ASDF的compile-bundle-op为何未生成package-inferred-system项目的FASL？

现象描述 #

在传统ASDF项目中，compile-bundle-op和monolithic-compile-bundle-op均可正常生成对应FASL文件：

# compile-bundle-op 生成的FASL
<asdf-fasl-project-folder>/<project-name>--system.fasl

# monolithic-compile-bundle-op 生成的FASL
<asdf-fasl-project-folder>/<project-name>--all-systems.fasl 

但采用:package-inferred-system类的项目，仅能通过monolithic-compile-bundle-op生成FASL，compile-bundle-op无对应输出。

复现步骤 #

需确保两个项目均能被ASDF识别，执行以下shell命令创建测试项目：

mkdir sample-app
mkdir sample-app-classic-asdf
 
# 创建package-inferred-system项目
cat << 'EOF' > sample-app/sample-app.asd
;; 使用ASDF的package-inferred-system
(defsystem "sample-app"
  :class :package-inferred-system
  :depends-on ("sample-app/sample-app")) 
EOF

cat << 'EOF' > sample-app/sample-app.lisp
(defpackage :sample-app/sample-app
  (:nicknames :sample-app)
  (:use :cl)
  (:import-from :sample-app/sample-lib :ayy)
  (:import-from :alexandria :flatten)
  (:export :ayy-lmao))
(in-package :sample-app/sample-app)

(defun lmao ()
  (format t "SAMPLE-APP: Generating 'lmao'~%")
  "lmao")

(defun ayy-lmao ()
  (flatten (list (list (ayy)) (list (lmao)))))
EOF

cat << 'EOF' > sample-app/sample-lib.lisp
(defpackage :sample-app/sample-lib
  (:use :cl)
  (:export :ayy
           :lmao))
(in-package :sample-app/sample-lib)

(defun ayy () 
  (format t "SAMPLE-LIB: Generating 'ayy'~%")
  "ayy")

(defun lmao () 
  (format t "SAMPLE-LIB: Generating 'lmao'~%")
  "lmao")
EOF

# 创建传统ASDF项目
cat << 'EOF' > sample-app-classic-asdf/sample-app-classic-asdf.asd
(defsystem "sample-app-classic-asdf"
  :depends-on ("alexandria")
  :components ((:file "sample-lib")
               (:file "sample-app" :depends-on ("sample-lib"))))
EOF

cat << 'EOF' > sample-app-classic-asdf/sample-app.lisp
(defpackage :sample-app-classic-asdf
  (:use :cl)
  (:import-from :sample-lib :ayy)
  (:import-from :alexandria :flatten)
  (:export :ayy-lmao))
(in-package :sample-app-classic-asdf)

(defun lmao ()
  (format t "SAMPLE-APP: Generating 'lmao'~%")
  "lmao")

(defun ayy-lmao ()
  (flatten (list (list (ayy)) (list (lmao)))))
EOF

cat << 'EOF' > sample-app-classic-asdf/sample-lib.lisp
(defpackage :sample-lib
  (:use :cl)
  (:export :ayy
           :lmao))
(in-package :sample-lib)

(defun ayy () 
  (format t "SAMPLE-LIB: Generating 'ayy'~%")
  "ayy")

(defun lmao () 
  (format t "SAMPLE-LIB: Generating 'lmao'~%")
  "lmao")
EOF

验证操作 #

在Lisp REPL中执行以下命令：

(asdf:load-system "sample-app")
(asdf:load-system "sample-app-classic-asdf")
(asdf:oos 'asdf:compile-bundle-op "sample-app")
(asdf:oos 'asdf:compile-bundle-op "sample-app-classic-asdf")

观察FASL输出目录，sample-app（package-inferred-system项目）无compile-bundle-op生成的FASL文件，而传统项目正常生成。

原因分析 #

这不是ASDF的bug，而是package-inferred-system的设计特性与compile-bundle-op的行为逻辑共同导致的：

• compile-bundle-op的作用是仅编译并打包当前系统的直接组件，不包含依赖的其他系统。
• package-inferred-system本身没有显式定义的代码组件（比如:file），它的所有功能都依赖于自动生成的子系统（如sample-app/sample-app），这些子系统被视为独立的依赖系统，而非当前系统的直接组件。
• 因此，当对顶层的sample-app系统执行compile-bundle-op时，ASDF找不到需要打包的直接组件，自然不会生成FASL文件。
• 而monolithic-compile-bundle-op会递归包含当前系统的所有依赖（包括自动生成的子系统），所以能正常生成包含全部代码的FASL。

解决方案 #

如果需要为package-inferred-system项目生成对应compile-bundle-op的FASL，直接针对具体的子系统执行操作即可：

(asdf:oos 'asdf:compile-bundle-op "sample-app/sample-app")

这样会生成对应子系统代码的FASL文件。

内容的提问来源于stack exchange，提问作者Sebastian Carlos