profiles: Remove duplicates in manifest transactions.

Fixes <https://bugs.gnu.org/23874>.
Reported by Ricardo Wurmus <ricardo.wurmus@mdc-berlin.de>.

* guix/profiles.scm (manifest-transaction-effects): Delete duplicates in
install and remove.  Let multiple upgrades and downgrades shadow previous
transactions of the same kind.
* tests/profiles.scm
("manifest-transaction-effects no double install or upgrades")
("manifest-transaction-effects no double downgrade")
("manifest-transaction-effects no double removal"): New tests.

Signed-off-by: Ludovic Courtès <ludo@gnu.org>

2 files changed, 44 insertions, 2 deletions

diff --git a/guix/profiles.scm b/guix/profiles.scm
index 1b15257210..034591eb79 100644
--- a/guix/profiles.scm
+++ b/guix/profiles.scm
@@ -716,6 +716,12 @@ replace it."
     (manifest-pattern
       (name   (manifest-entry-name entry))
       (output (manifest-entry-output entry))))
+  (define manifest-entry-pair=?
+    (match-lambda*
+      (((m1a . m2a) (m1b . m2b))
+       (and (manifest-entry=? m1a m1b)
+            (manifest-entry=? m2a m2b)))
+      (_ #f)))
 
   (let loop ((input     (manifest-transaction-install transaction))
              (install   '())
@@ -724,8 +730,16 @@ replace it."
     (match input
       (()
        (let ((remove (manifest-transaction-remove transaction)))
-         (values (manifest-matching-entries manifest remove)
-                 (reverse install) (reverse upgrade) (reverse downgrade))))
+         (values (delete-duplicates
+                  (manifest-matching-entries manifest remove)
+                  manifest-entry=?)
+                 (delete-duplicates (reverse install) manifest-entry=?)
+                 (delete-duplicates
+                  (reverse upgrade)
+                  manifest-entry-pair=?)
+                 (delete-duplicates
+                  (reverse downgrade)
+                  manifest-entry-pair=?))))
       ((entry rest ...)
        ;; Check whether installing ENTRY corresponds to the installation of a
        ;; new package or to an upgrade.
diff --git a/tests/profiles.scm b/tests/profiles.scm
index 055924ba3e..f0a1a1d11c 100644
--- a/tests/profiles.scm
+++ b/tests/profiles.scm
@@ -183,6 +183,16 @@
            (equal? (list glibc) install)
            (equal? (list (cons guile-1.8.8 guile-2.0.9)) upgrade)))))
 
+(test-assert "manifest-transaction-effects no double install or upgrades"
+  (let* ((m0 (manifest (list guile-1.8.8)))
+         (t  (manifest-transaction
+              (install (list guile-2.0.9 glibc glibc)))))
+    (let-values (((remove install upgrade downgrade)
+                  (manifest-transaction-effects m0 t)))
+      (and (null? remove) (null? downgrade)
+           (equal? (list glibc) install)
+           (equal? (list (cons guile-1.8.8 guile-2.0.9)) upgrade)))))
+
 (test-assert "manifest-transaction-effects and downgrades"
   (let* ((m0 (manifest (list guile-2.0.9)))
          (t  (manifest-transaction (install (list guile-1.8.8)))))
@@ -191,6 +201,14 @@
       (and (null? remove) (null? install) (null? upgrade)
            (equal? (list (cons guile-2.0.9 guile-1.8.8)) downgrade)))))
 
+(test-assert "manifest-transaction-effects no double downgrade"
+  (let* ((m0 (manifest (list guile-2.0.9)))
+         (t  (manifest-transaction (install (list guile-1.8.8 guile-1.8.8)))))
+    (let-values (((remove install upgrade downgrade)
+                  (manifest-transaction-effects m0 t)))
+      (and (null? remove) (null? install) (null? upgrade)
+           (equal? (list (cons guile-2.0.9 guile-1.8.8)) downgrade)))))
+
 (test-assert "manifest-transaction-effects and pseudo-upgrades"
   (let* ((m0 (manifest (list guile-2.0.9)))
          (t  (manifest-transaction (install (list guile-2.0.9)))))
@@ -209,6 +227,16 @@
     (and (manifest-transaction-removal-candidate? guile-2.0.9 t)
          (not (manifest-transaction-removal-candidate? glibc t)))))
 
+(test-assert "manifest-transaction-effects no double removal"
+  (let* ((m0 (manifest (list guile-2.0.9)))
+         (t  (manifest-transaction
+              (remove (list (manifest-pattern (name "guile")))))))
+    (let-values (((remove install upgrade downgrade)
+                  (manifest-transaction-effects m0 t)))
+      (and (= 1 (length remove))
+           (manifest-transaction-removal-candidate? guile-2.0.9 t)
+           (null? install) (null? downgrade) (null? upgrade)))))
+
 (test-assertm "profile-derivation"
   (mlet* %store-monad
       ((entry ->   (package->manifest-entry %bootstrap-guile))