fix(aws): prevent endless loop when AWS config file is a directory (#3335)

When opening a directory as a file the intial open works, while
subsequent line-reads will fail with _is a directory_.
Since erroring line-reads were just skipped this lead to an
endless loop.

src/modules/aws.rs

@@ -1,6 +1,4 @@
 use std::collections::HashMap;
-use std::fs::File;
-use std::io::{BufRead, BufReader};
 use std::path::PathBuf;
 use std::str::FromStr;
 
@@ -10,7 +8,7 @@ use super::{Context, Module, RootModuleConfig};
 
 use crate::configs::aws::AwsConfig;
 use crate::formatter::StringFormatter;
-use crate::utils::render_time;
+use crate::utils::{read_file, render_time};
 
 type Profile = String;
 type Region = String;
@@ -40,19 +38,19 @@ fn get_config_file_path(context: &Context) -> Option<PathBuf> {
 fn get_aws_region_from_config(context: &Context, aws_profile: Option<&str>) -> Option<Region> {
     let config_location = get_config_file_path(context)?;
 
-    let file = File::open(&config_location).ok()?;
-    let reader = BufReader::new(file);
-    let lines = reader.lines().filter_map(Result::ok);
+    let contents = read_file(&config_location).ok()?;
 
     let region_line = if let Some(aws_profile) = aws_profile {
-        lines
+        contents
+            .lines()
             .skip_while(|line| line != &format!("[profile {}]", &aws_profile))
             .skip(1)
             .take_while(|line| !line.starts_with('['))
             .find(|line| line.starts_with("region"))
     } else {
-        lines
-            .skip_while(|line| line != "[default]")
+        contents
+            .lines()
+            .skip_while(|&line| line != "[default]")
             .skip(1)
             .take_while(|line| !line.starts_with('['))
             .find(|line| line.starts_with("region"))
@@ -91,11 +89,7 @@ fn get_credentials_duration(context: &Context, aws_profile: Option<&Profile>) ->
     {
         chrono::DateTime::parse_from_rfc3339(&expiration_date).ok()
     } else {
-        let credentials_location = get_credentials_file_path(context)?;
-
-        let file = File::open(&credentials_location).ok()?;
-        let reader = BufReader::new(file);
-        let lines = reader.lines().filter_map(Result::ok);
+        let contents = read_file(get_credentials_file_path(context)?).ok()?;
 
         let profile_line = if let Some(aws_profile) = aws_profile {
             format!("[{}]", aws_profile)
@@ -103,7 +97,8 @@ fn get_credentials_duration(context: &Context, aws_profile: Option<&Profile>) ->
             "[default]".to_string()
         };
 
-        let expiration_date_line = lines
+        let expiration_date_line = contents
+            .lines()
             .skip_while(|line| line != &profile_line)
             .skip(1)
             .take_while(|line| !line.starts_with('['))
@@ -182,7 +177,7 @@ pub fn module<'a>(context: &'a Context) -> Option<Module<'a>> {
 mod tests {
     use crate::test::ModuleRenderer;
     use ansi_term::Color;
-    use std::fs::File;
+    use std::fs::{create_dir, File};
     use std::io::{self, Write};
 
     #[test]
@@ -306,6 +301,37 @@ mod tests {
         assert_eq!(expected, actual);
     }
 
+    #[test]
+    fn credentials_file_is_ignored_when_is_directory() -> io::Result<()> {
+        let dir = tempfile::tempdir()?;
+        let config_path = dir.path().join("credentials");
+        create_dir(&config_path)?;
+
+        assert!(ModuleRenderer::new("aws")
+            .env(
+                "AWS_CREDENTIALS_FILE",
+                config_path.to_string_lossy().as_ref(),
+            )
+            .collect()
+            .is_none());
+
+        dir.close()
+    }
+
+    #[test]
+    fn config_file_path_is_ignored_when_is_directory() -> io::Result<()> {
+        let dir = tempfile::tempdir()?;
+        let config_path = dir.path().join("config");
+        create_dir(&config_path)?;
+
+        assert!(ModuleRenderer::new("aws")
+            .env("AWS_CONFIG_FILE", config_path.to_string_lossy().as_ref())
+            .collect()
+            .is_none());
+
+        dir.close()
+    }
+
     #[test]
     fn default_profile_set() -> io::Result<()> {
         let dir = tempfile::tempdir()?;