Fix numeric string property names

[howiezhao]

When a JSON Schema uses a purely numeric string as a property name (e.g. "123456"), generate_validator crashes with an assertion error during schema compilation.

This is because ref_mt:child in store.lua navigates the schema tree by calling decodepart on every path segment. decodepart converts any string that looks like a number to n + 1 (to compensate for Lua's 1-based array indices when resolving JSON Pointer fragments). This is correct for array-typed keywords like items or allOf, but wrong for map-typed keywords (properties, patternProperties, definitions, dependencies) whose keys are always arbitrary strings. A property named "123456" would be looked up as schema.properties[123457], which is nil, causing assert to fail.

Introduce decode_key(part, parent) which behaves like decodepart for all keywords except the four map-typed ones (properties, patternProperties, definitions, dependencies). Under those keywords the numeric conversion is skipped and the key is returned as a plain URL-unescaped string.

Update ref_mt:child to track the previous path segment and pass it as the parent context to decode_key.

[Tieske]

this has been fixed in lua-resty-ljsonschema fork since quite a while, available via LuaRocks

[howiezhao]

this has been fixed in lua-resty-ljsonschema fork since quite a while, available via LuaRocks

Wow, thanks for reminding me, awesome!