feat: custom upm config path

Currently openupm only searches for the users upm config in their home directory. But according to the docs users may override the file location by setting the UPM_USER_CONFIG_FILE env variable.

This change adds logic for using this variable as path if set.

src/io/upm-config-io.ts

@@ -47,6 +47,9 @@ export function ResolveDefaultUpmConfigPath(
   }
 
   return async (systemUser) => {
+    const customDir = tryGetEnv("UPM_USER_CONFIG_FILE");
+    if (customDir !== null) return path.resolve(customDir);
+
     const directory = await getConfigDirectory(systemUser);
     return path.join(directory, configFileName);
   };

test/io/upm-config-io.test.ts

@@ -8,27 +8,47 @@ import {
 } from "../../src/io/upm-config-io";
 import { exampleRegistryUrl } from "../domain/data-registry";
 import { mockService } from "../services/service.mock";
+import { tryGetEnv } from "../../src/utils/env-util";
+
+jest.mock("../../src/utils/env-util");
 
 describe("upm-config-io", () => {
   describe("resolve default path", () => {
+    const homeConfigPath = path.resolve("/some/home/dir/.upmconfig.toml");
+    const customConfigPath = path.resolve("/some/other/dir/.upmconfig.toml");
+
     function makeDependencies() {
       const getHomePath = mockService<GetHomePath>();
+      getHomePath.mockReturnValue(path.dirname(homeConfigPath));
+
+      jest.mocked(tryGetEnv).mockReturnValue(null);
 
       const resolveDefaultUpmConfigPath =
         ResolveDefaultUpmConfigPath(getHomePath);
 
       return { resolveDefaultUpmConfigPath, getHomePath } as const;
     }
 
+    it("should be UPM_USER_CONFIG_FILE if set", async () => {
+      const { resolveDefaultUpmConfigPath } = makeDependencies();
+      jest
+        .mocked(tryGetEnv)
+        .mockImplementation((key) =>
+          key === "UPM_USER_CONFIG_FILE" ? customConfigPath : null
+        );
+
+      const actual = await resolveDefaultUpmConfigPath(false);
+
+      expect(actual).toEqual(customConfigPath);
+    });
+
     describe("no system-user", () => {
       it("should be in home path", async () => {
-        const { resolveDefaultUpmConfigPath, getHomePath } = makeDependencies();
-        const expected = path.resolve("/some/home/dir/.upmconfig.toml");
-        getHomePath.mockReturnValue(path.dirname(expected));
+        const { resolveDefaultUpmConfigPath } = makeDependencies();
 
         const actual = await resolveDefaultUpmConfigPath(false);
 
-        expect(actual).toEqual(expected);
+        expect(actual).toEqual(homeConfigPath);
       });
     });
   });