loadConfig() falls back to ~/.gsd/defaults.json when no project config exists

[rodzved]

Enhancement PR

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Linked Issue

Closes #1683

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What this enhancement improves

loadConfig() in core.cjs — the central config resolution used by all GSD commands.

Before / After

Before:
When .planning/config.json is missing, loadConfig() returns hardcoded defaults. ~/.gsd/defaults.json is never consulted. Pre-project commands like map-codebase ignore user globals entirely.

.planning/config.json → if missing → hardcoded defaults

After:
When .planning/config.json is missing, loadConfig() reads ~/.gsd/defaults.json as an intermediate fallback before falling back to hardcoded defaults.

hardcoded defaults ← ~/.gsd/defaults.json ← .planning/config.json

How it was implemented

• get-shit-done/bin/lib/core.cjs — In the catch block of loadConfig(), added ~/.gsd/defaults.json reading with the same merge pattern used by buildNewProjectConfig() in config.cjs. Supports both flat keys (model_profile) and nested keys (git.branching_strategy, workflow.research). Includes depth → granularity migration.
• docs/CONFIGURATION.md — Updated Global Defaults section to clarify defaults.json applies to all commands, not just /gsd-new-project. Added merge order documentation.
• tests/core.test.cjs — Added 3 new tests: defaults.json fallback, no-defaults.json fallback, nested key support. Sandboxed HOME in loadConfig describe block to isolate from developer's real ~/.gsd/defaults.json.
• tests/commands.test.cjs — Sandboxed HOME in resolve-model describe block for test isolation.
• tests/config.test.cjs ��� Sandboxed HOME for config-ensure-section test.

Testing

How I verified the enhancement works

• All 2159 existing tests pass
• 3 new tests verify:
  1. defaults.json values override hardcoded defaults when no config.json exists
  2. Hardcoded defaults are returned when neither config.json nor defaults.json exists
  3. Nested keys (git.*, workflow.*) are correctly resolved from defaults.json

Platforms tested

• macOS
• Windows (including backslash path handling)
• Linux
• N/A (not platform-specific)

Runtimes tested

• Claude Code
• Gemini CLI
• OpenCode
• Other: ___
• N/A (not runtime-specific)

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Scope confirmation

• The implementation matches the scope approved in the linked issue — no additions or removals
• If scope changed during implementation, I updated the issue and got re-approval before continuing

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Checklist

• Issue linked above with Closes #NNN — PR will be auto-closed if missing
• Linked issue has the approved-enhancement label — PR will be closed if missing
• Changes are scoped to the approved enhancement — nothing extra included
• All existing tests pass (npm test)
• New or updated tests cover the enhanced behavior
• CHANGELOG.md updated
• Documentation updated if behavior or output changed
• No unnecessary dependencies added

Breaking changes

None. The merge order is additive — existing .planning/config.json files take full precedence as before. Only the "no config.json exists" path changes, and that path currently returns hardcoded defaults which have no user-facing contract.

[rodzved]

Update: Refactored the catch fallback in loadConfig() to use a flat merge loop instead of duplicating every key individually.

Before: Each config key was listed explicitly in the return object (29 lines), meaning any new key added to loadConfig() would need to be duplicated in the fallback path — a maintenance trap.

After: The fallback iterates over userDefaults entries, flattens nested sections (git.*, workflow.*) to top-level keys, and merges them into the defaults object. New keys added to defaults are automatically picked up without changes to the fallback path.

All 2159 tests still pass.

[trek-e]

This PR needs a rebase onto main. PR #1708 just merged, which refactored loadConfig() defaults into CONFIG_DEFAULTS — the same function this PR modifies. After rebase, the catch block should reference CONFIG_DEFAULTS instead of the local defaults object (which no longer exists).

CI checks are also missing — likely due to the stale base.

[rodzved]

Rebased onto main to pick up #1708 (CONFIG_DEFAULTS refactor). The catch block's { ...defaults } now spreads CONFIG_DEFAULTS via const defaults = CONFIG_DEFAULTS. All 2164 tests pass.