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  1. Documentation
  2. DOCS-14385 Summarize IDL changes re Compatibility Notes API V1
  3. DOCS-14013

Investigate changes in SERVER-51371: Create IDL definition for writeConcern



    • Sub-task
    • Status: Resolved
    • Major - P3
    • Resolution: Fixed
    • None
    • 4.9.0
    • manual, Server
    • ServerDocs2020: Apr27 - May4, ServerDocs2020: May4 - May11
    • true



      Downstream Change Summary

      We had to make two downstream-facing changes to how writeconcern arguments are parsed:
      1) The writeconcern argument to a command is a document; previously, this document could contain a field whose fieldname was any capitalization variant of "getLastError" (the value of this field was ignored). Now, we'll still parse writeconcern documents that contain a "getLastError" field (and ignore the value), but only with the capitalization "getLastError." So previously we'd parse both:
      a) {..., writeConcern: {w: 1, ..., getLastError: foo}}
      b) {...,writeConcern: {w: 1, ...,GetlastError: foo}}
      without error. But now, we'll only parse (a), and (b) will fail to parse.

      Note that the "getLastError" field in a writeconcern argument is deprecated, and has been ignored for as long as we can look back/remember (so ideally, nothing downstream should be using it anyway). Additionally, the writeconcern argument will still parse correctly with "wOpTime" or "wElectionId" fields present, though these options are also deprecated and their values are ignored, both before and after these changes. (To avoid confusion: these fields are accepted only when capitalized as spelled in the previous sentence, both before and after these changes; the getLastError behavior was unique).

      2) Previously, when we couldn't parse a writeconcern, we'd return a response to the client with a generic error code corresponding to some general error, like ErrorCodes::FailedToParse. Now, we'll return a unique error code, that doesn't have some general meaning.


      Description of Linked Ticket

      Add a strict IDL definition for writeConcern in basic_types.idl and update all IDL commands that aren't in API V1 to use writeConcern IDL definition.

      Scope of changes

      Impact to Other Docs

      MVP (Work and Date)

      Resources (Scope or Design Docs, Invision, etc.)


        Issue Links



              joseph.dougherty@mongodb.com Joseph Dougherty
              backlog-server-pm Backlog - Core Eng Program Management Team
              Joseph Dougherty Joseph Dougherty
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                1 year, 32 weeks, 2 days ago