fix(heft-sass-plugin): wire ignoreDeprecationsInDependencies to Sass quietDeps

[Copilot]

ignoreDeprecationsInDependencies was declared in the JSON schema, ISassProcessorOptions, and README but was silently dropped — never read from config and never forwarded to the Sass compiler. Setting it to true passed validation and had no effect.

Changes

• SassPlugin.ts: Add ignoreDeprecationsInDependencies?: boolean to ISassConfigurationJson; destructure it from the loaded config and pass it into ISassProcessorOptions
• SassProcessor.ts: Destructure ignoreDeprecationsInDependencies from options; set quietDeps: ignoreDeprecationsInDependencies on _scssOptions alongside the existing silenceDeprecations. Also added a Sass logger to _scssOptions that forwards compiler warnings (including deprecation warnings) to the heft terminal via writeWarningLine(), making them visible to developers.

quietDeps and silenceDeprecations are independent Sass compiler options and compose correctly — quietDeps suppresses deprecation warnings from dependency stylesheets only, while silenceDeprecations globally suppresses specific deprecation codes.

// config/sass.json — now actually works
{
  "ignoreDeprecationsInDependencies": true
}

Tests

Added two new tests in SassProcessor.test.ts under a describe('ignoreDeprecationsInDependencies option') block, backed by new fixtures (_partial-with-color-deprecation.scss and use-partial-with-color-deprecation.module.scss):

1. Verifies that deprecation warnings from a dependency partial appear in the terminal by default.
2. Verifies that those warnings are suppressed when ignoreDeprecationsInDependencies: true is set.

[iclanton]

@copilot - this needs a changelog entry.

[Copilot]

@copilot - this needs a changelog entry.

Added a changelog entry in common/changes/@rushstack/heft-sass-plugin/fix-ignoreDeprecationsInDependencies_2026-06-19-18-35.json (commit chore: add changelog entry for ignoreDeprecationsInDependencies fix).

[iclanton]

@copilot - It would be useful to have some tests for this.

[Copilot]

@copilot - It would be useful to have some tests for this.

Added tests in commit test(heft-sass-plugin): add tests for ignoreDeprecationsInDependencies option:

• SassProcessor.ts: Added a Sass logger to _scssOptions that forwards compiler warnings (including deprecation warnings) to the terminal via writeWarningLine(). This makes Sass deprecation warnings visible to developers and testable.
• New fixtures: _partial-with-color-deprecation.scss (uses the deprecated darken() color function) and use-partial-with-color-deprecation.module.scss (entry file that @uses the partial).
• New describe('ignoreDeprecationsInDependencies option') block with two tests:
  1. Verifies that deprecation warnings from a dependency partial appear in the terminal by default.
  2. Verifies that those warnings are suppressed when ignoreDeprecationsInDependencies: true is set.