[Bug] Pre- and post-hooks use parse phase values during the execution phase

[Klimmy]

Is this a new bug in dbt-core?

• I believe this is a new bug in dbt-core
• I have searched the existing issues, and I could not find an existing issue for this bug

Current Behavior

I'm unsure if that's expected, but when I run pre/post-hook with a variable, dbt compiles the hook statement using variable value from the parse phase.

In the following example, the pre-hook will be SELECT 999 instead of SELECT 111:

{% if execute %}
    {% set val = 111 %}
{% else %}
    {% set val = 999 %}
{% endif %}

{{
    config(
      pre_hook="SELECT " ~ val
    )
}}

SELECT 1 AS id

Expected Behavior

To have execution-phase values when the hook runs.

Steps To Reproduce

1. Add the model:
   hook_issue.sql

{% if execute %}
    {% set val = 111 %}
{% else %}
    {% set val = 999 %}
{% endif %}

{{ print("Model. Execute: " ~ execute ~ "; Value: " ~ val) }}

{{
    config(
      pre_hook="{{ print('Pre-hook. Execute: " ~ execute ~ "; Value: " ~ val ~ "') }}",
      post_hook="{{ print('Post-hook. Execute: " ~ execute ~ "; Value: " ~ val ~ "') }}",
    )
}}

SELECT 1 AS id

2. run dbt --no-partial-parse run --select models/hook_issue.sql
3. In the command line output you will see that the model will have 111 value during the execution, when hooks will still have 999.

Relevant log output

dbt --no-partial-parse run --select models/hook_issue.sql 
01:02:52  Running with dbt=1.8.0
01:02:52  Registered adapter: postgres=1.8.0
Model. Execute: False; Value: 999
Pre-hook. Execute: False; Value: 999
Post-hook. Execute: False; Value: 999
01:02:54  Found 8 models, 1 snapshot, 2 sources, 1 metric, 533 macros, 1 semantic model
01:02:54  
01:02:55  Concurrency: 1 threads (target='dev')
01:02:55  
01:02:55  1 of 1 START sql view model analytics.hook_issue ............................... [RUN]
Model. Execute: True; Value: 111
Pre-hook. Execute: False; Value: 999
Post-hook. Execute: False; Value: 999
01:02:55  1 of 1 OK created sql view model analytics.hook_issue .......................... [CREATE VIEW in 0.11s]
01:02:55  
01:02:55  Finished running 1 view model in 0 hours 0 minutes and 0.41 seconds (0.41s).
01:02:55  
01:02:55  Completed successfully
01:02:55  
01:02:55  Done. PASS=1 WARN=0 ERROR=0 SKIP=0 TOTAL=1

Environment

- OS: macOS 13.6.3
- Python: 3.11.9
- dbt-core: 1.8.0
- dbt-postgres: 1.8.0

Which database adapter are you using with dbt?

postgres

Additional Context

No response

[dbeatty10]

Thanks for reaching out about this and providing such a nice example @Klimmy 🤩

This is expected, and you're not the first to be surprised. See #6837 (comment) and other linked issues for explanations.

Example

Try out the following to see how you can still get the behavior you are after.

models/my_model.sql

{# jinja for parsing phase #}
{% if execute %}
    {% set val = 111 %}
{% else %}
    {% set val = 999 %}
{% endif %}

{# jinja for execution phase #}
{% set jinja_for_execution = """
{% if execute %}
    {% set val = 111 %}
{% else %}
    {% set val = 999 %}
{% endif %}
""" %}

{{
    config(
      pre_hook=[
        jinja_for_execution ~ "{{ print('❌ Pre-hook X. Execute: " ~ execute ~ "; Value: " ~ val ~ "') }}",
        jinja_for_execution ~ "{{ print('✅ Pre-hook Y. Execute: ' ~ execute ~ '; Value: ' ~ val ~ '') }}",
        jinja_for_execution ~ "SELECT {{ val }} AS pre_hook_sql",
        ],
    )
}}

SELECT 1 AS id

dbt --no-partial-parse run -s my_model

Output:

(dbt_1.8) $ dbt --no-partial-parse run -s my_model

17:13:05  Running with dbt=1.8.0
17:13:05  Registered adapter: postgres=1.8.0
❌ Pre-hook X. Execute: False; Value: 999
✅ Pre-hook Y. Execute: False; Value: 999
17:13:06  Found 2 models, 413 macros
17:13:06  
17:13:07  Concurrency: 5 threads (target='postgres')
17:13:07  
17:13:07  1 of 1 START sql view model dbt_dbeatty.my_model ............................... [RUN]
❌ Pre-hook X. Execute: False; Value: 999
✅ Pre-hook Y. Execute: True; Value: 111
17:13:07  1 of 1 OK created sql view model dbt_dbeatty.my_model .......................... [CREATE VIEW in 0.13s]
17:13:07  
17:13:07  Finished running 1 view model in 0 hours 0 minutes and 0.49 seconds (0.49s).
17:13:07  
17:13:07  Completed successfully
17:13:07  
17:13:07  Done. PASS=1 WARN=0 ERROR=0 SKIP=0 TOTAL=1

Since this is expected behavior rather than a bug, I'm going to close this issue as not planned.

But just let me know if you have any follow-up thoughts or questions.

[Klimmy]

Wow, thank you, @dbeatty10, for such a quick and detailed response!
It's clear now, apologize that I haven't found these discussions beforehand :)

[dbeatty10]

No need to apologize -- glad to connect you with helpful information.