Prevent link field migration from creating invalid link attributes

NW because needs tests.

Small nit only.

+++ b/core/modules/link/tests/src/Unit/Plugin/migrate/process/FieldLinkTest.php
@@ -89,4 +89,26 @@ public function canonicalizeUriDataProvider() {
+    ], $this->getMock(MigrateExecutableInterface::class), $this->getMockBuilder(Row::class)->disableOriginalConstructor()->getMock(), NULL);
...
+    ], $this->getMock(MigrateExecutableInterface::class), $this->getMockBuilder(Row::class)->disableOriginalConstructor()->getMock(), NULL);

Row is a simple value object, no need to disable the constructor on it.

Addressing feedback in #7. Also, we can reuse the MigrateExecutableInterface and Row mocks.

+++ b/core/modules/link/tests/src/Unit/Plugin/migrate/process/FieldLinkTest.php
@@ -89,4 +89,27 @@ public function canonicalizeUriDataProvider() {
+    $row = $this->getMock(Row::class);

Super nit: no need for a mock, just use the row object class directly. new Row()

All feedback addressed

Sorry, something is amiss. The patch in #8 is 2K and the next one in #11 is 140K. Thats is a big difference with no explanation. Maybe the wrong patch? Not working from HEAD?

Added Updated patch with an interdiff.

Thanks Vicki, I only looked at the interdiff. Didn't notice the size of the patch. This looks more sane now.

Apologies. I was juggling issues. Thanks @yogeshmpawar.

Committed and pushed a71337b86f to 8.8.x and 7530980cf9 to 8.7.x. Thanks!

+++ b/core/modules/link/src/Plugin/migrate/process/FieldLink.php
@@ -119,7 +119,9 @@ public function transform($value, MigrateExecutableInterface $migrate_executable
+    if (!$attributes || !is_array($attributes)) {

This can be made less complex.
if (!is_array($attributes)) {

Made this change on commit because it is very minor.