feat: 补全 /place structure 的结构注册，使其与自然生成一致

原版 PlaceCommand.placeStructure 只调 StructureStart.placeInChunk 摆放方块，从不把 StructureStart 注册进 StructureManager / 区块 StructureAccess，导致结构重启丢失、专属刷怪规则不激活。

新增 PlaceCommandMixin，在 placeStructure 返回前补做自然生成的三步：1) setStartForStructure 把 start 存进所在区块；2) createReferences 写 17x17 邻居引用；3) markUnsaved 强制存盘。全程 try-catch 兜底，注册失败不影响命令返回。

项目骨架参照 CarpetSLSAddition：Loom 1.18-SNAPSHOT + Gradle 9.7.1 + Java 25 + official 映射。

.gitignore

@@ -0,0 +1,30 @@
+# Gradle
+.gradle/
+build/
+!gradle/wrapper/gradle-wrapper.jar
+!**/src/main/**/build/
+!**/src/test/**/build/
+
+# Loom / Fabric
+run/
+remappedSrc/
+.loom-cache/
+
+# IDE
+.idea/
+*.ipr
+*.iws
+*.iml
+.vscode/
+*.launch
+.settings/
+.project
+.classpath
+bin/
+
+# macOS / Windows
+.DS_Store
+Thumbs.db
+
+# Logs
+*.log

build.gradle

@@ -0,0 +1,69 @@
+plugins {
+	id 'net.fabricmc.fabric-loom' version "${loom_version}"
+	id 'maven-publish'
+}
+
+version = project.mod_version
+group = project.maven_group
+
+base {
+	archivesName = project.archives_base_name
+}
+
+repositories {
+	maven {
+		url = "https://maven.fabricmc.net/"
+	}
+	maven {
+		url = "https://oss.sonatype.org/content/repositories/snapshots"
+	}
+}
+
+dependencies {
+	// To change the versions see the gradle.properties file
+	minecraft "com.mojang:minecraft:${project.minecraft_version}"
+	implementation "net.fabricmc:fabric-loader:${project.loader_version}"
+
+	// Fabric API
+	implementation "net.fabricmc.fabric-api:fabric-api:${project.fabric_version}"
+}
+
+processResources {
+	def modVersion = project.version
+	inputs.property "version", modVersion
+
+	filesMatching("fabric.mod.json") {
+		expand "version": modVersion
+	}
+}
+
+tasks.withType(JavaCompile).configureEach {
+	// Minecraft 26.1 and upwards uses Java 25.
+	it.options.release = 25
+}
+
+java {
+	withSourcesJar()
+
+	sourceCompatibility = JavaVersion.VERSION_25
+	targetCompatibility = JavaVersion.VERSION_25
+}
+
+jar {
+	def baseName = project.base.archivesName.get()
+	from("LICENSE") {
+		rename { "${it}_${baseName}"}
+	}
+}
+
+publishing {
+	publications {
+		mavenJava(MavenPublication) {
+			from components.java
+		}
+	}
+
+	repositories {
+		// Add repositories to publish to here.
+	}
+}

gradle.properties

@@ -0,0 +1,18 @@
+# Done to increase the memory available to gradle.
+org.gradle.jvmargs=-Xmx3G
+org.gradle.parallel=true
+org.gradle.configuration-cache=true
+
+# Fabric Properties
+# check these on https://fabricmc.net/develop
+minecraft_version=26.1.2
+loader_version=0.19.5
+loom_version=1.18-SNAPSHOT
+
+# Mod Properties
+mod_version=0.1
+maven_group=com.github.axtps
+archives_base_name=minecraft-place-mod
+
+# Dependencies
+fabric_version=0.155.3+26.1.2

gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,7 @@
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-9.7.1-bin.zip
+networkTimeout=10000
+validateDistributionUrl=true
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists

gradlew

@@ -0,0 +1,248 @@
+#!/bin/sh
+
+#
+# Copyright © 2015 the original authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#      https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+#
+# SPDX-License-Identifier: Apache-2.0
+#
+
+##############################################################################
+#
+#   gradlew start up script for POSIX generated by Gradle.
+#
+#   Important for running:
+#
+#   (1) You need a POSIX-compliant shell to run this script. If your /bin/sh is
+#       noncompliant, but you have some other compliant shell such as ksh or
+#       bash, then to run this script, type that shell name before the whole
+#       command line, like:
+#
+#           ksh gradlew
+#
+#       Busybox and similar reduced shells will NOT work, because this script
+#       requires all of these POSIX shell features:
+#         * functions;
+#         * expansions «$var», «${var}», «${var:-default}», «${var+SET}»,
+#           «${var#prefix}», «${var%suffix}», and «$( cmd )»;
+#         * compound commands having a testable exit status, especially «case»;
+#         * various built-in commands including «command», «set», and «ulimit».
+#
+#   Important for patching:
+#
+#   (2) This script targets any POSIX shell, so it avoids extensions provided
+#       by Bash, Ksh, etc; in particular arrays are avoided.
+#
+#       The "traditional" practice of packing multiple parameters into a
+#       space-separated string is a well documented source of bugs and security
+#       problems, so this is (mostly) avoided, by progressively accumulating
+#       options in "$@", and eventually passing that to Java.
+#
+#       Where the inherited environment variables (DEFAULT_JVM_OPTS, JAVA_OPTS,
+#       and GRADLE_OPTS) rely on word-splitting, this is performed explicitly;
+#       see the in-line comments for details.
+#
+#       There are tweaks for specific operating systems such as AIX, CygWin,
+#       Darwin, MinGW, and NonStop.
+#
+#   (3) This script is generated from the Groovy template
+#       https://github.com/gradle/gradle/blob/3d91ce3b8caaf77ad09f381f43615b715b53f72c/platforms/jvm/plugins-application/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       within the Gradle project.
+#
+#       You can find Gradle at https://github.com/gradle/gradle/.
+#
+##############################################################################
+
+# Attempt to set APP_HOME
+
+# Resolve links: $0 may be a link
+app_path=$0
+
+# Need this for daisy-chained symlinks.
+while
+    APP_HOME=${app_path%"${app_path##*/}"}  # leaves a trailing /; empty if no leading path
+    [ -h "$app_path" ]
+do
+    ls=$( ls -ld "$app_path" )
+    link=${ls#*' -> '}
+    case $link in             #(
+      /*)   app_path=$link ;; #(
+      *)    app_path=$APP_HOME$link ;;
+    esac
+done
+
+# This is normally unused
+# shellcheck disable=SC2034
+APP_BASE_NAME=${0##*/}
+# Discard cd standard output in case $CDPATH is set (https://github.com/gradle/gradle/issues/25036)
+APP_HOME=$( cd -P "${APP_HOME:-./}" > /dev/null && printf '%s\n' "$PWD" ) || exit
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD=maximum
+
+warn () {
+    echo "$*"
+} >&2
+
+die () {
+    echo
+    echo "$*"
+    echo
+    exit 1
+} >&2
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+nonstop=false
+case "$( uname )" in                #(
+  CYGWIN* )         cygwin=true  ;; #(
+  Darwin* )         darwin=true  ;; #(
+  MSYS* | MINGW* )  msys=true    ;; #(
+  NONSTOP* )        nonstop=true ;;
+esac
+
+
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD=$JAVA_HOME/jre/sh/java
+    else
+        JAVACMD=$JAVA_HOME/bin/java
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD=java
+    if ! command -v java >/dev/null 2>&1
+    then
+        die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+fi
+
+# Increase the maximum file descriptors if we can.
+if ! "$cygwin" && ! "$darwin" && ! "$nonstop" ; then
+    case $MAX_FD in #(
+      max*)
+        # In POSIX sh, ulimit -H is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC2039,SC3045
+        MAX_FD=$( ulimit -H -n ) ||
+            warn "Could not query maximum file descriptor limit"
+    esac
+    case $MAX_FD in  #(
+      '' | soft) :;; #(
+      *)
+        # In POSIX sh, ulimit -n is undefined. That's why the result is checked to see if it worked.
+        # shellcheck disable=SC2039,SC3045
+        ulimit -n "$MAX_FD" ||
+            warn "Could not set maximum file descriptor limit to $MAX_FD"
+    esac
+fi
+
+# Collect all arguments for the java command, stacking in reverse order:
+#   * args from the command line
+#   * the main class name
+#   * -classpath
+#   * -D...appname settings
+#   * --module-path (only if needed)
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and GRADLE_OPTS environment variables.
+
+# For Cygwin or MSYS, switch paths to Windows format before running java
+if "$cygwin" || "$msys" ; then
+    APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
+
+    JAVACMD=$( cygpath --unix "$JAVACMD" )
+
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    for arg do
+        if
+            case $arg in                                #(
+              -*)   false ;;                            # don't mess with options #(
+              /?*)  t=${arg#/} t=/${t%%/*}              # looks like a POSIX filepath
+                    [ -e "$t" ] ;;                      #(
+              *)    false ;;
+            esac
+        then
+            arg=$( cygpath --path --ignore --mixed "$arg" )
+        fi
+        # Roll the args list around exactly as many times as the number of
+        # args, so each arg winds up back in the position where it started, but
+        # possibly modified.
+        #
+        # NB: a `for` loop captures its iteration list before it begins, so
+        # changing the positional parameters here affects neither the number of
+        # iterations, nor the values presented in `arg`.
+        shift                   # remove old arg
+        set -- "$@" "$arg"      # push replacement arg
+    done
+fi
+
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
+
+# Collect all arguments for the java command:
+#   * DEFAULT_JVM_OPTS, JAVA_OPTS, and optsEnvironmentVar are not allowed to contain shell fragments,
+#     and any embedded shellness will be escaped.
+#   * For example: A user cannot expect ${Hostname} to be expanded, as it is an environment variable and will be
+#     treated as '${Hostname}' itself on the command line.
+
+set -- \
+        "-Dorg.gradle.appname=$APP_BASE_NAME" \
+        -jar "$APP_HOME/gradle/wrapper/gradle-wrapper.jar" \
+        "$@"
+
+# Stop when "xargs" is not available.
+if ! command -v xargs >/dev/null 2>&1
+then
+    die "xargs is not available"
+fi
+
+# Use "xargs" to parse quoted args.
+#
+# With -n1 it outputs one arg per line, with the quotes and backslashes removed.
+#
+# In Bash we could simply go:
+#
+#   readarray ARGS < <( xargs -n1 <<<"$var" ) &&
+#   set -- "${ARGS[@]}" "$@"
+#
+# but POSIX shell has neither arrays nor command substitution, so instead we
+# post-process each arg (as a line of input to sed) to backslash-escape any
+# character that might be a shell metacharacter, then use eval to reverse
+# that process (while maintaining the separation between arguments), and wrap
+# the whole thing up as a single "set" statement.
+#
+# This will of course break if any of these variables contains a newline or
+# an unmatched quote.
+#
+
+eval "set -- $(
+        printf '%s\n' "$DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS" |
+        xargs -n1 |
+        sed ' s~[^-[:alnum:]+,./:=@_]~\\&~g; ' |
+        tr '\n' ' '
+    )" '"$@"'
+
+exec "$JAVACMD" "$@"

gradlew.bat

@@ -0,0 +1,82 @@
+@rem
+@rem Copyright 2015 the original author or authors.
+@rem
+@rem Licensed under the Apache License, Version 2.0 (the "License");
+@rem you may not use this file except in compliance with the License.
+@rem You may obtain a copy of the License at
+@rem
+@rem      https://www.apache.org/licenses/LICENSE-2.0
+@rem
+@rem Unless required by applicable law or agreed to in writing, software
+@rem distributed under the License is distributed on an "AS IS" BASIS,
+@rem WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+@rem See the License for the specific language governing permissions and
+@rem limitations under the License.
+@rem
+@rem SPDX-License-Identifier: Apache-2.0
+@rem
+
+@if "%DEBUG%"=="" @echo off
+@rem ##########################################################################
+@rem
+@rem  gradlew startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables, and ensure extensions are enabled
+setlocal EnableExtensions
+
+set DIRNAME=%~dp0
+if "%DIRNAME%"=="" set DIRNAME=.
+@rem This is normally unused
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Resolve any "." and ".." in APP_HOME to make it shorter.
+for %%i in ("%APP_HOME%") do set APP_HOME=%%~fi
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS="-Xmx64m" "-Xms64m"
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if %ERRORLEVEL% equ 0 goto execute
+
+echo. 1>&2
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH. 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
+
+"%COMSPEC%" /c exit 1
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto execute
+
+echo. 1>&2
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME% 1>&2
+echo. 1>&2
+echo Please set the JAVA_HOME variable in your environment to match the 1>&2
+echo location of your Java installation. 1>&2
+
+"%COMSPEC%" /c exit 1
+
+:execute
+@rem Setup the command line
+
+
+
+@rem Execute gradlew
+@rem endlocal doesn't take effect until after the line is parsed and variables are expanded
+@rem which allows us to clear the local environment before executing the java command
+endlocal & "%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -jar "%APP_HOME%\gradle\wrapper\gradle-wrapper.jar" %* & call :exitWithErrorLevel
+
+:exitWithErrorLevel
+@rem Use "%COMSPEC%" /c exit to allow operators to work properly in scripts
+"%COMSPEC%" /c exit %ERRORLEVEL%

settings.gradle

@@ -0,0 +1,12 @@
+pluginManagement {
+	repositories {
+		maven {
+			name = 'Fabric'
+			url = 'https://maven.fabricmc.net/'
+		}
+		mavenCentral()
+		gradlePluginPortal()
+	}
+}
+
+rootProject.name = 'minecraft-place-mod'

src/main/java/com/github/axtps/placemod/PlaceMod.java

@@ -0,0 +1,15 @@
+package com.github.axtps.placemod;
+
+import net.fabricmc.api.ModInitializer;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+public class PlaceMod implements ModInitializer {
+	public static final String MOD_ID = "minecraft-place-mod";
+	public static final Logger LOGGER = LoggerFactory.getLogger(MOD_ID);
+
+	@Override
+	public void onInitialize() {
+		LOGGER.info("Minecraft Place Mod initialized.");
+	}
+}

src/main/java/com/github/axtps/placemod/mixin/PlaceCommandMixin.java

@@ -0,0 +1,88 @@
+package com.github.axtps.placemod.mixin;
+
+import com.github.axtps.placemod.PlaceMod;
+import net.minecraft.core.SectionPos;
+import net.minecraft.server.commands.PlaceCommand;
+import net.minecraft.server.level.ServerLevel;
+import net.minecraft.world.level.ChunkPos;
+import net.minecraft.world.level.StructureManager;
+import net.minecraft.world.level.chunk.ChunkAccess;
+import net.minecraft.world.level.chunk.ChunkGenerator;
+import net.minecraft.world.level.levelgen.structure.BoundingBox;
+import net.minecraft.world.level.levelgen.structure.Structure;
+import net.minecraft.world.level.levelgen.structure.StructureStart;
+import org.spongepowered.asm.mixin.Mixin;
+import org.spongepowered.asm.mixin.injection.At;
+import org.spongepowered.asm.mixin.injection.Inject;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
+import org.spongepowered.asm.mixin.injection.callback.LocalCapture;
+
+/**
+ * 让 /place structure 生成的结构"跟自然生成一样"。
+ *
+ * 原版 PlaceCommand.placeStructure 只调了 StructureStart.placeInChunk 摆放方块，
+ * 从不把 StructureStart 注册进 StructureManager / 区块 StructureAccess。
+ * 结果：结构不进 StructureManager、不写区块 NBT 引用 → 重启丢失、专属刷怪规则不激活。
+ *
+ * 本 Mixin 在 placeStructure 返回前，补做自然生成的注册步骤：
+ *   1. 对结构所在区块 setStartForStructure，把 start 存进区块；
+ *   2. 调 ChunkGenerator.createReferences 写周围区块引用（跟自然生成同款逻辑）；
+ *   3. markUnsaved 标记涉及的区块，强制存盘。
+ */
+@Mixin(PlaceCommand.class)
+public class PlaceCommandMixin {
+
+	@Inject(method = "placeStructure", at = @At("RETURN"), locals = LocalCapture.CAPTURE_FAILHARD)
+	private static void placemod$registerStructure(net.minecraft.commands.CommandSourceStack source,
+												   net.minecraft.core.Holder.Reference<Structure> structureHolder,
+												   net.minecraft.core.BlockPos pos,
+												   CallbackInfo ci,
+												   ServerLevel level,
+												   Structure structure,
+												   ChunkGenerator generator,
+												   StructureStart start) {
+		if (start == null || !start.isValid()) {
+			return;
+		}
+
+		try {
+			StructureManager structureManager = level.structureManager();
+			BoundingBox box = start.getBoundingBox();
+
+			// 结构包围盒覆盖的区块范围
+			ChunkPos minChunk = new ChunkPos(
+					SectionPos.blockToSectionCoord(box.minX()),
+					SectionPos.blockToSectionCoord(box.minZ()));
+			ChunkPos maxChunk = new ChunkPos(
+					SectionPos.blockToSectionCoord(box.maxX()),
+					SectionPos.blockToSectionCoord(box.maxZ()));
+
+			// 1) 把 StructureStart 存进它自己所在的区块
+			//    （自然生成在 ChunkGenerator.createStructures 里做）
+			ChunkPos startChunk = start.getChunkPos();
+			ChunkAccess startChunkAccess = level.getChunk(startChunk.x(), startChunk.z());
+			structureManager.setStartForStructure(
+					SectionPos.bottomOf(startChunkAccess), structure, start, startChunkAccess);
+			startChunkAccess.markUnsaved();
+
+			// 2) 引用写入：对涉及的每个区块调 createReferences，
+			//    它内部会扫 17x17 邻居，把相交的 StructureStart 引用写进区块。
+			//    跟自然生成用的是同一个方法，保证"完全一样"。
+			ChunkPos.rangeClosed(minChunk, maxChunk).forEach(cp -> {
+				ChunkAccess chunk = level.getChunk(cp.x(), cp.z());
+				try {
+					generator.createReferences(level, structureManager, chunk);
+					chunk.markUnsaved();
+				} catch (Exception e) {
+					PlaceMod.LOGGER.error("[place-mod] createReferences 失败 @ {}: {}", cp, e.toString());
+				}
+			});
+
+			PlaceMod.LOGGER.info("[place-mod] 已为结构 {} 补注册 StructureStart @ {}",
+					structure, startChunk);
+		} catch (Throwable t) {
+			// 注册失败不能影响命令本身的成功返回
+			PlaceMod.LOGGER.error("[place-mod] 补注册结构时出错（已忽略）: ", t);
+		}
+	}
+}

src/main/resources/fabric.mod.json

@@ -0,0 +1,31 @@
+{
+	"schemaVersion": 1,
+	"id": "minecraft-place-mod",
+	"version": "${version}",
+	"name": "Minecraft Place Mod",
+	"description": "A mod which promotes the /place command — makes /place structure-generated structures behave exactly like naturally generated ones (registered into StructureManager, persisted to chunk NBT).",
+	"authors": [
+		"ApTx2012"
+	],
+	"contact": {
+		"homepage": "https://github.com/ApTx2012/Minecraft-place-mod",
+		"sources": "https://github.com/ApTx2012/Minecraft-place-mod"
+	},
+	"license": "MIT",
+	"icon": "assets/minecraft-place-mod/icon.png",
+	"environment": "*",
+	"entrypoints": {
+		"main": [
+			"com.github.axtps.placemod.PlaceMod"
+		]
+	},
+	"mixins": [
+		"minecraft-place-mod.mixins.json"
+	],
+	"depends": {
+		"fabricloader": ">=0.19.5",
+		"minecraft": "~26.1.2",
+		"java": ">=25",
+		"fabric-api": "*"
+	}
+}

src/main/resources/minecraft-place-mod.mixins.json

@@ -0,0 +1,11 @@
+{
+	"required": true,
+	"package": "com.github.axtps.placemod.mixin",
+	"compatibilityLevel": "JAVA_21",
+	"mixins": [
+		"PlaceCommandMixin"
+	],
+	"injectors": {
+		"defaultRequire": 1
+	}
+}