flutter 安装目录下面的.pub-cache目录
用户目录下面的.pub-cache目录

这两个看着差不多

都是存放了flutter package 什么的

具体什么区别？
怎么产生的？

从flutter命令开始查。

1、flutter命令过程

flutter xx
dart xxx

source "$BIN_DIR/internal/shared.sh"
shared::execute "$@"

function upgrade_flutter () (
  mkdir -p "$FLUTTER_ROOT/bin/cache"

  local revision="$(cd "$FLUTTER_ROOT"; git rev-parse HEAD)"
  local compilekey="$revision:$FLUTTER_TOOL_ARGS"

 
  if [[ ! -f "$SNAPSHOT_PATH" || ! -s "$STAMP_PATH" || "$(cat "$STAMP_PATH")" != "$compilekey" || "$FLUTTER_TOOLS_DIR/pubspec.yaml" -nt "$FLUTTER_TOOLS_DIR/pubspec.lock" ]]; then
    
    export PUB_ENVIRONMENT="$PUB_ENVIRONMENT:flutter_install"
    if [[ -d "$FLUTTER_ROOT/.pub-cache" ]]; then
      export PUB_CACHE="${PUB_CACHE:-"$FLUTTER_ROOT/.pub-cache"}"
    fi



    # Compile...
    "$DART" --verbosity=error 
    --disable-dart-dev 

    $FLUTTER_TOOL_ARGS 

    --snapshot="$SNAPSHOT_PATH" 

    --packages="$FLUTTER_TOOLS_DIR/.dart_tool/package_config.json" 

    --no-enable-mirrors "$SCRIPT_PATH"

    
    echo "$compilekey" > "$STAMP_PATH"
  fi 
  exit $?
)

    if [[ -d "$FLUTTER_ROOT/.pub-cache" ]]; then
      export PUB_CACHE="${PUB_CACHE:-"$FLUTTER_ROOT/.pub-cache"}"
    fi

搜索PUB_CACHE

  String? _getRootPubCacheIfAvailable() {
    if (_platform.environment.containsKey(_kPubCacheEnvironmentKey)) {
      return _platform.environment[_kPubCacheEnvironmentKey];
    }

    final String cachePath = _fileSystem.path.join(Cache.flutterRoot!, '.pub-cache');
    if (_fileSystem.directory(cachePath).existsSync()) {
      _logger.printTrace('Using $cachePath for the pub cache.');
      return cachePath;
    }

    // Use pub's default location by returning null.
    return null;
  }

2，flutter 、dart命令

function shared::execute() {
 
  BIN_NAME="$(basename "$PROG_NAME")"
  case "$BIN_NAME" in
    flutter*)
 
      exec "$DART" 
--disable-dart-dev 
--packages="$FLUTTER_TOOLS_DIR/.dart_tool/package_config.json" $FLUTTER_TOOL_ARGS 
"$SNAPSHOT_PATH"
 "$@"

      ;;


    dart*)
      exec "$DART" "$@"
      ;;


    *)
      >&2 echo "Error! Executable name $BIN_NAME not recognized!"
      exit 1
      ;;
  esac
}

flutter --version
dart --version
执行的区别如下：

$FLUTTERROOT/bin/cache/dart-sdk/bin/dart 

--disable-dart-dev 

--packages=$FLUTTERROOT/packages/flutter_tools/.dart_tool/package_config.json 

$FLUTTERROOT/bin/cache/flutter_tools.snapshot 

--version

$FLUTTERROOT/bin/cache/dart-sdk/bin/dart --version

dart flutter_tools.snapshot
dart