feat: support partial writes

[alespour]

Proposed Changes

Adds partial-write support with structured error details in PartialWriteError, including per-line lineNumber, errorMessage, and originalLine so callers can decide whether to drop/retry/fix specific lines in a batch.

This also aligns write routing with the rollout contract:

• Default write endpoint is now /api/v3/write_lp
• acceptPartial defaults to true (server default behavior)
• accept_partial=false is sent only when partial writes are explicitly disabled
• New compatibility option useV2Api routes writes to /api/v2/write for Clustered/v2-compatible backends

Configuration surfaces now include:

• Write option: acceptPartial, useV2Api
• Client config / connection string keys: writeAcceptPartial, writeUseV2Api
• Environment variables: INFLUX_WRITE_ACCEPT_PARTIAL, INFLUX_WRITE_USE_V2_API

Validation:

• useV2Api=true with noSync=true is rejected before request dispatch.

See Partial writes in InfluxDB documentation.

Example:

const client = new InfluxDBClient({
  host: 'http://localhost:8181',
  token: 'YOUR_TOKEN',
  database: 'my_db',
})

try {
  await client.write(lp) // acceptPartial=true by default
} catch (err) {
  if (err instanceof PartialWriteError) {
    for (const lineErr of err.lineErrors) {
      console.log(
        `line ${lineErr.lineNumber} failed: ${lineErr.errorMessage} (${lineErr.originalLine})`
      )
    }
  } else {
    console.log(err)
  }
}

Optional v2 compatibility mode:

const client = new InfluxDBClient({
  ...
  writeOptions: {
    useV2Api: true,
  },
})

await client.write(lp)

Checklist

• CHANGELOG.md updated
• Rebased/mergeable
• A test has been added if appropriate
• Tests pass
• Commit messages are conventional

[Copilot]

Pull request overview

Adds client-side support for InfluxDB v3 partial writes by introducing a structured PartialWriteError and aligning write routing defaults with the v3 /api/v3/write_lp contract, while preserving v2 compatibility via an explicit option.

Changes:

• Introduces PartialWriteError (with per-line error details) and updates HttpError message formatting for v3 write errors.
• Switches default write routing to /api/v3/write_lp, adds acceptPartial/useV2Api options, and wires them through connection string + env parsing.
• Updates unit/integration tests and documentation to cover partial-write behavior and v2 compatibility mode.

Reviewed changes

Copilot reviewed 12 out of 12 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
packages/client/src/errors.ts	Adds PartialWriteError + parsing utilities; adjusts v3 write error message formatting.
packages/client/src/impl/WriteApiImpl.ts	Routes writes to v3 by default; adds accept_partial=false + useV2Api routing + validation; converts HttpError → PartialWriteError when applicable.
packages/client/src/options.ts	Adds acceptPartial/useV2Api to WriteOptions, defaults, and parses new connection/env keys.
packages/client/src/InfluxDBClient.ts	Documents new connection string and env configuration keys.
packages/client/test/unit/errors.test.ts	Adds coverage for new v3 error formatting and PartialWriteError.fromHttpError.
packages/client/test/unit/Write.test.ts	Updates expected write endpoints; adds tests for acceptPartial, useV2Api, validation, and PartialWriteError behavior.
packages/client/test/unit/Influxdb.test.ts	Adds tests for connection string and env parsing of new write options; updates expected default write path in mocks.
packages/client/test/integration/e2e.test.ts	Adds E2E assertions for partial-write structured errors and v2 compatibility behavior.
packages/client/test/unit/impl/node/NodeHttpTransport.test.ts	Increases wait time / improves diagnostics for a cancellation-related timing assertion.
packages/client/test/unit/impl/browser/FetchTransport.test.ts	Same timing stabilization for fetch transport test.
README.md	Documents partial write defaults, PartialWriteError, and v2 compatibility option.
CHANGELOG.md	Notes breaking change: v3 write defaults + partial write support.

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[Copilot]

Pull request overview

Copilot reviewed 12 out of 12 changed files in this pull request and generated 2 comments.

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[Copilot]

Pull request overview

Copilot reviewed 12 out of 12 changed files in this pull request and generated 2 comments.

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[Copilot]

Pull request overview

Copilot reviewed 13 out of 13 changed files in this pull request and generated 3 comments.

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[karel-rehor]

Partial review encountered a minor problem with comments that needs to be addressed.

[karel-rehor]

I tried the steps in PR description and in new README.md section with a local client and setup with Influxdb3 Core (with node v20.19.6 and latest v25.9). Everything works as documented.

Tests also run locally without issue.

Looks good to me. 🚴 🏁