In monorepo root, disallow dependencies in favor of devDependencies

.changeset/wicked-points-own.md

@@ -0,0 +1,5 @@
+---
+"@manypkg/cli": minor
+---
+
+Change the `ROOT_HAS_DEV_DEPENDENCIES` rule to `ROOT_HAS_PROD_DEPENDENCIES`. Monorepo root should use `devDependencies` instead of `dependencies` for better support of production-only installs, useful in eg Docker builds.

README.md

@@ -294,15 +294,15 @@ This is so that `peerDependencies` are available in the package during developme
 
 The range for the dependency specified in `peerDependencies` is added to `devDependencies` unless the package is already a non-peer dependency elsewhere in the repo in which, that range is used instead.
 
-## Root has devDependencies
+## Root has prod dependencies
 
-Key: `ROOT_HAS_DEV_DEPENDENCIES`
+Key: `ROOT_HAS_PROD_DEPENDENCIES`
 
-The root package should not have any `devDependencies`, instead all dependencies should be in `dependencies`
+The root package should not have any production `dependencies`, instead all dependencies should be in `devDependencies`.
 
 ### Why it's a rule
 
-The root `package.json` of a monorepo is not published so whether a dependency is in `devDependencies` or `dependencies` does not make a difference and having one place to put dependencies in the root means that people do not have to arbitrarily decide where a dependency should go every time they install one.
+The root `package.json` of a monorepo is not published so whether a dependency is in `devDependencies` or `dependencies` does not make a difference and having one place to put dependencies in the root means that people do not have to arbitrarily decide where a dependency should go every time they install one. We prefer `devDependencies` because a monorepo root should contain only tooling dependencies.
 
 ### How it's fixed
 

package.json

@@ -22,7 +22,7 @@
       "jest-watch-typeahead/testname"
     ]
   },
-  "dependencies": {
+  "devDependencies": {
     "@babel/core": "^7.20.5",
     "@babel/plugin-transform-runtime": "^7.19.6",
     "@babel/preset-env": "^7.20.2",

packages/cli/src/checks/ROOT_HAS_DEV_DEPENDENCIES.ts → packages/cli/src/checks/ROOT_HAS_PROD_DEPENDENCIES.ts

@@ -3,31 +3,31 @@ import pc from "picocolors";
 import { Package } from "@manypkg/get-packages";
 
 type ErrorType = {
-  type: "ROOT_HAS_DEV_DEPENDENCIES";
+  type: "ROOT_HAS_PROD_DEPENDENCIES";
   workspace: Package;
 };
 
 export default makeCheck<ErrorType>({
   type: "root",
   validate: (rootWorkspace) => {
-    if (rootWorkspace.packageJson.devDependencies) {
-      return [{ type: "ROOT_HAS_DEV_DEPENDENCIES", workspace: rootWorkspace }];
+    if (rootWorkspace.packageJson.dependencies) {
+      return [{ type: "ROOT_HAS_PROD_DEPENDENCIES", workspace: rootWorkspace }];
     }
     return [];
   },
   fix: (error) => {
-    error.workspace.packageJson.dependencies = sortObject({
+    error.workspace.packageJson.devDependencies = sortObject({
       ...error.workspace.packageJson.devDependencies,
       ...error.workspace.packageJson.dependencies,
     });
 
-    delete error.workspace.packageJson.devDependencies;
+    delete error.workspace.packageJson.dependencies;
   },
   print: () => {
     return `the root package.json contains ${pc.yellow(
-      "devDependencies"
-    )}, this is disallowed as ${pc.yellow("devDependencies")} vs ${pc.green(
       "dependencies"
+    )}, this is disallowed as ${pc.yellow("dependencies")} vs ${pc.green(
+      "devDependencies"
     )} in a private package does not affect anything and creates confusion.`;
   },
 });

packages/cli/src/checks/index.ts

@@ -3,7 +3,7 @@ import INTERNAL_MISMATCH from "./INTERNAL_MISMATCH";
 import INVALID_DEV_AND_PEER_DEPENDENCY_RELATIONSHIP from "./INVALID_DEV_AND_PEER_DEPENDENCY_RELATIONSHIP";
 import INVALID_PACKAGE_NAME from "./INVALID_PACKAGE_NAME";
 import MULTIPLE_DEPENDENCY_TYPES from "./MULTIPLE_DEPENDENCY_TYPES";
-import ROOT_HAS_DEV_DEPENDENCIES from "./ROOT_HAS_DEV_DEPENDENCIES";
+import ROOT_HAS_PROD_DEPENDENCIES from "./ROOT_HAS_PROD_DEPENDENCIES";
 import UNSORTED_DEPENDENCIES from "./UNSORTED_DEPENDENCIES";
 import INCORRECT_REPOSITORY_FIELD from "./INCORRECT_REPOSITORY_FIELD";
 import WORKSPACE_REQUIRED from "./WORKSPACE_REQUIRED";
@@ -14,7 +14,7 @@ export let checks = {
   INVALID_DEV_AND_PEER_DEPENDENCY_RELATIONSHIP,
   INVALID_PACKAGE_NAME,
   MULTIPLE_DEPENDENCY_TYPES,
-  ROOT_HAS_DEV_DEPENDENCIES,
+  ROOT_HAS_PROD_DEPENDENCIES,
   UNSORTED_DEPENDENCIES,
   INCORRECT_REPOSITORY_FIELD,
   WORKSPACE_REQUIRED,