Add ADR-012: JSON and JSON-Schema Support Libraries for C++

[Ozaq]

Description

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By opening this pull request, I affirm the following:

• All authors agree to the Contributor License Agreement.
• The code follows the project's coding standards.
• I have performed self-review and added comments where needed.
• I have added or updated tests to verify that my changes are effective and functional.
• I have run all existing tests and confirmed they pass.

[pmaciel]

Excellent study and conclusions. The core advantage is supporting JSON Schema, which will allow a much improved multi-package exchange of information.

I would not weigh the necessity of validating YAML as necessary because at this level the JSON information interchange is certinly adequate, and I see removing YAML at the low level of the stack a good direction (hence I would have finally chosen differently). But this requires a wider agreement and coordination that we're maybe to late to enforce.

The choice is a solid one -- thanks for the hard work!!

[Ozaq]

Excellent study and conclusions. The core advantage is supporting JSON Schema, which will allow a much improved multi-package exchange of information.

I would not weigh the necessity of validating YAML as necessary because at this level the JSON information interchange is certinly adequate, and I see removing YAML at the low level of the stack a good direction (hence I would have finally chosen differently). But this requires a wider agreement and coordination that we're maybe to late to enforce.

The choice is a solid one -- thanks for the hard work!!

We are fully entrenched in YAML, there is so much YAML config. It would a large improvement if we would document the desired YAML structure. Right now we have to pry this knowledge from the code.

[pgeier]

The fact that valijsons adapter architecture allows replacing/adapting any parsing, schema and regex libraries, is a big plus.
JSON, JSON Schema and REGEX is all well defined - the library binds them together. By using a YAML parser we should be able to directly proper error messages - which is a benefit over doing a JSON -> YAML conversion first?
The std::regex is not known to be very performant.

[simondsmart]

Looks well thought through. I would be happy to accept this.

would be

[simondsmart]

Why does it not fit our use case?

[Ozaq]

I believe we also want to be able to write json.

[pmaciel]

Definitely 👍

[marcosbento]

The proposed choice seems to be the most adequate for our purpose.

ecFlow already uses nlohman-json (with the headers embedded into the repo). Once this is accepted, we will gladly adopt it.

[mcocdawc]

Looks very good. My question is only about the proposed example usage.

[tlmquintino]

Rebased/merged main and renumbered this ADR 009 → 012: ADR-009 was taken by the Repository Audit Store ADR merged via #68, so this one moves to the next free number. Changes made on the branch to unblock the merge:

• ADR-009-JSON-Support.md → ADR-012-JSON-Support.md; H1 updated to Architectural Decision Record 012 (also fixed the Arcitectural typo).
• Resolved the ADR/README.md index conflict (kept 009–011, added the ADR-012 row).
• Fixed a broken index link — it previously pointed at ADR-009-JSON-Schema.md, which never existed (the file is …-JSON-Support.md).
• Updated the PR title (was "Add ADR-009 JSON-Suport").

The technical content is unchanged. Two optional consistency notes for @Ozaq / reviewers (not changed here, to preserve the approved content):

• The ADR template expects ## Status and ## Last Updated sections; ADR-009/010/011 carry them. Consider adding them (the index lists this as Accepted).
• Heading is ## Decisions; the template/house style uses ## Decision.

[tlmquintino]

Follow-up: applied the two consistency fixes as well (commit ed3b0a0) — added ## Status (Accepted) and ## Last Updated sections, renamed ## Decisions → ## Decision, and switched prose to British English (analyses; serialise/deserialise); the C++ code block is unchanged. The ADR now matches the template and ADR-009/010/011.

[Ozaq]

Wooohoo :D Nice! Thanks for fixing my leftovers @tlmquintino