Add afterEmit plugin hook (#1353)

Cheatoid · Perryvw · web-flow · commit bf879531c1da · 2023-11-19T16:23:20.000+01:00
* Add `afterEmit` plugin hook This function would run after Lua files have been written to disk (in order to allow plugins to perform post-build tasks such as optimizing/minifying/obfuscating/bytecode-compilation/etc). * Update plugins.ts * Create afterEmit.ts * Add test for plugin (cherry picked from commit ab6099c) --------- Co-authored-by: Perry van Wesel <Perryvw@users.noreply.github.com>
diff --git a/src/transpilation/plugins.ts b/src/transpilation/plugins.ts
@@ -46,6 +46,20 @@ export interface Plugin {
         result: EmitFile[]
     ) => ts.Diagnostic[] | void;
 
+    /**
+     * This function is called after translating the input program to Lua, after resolving dependencies, after bundling and writing files to disk.
+     */
+    afterEmit?: (
+        program: ts.Program,
+        options: CompilerOptions,
+        emitHost: EmitHost,
+        result: EmitFile[]
+    ) => ts.Diagnostic[] | void;
+
+    /**
+     * This function is called when trying to resolve the .lua file corresponding to a Lua require statement. Allows you to provide
+     * your own module resolution logic. If return value is undefined, regular module resolution is done.
+     */
     moduleResolution?: (
         moduleIdentifier: string,
         requiringFile: string,
diff --git a/src/transpilation/transpiler.ts b/src/transpilation/transpiler.ts
@@ -90,6 +90,13 @@ export class Transpiler {
             }
         }
 
+        for (const plugin of plugins) {
+            if (plugin.afterEmit) {
+                const afterEmitPluginDiagnostics = plugin.afterEmit(program, options, this.emitHost, emitPlan) ?? [];
+                diagnostics.push(...afterEmitPluginDiagnostics);
+            }
+        }
+
         if (options.tstlVerbose) {
             console.log("Emit finished!");
         }
diff --git a/test/transpile/plugins/afterEmit.ts b/test/transpile/plugins/afterEmit.ts
@@ -0,0 +1,24 @@
+import * as ts from "typescript";
+import * as tstl from "../../../src";
+
+const plugin: tstl.Plugin = {
+    afterEmit(program: ts.Program, options: tstl.CompilerOptions, emitHost: tstl.EmitHost, result: tstl.EmitFile[]) {
+        void program;
+        void options;
+        void emitHost;
+        void result;
+
+        const diagnostic = {
+            category: ts.DiagnosticCategory.Message,
+            messageText: "After emit diagnostic message!",
+            code: 1234,
+            file: program.getSourceFiles()[0],
+            start: undefined,
+            length: undefined,
+        } satisfies ts.Diagnostic;
+        return [diagnostic];
+    },
+};
+
+// eslint-disable-next-line import/no-default-export
+export default plugin;
diff --git a/test/transpile/plugins/plugins.spec.ts b/test/transpile/plugins/plugins.spec.ts
@@ -1,5 +1,6 @@
 import * as path from "path";
 import * as util from "../../util";
+import * as ts from "typescript";
 
 test("printer", () => {
     util.testModule``
@@ -160,3 +161,24 @@ test("beforeEmit plugin bundle", () => {
         expect(f.lua).toContain("-- Comment added by beforeEmit plugin");
     }
 });
+
+test("afterEmit plugin", () => {
+    const { diagnostics } = util.testModule`
+        console.log("Hello, World!");
+        [].push(1,2,3); // Use lualib code
+    `
+        .addExtraFile(
+            "extrafile.ts",
+            `
+                console.log("Hello, Mars!");
+            `
+        )
+        .setOptions({ luaPlugins: [{ name: path.join(__dirname, "afterEmit.ts") }] })
+        .getLuaResult();
+
+    // Expect to see the diagnostic returned by the plugin in the output
+    const diagnostic = diagnostics.find(d => d.code === 1234);
+    expect(diagnostic).toBeDefined();
+    expect(diagnostic?.category).toBe(ts.DiagnosticCategory.Message);
+    expect(diagnostic?.messageText).toContain("After emit");
+});

Original file line number	Diff line number	Diff line change
`@@ -90,6 +90,13 @@ export class Transpiler {`
`90`	`90`	`}`
`91`	`91`	`}`
`92`	`92`
	`93`	`+ for (const plugin of plugins) {`
	`94`	`+ if (plugin.afterEmit) {`
	`95`	`+ const afterEmitPluginDiagnostics = plugin.afterEmit(program, options, this.emitHost, emitPlan) ?? [];`
	`96`	`+ diagnostics.push(...afterEmitPluginDiagnostics);`
	`97`	`+ }`
	`98`	`+ }`
	`99`	`+`
`93`	`100`	`if (options.tstlVerbose) {`
`94`	`101`	`console.log("Emit finished!");`
`95`	`102`	`}`