fix(docgen): honour System.Text.Json ignore conditions and property names

[dipkakwani]

Partially Fixes #12836 #12828

Changes

• tools/DocGen looked up Newtonsoft's [JsonIgnore]/[JsonProperty], but the RPC layer has serialized with System.Text.Json. Both libraries declare a JsonIgnoreAttribute, so the lookups compiled, always returned null, and silently reported that nothing was ever hidden or renamed. Retargeted to System.Text.Json.Serialization.
• Only JsonIgnoreCondition.Always hides a member; Never and the conditional forms still reach the wire and stay documented.

Types of changes

What types of changes does your code introduce?

• Bugfix (a non-breaking change that fixes an issue)
• New feature (a non-breaking change that adds functionality)
• Breaking change (a change that causes existing functionality not to work as expected)
• Optimization
• Refactoring
• Documentation update
• Build-related changes
• Other: Description

Testing

Requires testing

• Yes
• No

If yes, did you write tests?

• Yes
• No

Documentation

Requires documentation update

• [] Yes
• No

Requires explanation in Release Notes

• Yes
• No

Remarks

Partially addresses #12836 (fields renamed or omitted on the wire) and #12828 (internal CLR members leaking into the schema): [JsonIgnore]members are no longer published, and [JsonPropertyName] renames are now honoured. Both close once the generator also resolves [JsonConverter]-backed types, in a follow-up PR.

[claude]

Review: fix(docgen): honour System.Text.Json ignore conditions and property names

• Gather context (diff, DocGen sources, serializer options)
• Analyze correctness / edge cases
• Post review

Verdict: looks correct — no Critical/High/Medium findings. The diagnosis in the description checks out and I verified each claim against the tree.

What I verified

• Newtonsoft lookups were indeed dead. No Newtonsoft reference remains anywhere in tools/DocGen/, Nethermind.JsonRpc, or Nethermind.Facade, so the old GetCustomAttribute<Newtonsoft.Json.JsonIgnoreAttribute>() / JsonPropertyAttribute calls could only ever return null. Dropping the using is safe — nothing else in the file used it.
• JsonIgnoreCondition.Always is the right predicate. JsonIgnoreAttribute.Condition defaults to Always, so a bare [JsonIgnore] (e.g. Error.SuppressWarning, Nethermind.JsonRpc/Error.cs:19) is now correctly dropped from the docs.
• Keeping Never / WhenWritingNull / WhenWritingDefault documented is correct and matters in practice — those forms are used widely (ReceiptForRpc, ParityTransaction, FeeHistoryResults, PeerInfo, EthCapabilities, …), and all of them can reach the wire. Never in particular is an opt-in override of the global DefaultIgnoreCondition = WhenWritingNull (EthereumJsonSerializer.cs:96), so hiding it would have been a real regression.
• Null-safety of the new expression is fine: with no attribute, ?.Condition is null, and null is not JsonIgnoreCondition.Always → property kept.
• [JsonPropertyName] renames now resolve (Error, SignTransactionResult, EthProtocolInfo, JsonRpcSubscriptionResponse, …), and STJ gives [JsonPropertyName] precedence over the naming policy, matching the fallback order here.

Findings

Low — camelCase fallback still diverges from the serializer's policy (JsonRpcGenerator.cs:356). Posted as an inline suggestion: delegate to JsonNamingPolicy.CamelCase.ConvertName(...), the same policy EthereumJsonSerializer uses, instead of the hand-rolled first-char lowercase. No current DTO is affected (YParity converts identically either way), so it's cosmetic today. Fix this →

Low — public fields are still invisible to the generator. EthereumJsonSerializer sets IncludeFields = true (EthereumJsonSerializer.cs:95), but GetSerializableProperties only walks GetProperties(...). No RPC result DTO currently exposes a public field, so there is no doc gap today — worth folding into the follow-up PR alongside the [JsonConverter] work.

Low — OrderBy(p => p.Name) sorts by CLR name, not the serialized name. Now that renames are honoured, a rename can put the docs list out of alphabetical order relative to what a reader sees. No current DTO hits this (e.g. Raw/Transaction → raw/tx stays ordered).

Low — no regression test (repo rule: bug fixes get one). tools/DocGen has no test project, so a test would mean standing one up — reasonable to skip for a tools-only fix, but please eyeball the regenerated docs diff (members disappearing should only be the [JsonIgnore]/Always ones) before merging.

Notes

Nothing consensus-, security-, or hot-path-relevant here — this is a docs generator, not client runtime code. I was not able to run dotnet build tools/DocGen/DocGen.csproj in this environment (command not permitted), so compilation is unverified locally; given System.Text.Json.Serialization is in the BCL and no other Newtonsoft symbol is used in the file, I expect CI to be green.

View job run • branch fix/docgen-wire-shape