From 38fbfca6ca1f3bf97099e6b4c8058f3203ddf1c8 Mon Sep 17 00:00:00 2001
From: Gerda Shank <gerda@dbtlabs.com>
Date: Fri, 5 May 2023 14:15:11 -0400
Subject: [PATCH 1/3] Raise error if dependent project depends on current
 project

---
 core/dbt/exceptions.py      | 13 +++++++++++++
 core/dbt/parser/manifest.py | 11 ++++++++++-
 2 files changed, 23 insertions(+), 1 deletion(-)

diff --git a/core/dbt/exceptions.py b/core/dbt/exceptions.py
index e92948d9ad0..2471dce5442 100644
--- a/core/dbt/exceptions.py
+++ b/core/dbt/exceptions.py
@@ -871,6 +871,19 @@ def get_message(self) -> str:
         return msg
 
 
+class ProjectDependencyCycleError(ParsingError):
+    def __init__(self, pub_project_name, project_name):
+        self.pub_project_name = pub_project_name
+        self.project_name = project_name
+        super().__init__(msg=self.get_message())
+
+    def get_message(self) -> str:
+        return (
+            f"A project dependency cycle has been detected. The current project {self.project_name} "
+            f"depends on {self.pub_project_name} which also depends on the current project."
+        )
+
+
 class MacroArgTypeError(CompilationError):
     def __init__(self, method_name: str, arg_name: str, got_value: Any, expected_type):
         self.method_name = method_name
diff --git a/core/dbt/parser/manifest.py b/core/dbt/parser/manifest.py
index a0b1f34de37..fdce9d7d553 100644
--- a/core/dbt/parser/manifest.py
+++ b/core/dbt/parser/manifest.py
@@ -103,7 +103,12 @@
     PublicModel,
     ProjectDependencies,
 )
-from dbt.exceptions import TargetNotFoundError, AmbiguousAliasError, PublicationConfigNotFound
+from dbt.exceptions import (
+    TargetNotFoundError,
+    AmbiguousAliasError,
+    PublicationConfigNotFound,
+    ProjectDependencyCycleError,
+)
 from dbt.parser.base import Parser
 from dbt.parser.analysis import AnalysisParser
 from dbt.parser.generic_test import GenericTestParser
@@ -1712,6 +1717,10 @@ def write_publication_artifact(root_project: RuntimeConfig, manifest: Manifest):
     # Get dependencies from publication dependencies
     for pub_project in manifest.publications.values():
         for project_name in pub_project.dependencies:
+            if project_name == root_project.project_name:
+                raise ProjectDependencyCycleError(
+                    pub_project_name=pub_project.project_name, project_name=project_name
+                )
             if project_name not in dependencies:
                 dependencies.append(project_name)
 

From ac68aeb7ba22afad46a085cfc34e2392c3354ca0 Mon Sep 17 00:00:00 2001
From: Gerda Shank <gerda@dbtlabs.com>
Date: Tue, 9 May 2023 09:40:54 -0400
Subject: [PATCH 2/3] Test for project dependency cycle

---
 .../multi_project/test_publication.py         | 24 ++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

diff --git a/tests/functional/multi_project/test_publication.py b/tests/functional/multi_project/test_publication.py
index 2725cb4c8bc..c85efe9f4d2 100644
--- a/tests/functional/multi_project/test_publication.py
+++ b/tests/functional/multi_project/test_publication.py
@@ -4,7 +4,11 @@
 
 from dbt.tests.util import run_dbt, get_artifact, write_file, copy_file
 from dbt.contracts.publication import PublicationArtifact, PublicModel
-from dbt.exceptions import PublicationConfigNotFound, TargetNotFoundError
+from dbt.exceptions import (
+    PublicationConfigNotFound,
+    TargetNotFoundError,
+    ProjectDependencyCycleError,
+)
 
 
 model_one_sql = """
@@ -257,3 +261,21 @@ def test_multi_projects(self, project, project_alt):
         write_file(dependencies_alt_yml, project.project_root, "dependencies.yml")
         results = run_dbt(["run", "--project-dir", str(project.project_root)])
         assert len(results) == 4
+
+
+class TestProjectCycles:
+    @pytest.fixture(scope="class")
+    def models(self):
+        return {
+            "model_one.sql": model_one_sql,
+        }
+
+    def test_project_cycles(self, project):
+        write_file(dependencies_yml, "dependencies.yml")
+        # Create a project dependency that's the same as the current project
+        m_pub_json = marketing_pub_json.replace('"dependencies": []', '"dependencies": ["test"]')
+        (pathlib.Path(project.project_root) / "publications").mkdir(parents=True, exist_ok=True)
+        write_file(m_pub_json, project.project_root, "publications", "marketing_publication.json")
+
+        with pytest.raises(ProjectDependencyCycleError):
+            run_dbt(["parse"])

From 1a01028d2ed165eb86fb1562df0ecc15af34c502 Mon Sep 17 00:00:00 2001
From: Gerda Shank <gerda@dbtlabs.com>
Date: Tue, 9 May 2023 09:41:54 -0400
Subject: [PATCH 3/3] Changie

---
 .changes/unreleased/Features-20230509-094147.yaml | 6 ++++++
 1 file changed, 6 insertions(+)
 create mode 100644 .changes/unreleased/Features-20230509-094147.yaml

diff --git a/.changes/unreleased/Features-20230509-094147.yaml b/.changes/unreleased/Features-20230509-094147.yaml
new file mode 100644
index 00000000000..21cd583e46c
--- /dev/null
+++ b/.changes/unreleased/Features-20230509-094147.yaml
@@ -0,0 +1,6 @@
+kind: Features
+body: Check for project dependency cycles
+time: 2023-05-09T09:41:47.2-04:00
+custom:
+  Author: gshank
+  Issue: "7468"