Improve error messages + add release.md requirements (#3361)

* Improve error messages on after and before argument + add release.me requirement to README

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* add tests + refer to contribution page for contributers

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Add working test for the new error messages

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* remove commented out code

---------

Co-authored-by: Sascha Dobbelaere <sd@tweave.tech>
Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

README.md

@@ -122,7 +122,8 @@ poetry install --with integrations
 poetry run pytest
 ```
 
-This will install all the dependencies (including dev ones) and run the tests.
+For all further detail, check out the [Contributing Page](CONTRIBUTING.md)
+
 
 ### Pre commit
 

RELEASE.md

@@ -0,0 +1,4 @@
+Release type: patch
+
+- Improved error message when supplying in incorrect before or after argument with using relay and pagination.
+- Add extra PR requirement in README.md

strawberry/relay/types.py

@@ -808,11 +808,20 @@ def resolve_connection(
 
         if after:
             after_type, after_parsed = from_base64(after)
-            assert after_type == PREFIX
+            if after_type != PREFIX:
+                # When the base64 hash doesnt exist, the after_type seems to return
+                # arrayconnEction instead of PREFIX. Let's raise a predictable
+                # instead of "An unknown error occurred."
+                raise TypeError("Argument 'after' contains a non-existing value.")
+
             start = int(after_parsed) + 1
         if before:
             before_type, before_parsed = from_base64(before)
-            assert before_type == PREFIX
+            if before_type != PREFIX:
+                # When the base64 hash doesnt exist, the after_type seems to return
+                # arrayconnEction instead of PREFIX. Let's raise a predictable
+                # instead of "An unknown error occurred.
+                raise TypeError("Argument 'before' contains a non-existing value.")
             end = int(before_parsed)
 
         if isinstance(first, int):

tests/relay/test_fields.py

@@ -1574,3 +1574,53 @@ class Query:
     }
     '''
     assert str(schema) == textwrap.dedent(expected).strip()
+
+
+before_after_test_query = """
+query fruitsBeforeAfterTest (
+    $before: String = null,
+    $after: String = null,
+) {
+    fruits (
+        before: $before
+        after: $after
+    ) {
+        edges {
+            cursor
+            node {
+                id
+            }
+        }
+    }
+}
+"""
+
+
+async def test_query_before_error():
+    """
+    Verify if the error raised on a non-existing before hash
+    raises the correct error
+    """
+    # with pytest.raises(ValueError):
+    index = to_base64("Fake", 9292292)
+    result = await schema.execute(
+        before_after_test_query,
+        variable_values={"before": index},
+    )
+    assert result.errors is not None
+    assert "Argument 'before' contains a non-existing value" in str(result.errors)
+
+
+def test_query_after_error():
+    """
+    Verify if the error raised on a non-existing before hash
+    raises the correct error
+    """
+    index = to_base64("Fake", 9292292)
+    result = schema.execute_sync(
+        before_after_test_query,
+        variable_values={"after": index},
+    )
+
+    assert result.errors is not None
+    assert "Argument 'after' contains a non-existing value" in str(result.errors)