fix: escape "$" character to avoid bash interpreting (#884)

src/context.rs

@@ -270,7 +270,7 @@ fn get_current_branch(repository: &Repository) -> Option<String> {
     shorthand.map(std::string::ToString::to_string)
 }
 
-#[derive(Debug, Clone)]
+#[derive(Debug, Clone, PartialEq)]
 pub enum Shell {
     Bash,
     Fish,

src/module.rs

@@ -191,18 +191,17 @@ fn ansi_strings_modified(ansi_strings: Vec<ANSIString>, shell: Shell) -> Vec<ANS
                             _ => x.to_string(),
                         }
                     }
-                    MAYBE_ESCAPE_END => {
-                        if escaped {
+                    MAYBE_ESCAPE_END if escaped => {
                         escaped = false;
                         match shell {
                             Shell::Bash => String::from("m\u{5c}\u{5d}"), // => m\]
                             Shell::Zsh => String::from("m\u{25}\u{7d}"),  // => m%}
                             _ => x.to_string(),
                         }
-                        } else {
-                            x.to_string()
-                        }
                     }
+                    // escape the $ character to avoid $() code injection on bash shell,
+                    // see #658 for more
+                    '$' if Shell::Bash == shell => String::from("\\$"),
                     _ => x.to_string(),
                 })
                 .collect();