Widen Postgrex.Result.t num_rows typespec to include :copy_stream and nil#767
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cgarvis wants to merge 1 commit into
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Widen Postgrex.Result.t num_rows typespec to include :copy_stream and nil#767cgarvis wants to merge 1 commit into
cgarvis wants to merge 1 commit into
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The COPY IN streaming path sets num_rows to the atom :copy_stream as a sentinel value (protocol.ex:2733), and multi-command transaction results set num_rows to nil (protocol.ex:3099). Both are intentional and tested, but the @type t declaration only allowed integer. Widen num_rows to integer | :copy_stream | nil to match the actual runtime values produced by the driver.
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The
@type tdeclaration inPostgrex.Resultdeclaresnum_rows: integer, but the driver produces two other values in practice:num_rows: :copy_stream— set bycopied/1inprotocol.ex(line 2733) as a sentinel while a COPY FROM STDIN stream is in progress.num_rows: nil— set bydone/2inprotocol.ex(line 3099) for multi-command transaction results (e.g.ROLLBACK TO SAVEPOINT ...;RELEASE SAVEPOINT ...).Both values are intentional and have existing test coverage (stream_test.exs lines 412, 681, 709, 749 explicitly assert
num_rows: :copy_stream). The typespec was too narrow.This mismatch is surfaced as a
:badstructfielddiagnostic by the set-theoretic type checker being developed in elixir-lang/elixir#15366.Change
The
@moduledocdescription ofnum_rowsis updated to document the two additional values.Notes for callers
Widening
num_rowsto allow an atom or nil is a typespec-only change with no runtime effect. Downstream code that pattern-matches or arithmetic-operates onnum_rowsassuming it is always an integer was already broken at runtime; this change makes the contract explicit.Compile and test status
mix compileis clean under both the standard Elixir release and the local Elixir build from elixir-lang/elixir#15366.The full test suite requires a running PostgreSQL instance. Tests pass locally where Postgres is available; CI will provide full coverage.