System.Text.Json Retrieve Line / Column Numbers

[LostTime76]

Apologies if the solution to this already exists, but upon initial inspection of using System.Text.Json, I cannot seem to find it. Please kindly point me in the correct direction.

I would like to be able to get line and column numbers reliably from either utf8jsonreader and [optionally / additionally] JsonDocument type APIs. Looking at Newtonsoft, it seems like the JsonTextReader supports these properties on the reader. Poking around some other issues, it seems like LineNumber was supposed to be exposed in an issue in 2019, but got left in some sort of limbo.

Using utf8jsonreader directly allows me to parse json documents in complex scenarios not supported by higher level APIs. However, this also means I would like to direct the user to the exact line and column for information or errors.

Before anybody jumps in and says that JsonException is what I am looking for (which contains line / columns), no it is not. A json document can have a perfectly valid parse-able state, but an invalid logical state based on complex logic. That complex logic is what a schema / reader can't really implement easily.

It is a shame that these properties are not exposed right now, because as I understand it, the values already exist down inside the implementation. I will have to use newtonsoft at least until these are exposed.

[ghost]

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Issue Details

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Apologies if the solution to this already exists, but upon initial inspection of using System.Text.Json, I cannot seem to find it. Please kindly point me in the correct direction.

I am using the JsonDocument to parse JsonElements from a .json file. I have a lot of custom logic for parsing each element: properties, allowed types, etc.. that cannot be easily validated with a schema. Properties are dependent on other properties existing or not.. you can omit fields if you specify other fields or property values, yadda yadda.

I do not want to use the lower level Utf8JsonReader and re implement all of the nice things JsonDocument / JsonElement give me. It would be highly beneficial if JsonElement could implement line & column information in some form within a document, whether its just where the element starts, where it starts, ends, etc.. This allows me to directly point to a position within an input .json file to flag an error to the user so they can fix the document.

I have no reference point on how difficult this would be or the repercussions, because I am not involved in this code base.

Author:	LostTime76
Assignees:	-
Labels:	api-suggestion, area-System.Text.Json, untriaged
Milestone:	-

[layomia]

Moving to consider in .NET 7.

[eiriktsarpalis]

Duplicate of #50629.