Support both yaml and yml file extension for project config files

.changes/unreleased/Features-20250131-164002.yaml

@@ -0,0 +1,6 @@
+kind: Features
+body: Support both yaml and yml file extension for project config files
+time: 2025-01-31T16:40:02.049453+11:00
+custom:
+    Author: morgan-dgk
+    Issue: '#5002 #8738'

.pre-commit-config.yaml

@@ -5,7 +5,7 @@ exclude: ^(core/dbt/docs/build/|core/dbt/common/events/types_pb2.py|core/dbt/eve
 
 # Force all unspecified python hooks to run python 3.9
 default_language_version:
-  python: python3
+  python: python3.9
 
 repos:
 - repo: https://github.com/pre-commit/pre-commit-hooks

core/dbt/clients/yaml_helper.py

@@ -1,3 +1,4 @@
+import os
 from typing import Any, Dict, Optional
 
 import yaml
@@ -66,3 +67,12 @@ def load_yaml_text(contents, path=None):
             error = str(e)
 
         raise dbt_common.exceptions.base.DbtValidationError(error)
+
+
+def get_yaml_path(path: str) -> str:
+    if os.path.exists("{}.yml".format(path)):
+        return path + ".yml"
+    elif os.path.exists("{}.yaml".format(path)):
+        return path + ".yaml"
+    else:
+        return ""

core/dbt/config/profile.py

@@ -3,7 +3,7 @@
 from typing import Any, Dict, Optional, Tuple
 
 from dbt.adapters.contracts.connection import Credentials, HasCredentials
-from dbt.clients.yaml_helper import load_yaml_text
+from dbt.clients.yaml_helper import get_yaml_path, load_yaml_text
 from dbt.contracts.project import ProfileConfig
 from dbt.events.types import MissingProfileTarget
 from dbt.exceptions import (
@@ -31,7 +31,7 @@
 
 
 def read_profile(profiles_dir: str) -> Dict[str, Any]:
-    path = os.path.join(profiles_dir, "profiles.yml")
+    path = get_yaml_path(os.path.join(profiles_dir, "profiles"))
 
     contents = None
     if os.path.isfile(path):

core/dbt/config/project.py

@@ -8,7 +8,7 @@
 
 from dbt import deprecations
 from dbt.adapters.contracts.connection import QueryComment
-from dbt.clients.yaml_helper import load_yaml_text
+from dbt.clients.yaml_helper import get_yaml_path, load_yaml_text
 from dbt.config.selectors import SelectorDict
 from dbt.config.utils import normalize_warn_error_options
 from dbt.constants import (
@@ -99,8 +99,10 @@ def load_yml_dict(file_path):
 
 
 def package_and_project_data_from_root(project_root):
-    packages_yml_dict = load_yml_dict(f"{project_root}/{PACKAGES_FILE_NAME}")
-    dependencies_yml_dict = load_yml_dict(f"{project_root}/{DEPENDENCIES_FILE_NAME}")
+    packages_yml_dict = load_yml_dict(get_yaml_path(f"{project_root}/{PACKAGES_FILE_NAME}"))
+    dependencies_yml_dict = load_yml_dict(
+        get_yaml_path(f"{project_root}/{DEPENDENCIES_FILE_NAME}")
+    )
 
     if "packages" in packages_yml_dict and "packages" in dependencies_yml_dict:
         msg = "The 'packages' key cannot be specified in both packages.yml and dependencies.yml"
@@ -184,7 +186,7 @@ def value_or(value: Optional[T], default: T) -> T:
 
 def load_raw_project(project_root: str) -> Dict[str, Any]:
     project_root = os.path.normpath(project_root)
-    project_yaml_filepath = os.path.join(project_root, DBT_PROJECT_FILE_NAME)
+    project_yaml_filepath = get_yaml_path(os.path.join(project_root, DBT_PROJECT_FILE_NAME))
 
     # get the project.yml contents
     if not path_exists(project_yaml_filepath):
@@ -197,7 +199,7 @@ def load_raw_project(project_root: str) -> Dict[str, Any]:
     project_dict = _load_yaml(project_yaml_filepath)
 
     if not isinstance(project_dict, dict):
-        raise DbtProjectError(f"{DBT_PROJECT_FILE_NAME} does not parse to a dictionary")
+        raise DbtProjectError(f"{project_yaml_filepath} does not parse to a dictionary")
 
     if "tests" in project_dict and "data_tests" not in project_dict:
         project_dict["data_tests"] = project_dict.pop("tests")
@@ -792,7 +794,7 @@ def read_project_flags(project_dir: str, profiles_dir: str) -> ProjectFlags:
         # want to throw an error for non-existence of dbt_project.yml here
         # because it breaks things.
         project_root = os.path.normpath(project_dir)
-        project_yaml_filepath = os.path.join(project_root, DBT_PROJECT_FILE_NAME)
+        project_yaml_filepath = get_yaml_path(os.path.join(project_root, DBT_PROJECT_FILE_NAME))
         if path_exists(project_yaml_filepath):
             try:
                 project_dict = load_raw_project(project_root)

core/dbt/constants.py

@@ -11,8 +11,8 @@
     "https://docs.getdbt.com/docs/package-management#section-specifying-package-versions"
 )
 
-DBT_PROJECT_FILE_NAME = "dbt_project.yml"
-PACKAGES_FILE_NAME = "packages.yml"
+DBT_PROJECT_FILE_NAME = "dbt_project"
+PACKAGES_FILE_NAME = "packages"
 DEPENDENCIES_FILE_NAME = "dependencies.yml"
 PACKAGE_LOCK_FILE_NAME = "package-lock.yml"
 MANIFEST_FILE_NAME = "manifest.json"

core/dbt/task/base.py

@@ -21,6 +21,7 @@
 )
 from dbt.artifacts.schemas.run import RunResult
 from dbt.cli.flags import Flags
+from dbt.clients.yaml_helper import get_yaml_path
 from dbt.compilation import Compiler
 from dbt.config import RuntimeConfig
 from dbt.config.profile import read_profile
@@ -88,6 +89,7 @@ def get_nearest_project_dir(project_dir: Optional[str]) -> Path:
     if project_dir:
         cur_dir = Path(project_dir)
         project_file = Path(project_dir) / DBT_PROJECT_FILE_NAME
+        project_file = Path(get_yaml_path(str(project_file)))
         if project_file.is_file():
             return cur_dir
         else: