fix: provide empty string to 0 length process environment variables (#5679)

* fix: provide empty string to len 0 process env vars

For process loaded env vars, its a bug to give them the literal value '""'
if the provided length is 0.

* fix: add test and remove unneeded branch

Removes the redundant branch for empty env vars and adds a test for the
process specific case.

* fix: remove empty_string_value

Removes the constant in favor of using the empty values or passing the
literal "".

* style: format env.test.ts

2 files changed, 13 insertions, 9 deletions

diff --git a/src/env_loader.zig b/src/env_loader.zig
index b8fa90d45..6957a1a26 100644
--- a/src/env_loader.zig
+++ b/src/env_loader.zig
@@ -35,8 +35,6 @@ pub const Loader = struct {
 
     did_load_process: bool = false,
 
-    const empty_string_value: string = "\"\"";
-
     pub fn has(this: *const Loader, input: []const u8) bool {
         const value = this.map.get(input) orelse return false;
         if (value.len == 0) return false;
@@ -304,7 +302,7 @@ pub const Loader = struct {
                     }
                 } else {
                     while (iter.next()) |entry| {
-                        const value: string = if (entry.value_ptr.value.len == 0) empty_string_value else entry.value_ptr.value;
+                        const value: string = entry.value_ptr.value;
                         const key = std.fmt.allocPrint(key_allocator, "process.env.{s}", .{entry.key_ptr.*}) catch unreachable;
 
                         e_strings[0] = js_ast.E.String{
@@ -358,15 +356,11 @@ pub const Loader = struct {
                 var key = env[0..i];
                 var value = env[i + 1 ..];
                 if (key.len > 0) {
-                    if (value.len > 0) {
-                        this.map.put(key, value) catch unreachable;
-                    } else {
-                        this.map.put(key, empty_string_value) catch unreachable;
-                    }
+                    this.map.put(key, value) catch unreachable;
                 }
             } else {
                 if (env.len > 0) {
-                    this.map.put(env, empty_string_value) catch unreachable;
+                    this.map.put(env, "") catch unreachable;
                 }
             }
         }
diff --git a/test/cli/run/env.test.ts b/test/cli/run/env.test.ts
index 3ed300477..1c2d51e8e 100644
--- a/test/cli/run/env.test.ts
+++ b/test/cli/run/env.test.ts
@@ -385,6 +385,16 @@ test(".env with zero length strings", () => {
   expect(stdout).toBe("||0|0");
 });
 
+test("process with zero length environment variable", () => {
+  const dir = tempDirWithFiles("process-issue-zerolength", {
+    "index.ts": "console.log(`'${process.env.TEST_ENV_VAR}'`);",
+  });
+  const { stdout } = bunRun(`${dir}/index.ts`, {
+    TEST_ENV_VAR: "",
+  });
+  expect(stdout).toBe("''");
+});
+
 test(".env in a folder doesn't throw an error", () => {
   const dir = tempDirWithFiles("dotenv-issue-3670", {
     ".env": {