Addresses Copilot's round-2 review on #2035. It reported "no new comments"
but carried three *suppressed* ones; all three reproduced against the
pinned SDK.
1. The `;` path-parameter operator is absent from the SDK's operator list,
so `{;id}` parsed as a variable literally named ";id" and expanded to
nothing. Added the operator and its named expansion (`;a=1;b=2`).
2. An RFC 6570 prefix modifier was folded into the variable name: `{id:3}`
yielded a variable called "id:3" and expanded to nothing. Varspecs are
now parsed properly and the value truncated before encoding. Truncation
is by code point, since `String.prototype.slice` counts UTF-16 units and
would split an astral character into a lone surrogate.
For both of these the wrong URI is the lesser problem: a form has to
*name* the variables it asks the user to fill, so the panel was
rendering fields labelled `;id` and `id:3` that nobody could use.
3. Requiredness was applied per variable, but it is a property of the
*expression*: RFC 6570 drops undefined names from a multi-name
expression, so `{a,b}` with only `a` filled expands to `a`'s value --
the SDK does this too. The panel was refusing input the expander would
have accepted. `hasRequiredValues` now encodes "any one name in a
required group suffices", and such a field reads "Any one of: a, b"
rather than falsely claiming each is mandatory.
Two structural consequences, each pinned by a test:
- Takeover is now per TEMPLATE rather than per expression. Splicing
corrected fragments into a template the SDK re-expands would leave its
cross-expression `?`-to-`&` rewrite blind to the fragments already
resolved.
- Expansion is split into a strict variant that throws and a lenient one
that returns the raw template. `readResourceFromTemplate` wraps the
thrown error with the template name -- three pre-existing integration
tests assert that -- while the form must not throw on a server-supplied
template, since that would take out the panel on render. The strict
variant constructs the SDK template unconditionally, because that
construction is what validates syntax: otherwise `x://{;a}{b,c` would
take the own-expansion path and its unclosed tail would pass as literal
text with nothing objecting.
Signed-off-by: cliffhall <cliff@futurescale.com>
Addresses Copilot's review on #2035. All three findings reproduced against
the pinned SDK before acting.
1. `#` was misclassified as required. Measured: `x://a{#frag}` with no
`frag` expands to exactly `x://a`, a well-formed URI naming a real
resource -- unlike `{+path}` (`x://a/`) or a simple `{userId}`
(`file:///users//profile`), which leave an empty path segment. Moved `#`
into the omittable set; the required cases now assert what the URI
*becomes* when blank, so the rule is checked rather than asserted.
2. Delegating to the SDK did not actually give RFC 6570 expansion.
`UriTemplate.expandPart` takes an early `names.length > 1` branch that
raw-joins values, skipping both `encodeValue` and the operator prefix:
`x://{a,b}` with `a = "foo/bar"` expands to `x://foo/bar,q` -- the very
unencoded-slash defect this PR is about -- and `x://a{/p,q}` to
`x://ax y,z`. Only `?`/`&` are correct, being dispatched earlier.
Fixing that in the web client alone would have left the TUI and CLI
wrong, since `readResourceFromTemplate` expands through the same class.
So parse/classify/expand now live in `core/mcp/uriTemplate.ts` and both
call sites use it. The correction is surgical: a multi-name non-query
expression is expanded here and spliced in as literal text before the
SDK sees the template (safe -- both encoders escape `{`/`}`), while
every single-name and query expression still goes through the SDK
untouched. The preview applies the same correction, so it cannot
promise a URI that submitting would not send.
3. The showcase promised a blank `{?topic}` read that did not work.
`UriTemplate.match()` compiles `{?topic}` to a *required*
`\?topic=([^&]+)`, so `match("foobar://events")` returns null and the
read 404s. A real server exposes the unfiltered collection as its own
resource; the showcase now registers `foobar://events` so the
documented step resolves. Verified end to end through the CLI.
Signed-off-by: cliffhall <cliff@futurescale.com>
