Add Caller addresses function (#6514)

## Description
Adds a new `caller_addresses` function to return a list of all owners of
input coins and messages to a transaction

## Checklist

- [x] I have linked to any relevant issues.
- [x] I have commented my code, particularly in hard-to-understand
areas.
- [x] I have updated the documentation where relevant (API docs, the
reference, and the Sway book).
- [ ] If my change requires substantial documentation changes, I have
[requested support from the DevRel
team](https://github.com/FuelLabs/devrel-requests/issues/new/choose)
- [x] I have added tests that prove my fix is effective or that my
feature works.
- [x] I have added (or requested a maintainer to add) the necessary
`Breaking*` or `New Feature` labels where relevant.
- [x] I have done my best to ensure that my PR adheres to [the Fuel Labs
Code Review
Standards](https://github.com/FuelLabs/rfcs/blob/master/text/code-standards/external-contributors.md).
- [x] I have requested a review from the relevant team or maintainers.

---------

Co-authored-by: Sophie Dankel <47993817+sdankel@users.noreply.github.com>

sway-lib-std/src/auth.sw

@@ -6,8 +6,16 @@ use ::contract_id::ContractId;
 use ::identity::Identity;
 use ::option::Option::{self, *};
 use ::result::Result::{self, *};
-use ::inputs::{Input, input_coin_owner, input_count, input_message_recipient, input_type,};
+use ::inputs::{
+    Input,
+    input_coin_owner,
+    input_count,
+    input_message_recipient,
+    input_message_sender,
+    input_type,
+};
 use ::revert::revert;
+use ::vec::Vec;
 
 /// The error type used when an `Identity` cannot be determined.
 pub enum AuthError {
@@ -192,6 +200,52 @@ pub fn caller_address() -> Result<Address, AuthError> {
     }
 }
 
+/// Get the owners of the inputs (of type `Input::Coin` or `Input::Message`) to a
+/// `TransactionScript`.
+///
+/// # Additional Information
+///
+/// The list is not deduplicated, so there may be repeated addresses in the returned vector.
+///
+/// # Returns
+///
+/// * [Vec<Address>] - The addresses of the owners of the inputs.
+///
+/// # Examples
+///
+/// ```sway
+/// use std::auth::caller_addresses;
+///
+/// fn foo(some_address: Address) {
+///     let addresses = caller_addresses();
+///
+///     assert(addresses.get(0).unwrap() == some_address);
+/// }
+/// ```
+pub fn caller_addresses() -> Vec<Address> {
+    let inputs = input_count().as_u64();
+    let mut addresses = Vec::new();
+    let mut iter = 0;
+
+    while iter < inputs {
+        // Call the corresponding function based on the input type.
+        let input_owner = match input_type(iter) {
+            Some(Input::Coin) => input_coin_owner(iter),
+            Some(Input::Message) => input_message_sender(iter),
+            _ => None, // If not Coin or Message, loop continues.
+        };
+
+        // If we successfully retrieved an owner address, add it to the vector.
+        if let Some(address) = input_owner {
+            addresses.push(address);
+        }
+
+        iter += 1;
+    }
+
+    addresses
+}
+
 /// Get the current predicate's address when called in an internal context.
 ///
 /// # Returns

test/src/sdk-harness/test_artifacts/auth_testing_abi/src/main.sw

@@ -4,4 +4,5 @@ abi AuthTesting {
     fn is_caller_external() -> bool;
     fn returns_msg_sender(expected_id: ContractId) -> bool;
     fn returns_msg_sender_address(expected_id: Address) -> bool;
+    fn returns_caller_addresses() -> Vec<Address>;
 }

test/src/sdk-harness/test_artifacts/auth_testing_contract/src/main.sw

@@ -43,4 +43,8 @@ impl AuthTesting for Contract {
         }
         ret
     }
+
+    fn returns_caller_addresses() -> Vec<Address> {
+        caller_addresses()
+    }
 }