feat(cli): support multiple env file argument (#26527)

Closes #26425 

## Overview

This PR adds support for specifying multiple environment files as
arguments when using the Deno CLI. Subsequent files override
pre-existing variables defined in previous files.

If the same variable is defined in the environment and in the file, the
value from the environment takes precedence.

## Example Usage
```bash
deno run --allow-env --env-file --env-file=".env.one" --env-file=".env.two" script.ts
```

---------

Co-authored-by: Bartek Iwańczuk <biwanczuk@gmail.com>

1 files changed, 10 insertions, 7 deletions

diff --git a/cli/args/mod.rs b/cli/args/mod.rs
index 318a6ca76..ec75d7a10 100644
--- a/cli/args/mod.rs
+++ b/cli/args/mod.rs
@@ -1128,7 +1128,7 @@ impl CliOptions {
     self.flags.otel_config()
   }
 
-  pub fn env_file_name(&self) -> Option<&String> {
+  pub fn env_file_name(&self) -> Option<&Vec<String>> {
     self.flags.env_file.as_ref()
   }
 
@@ -1935,19 +1935,22 @@ pub fn config_to_deno_graph_workspace_member(
   })
 }
 
-fn load_env_variables_from_env_file(filename: Option<&String>) {
-  let Some(env_file_name) = filename else {
+fn load_env_variables_from_env_file(filename: Option<&Vec<String>>) {
+  let Some(env_file_names) = filename else {
     return;
   };
-  match from_filename(env_file_name) {
-    Ok(_) => (),
-    Err(error) => {
-      match error {
+
+  for env_file_name in env_file_names.iter().rev() {
+    match from_filename(env_file_name) {
+      Ok(_) => (),
+      Err(error) => {
+        match error {
           dotenvy::Error::LineParse(line, index)=> log::info!("{} Parsing failed within the specified environment file: {} at index: {} of the value: {}",colors::yellow("Warning"), env_file_name, index, line),
           dotenvy::Error::Io(_)=> log::info!("{} The `--env-file` flag was used, but the environment file specified '{}' was not found.",colors::yellow("Warning"),env_file_name),
           dotenvy::Error::EnvVar(_)=> log::info!("{} One or more of the environment variables isn't present or not unicode within the specified environment file: {}",colors::yellow("Warning"),env_file_name),
           _ => log::info!("{} Unknown failure occurred with the specified environment file: {}", colors::yellow("Warning"), env_file_name),
         }
+      }
     }
   }
 }