Node 25.7.0 broke extensionless CJS scripts in "type": "module"
packages, such as yargs/yargs in yargs 17.x imported by c8; this
behavior was temporarily rolled back in Node 25.8.1 but is now
restored in 26.0.0 and future versions.  Until either yargs releases a
backported fix for yargs 17.x, or c8 fixes its import statement, or c8
upgrades to yargs 18.x (all three of those efforts have been stalled
for months), we need to work around this with an override.

yargs/yargs#2509
yargs/yargs#2514
bcoe/c8#582
bcoe/c8#581
bcoe/c8#578

Signed-off-by: Anders Kaseorg <[email protected]>

Node 25.7.0 broke extensionless CJS scripts in "type": "module"
packages, such as yargs/yargs in yargs 17.x imported by c8; this
behavior was temporarily rolled back in Node 25.8.1 but is now
restored in 26.0.0 and future versions.  Until either yargs releases a
backported fix for yargs 17.x, or c8 fixes its import statement, or c8
upgrades to yargs 18.x (all three of those efforts have been stalled
for months), we need to work around this with an override.

yargs/yargs#2509
yargs/yargs#2514
bcoe/c8#582
bcoe/c8#581
bcoe/c8#578

Signed-off-by: Anders Kaseorg <[email protected]>

Node 25.7.0 broke extensionless CJS scripts in "type": "module"
packages, such as yargs/yargs in yargs 17.x imported by c8; this
behavior was temporarily rolled back in Node 25.8.1 but is now
restored in 26.0.0 and future versions.  Until either yargs releases a
backported fix for yargs 17.x, or c8 fixes its import statement, or c8
upgrades to yargs 18.x (all three of those efforts have been stalled
for months), we need to work around this with an override.

yargs/yargs#2509
yargs/yargs#2514
bcoe/c8#582
bcoe/c8#581
bcoe/c8#578

Signed-off-by: Anders Kaseorg <[email protected]>

Node 25.7.0 broke extensionless CJS scripts in "type": "module"
packages, such as yargs/yargs in yargs 17.x imported by c8; this
behavior was temporarily rolled back in Node 25.8.1 but is now
restored in 26.0.0 and future versions.  Until either yargs releases a
backported fix for yargs 17.x, or c8 fixes its import statement, or c8
upgrades to yargs 18.x (all three of those efforts have been stalled
for months), we need to work around this with an override.

yargs/yargs#2509
yargs/yargs#2514
bcoe/c8#582
bcoe/c8#581
bcoe/c8#578

Signed-off-by: Anders Kaseorg <[email protected]>

Node 25.7.0 broke extensionless CJS scripts in "type": "module"
packages, such as yargs/yargs in yargs 17.x imported by c8; this
behavior was temporarily rolled back in Node 25.8.1 but is now
restored in 26.0.0 and future versions.  Until either yargs releases a
backported fix for yargs 17.x, or c8 fixes its import statement, or c8
upgrades to yargs 18.x (all three of those efforts have been stalled
for months), we need to work around this with an override.

yargs/yargs#2509
yargs/yargs#2514
bcoe/c8#582
bcoe/c8#581
bcoe/c8#578

Signed-off-by: Anders Kaseorg <[email protected]>

…ha 11 / c8 / yargs) (#499)

* @W-22850150 chore: support Node 26 in CI and modernize test harness (mocha 11 / c8 / yargs)

Add Node 26 to the CI test matrix and modernize the mocha/c8/yargs
toolchain so the suite is green on Node 22, 24, and 26.

CI matrix
- ci.yml: add 26.x to the Linux matrix and the (continue-on-error)
  Windows matrix; document why Node 26 floats on Windows.

mocha 10 -> 11 (catalog bump in pnpm-workspace.yaml)
- Bumping mocha drops the deprecated transitive yargs 16 that mocha 10
  dragged into the test tree (the harness now only pulls yargs 17).
- mocha 11 loads test files via native ESM import() instead of CJS
  require(), which surfaced two issues, both fixed here:

  1. applicationinsights default-import broke. The legacy CommonJS
     `applicationinsights` package has no synthesized default export
     under the native-ESM (tsx) loader, so `import appInsights from
     'applicationinsights'` resolved to `undefined` and the whole
     telemetry suite (69 tests) failed. Switched the SDK source and
     test to a namespace import (`import * as appInsights`), which
     resolves correctly under mocha, tsx, and the production ESM build.
     The 3 tests that spied the TelemetryClient constructor (a frozen,
     non-configurable ESM namespace binding) now spy the SDK's own
     `Telemetry.prototype.createClient` seam and assert the constructed
     client's resolved instrumentationKey instead.

  2. c8/V8 coverage double-counting. `--import tsx` registers BOTH a
     CJS require hook and an ESM load hook, so modules reachable through
     both interop paths were emitted by V8 as two scripts for the same
     URL; c8 merges by URL and summed their function/branch ranges,
     inflating the function denominator (1185 -> 3069) and dropping
     reported coverage ~10 points even though all tests passed. Switched
     every package's mocharc (and the CLI e2e scripts) to the ESM-only
     hook `import=tsx/esm`, which loads each source exactly once and
     restores coverage to the pre-bump baseline. Thresholds unchanged.

yargs / Node 26
- On Node 26, c8 crashed at startup ("require is not defined in ES
  module scope") because it does `require('yargs/yargs')` and yargs
  17.7.2's `require` export condition points at an extensionless file
  containing raw CommonJS; Node 26 now parses extensionless files in a
  type:module package as ESM. Applied a pnpm patch to yargs 17.7.2 that
  faithfully reproduces the merged upstream fix (yargs/yargs#2514): add
  a real `yargs.cjs`, repoint `exports["./yargs"].require` to it, and
  reduce the extensionless `yargs` to a re-export. Avoids pinning the
  17.7.3 prerelease while keeping the trusted 17.7.2 in the tree.

hygiene
- gitignore test-results.json in the mrt-* packages (CI artifact, like
  the other packages already do).

Verified: full test:ci green for all packages on Node 24.14 and 26.3.0
(tests pass + coverage thresholds met); lint, typecheck, format, and
frozen-lockfile install all clean.

* @W-22850150 docs: document the temporary yargs Node 26 patch in patches/README.md

* @W-22850150 ci: bypass coverage gate on Windows for SDK and MCP

The tsx ESM loader (import=tsx/esm) collects unreliable V8 coverage on
Windows: source files are mis-attributed (distinct file:// URL
casing/format vs. the Linux paths c8 remaps against), so SDK reported
0% and MCP 90.87% on the Windows runner even though every test passed.
This regressed the (continue-on-error) test-windows job.

Follow the existing CLI pattern: add a `test:ci:win` script
(c8 --check-coverage=false) to the SDK and MCP packages and use it in
the Windows CI steps. Coverage thresholds are still enforced on Linux,
where attribution is accurate; coverage is still generated and uploaded
on Windows for inspection.

Follow up on 59a1c9a.
Using `[email protected]` allows us to use a unified `yargs` version for all
supproted Node.js versions instead of having a workaround for Node.js 26 (and
newer).
See yargs/yargs#2514 for details on the `yargs` fix.

This approach has two advantages:
- It simplifies the build process by having a unified approach for every Node.js
  version
- It (moderately) speeds up the Node.js 26 CI, as it can now use a
  straightforward `npm ci`, and no longer needs to perform package resolution
  with `npm install`.

Related to brianc#132