, this));
   }
 
   /**
@@ -2309,8 +2297,9 @@ export class Block implements IASTNodeLocation, IDeletable {
    *
    * @param type The type of the connection to create.
    * @returns A new connection of the specified type.
+   * @internal
    */
-  protected makeConnection_(type: number): Connection {
+  makeConnection_(type: ConnectionType): Connection {
     return new Connection(this, type);
   }
 

core/block_svg.ts

@@ -1474,8 +1474,9 @@ export class BlockSvg
    *
    * @param type The type of the connection to create.
    * @returns A new connection of the specified type.
+   * @internal
    */
-  protected override makeConnection_(type: number): RenderedConnection {
+  override makeConnection_(type: ConnectionType): RenderedConnection {
     return new RenderedConnection(this, type);
   }
 

core/inputs/dummy_input.ts

@@ -18,6 +18,6 @@ export class DummyInput extends Input {
    * @param block The block containing this input.
    */
   constructor(public name: string, block: Block) {
-    super(name, block, null);
+    super(name, block);
   }
 }

core/inputs/input.ts

@@ -18,6 +18,7 @@ import '../field_label.js';
 import type {Block} from '../block.js';
 import type {BlockSvg} from '../block_svg.js';
 import type {Connection} from '../connection.js';
+import type {ConnectionType} from '../connection_type.js';
 import type {Field} from '../field.js';
 import * as fieldRegistry from '../field_registry.js';
 import type {RenderedConnection} from '../rendered_connection.js';
@@ -36,19 +37,14 @@ export class Input {
 
   public readonly type: inputTypes = inputTypes.CUSTOM;
 
+  public connection: Connection | null = null;
+
   /**
    * @param name Language-neutral identifier which may used to find this input
    *     again.
    * @param sourceBlock The block containing this input.
-   * @param connection Optional connection for this input. If this is a custom
-   *     input, `null` will always be passed, and then the subclass can
-   *     optionally construct a connection.
    */
-  constructor(
-    public name: string,
-    private sourceBlock: Block,
-    public connection: Connection | null
-  ) {}
+  constructor(public name: string, private sourceBlock: Block) {}
 
   /**
    * Get the source block for this input.
@@ -296,6 +292,18 @@ export class Input {
       this.connection.dispose();
     }
   }
+
+  /**
+   * Constructs a connection based on the type of this input's source block.
+   * Properly handles constructing headless connections for headless blocks
+   * and rendered connections for rendered blocks.
+   *
+   * @returns a connection of the given type, which is either a headless
+   *     or rendered connection, based on the type of this input's source block.
+   */
+  protected makeConnection(type: ConnectionType): Connection {
+    return this.sourceBlock.makeConnection_(type);
+  }
 }
 
 export namespace Input {

core/inputs/statement_input.ts

@@ -6,6 +6,7 @@
 
 import type {Block} from '../block.js';
 import type {Connection} from '../connection.js';
+import {ConnectionType} from '../connection_type.js';
 import {Input} from './input.js';
 import {inputTypes} from './input_types.js';
 
@@ -13,20 +14,18 @@ import {inputTypes} from './input_types.js';
 export class StatementInput extends Input {
   readonly type = inputTypes.STATEMENT;
 
+  public connection: Connection;
+
   /**
    * @param name Language-neutral identifier which may used to find this input
    *     again.
    * @param block The block containing this input.
-   * @param connection The statement connection for this input.
    */
-  constructor(
-    public name: string,
-    block: Block,
-    public connection: Connection
-  ) {
+  constructor(public name: string, block: Block) {
     // Errors are maintained for people not using typescript.
     if (!name) throw new Error('Statement inputs must have a non-empty name');
-    if (!connection) throw new Error('Value inputs must have a connection');
-    super(name, block, connection);
+
+    super(name, block);
+    this.connection = this.makeConnection(ConnectionType.NEXT_STATEMENT);
   }
 }

core/inputs/value_input.ts

@@ -5,7 +5,7 @@
  */
 
 import type {Block} from '../block.js';
-import type {Connection} from '../connection.js';
+import {ConnectionType} from '../connection_type.js';
 import {Input} from './input.js';
 import {inputTypes} from './input_types.js';
 
@@ -17,16 +17,11 @@ export class ValueInput extends Input {
    * @param name Language-neutral identifier which may used to find this input
    *     again.
    * @param block The block containing this input.
-   * @param connection The value connection for this input.
    */
-  constructor(
-    public name: string,
-    block: Block,
-    public connection: Connection
-  ) {
+  constructor(public name: string, block: Block) {
     // Errors are maintained for people not using typescript.
     if (!name) throw new Error('Value inputs must have a non-empty name');
-    if (!connection) throw new Error('Value inputs must have a connection');
-    super(name, block, connection);
+    super(name, block);
+    this.connection = this.makeConnection(ConnectionType.INPUT_VALUE);
   }
 }