transformations: '--with-source' now operates in depth.

The '--with-source' option is the first one that was implemented, and
it's the only one that would operate only on leaf packages rather than
traversing the dependency graph.  This change makes it consistent with
the rest of the transformation options.

* guix/transformations.scm (evaluate-source-replacement-specs): New
procedure.
(transform-package-source): Rewrite using it.
* tests/transformations.scm ("options->transformation, with-source, no
matches"): Rewrite since we no longer get a warning.
("options->transformation, with-source, in depth"): New test.
* doc/guix.texi (Package Transformation Options): Adjust examples.

1 files changed, 25 insertions, 7 deletions

diff --git a/tests/transformations.scm b/tests/transformations.scm
index dbfe523518..47b1fc650d 100644
--- a/tests/transformations.scm
+++ b/tests/transformations.scm
@@ -103,16 +103,11 @@
                                           "sha256" f))))))))))
 
 (test-assert "options->transformation, with-source, no matches"
-  ;; When a transformation in not applicable, a warning must be raised.
   (let* ((p (dummy-package "foobar"))
          (s (search-path %load-path "guix.scm"))
          (t (options->transformation `((with-source . ,s)))))
-    (let* ((port (open-output-string))
-           (new  (parameterize ((guix-warning-port port))
-                   (t p))))
-      (and (eq? new p)
-           (string-contains (get-output-string port)
-                            "had no effect")))))
+    (eq? (package-source (t p))
+         (package-source p))))
 
 (test-assert "options->transformation, with-source, PKG=URI"
   (let* ((p (dummy-package "foo"))
@@ -147,6 +142,29 @@
                        (add-to-store store (basename s) #t
                                      "sha256" s)))))))
 
+(test-assert "options->transformation, with-source, in depth"
+  (let* ((p0 (dummy-package "foo" (version "0.0")))
+         (s  (search-path %load-path "guix.scm"))
+         (f  (string-append "foo@42.0=" s))
+         (t  (options->transformation `((with-source . ,f))))
+         (p1 (dummy-package "bar" (inputs (list p0))))
+         (p2 (dummy-package "baz" (inputs (list p1)))))
+    (with-store store
+      (let ((new (t p2)))
+        (and (not (eq? new p2))
+             (match (package-inputs new)
+               ((("bar" p1*))
+                (match (package-inputs p1*)
+                  ((("foo" p0*))
+                   (and (not (eq? p0* p0))
+                        (string=? (package-name p0*) (package-name p0))
+                        (string=? (package-version p0*) "42.0")
+                        (string=? (add-to-store store (basename s) #t
+                                                "sha256" s)
+                                  (run-with-store store
+                                    (lower-object
+                                     (package-source p0*))))))))))))))
+
 (test-assert "options->transformation, with-input"
   (let* ((p (dummy-package "guix.scm"
               (inputs `(("foo" ,(specification->package "coreutils"))