Add support for multiple environment files

package.json

@@ -466,8 +466,14 @@
                 "description": "Various levels of logging shown in the debug console. When set to 'log' or 'verbose', the logs will also be written to a file."
               },
               "envFile": {
-                "type": "string",
-                "description": "Absolute path to a file containing environment variable definitions.",
+                "type": [
+                  "string",
+                  "array"
+                ],
+                "items": {
+                  "type": "string"
+                },
+                "description": "Absolute path to a file containing environment variable definitions. Multiple files can be specified by provided an array of absolute paths",
                 "default": "${workspaceFolder}/.env"
               },
               "backend": {

src/debugAdapter/goDebug.ts

@@ -13,7 +13,7 @@ import { existsSync, lstatSync } from 'fs';
 import { basename, dirname, extname } from 'path';
 import { spawn, ChildProcess, execSync, spawnSync, execFile } from 'child_process';
 import { Client, RPCConnection } from 'json-rpc2';
-import { parseEnvFile, getBinPathWithPreferredGopath, getInferredGopath, getCurrentGoWorkspaceFromGOPATH, envPath, fixDriveCasingInWindows } from '../goPath';
+import { parseEnvFile, parseEnvFiles, getBinPathWithPreferredGopath, getInferredGopath, getCurrentGoWorkspaceFromGOPATH, envPath, fixDriveCasingInWindows } from '../goPath';
 
 const fsAccess = util.promisify(fs.access);
 const fsUnlink = util.promisify(fs.unlink);
@@ -217,7 +217,7 @@ interface LaunchRequestArguments extends DebugProtocol.LaunchRequestArguments {
 	init?: string;
 	trace?: 'verbose' | 'log' | 'error';
 	/** Optional path to .env file. */
-	envFile?: string;
+	envFile?: string | string[];
 	backend?: string;
 	output?: string;
 	/** Delve LoadConfig parameters **/
@@ -315,14 +315,23 @@ class Delve {
 			}
 
 			// read env from disk and merge into env variables
-			let fileEnv = {};
+			const envs = [process.env];
+
 			try {
-				fileEnv = parseEnvFile(launchArgs.envFile);
+				if (typeof launchArgs.envFile === 'string') {
+					envs.push(parseEnvFile(launchArgs.envFile));
+				}
+
+				if (Array.isArray(launchArgs.envFile)) {
+					envs.push(...parseEnvFiles(launchArgs.envFile));
+				}
 			} catch (e) {
 				return reject(e);
 			}
 
-			const env = Object.assign({}, process.env, fileEnv, launchArgsEnv);
+			envs.push(launchArgsEnv);
+
+			const env = Object.assign({}, ...envs);
 
 			const dirname = isProgramDirectory ? program : path.dirname(program);
 			if (!env['GOPATH'] && (mode === 'debug' || mode === 'test')) {

src/goPath.ts

@@ -142,6 +142,10 @@ export function parseEnvFile(path: string): { [key: string]: string } {
 	}
 }
 
+export function parseEnvFiles(paths: string[]): { [key: string]: string }[] {
+	return paths.map(path => parseEnvFile(path));
+}
+
 // Walks up given folder path to return the closest ancestor that has `src` as a child
 export function getInferredGopath(folderPath: string): string {
 	if (!folderPath) {