path module — 4 remaining gaps (follow-ups to #681)

[proggeramlug]

Repro

import * as path from "node:path";
console.log("dirname /:", path.dirname("/"));
console.log("join with trailing:", path.join("/foo/", "/bar/", "baz"));
console.log("matchesGlob:", path.matchesGlob("foo.txt", "*.txt"));
console.log("toNamespacedPath:", path.toNamespacedPath("/foo/bar"));
console.log("after toNamespacedPath:", "still alive");

Actual (Perry v0.5.894)

dirname /: 
join with trailing: /bar/baz
matchesGlob: undefined
TypeError: value is not a function
    at <anonymous>

(Then exits. The after toNamespacedPath line never prints.)

Expected (Node)

dirname /: /
join with trailing: /foo/bar/baz
matchesGlob: true
toNamespacedPath: /foo/bar
after toNamespacedPath: still alive

Four distinct bugs

1. path.dirname("/") returns empty string instead of "/"

Per spec, the dirname of the root is the root itself. Perry returns "".

2. path.join("/foo/", "/bar/", "baz") resets on absolute paths in the middle

Node returns /foo/bar/baz (trailing slashes are consumed, then all segments joined). Perry returns /bar/baz — looks like it resets on the second absolute segment.

Closely related to #681, which fixed the zero-args case (path.join() → "."). The non-zero-args trailing-slash case still differs.

3. path.matchesGlob(path, pattern) is undefined

Newer API (Node 22.5+). Perry doesn't have it. Calling it throws TypeError.

4. path.toNamespacedPath(path) throws TypeError: value is not a function, terminating the script

This is the worst of the four. Calling path.toNamespacedPath("/foo/bar") should be a no-op on POSIX (Windows-only effect) and return its input. Instead Perry throws an unhandled TypeError that terminates the script — so any code after it (including unrelated probes) is silently dropped.

This is what makes test-files/test_parity_path.ts end at 37 of 42 expected lines today: lines 38-42 (the path.delimiter / path.sep / posix.* / win32.* checks) never run because the throw escapes upward.

Impact

The first three are normal "method not implemented" gaps. The fourth is a footgun: any consumer who calls path.toNamespacedPath expecting a no-op gets their program terminated. Common in cross-platform path-handling code.

Together these four are the entire remaining diff in test-files/test_parity_path.ts. Fix them and the parity test reaches full byte-for-byte PASS (diff = 0, joining test_parity_os as the second module to fully match).

Acceptance

The 5-line repro above prints output matching Node, including the final "after toNamespacedPath" line proving the throw is gone.

Related

• Follow-up to path.join() (zero args) throws TypeError instead of returning . #681 (closed; only zero-args path.join() case fixed).
• Surfaced via test-files/test_parity_path.ts (diff = 15 in v0.5.894 sweep).