[dhensby]

Fixes #1810.

Since 20.3.0 (#1774), NVarChar and VarBinary write the PLP header unless length <= maximumLength, but the PLP terminator only if length > maximumLength. A length that is neither, such as undefined for a TVP column whose length was left out, or NaN, gets a max TYPE_INFO and PLP header but no terminator, and the server fails the request with "The stream ended unexpectedly". VarChar decides both in one if/else and isn't affected. (node-mssql's length: 'max' took the same path; node-mssql now converts that on its side.)

Changes

• Both types decide the header and the terminator from the same test, so such a value is sent as a terminated max value again: what writeTypeInfo declares, and what 20.2.3 sent.
• Bytes for numeric lengths are unchanged. I compared whole payloads against 20.2.3 for callProcedure (input and output), execSql, execute, TVPs and bulk load, across lengths undefined, null, 0, 1, the maximum, maximum + 1, 65535, Infinity, NaN, 'max' and numeric strings, with null, empty, short, surrogate-pair and over-maximum values: every case matches 20.2.3 byte for byte.

This is deliberately minimal so it can ship as a 20.3.x patch. #1780 replaces writeValue with compileWriter, whose single if/else already handles this, so #1780 can supersede it: when rebasing #1780, take its side of the two writeValue hunks, and the new tests pass unchanged on top of it.

Tests

• test/unit/data-type.ts: NVarChar (string) and VarBinary (Buffer) values with length: undefined and length: NaN serialize as PLP values ending with the terminator. These four fail on master. The writeTypeInfo tests also pin that both lengths are declared as max; those assertions already pass on master.
• test/integration/tvp-test.ts: returns the same data when string column lengths are left out sends a TVP whose VarChar and NVarChar columns have no length. On master it fails with an AggregateError wrapping "The stream ended unexpectedly". The shared test type has no binary column, so VarBinary is covered by the unit tests; I also checked a TVP VarBinary column without a length and execSql with length: NaN by hand against SQL Edge (both fail on master, both work with this change and on 20.2.3).

Checks

• npm run lint (eslint and tsc)
• npm run build
• Unit tests: 603 passing
• Integration tests against Azure SQL Edge: all passing except the UDT test in datatypes-in-results-test.ts, which needs CLR, which SQL Edge doesn't have
• commitlint was not run: it isn't installed in the dev dependencies. The commit message follows the conventional format.

🤖 Generated with Claude Code

[arthurschreiber]

Thanks for catching this! ❤️

[github-actions]

🎉 This PR is included in version 20.3.5 🎉

The release is available on:

• npm package (@next dist-tag)
• GitHub release

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