dpkg: During unpack print a removal message due to Conflicts

When deciding whether to de-configure a package due to Breaks we print
a message stating so, as well as when we are actually de-configuring
them. When deciding whether to remove a package due to Conflicts we also
print a message, but were not printing anything when removing these
package which seems rather confusing and makes the installation non
obvious.

Closes: #985401

src/unpack.c

@@ -1624,6 +1624,11 @@ void process_archive(const char *filename) {
     /* We need to have the most up-to-date info about which files are
      * what ... */
     ensure_allinstfiles_available();
+    printf(_("Removing %s (%s), to allow configuration of %s (%s) ...\n"),
+           pkg_name(conflictor, pnaw_nonambig),
+           versiondescribe(&conflictor->installed.version, vdew_nonambig),
+           pkg_name(pkg, pnaw_nonambig),
+           versiondescribe(&pkg->installed.version, vdew_nonambig));
     removal_bulk(conflictor);
   }
 

tests/t-conflicts/Makefile

@@ -11,5 +11,14 @@ test-case:
 	$(call pkg_is_not_installed,pkg-b)
 	-$(DPKG_PURGE) pkg-a pkg-b
 
+	# Test installation generating removal of conflicts.
+	$(DPKG_INSTALL) pkg-b.deb
+	# Set up the desired transaction.
+	echo pkg-b deinstall | $(BEROOT) $(DPKG) --set-selections
+	$(DPKG_INSTALL) pkg-a.deb
+	$(call pkg_is_installed,pkg-a)
+	$(call pkg_is_not_installed,pkg-b)
+	-$(DPKG_PURGE) pkg-a pkg-b
+
 test-clean:
 	-$(DPKG_PURGE) pkg-a pkg-b