add invalidateOnEnvChange to resolver

packages/core/core/src/requests/PathRequest.js

@@ -67,6 +67,12 @@ async function run({input, api, options}: RunOpts) {
   });
   let result: ResolverResult = await resolverRunner.resolve(input.dependency);
 
+  if (result.invalidateOnEnvChange) {
+    for (let env of result.invalidateOnEnvChange) {
+      api.invalidateOnEnvChange(env);
+    }
+  }
+
   if (result.invalidateOnFileCreate) {
     for (let file of result.invalidateOnFileCreate) {
       api.invalidateOnFileCreate(
@@ -105,6 +111,7 @@ type ResolverResult = {|
   assetGroup: ?AssetGroup,
   invalidateOnFileCreate?: Array<FileCreateInvalidation>,
   invalidateOnFileChange?: Array<FilePath>,
+  invalidateOnEnvChange?: Array<string>,
   diagnostics?: Array<Diagnostic>,
 |};
 
@@ -185,6 +192,7 @@ export class ResolverRunner {
     let diagnostics: Array<Diagnostic> = [];
     let invalidateOnFileCreate = [];
     let invalidateOnFileChange = [];
+    let invalidateOnEnvChange = [];
     for (let resolver of resolvers) {
       try {
         let result = await resolver.plugin.resolve({
@@ -208,6 +216,10 @@ export class ResolverRunner {
             dependency.priority = Priority[result.priority];
           }
 
+          if (result.invalidateOnEnvChange) {
+            invalidateOnEnvChange.push(...result.invalidateOnEnvChange);
+          }
+
           if (result.invalidateOnFileCreate) {
             invalidateOnFileCreate.push(...result.invalidateOnFileCreate);
           }
@@ -221,6 +233,7 @@ export class ResolverRunner {
               assetGroup: null,
               invalidateOnFileCreate,
               invalidateOnFileChange,
+              invalidateOnEnvChange,
             };
           }
 
@@ -251,6 +264,7 @@ export class ResolverRunner {
               },
               invalidateOnFileCreate,
               invalidateOnFileChange,
+              invalidateOnEnvChange,
             };
           }
 
@@ -286,6 +300,7 @@ export class ResolverRunner {
         assetGroup: null,
         invalidateOnFileCreate,
         invalidateOnFileChange,
+        invalidateOnEnvChange,
       };
     }
 
@@ -308,6 +323,7 @@ export class ResolverRunner {
       assetGroup: null,
       invalidateOnFileCreate,
       invalidateOnFileChange,
+      invalidateOnEnvChange,
       diagnostics,
     };
   }

packages/core/integration-tests/test/integration/resolver-can-invalidateonenvchange/.parcelrc

@@ -0,0 +1,4 @@
+{
+  "extends": "@parcel/config-default",
+  "resolvers": ["parcel-resolver-can-invalidateonenvchange"]
+}

packages/core/integration-tests/test/integration/resolver-can-invalidateonenvchange/index.js

@@ -0,0 +1 @@
+const willBeReplaced = true;

packages/core/integration-tests/test/integration/resolver-can-invalidateonenvchange/package.json

@@ -0,0 +1,4 @@
+{
+    "name": "test-resolver-invalidateonenevchange",
+    "private": true
+}

packages/core/integration-tests/test/plugin.js

@@ -190,4 +190,24 @@ parcel-transformer-b`,
 
     assert.equal(await run(b), 2);
   });
+
+  it('should allow resolvers to invalidateOnEnvChange', async () => {
+    async function assertAsset(replacedCode) {
+      let b = await bundle(
+        path.join(
+          __dirname,
+          '/integration/resolver-can-invalidateonenvchange/index.js',
+        ),
+        {
+          shouldDisableCache: false,
+          inputFS: overlayFS,
+          env: {replacedCode},
+        },
+      );
+      let code = await b.getBundles()[0].getEntryAssets()[0].getCode();
+      assert(code.indexOf(replacedCode) !== -1);
+    }
+    await assertAsset('const replaced = 1;');
+    await assertAsset('const replaced = 2;');
+  });
 });

packages/core/types/index.js

@@ -1499,6 +1499,8 @@ export type ResolveResult = {|
   +invalidateOnFileCreate?: Array<FileCreateInvalidation>,
   /** A list of files that should invalidate the resolution if modified or deleted. */
   +invalidateOnFileChange?: Array<FilePath>,
+  /** Invalidates the resolution when the given environment variable changes.*/
+  +invalidateOnEnvChange?: Array<string>,
 |};
 
 /**