Dart-sass

* **Potentially breaking bug fix**: Properly throw an error for Unicode ranges
that have too many `?`s after hexadecimal digits, such as `U+12345??`.

* **Potentially breaking bug fix:** Fixed a bug where certain local variable
declarations nested within multiple `if` statements would incorrectly
override a global variable. It's unlikely that any real stylesheets were
relying on this bug, but if so they can simply add `!global` to the variable
declaration to preserve the old behavior.

* **Potentially breaking bug fix:** Fix a bug where imports of root-relative
URLs (those that begin with `/`) in `import` rules would be passed to
both Dart and JS importers as `file:` URLs.

* Properly support selector lists for the `$extendee` argument to
`selector.extend()` and `selector.replace()`.

* Fix an edge case where `extend` wouldn't affect a selector within a
pseudo-selector such as `:is()` that itself extended other selectors.

* Fix a race condition where `meta.load-css()` could trigger an internal error
when running in asynchronous mode.

Dart API

* Use the `internal` annotation to indicate which `Value` APIs are available
for public use.

* Fix a bug where the quiet dependency flag didn't silence warnings in some
stylesheets loaded using `import`.

* Fix a couple bugs that could prevent some members from being found in certain
files that use a mix of imports and the module system.

* Fix incorrect recommendation for migrating division expressions that reference
namespaced variables.

JS API

* Add a `quietDeps` option which silences compiler warnings from stylesheets
loaded through importers and load paths.

* Add a `verbose` option which causes the compiler to emit all deprecation
warnings, not just 5 per feature.

* Fix a bug where `--update` would always compile any file that depends on a
built-in module.

* Fix the URL for the `-moz-document` deprecation message.

* Fix a bug with `for` loops nested inside property declarations.

* Don't emit the same warning in the same location multiple times.

* Cap deprecation warnings at 5 per feature by default.

Command Line Interface

* Add a `--quiet-deps` flag which silences compiler warnings from stylesheets
loaded through `--load-path`s.

* Add a `--verbose` flag which causes the compiler to emit all deprecation
warnings, not just 5 per feature.

Dart API

* Add a `quietDeps` argument to `compile()`, `compileString()`,
`compileAsync()`, and `compileStringAsync()` which silences compiler warnings
from stylesheets loaded through importers, load paths, and `package:` URLs.

* Add a `verbose` argument to `compile()`, `compileString()`, `compileAsync()`,
and `compileStringAsync()` which causes the compiler to emit all deprecation
warnings, not just 5 per feature.

* Deprecate the use of `/` for division. The new `math.div()` function should be
used instead. See [this page][] for details.

[this page]: https://sass-lang.com/documentation/breaking-changes/slash-div

* Add a `list.slash()` function that returns a slash-separated list.

* **Potentially breaking bug fix:** The heuristics around when potentially
slash-separated numbers are converted to slash-free numbers—for example, when
`1/2` will be printed as `0.5` rather than `1/2`—have been slightly expanded.
Previously, a number would be made slash-free if it was passed as an argument
to a *user-defined function*, but not to a *built-in function*. Now it will be
made slash-free in both cases. This is a behavioral change, but it's unlikely
to affect any real-world stylesheets.

* [`:is()`][] now behaves identically to `:matches()`.

[`:is()`]: https://developer.mozilla.org/en-US/docs/Web/CSS/:is

* Fix a bug where non-integer numbers that were very close to integer
values would be incorrectly formatted in CSS.

* Fix a bug where very small number and very large negative numbers would be
incorrectly formatted in CSS.

JS API

* The `this` context for importers now has a `fromImport` field, which is `true`
if the importer is being invoked from an `import` and `false` otherwise.
Importers should only use this to determine whether to load [import-only
files].

[import-only files]: https://sass-lang.com/documentation/at-rules/import#import-only-files

Dart API

* Add an `Importer.fromImport` getter, which is `true` if the current
`Importer.canonicalize()` call comes from an `import` rule and `false`
otherwise. Importers should only use this to determine whether to load
[import-only files].