Add missing wandb Hydra config group to minimal-hydra-example

[johndmulhausen]

Problem

Running the minimal Hydra example fails immediately at config composition:

hydra.errors.MissingConfigException: In 'defaults': Could not find 'wandb/default'

examples/minimal-hydra-example/configs/defaults.yaml lists - wandb: default in its Hydra defaults, but the configs/wandb/ directory does not exist in the repo.

Root cause

The repo-root .gitignore contains a bare wandb pattern (line 3, intended for wandb run-output directories), which also matches configs/wandb/ — git check-ignore -v confirms it. The config group was silently swallowed and never committed.

Fix

1. examples/minimal-hydra-example/configs/wandb/default.yaml (new): defines the config group with a top-level setup: mapping, matching how it is consumed and documented:
   • main.py uses exactly one thing from this group: wandb.init(**cfg.wandb.setup), so the group must be a mapping of valid wandb.init kwargs under setup:.
   • The README states the project is called example-hydra and documents overriding entity with wandb.setup.entity=<entity_name> (same override path used for wandb_sweep.yaml). Declaring entity: null is load-bearing: Hydra struct mode rejects overrides of keys that do not exist, so without it the documented override would fail. entity=None is wandb.init's default (use your default entity).
   • File style matches the sibling group configs (leading --- document marker, no # @package directive, same as configs/model/default.yaml and configs/optimizer/*.yaml).
2. .gitignore: adds !examples/minimal-hydra-example/configs/wandb/ immediately after the wandb pattern so the config group cannot be silently re-lost (for example, a future configs/wandb/offline.yaml would otherwise be skipped by git add with no warning).

Verification

Compose test (hydra-core 1.3.4 / omegaconf 2.3.1):

from hydra import compose, initialize_config_dir
import os
cfg_dir = os.path.abspath("examples/minimal-hydra-example/configs")
with initialize_config_dir(version_base=None, config_dir=cfg_dir):
    cfg = compose(config_name="defaults")
    assert cfg.wandb.setup.project == "example-hydra"
    cfg2 = compose(config_name="defaults", overrides=["wandb.setup.entity=test-entity"])
    assert cfg2.wandb.setup.entity == "test-entity"

• Before this change: fails with MissingConfigException: In 'defaults': Could not find 'wandb/default' (the exact error from [Bug]: minimal-hydra-example is missing wandb config #482).
• After: both composes pass; composed group is {'setup': {'project': 'example-hydra', 'entity': None}}.
• Sanity check: wandb.init(project="example-hydra", entity=None, mode="offline") runs and finishes cleanly (wandb 0.26.1).

Fixes #482

🤖 Generated with Claude Code

[Copilot]

Pull request overview

Fixes the minimal Hydra example failing during config composition by adding the missing wandb config group and preventing it from being ignored by git.

Changes:

• Add examples/minimal-hydra-example/configs/wandb/default.yaml so - wandb: default composes successfully.
• Update repo-root .gitignore to explicitly allow committing the examples/minimal-hydra-example/configs/wandb/ directory despite the global wandb ignore rule.

Reviewed changes

Copilot reviewed 1 out of 2 changed files in this pull request and generated no comments.

File	Description
examples/minimal-hydra-example/configs/wandb/default.yaml	Adds the missing Hydra config group providing setup kwargs consumed by wandb.init(**cfg.wandb.setup).
.gitignore	Prevents the configs/wandb/ group from being ignored by the global wandb pattern.

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