Response from Phoebe Goldman hand-forwarded because of problems with common-lisp.net's email server:

A few things.

1. ECHO-OP should not be selfward. SELFWARD-OPERATION is for (OPERATION COMPONENT) pairs which depend on (DIFFERENT-OPERATION COMPONENT) for the same COMPONENT. For example, LOAD-OP is selfward with respect to COMPILE-OP, because in order to perform (load-op FILE), you must first perform (compile-op FILE). Your ECHO-OP has no such dependency. In this case, I believe you want ECHO-OP to be downward and sideways, meaning that (ECHO-OP MODULE) depends on (ECHO-OP MODULE-COMPONENT) for each of the children MODULE-COMPONENTs of the MODULE, and that (ECHO-OP SOURCE-FILE) depends on (ECHO-OP EARLIER-SOURCE-FILE) for each of the EARLIER-SOURCE-FILEs in SOURCE-FILE's :DEPENDS-ON list. This way, when you call (OPERATE 'ECHO-OP (FIND-SYSTEM "whatever")), ASDF will do a depth-first dependency-order traversal of your system.

2. Your COMPONENT-DEPENDS-ON method is wrong. No pair of (OPERATION COMPONENT) should ever depend on the same (OPERATION COMPONENT). What you're saying is, "in order to perform (ECHO-OP FILE), you must first perform (ECHO-OP FILE)."

3. For operations that subclass one or more of DOWNWARD- UPWARD- SIDEWAY- SELFWARD- or NON-PROPOGATING-OPERATION, you don't need to define a COMPONENT-DEPENDS-ON method.

4. Most (OPERATION COMPONENT) pairs have very uninteresting sets of input files. (COMPILE-OP CL-SOURCE-FILE) has one input file, the .lisp source file. (LOAD-OP CL-SOURCE-FILE) has one input file, the .fasl compiled file. (ECHO-OP CL-SOURCE-FILE) will have no input files at all, unless you define a method on INPUT-FILES to list them.

I think the following definition of ECHO-OP might be enlightening to you:

(uiop:define-package :echo-op
  (:use :cl)
  (:export #:echo-op))
(in-package :echo-op)

(defclass echo-op (asdf:sideway-operation asdf:downward-operation) ())

(defun print-input-files (op c)
  (format t "~&Operation ~a on component ~a has input files:~{~%  ~a~}~%"
          op c (asdf:input-files op c)))

(defun print-dependencies (op c)
  (format t "~&Operation ~a on component ~a depends on ~{~%  ~a~}~%"
          op c (asdf:component-depends-on op c)))

(defmethod asdf:perform ((op echo-op) c)
  (flet ((do-operations (thunk)
           (funcall thunk op c)
           (funcall thunk (asdf:make-operation 'asdf:compile-op) c)
           (funcall thunk (asdf:make-operation 'asdf:load-op) c)))
    (format t "~&~%Input files for component ~a with a variety of operations:~%~%" c)
    (do-operations #'print-input-files)
    (format t "~&~%Dependencies for component ~a with a variety of operations:~%~%" c)
    (do-operations #'print-dependencies)))

Note that:

1. The only method I have defined is on PERFORM, and it is a primary method, not an :AROUND method. ASDF already has all the COMPONENT-DEPENDS-ON methods I need.
2. I print the COMPONENT-DEPENDS-ON list in addition to the INPUT-FILES list.
3. I print both the COMPONENT-DEPENDS-ON and INPUT-FILES lists for all three of ECHO-OP, COMPILE-OP and LOAD-OP.

I recommend you load this version, try (ASDF:OPERATE 'ECHO-OP:ECHO-OP (ASDF:FIND-SYSTEM "echo-op-test") :FORCE T) and see what output you get.

cheers,
phoebe