[Bug] partial_parse.msgpack Only Written to --target-path When Project Is Modified

[d-cole]

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

When there are no changes to a dbt project and the flags --partial-parse-file-path and --target-path are used all artifacts except for partial_parse.msgpack are written to --target-path. This can lead to unexpected results when configuring CI to update artifacts for partial parsing.

This is easily resolvable by checking for the existence of <new_target_path>/partial_parse.msgpack so I'm not sure if this qualifies as a bug or a code docs issue.

Expected Behavior

partial_parse.msgpack is written to --target-path even when the dbt project has no modifications.

Steps To Reproduce

Steps to reproduce

1. Follow setup steps here: https://github.com/dbt-labs/jaffle_shop_duckdb

2. Run dbt parse writing artifacts to default target/

dbt parse
15:14:17  Running with dbt=1.8.0
15:14:17  Registered adapter: duckdb=1.8.0
15:14:17  Unable to do partial parsing because saved manifest not found. Starting full parse.
...

ls target/
manifest.json           partial_parse.msgpack   perf_info.json          semantic_manifest.json

3. Run dbt parse --partial-parse-file-path target/partial_parse.msgpack --target-path ./new_target_path

dbt parse --partial-parse-file-path target/partial_parse.msgpack --target-path ./new_target_path
15:26:31  Running with dbt=1.8.0
15:26:31  Registered adapter: duckdb=1.8.0
...

ls ./new_target_path
manifest.json           perf_info.json          semantic_manifest.json

Relevant log output

No response

Environment

- OS: macOS-14.5-arm64-arm-64bit
- Python: 3.9.10
- dbt: 1.8.0

Which database adapter are you using with dbt?

dbt-bigquery=1.8.0
duckdb=1.8.0

Additional Context

No response

[dbeatty10]

Thanks for reaching out @d-cole !

I see what you are saying: when there are modifications and when the --partial-parse-file-path flag is used, then partial_parse.msgpack is written to the --target-path but it isn't written otherwise.

But since --partial-parse-file-path is an intentionally undocumented private/hidden flag not meant for dbt users, I'm going to close both this and #10559 as "not planned".