Any way to enforce strict mode on all maps by default?

[ar-sematell]

I'm handling a dynamic env, which is represented by a map[string]any.
When using expr.Env, it only enforces the strict mode to the immediate map, but not any nested maps.
I want to enforce that any path or reference to this dynamic environment is accessible and valid, pretty much like a strict validation.

• Only allow accessing existing variables and their nested attributes, erroring otherwise, like in the existing expr.Env behavior
• Only allow accessing slice indexes that are given in the expr.Env or any nested attribute

Example:

// This compiles without error, but should error:
_, err := expr.Compile(`var1.attr2`,
	expr.Env(map[string]any{
		"var1": map[string]any{
			"attr1": 1,
		},
	}),
)
require.Error(t, err)

[antonmedv]

If a map-like structure is required, use types.Map instead of map[string]any. types.Map defines a closed set of allowed keys.

env := types.Map{
    "var1": types.Map{
        "attr1": types.Int,
    },
}

_, err := expr.Compile(`var1.attr2`, expr.Env(env))
require.Error(t, err)

If additional dynamic keys are needed, types.Extra can be used to define a fallback type for unspecified keys.

[ar-sematell]

I will test it, but I don't know if a dynamically parsed json structure would default to a custom map type.

I don't control the input nor the program, but I want it to be strictly validated.

All I receive is a json parsed object and a program.

[antonmedv]

You can construct typed env from you JSON document. Traverse the JSON and generate types.Map.