feat: strict custom property

packages/cli/src/config/projects-config.ts

@@ -13,16 +13,19 @@ import type {
 import { processProjects } from './process-projects';
 import { createDefaultOptions, mergeBuildOptions, validateOptions } from './resolve-options';
 import { resolveNpmRequests } from './resolve-requests';
-import type { ModuleResolver } from '@stylable/core/dist/index-internal';
-import type { processNamespace } from '@stylable/core';
+import type { StylableConfig } from '@stylable/core';
 import type { IFileSystem } from '@file-services/types';
 
 interface StylableRuntimeConfigs {
     stcConfig?: Configuration<string> | undefined;
-    defaultConfig?: {
-        resolveModule?: ModuleResolver;
-        resolveNamespace?: typeof processNamespace;
-    };
+    defaultConfig?: Pick<
+        StylableConfig,
+        | 'resolveNamespace'
+        | 'requireModule'
+        | 'resolveModule'
+        | 'flags'
+        | 'experimentalSelectorInference'
+    >;
 }
 
 export async function projectsConfig(

packages/core-test-kit/src/generate-test-util.ts

@@ -15,6 +15,7 @@ import {
     createStylableFileProcessor,
     postProcessor,
     replaceValueHook,
+    defaultFeatureFlags,
 } from '@stylable/core/dist/index-internal';
 import { isAbsolute } from 'path';
 import * as postcss from 'postcss';
@@ -108,9 +109,9 @@ export function processSource(
     options: { from?: string } = {},
     resolveNamespace?: typeof processNamespace
 ) {
-    return new StylableProcessor(new Diagnostics(), resolveNamespace).process(
-        postcss.parse(source, options)
-    );
+    return new StylableProcessor(new Diagnostics(), resolveNamespace, {
+        ...defaultFeatureFlags,
+    }).process(postcss.parse(source, options));
 }
 
 export function createProcess(

packages/core/src/create-stylable-processor.ts

@@ -3,6 +3,7 @@ import { cssParse, CssParser } from './parser';
 import { processNamespace, StylableProcessor } from './stylable-processor';
 import type { StylableMeta } from './stylable-meta';
 import type { Diagnostics } from './diagnostics';
+import { defaultFeatureFlags, type FeatureFlags } from './features/feature';
 
 export function createStylableFileProcessor({
     fileSystem,
@@ -11,8 +12,10 @@ export function createStylableFileProcessor({
     cssParser = cssParse,
     cache,
     createDiagnostics,
+    flags = { ...defaultFeatureFlags },
 }: {
     fileSystem: MinimalFS;
+    flags?: FeatureFlags;
     onProcess?: (meta: StylableMeta, path: string) => StylableMeta;
     resolveNamespace?: typeof processNamespace;
     cssParser?: CssParser;
@@ -21,9 +24,11 @@ export function createStylableFileProcessor({
 }) {
     return cachedProcessFile<StylableMeta>(
         (from, content) => {
-            return new StylableProcessor(createDiagnostics?.(from), resolveNamespace).process(
-                cssParser(content, { from })
-            );
+            return new StylableProcessor(
+                createDiagnostics?.(from),
+                resolveNamespace,
+                flags
+            ).process(cssParser(content, { from }));
         },
         (resolvedPath: string) => {
             return fileSystem.readFileSync(resolvedPath, 'utf8');

packages/core/src/features/css-custom-property.ts

@@ -60,6 +60,12 @@ export const diagnostics = {
         'error',
         () => `missing custom property name for "var(--[PROP NAME])"`
     ),
+    UNDEFINED_CSS_CUSTOM_PROP: createDiagnosticReporter(
+        '01011',
+        'error',
+        (name) =>
+            `Undefined "${name}" custom property. Please define the property using '@property' or import it with '@st-import' when 'strictCustomProperty' is enabled.`
+    ),
 };
 
 const dataKey = plugableRecord.key<{
@@ -273,8 +279,19 @@ function addCSSProperty({
         return;
     }
     // usages bailout: addition of weak definition reference `--x: var(--x)`
-    if (!final && !!STSymbol.get(context.meta, name, `cssVar`)) {
-        return;
+    if (!final) {
+        const existing = STSymbol.get(context.meta, name, `cssVar`);
+        if (existing) {
+            // already defined
+            return;
+            // eslint-disable-next-line no-constant-condition
+        } else if (context.meta.type === 'stylable' && context.meta.flags.strictCustomProperty) {
+            // strict mode
+            context.diagnostics.report(diagnostics.UNDEFINED_CSS_CUSTOM_PROP(name), {
+                node,
+                word: name,
+            });
+        }
     }
 
     // define symbol

packages/core/src/features/feature.ts

@@ -12,6 +12,13 @@ import type { ImmutableSelectorNode } from '@tokey/css-selector-parser';
 import type { Diagnostics } from '../diagnostics';
 import type { ParsedValue } from '../types';
 
+export interface FeatureFlags {
+    strictCustomProperty: boolean;
+}
+export const defaultFeatureFlags: FeatureFlags = {
+    strictCustomProperty: false,
+};
+
 export type SelectorNodeContext = [
     index: number,
     nodes: ImmutableSelectorNode[],

packages/core/src/index-internal.ts

@@ -25,6 +25,7 @@ export {
     CSSCustomProperty,
     STStructure,
 } from './features';
+export { defaultFeatureFlags } from './features/feature';
 export type {
     MappedStates,
     StateParsedValue,

packages/core/src/stylable-meta.ts

@@ -24,6 +24,7 @@ import {
     CSSContains,
     STStructure,
 } from './features';
+import type { FeatureFlags } from './features/feature';
 
 const features = [
     STSymbol,
@@ -61,7 +62,11 @@ export class StylableMeta {
     // Generated during transform
     public targetAst?: postcss.Root;
     public globals: Record<string, boolean> = {};
-    constructor(public sourceAst: postcss.Root, public diagnostics: Diagnostics) {
+    constructor(
+        public sourceAst: postcss.Root,
+        public diagnostics: Diagnostics,
+        public flags: FeatureFlags
+    ) {
         // initiate features
         const context: FeatureContext = { meta: this, diagnostics };
         for (const { hooks } of features) {

packages/core/src/stylable-processor.ts

@@ -26,15 +26,17 @@ import {
     stringifySelector,
 } from './helpers/selector';
 import { isChildOfAtRule } from './helpers/rule';
+import { defaultFeatureFlags, type FeatureFlags } from './features/feature';
 
 export class StylableProcessor implements FeatureContext {
     public meta!: StylableMeta;
     constructor(
         public diagnostics = new Diagnostics(),
-        private resolveNamespace = STNamespace.defaultProcessNamespace
+        private resolveNamespace = STNamespace.defaultProcessNamespace,
+        public flags: FeatureFlags = { ...defaultFeatureFlags }
     ) {}
     public process(root: postcss.Root): StylableMeta {
-        this.meta = new StylableMeta(root, this.diagnostics);
+        this.meta = new StylableMeta(root, this.diagnostics, this.flags);
 
         STStructure.hooks.analyzeInit(this);
         STImport.hooks.analyzeInit(this);

packages/core/src/stylable.ts

@@ -22,6 +22,7 @@ import { STImport, STScope, STVar, STMixin, CSSClass, CSSCustomProperty } from '
 import { Dependency, visitMetaCSSDependencies } from './visit-meta-css-dependencies';
 import * as postcss from 'postcss';
 import { warnOnce } from './helpers/deprecation';
+import { defaultFeatureFlags, type FeatureFlags } from './features/feature';
 
 export interface StylableConfigBase {
     projectRoot: string;
@@ -35,6 +36,7 @@ export interface StylableConfigBase {
     resolverCache?: StylableResolverCache;
     fileProcessorCache?: Record<string, CacheItem<StylableMeta>>;
     experimentalSelectorInference?: boolean;
+    flags?: Partial<FeatureFlags>;
 }
 
 export type StylableConfig = StylableConfigBase &
@@ -53,6 +55,8 @@ export type StylableConfig = StylableConfigBase &
 const globalDefaultSupportedConfigs = new Set([
     'resolveModule',
     'resolveNamespace',
+    'requireModule',
+    'flags',
     'experimentalSelectorInference',
 ]);
 export function validateDefaultConfig(defaultConfigObj: any) {
@@ -98,6 +102,7 @@ export class Stylable {
     // This cache is fragile and should be fresh if onProcess/resolveNamespace/cssParser is different
     protected fileProcessorCache?: Record<string, CacheItem<StylableMeta>>;
     private experimentalSelectorInference: boolean;
+    public flags: FeatureFlags;
     constructor(config: StylableConfig) {
         this.experimentalSelectorInference =
             config.experimentalSelectorInference === false ? false : true;
@@ -124,12 +129,17 @@ export class Stylable {
         this.cssParser = config.cssParser || cssParse;
         this.resolverCache = config.resolverCache || new Map();
         this.fileProcessorCache = config.fileProcessorCache;
+        this.flags = {
+            ...defaultFeatureFlags,
+            ...config.flags,
+        };
         this.fileProcessor = createStylableFileProcessor({
             fileSystem: this.fileSystem,
             onProcess: this.onProcess,
             resolveNamespace: this.resolveNamespace,
             cssParser: this.cssParser,
             cache: this.fileProcessorCache,
+            flags: this.flags,
         });
 
         this.resolver = this.createResolver();
@@ -179,7 +189,7 @@ export class Stylable {
     public createProcessor({
         resolveNamespace = this.resolveNamespace,
     }: CreateProcessorOptions = {}) {
-        return new StylableProcessor(new Diagnostics(), resolveNamespace);
+        return new StylableProcessor(new Diagnostics(), resolveNamespace, this.flags);
     }
     private createTransformer(options: Partial<TransformerOptions> = {}) {
         return new StylableTransformer({

packages/core/test/features/css-custom-property.spec.ts

@@ -290,6 +290,44 @@ describe(`features/css-custom-property`, () => {
 
         expect(CSSCustomProperty.getRuntimeTypedDefinitionNames(meta)).to.eql(['--c', '--d']);
     });
+    it('should warn on undefined property in strict mode', () => {
+        testStylableCore(
+            {
+                '/invalid.st.css': `
+                    .root {
+                        /* 
+                            @analyze-error word(--prop) ${customPropertyDiagnostics.UNDEFINED_CSS_CUSTOM_PROP(
+                                '--prop'
+                            )}
+                            @decl --invalid-prop: green 
+                        */
+                        --prop: green;
+
+                        /* 
+                            @analyze-error word(--prop2) ${customPropertyDiagnostics.UNDEFINED_CSS_CUSTOM_PROP(
+                                '--prop2'
+                            )}
+                            @decl color: var(--invalid-prop2) 
+                        */
+                        color: var(--prop2);
+                    }
+                `,
+                '/valid.st.css': `
+                    @st-import [--prop] from './invalid.st.css';
+                    @property --prop2;
+
+                    .root {
+                        /* @decl --invalid-prop: green */
+                        --prop: green;
+
+                        /* @decl color: var(--valid-prop2) */
+                        color: var(--prop2);
+                    }
+                `,
+            },
+            { stylableConfig: { flags: { strictCustomProperty: true } } }
+        );
+    });
     it.skip(`should escape`, () => {
         const { sheets } = testStylableCore(`
             .root {
@@ -1038,8 +1076,9 @@ describe(`features/css-custom-property`, () => {
     });
     describe('native css', () => {
         it('should not namespace', () => {
-            const { stylable } = testStylableCore({
-                '/native.css': deindent(`
+            const { stylable } = testStylableCore(
+                {
+                    '/native.css': deindent(`
                     @property --a {
                         syntax: '<color>';
                         initial-value: green;
@@ -1049,7 +1088,7 @@ describe(`features/css-custom-property`, () => {
                         --b: var(--c);
                     }
                 `),
-                '/entry.st.css': `
+                    '/entry.st.css': `
                     @st-import [--a, --b, --c] from './native.css';
 
                     .root {
@@ -1063,7 +1102,9 @@ describe(`features/css-custom-property`, () => {
                         --c: var(--c);
                     }
                 `,
-            });
+                },
+                { stylableConfig: { flags: { strictCustomProperty: true } } }
+            );
 
             const { meta: nativeMeta } = stylable.transform('/native.css');
             const { meta } = stylable.transform('/entry.st.css');
@@ -1084,6 +1125,23 @@ describe(`features/css-custom-property`, () => {
                 `)
             );
         });
+        it('should ignore strictCustomProperty', () => {
+            const { stylable } = testStylableCore(
+                {
+                    '/entry.css': `
+                        .root {
+                            /* @decl --a: var(--z) */
+                            --a: var(--z);
+                        }
+                    `,
+                },
+                { stylableConfig: { flags: { strictCustomProperty: true } } }
+            );
+
+            const { meta } = stylable.transform('/entry.css');
+
+            shouldReportNoDiagnostics(meta);
+        });
         it('should ignore stylable specific transformations', () => {
             const { stylable } = testStylableCore({
                 '/native.css': deindent(`