Guard import.meta.env in ConfigProvider.fromEnv

.changeset/configprovider-import-meta-env.md

@@ -0,0 +1,5 @@
+---
+"effect": patch
+---
+
+Remove the default `import.meta.env` lookup from `ConfigProvider.fromEnv`, fixing module analysis failures in runtimes that do not support `import.meta`, closes #6358.

packages/effect/CONFIG.md

@@ -347,7 +347,7 @@ Effect.runSync(host) // "localhost"
 
 **How `_` splitting works**: env var names are split on `_` to build a tree. This means `DATABASE_HOST=localhost` is accessible at both `["DATABASE_HOST"]` (flat) and `["DATABASE", "HOST"]` (nested). Querying `["DATABASE"]` returns a Record node with child key `"HOST"`.
 
-Pass `{ env: { ... } }` for testing. Omit to use `process.env` (merged with `import.meta.env` when available).
+Pass `{ env: { ... } }` for testing. Omit to use `process.env` when available.
 
 ### `ConfigProvider.fromUnknown` — Plain JS Objects
 

packages/effect/src/ConfigProvider.ts

@@ -850,8 +850,8 @@ function emptyStringAsMissing(value: string | undefined, preserveEmptyStrings: b
  * purely numeric names, the node is reported as an `Array`; otherwise as a
  * `Record`.
  *
- * The default environment merges `process.env` and `import.meta.env` (when
- * available). Override by passing `{ env: { ... } }`.
+ * The default environment reads `process.env` when available. For runtimes that
+ * expose environment variables elsewhere, pass `{ env: { ... } }`.
  *
  * Literal empty strings are treated as missing values when loaded as values by
  * default. Pass `{ preserveEmptyStrings: true }` to keep empty strings as
@@ -892,8 +892,7 @@ export function fromEnv(options?: {
   const env: Record<string, string | undefined> = options?.env ?? {
     ...(globalThis as {
       readonly process?: { readonly env?: Record<string, string | undefined> }
-    }).process?.env,
-    ...(import.meta as any)?.env
+    }).process?.env
   }
   const preserveEmptyStrings = options?.preserveEmptyStrings === true
   const trie = buildEnvTrie(env)

packages/effect/test/ConfigProvider.test.ts

@@ -1,6 +1,7 @@
 import { describe, it } from "@effect/vitest"
 import { deepStrictEqual } from "@effect/vitest/utils"
 import { ConfigProvider, Effect, FileSystem, Layer, Path, PlatformError, Result } from "effect"
+import * as Fs from "node:fs"
 
 const notFound = (method: string): PlatformError.PlatformError =>
   PlatformError.systemError({
@@ -289,6 +290,46 @@ describe("ConfigProvider", () => {
   })
 
   describe("fromEnv", () => {
+    it("uses the default environment when no env is provided", async () => {
+      const key = "EFFECT_CONFIG_PROVIDER_TEST_DEFAULT_ENV"
+      const previous = process.env[key]
+      process.env[key] = "value1"
+      try {
+        const provider = ConfigProvider.fromEnv()
+        await assertSuccess(provider, [key], ConfigProvider.makeValue("value1"))
+      } finally {
+        if (previous === undefined) {
+          delete process.env[key]
+        } else {
+          process.env[key] = previous
+        }
+      }
+    })
+
+    it("uses an explicit env over the default environment", async () => {
+      const key = "EFFECT_CONFIG_PROVIDER_TEST_DEFAULT_ENV"
+      const previous = process.env[key]
+      process.env[key] = "default"
+      try {
+        const provider = ConfigProvider.fromEnv({ env: { [key]: "explicit" } })
+        await assertSuccess(provider, [key], ConfigProvider.makeValue("explicit"))
+      } finally {
+        if (previous === undefined) {
+          delete process.env[key]
+        } else {
+          process.env[key] = previous
+        }
+      }
+    })
+
+    it("does not reference import.meta.env in the common ConfigProvider module", () => {
+      const sourcePath = Fs.existsSync("src/ConfigProvider.ts")
+        ? "src/ConfigProvider.ts"
+        : "packages/effect/src/ConfigProvider.ts"
+      const source = Fs.readFileSync(sourcePath, "utf8")
+      deepStrictEqual(source.includes("import.meta.env"), false)
+    })
+
     it("env without an underscore", async () => {
       const env = { A: "value1" }
       const provider = ConfigProvider.fromEnv({ env })