Fix resolution of packages-install-path when it uses env_var

[tatiana]

Some dbt projects are generic and are configured in a way that the packages-install-path is jinja templated. For example:

packages-install-path: 'dbt_packages{{ "_" + env_var("dbt_packages_suffix","") if env_var("dbt_packages_suffix","")!="" }}'

When attempting to use this with

• ProjectConfig.install_dbt_deps=True
• ProjectConfig.copy_dbt_packages=True

Users who have this configuration face the following error:

[2025-12-11, 10:54:23 UTC] {local.py:474} INFO - Copying dbt packages to temporary folder.
[2025-12-11, 10:54:23 UTC] {project.py:77} INFO - Copying dbt packages to temporary folder...
[2025-12-11, 10:54:23 UTC] {taskinstance.py:3336} ERROR - Task failed with exception
Traceback (most recent call last):
  File "/usr/local/lib/python3.11/site-packages/airflow/models/taskinstance.py", line 776, in _execute_task
    result = _execute_callable(context=context, **execute_callable_kwargs)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/airflow/models/taskinstance.py", line 742, in _execute_callable
    return ExecutionCallableRunner(
           ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/airflow/utils/operator_helpers.py", line 252, in run
    return self.func(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/cosmos/operators/base.py", line 310, in execute
    self.build_and_run_cmd(context=context, cmd_flags=self.add_cmd_flags())
  File "/usr/local/lib/python3.11/site-packages/cosmos/operators/local.py", line 842, in build_and_run_cmd
    result = self.run_command(
             ^^^^^^^^^^^^^^^^^
  File "/usr/local/lib/python3.11/site-packages/cosmos/operators/local.py", line 601, in run_command
    self._clone_project(tmp_dir_path)
  File "/usr/local/lib/python3.11/site-packages/cosmos/operators/local.py", line 475, in _clone_project
    copy_dbt_packages(Path(self.project_dir), tmp_dir_path)
  File "/usr/local/lib/python3.11/site-packages/cosmos/dbt/project.py", line 91, in copy_dbt_packages
    shutil.copy2(src_path, dst_path)
  File "/usr/local/lib/python3.11/shutil.py", line 448, in copy2
    copyfile(src, dst, follow_symlinks=follow_symlinks)
  File "/usr/local/lib/python3.11/shutil.py", line 256, in copyfile
    with open(src, 'rb') as fsrc:
         ^^^^^^^^^^^^^^^
FileNotFoundError: [Errno 2] No such file or directory: '/usr/local/airflow/dags/dbt/pr_3531_13_dbt_vip_enrichment/dbt_packages{{ "_" + env_var("dbt_packages_suffix","") if env_var("dbt_packages_suffix","")!="" }}'

This is because when we implemented #1768 we did not forsee the parameter could be a template.

This PR aims to solve this issue.

Observation: we'll need to release this not only as part of 1.12.0, but also cherry-pick it and, exceptionally, backport it to v1.10.3 and 1.11.3.

[netlify]

✅ Deploy Preview for sunny-pastelito-5ecb04 canceled.

Name	Link
🔨 Latest commit	77040e8
🔍 Latest deploy log	https://app.netlify.com/projects/sunny-pastelito-5ecb04/deploys/693ae72ef089f700086c921f

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 97.85%. Comparing base (ea2cfea) to head (77040e8).
⚠️ Report is 3 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2194   +/-   ##
=======================================
  Coverage   97.85%   97.85%           
=======================================
  Files          94       94           
  Lines        6058     6065    +7     
=======================================
+ Hits         5928     5935    +7     
  Misses        130      130           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[Copilot]

Pull request overview

This PR fixes an issue where the packages-install-path parameter in dbt_project.yml fails when it contains Jinja2 template expressions with env_var functions. The fix resolves these templates before attempting to copy dbt packages, preventing FileNotFoundError exceptions.

Key Changes:

• Introduced _resolve_env_var() function to render Jinja2 templates containing env_var expressions
• Updated get_dbt_packages_subpath() to resolve environment variables in the packages-install-path before returning

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
cosmos/dbt/project.py	Added _resolve_env_var() function and integrated it into get_dbt_packages_subpath() to resolve templated paths
tests/dbt/test_project.py	Added comprehensive test coverage for _resolve_env_var() with simple, complex, and conditional templates

---

💡 Add Copilot custom instructions for smarter, more guided reviews. Learn how to get started.

[pankajkoti]

LGTM. The PR description says we need to backport to 1.10.x. If we're planning to backport this to 1.10.x. We also need to release a 1.11.x so that the upgrade experience is continuos. Can we please also update this in the PR description?