ConvertTokens.php cannot handle NULL values

Thanks for the patch, good find. We'll need to add some tests for this, ideally a unit test may already exist otherwise we can try add one.

Also, checkout the Drupal coding standards, we always put brackets for if statements like that.

+++ b/core/modules/user/src/Plugin/migrate/process/ConvertTokens.php
@@ -40,6 +40,11 @@ public function transform($value, MigrateExecutableInterface $migrate_executable
+    if ($value == NULL) $value = '';

When using ==, an empty string ('') will resolve to NULL. This should use is_null() or ===.

Agreed with @benjy that this needs a test (I believe there is a unit test of ConvertTokens, so all you'd need is an additional assert in there) and brackets for the if statement. Otherwise, looks fine and dandy to me.

Per IRC conversation, existing tests do not exist to extend to cover this use case. My suggestion is to open a new issue to cover that.

We need to fix the tests in this issue -- the reason being that committers generally don't like to commit a bug fix that is unaccompanied by test coverage. I believe ConvertTokens already has a test, so it should be reasonably simple to add an assertion or two.

There is no ConvertTokens test yet...
Attached is a patch that adds this test, and tests for normal token conversion, as well as conversion with a NULL value.

This oughta help :)

Since 95% of the patch is by @svendecabooter and @johnstorey, I feel OK RTBCing this. Full speed ahead!

Nit-pick, fixed on commit:

+    // value, sometimes that filters down to here. str_replace cannot
+    // handle NULLs as he subject, so we reset to an empty string.

str_replace()
"the" subject

Committed and pushed to 8.0.x. Thanks!