Refactor insertDayDiet to return DayDiet and throw on failure

[Codex]

insertDayDiet now guarantees a DayDiet result or throws, removing nullable insert behavior and tightening downstream handling.

• Domain contracts: insertDayDiet returns Promise<DayDiet> (non-null) across repository and gateway interfaces.
• Infrastructure: Supabase and guest gateways now always return the created DayDiet; Supabase adds a guard for missing data.
• Application: Day use case caches the inserted day and rethrows errors instead of swallowing nulls.
• Docs & tests: Architecture guide updated to describe the non-null contract; new guest gateway test ensures insertion returns and persists a DayDiet.

Example:

// Supabase gateway
const inserted = await insertDayDiet(newDay) // returns DayDiet or throws
dayCacheStore.upsertToCache(inserted)

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• test.supabase.co
  • Triggering command: /opt/hostedtoolcache/node/24.14.0/x64/bin/node /opt/hostedtoolcache/node/24.14.0/x64/bin/node --conditions node --conditions development /home/REDACTED/work/macroflows/macroflows/node_modules/.pnpm/tinypool@1.1.1/node_modules/tinypool/dist/entry/process.js --global cal/bin/git pull.rebase (dns block)
  • Triggering command: /opt/hostedtoolcache/node/24.14.0/x64/bin/node /opt/hostedtoolcache/node/24.14.0/x64/bin/node --conditions node --conditions development /home/REDACTED/work/macroflows/macroflows/node_modules/.pnpm/tinypool@1.1.1/node_modules/tinypool/dist/entry/process.js hash-object (dns block)
  • Triggering command: /opt/hostedtoolcache/node/24.14.0/x64/bin/node /opt/hostedtoolcache/node/24.14.0/x64/bin/node --conditions node --conditions development /home/REDACTED/work/macroflows/macroflows/node_modules/.pnpm/tinypool@1.1.1/node_modules/tinypool/dist/entry/process.js --skipLibCheck /usr/bin/cat roflows node nfig/composer/vendor/bin/git cat /pro�� o | grep "physical id" | sort |usrc/modules/diet/day-diet/infrastructure/guest/guestDayGateway.tuniq tr /usr/bin/sort roflows getconf /usr/sbin/git ss.js (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

Original prompt

---

This section details on the original issue you should resolve

<issue_title>Remove nullability from insertDayDiet return type</issue_title>
<issue_description># Remove nullability from insertDayDiet return type

Description:
Refactor the insertDayDiet function so that it never returns null. Instead, ensure it always returns a valid result or throws a domain error. Update all usages and tests to reflect this change, and document the new behavior.

Scope:

• src/modules/diet/day-diet/domain/dayDietRepository.ts
• All modules and files that use insertDayDiet
• Related tests and documentation

Motivation:
Removing nullability from the return type improves type safety, predictability, and reduces the risk of runtime errors. It also clarifies the contract for consumers of the API.

Acceptance Criteria:

• insertDayDiet never returns null
• All usages are updated to handle the new return type
• All affected tests and documentation are updated

Additional Context:

• Review all usages of insertDayDiet in the codebase
• See docs/audit_domain_diet_day-diet.md for related notes

Environment:

• App Version: v0.12.0-dev..5+issue.325
• OS: Linux
• Shell: zsh

Labels:

• refactor
• backend
• complexity-medium
• improvement

reportedBy: github-copilot.v1/github-issue-unified
</issue_description>

Comments on the Issue (you are @codex[agent] in this section)

• Fixes Remove nullability from insertDayDiet return type #793

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Project	Deployment	Actions	Updated (UTC)
macroflows	Ready	Preview, Comment	Mar 25, 2026 9:06pm