Code review, cleanup, removal of dead/dangerous host functions (#1085)

Most of this is fairly trivial cleanup _except_ the part where I'm
removing 2 host functions:

  - get_invoking_contract
  - get_current_call_stack

These are vestigial from the older auth scheme and are potential
footguns to leave exposed; the consensus seems to be that anything you
_should_ do with them you can do better with the new auth system, so
exposing them is just asking for trouble.

soroban-env-common/env.json

@@ -30,13 +30,6 @@
                 },
                 {
                     "export": "0",
-                    "name": "get_invoking_contract",
-                    "args": [],
-                    "return": "AddressObject",
-                    "docs": "Get the address object of the contract which invoked the running contract. Traps if the running contract was not invoked by a contract."
-                },
-                {
-                    "export": "1",
                     "name": "obj_cmp",
                     "args": [
                         {
@@ -52,7 +45,7 @@
                     "docs": "Compare two objects, or at least one object to a non-object, structurally. Returns -1 if a<b, 1 if a>b, or 0 if a==b."
                 },
                 {
-                    "export": "2",
+                    "export": "1",
                     "name": "contract_event",
                     "args": [
                         {
@@ -68,35 +61,28 @@
                     "docs": "Records a contract event. `topics` is expected to be a `SCVec` with length <= 4 that cannot contain `Vec`, `Map`, or `Bytes` with length > 32."
                 },
                 {
-                    "export": "3",
+                    "export": "2",
                     "name": "get_ledger_version",
                     "args": [],
                     "return": "U32Val",
                     "docs": "Return the protocol version of the current ledger as a u32."
                 },
                 {
-                    "export": "4",
+                    "export": "3",
                     "name": "get_ledger_sequence",
                     "args": [],
                     "return": "U32Val",
                     "docs": "Return the sequence number of the current ledger as a u32."
                 },
                 {
-                    "export": "5",
+                    "export": "4",
                     "name": "get_ledger_timestamp",
                     "args": [],
                     "return": "U64Val",
                     "docs": "Return the timestamp number of the current ledger as a u64."
                 },
                 {
-                    "export": "6",
-                    "name": "get_current_call_stack",
-                    "args": [],
-                    "return": "VecObject",
-                    "docs": "Returns the full call stack from the first contract call to the current one as a vector of vectors, where the inside vector contains the contract id as Hash, and a function as a Symbol."
-                },
-                {
-                    "export": "7",
+                    "export": "5",
                     "name": "fail_with_error",
                     "args": [
                         {
@@ -108,21 +94,21 @@
                     "docs": "Causes the currently executing contract to fail immediately with a provided error code, which must be of error-type `ScErrorType::Contract`. Does not actually return."
                 },
                 {
-                    "export": "8",
+                    "export": "6",
                     "name": "get_ledger_network_id",
                     "args": [],
                     "return": "BytesObject",
                     "docs": "Return the network id (sha256 hash of network passphrase) of the current ledger as `Bytes`. The value is always 32 bytes in length."
                 },
                 {
-                    "export": "9",
+                    "export": "7",
                     "name": "get_current_contract_address",
                     "args": [],
                     "return": "AddressObject",
                     "docs": "Get the Address object for the current contract."
                 },
                 {
-                    "export": "a",
+                    "export": "8",
                     "name": "get_max_expiration_ledger",
                     "args": [],
                     "return": "U32Val",
@@ -1178,7 +1164,7 @@
                         }
                     ],
                     "return": "u64",
-                    "docs": "Binary search a sorted vector for a given element. If it exists, the high-32 bits of the return value is 0x0001 and the low-32 bits contain the u32 index of the element. If it does not exist, the high-32 bits of the return value is 0x0000 and the low-32 bits contain the u32 index at which the element would need to be inserted into the vector to maintain sorted order."
+                    "docs": "Binary search a sorted vector for a given element. If it exists, the high 32 bits of the return value is 0x0000_0001 and the low 32 bits contain the u32 index of the element. If it does not exist, the high 32 bits of the return value is 0x0000_0000 and the low-32 bits contain the u32 index at which the element would need to be inserted into the vector to maintain sorted order."
                 },
                 {
                     "export": "g",

soroban-env-common/src/meta.rs

@@ -58,7 +58,7 @@ soroban_env_macros::generate_env_meta_consts!(
 #[cfg(not(feature = "next"))]
 soroban_env_macros::generate_env_meta_consts!(
     ledger_protocol_version: 20,
-    pre_release_version: 61,
+    pre_release_version: 62,
 );
 
 pub const fn get_ledger_protocol_version(interface_version: u64) -> u32 {

soroban-env-common/src/vmcaller_env.rs

@@ -36,17 +36,17 @@ impl<'a, T> VmCaller<'a, T> {
         match &self.0 {
             Some(caller) => Ok(caller),
             None => Err(Error::from_type_and_code(
-                ScErrorType::WasmVm,
-                ScErrorCode::MissingValue,
+                ScErrorType::Context,
+                ScErrorCode::InternalError,
             )),
         }
     }
     pub fn try_mut(&mut self) -> Result<&mut wasmi::Caller<'a, T>, Error> {
         match &mut self.0 {
             Some(caller) => Ok(caller),
             None => Err(Error::from_type_and_code(
-                ScErrorType::WasmVm,
-                ScErrorCode::MissingValue,
+                ScErrorType::Context,
+                ScErrorCode::InternalError,
             )),
         }
     }
@@ -122,15 +122,15 @@ macro_rules! generate_vmcaller_checked_env_trait {
 
         /// This trait is a variant of the [Env](crate::Env) trait used to
         /// define the interface implemented by Host. The wasmi VM dispatch
-        /// functions call methods on `VmCallerEnv`, passing a
-        /// [`VmCaller`] that wraps the wasmi Caller context, and then convert
-        /// any `Result::Err(...)` return value into a VM trap, halting VM
-        /// execution.
+        /// functions (in soroban_env_host::dispatch) call methods on
+        /// `VmCallerEnv`, passing a [`VmCaller`] that wraps the wasmi Caller
+        /// context, and then convert any `Result::Err(...)` return value into a
+        /// VM trap, halting VM execution.
         ///
-        /// There is also a blanket `impl<T:VmCallerEnv> Env for
-        /// T` that implements the `Env` for any `VmCallerEnv` by
-        /// passing [`VmCaller::none()`] for the first argument, allowing user
-        /// code such as the native contract to avoid writing `VmCaller::none()`
+        /// There is also a blanket `impl<T:VmCallerEnv> Env for T` that
+        /// implements the `Env` for any `VmCallerEnv` by passing
+        /// [`VmCaller::none()`] for the first argument, allowing user code such
+        /// as the native contract to avoid writing `VmCaller::none()`
         /// everywhere.
         pub trait VmCallerEnv: EnvBase
         {
@@ -172,6 +172,10 @@ macro_rules! vmcaller_none_function_helper {
     {fn $fn_id:ident($($arg:ident:$type:ty),*) -> $ret:ty}
     =>
     {
+        // We call `augment_err_result` here to give the Env a chance to attach
+        // context (eg. a backtrace) to any error that was generated by code
+        // that didn't have an Env on hand when creating the error. This will at
+        // least localize the error to a given Env call.
         fn $fn_id(&self, $($arg:$type),*) -> Result<$ret, Self::Error> {
             self.augment_err_result(<Self as VmCallerEnv>::$fn_id(self, &mut VmCaller::none(), $($arg),*))
         }

soroban-env-guest/src/guest.rs

@@ -12,7 +12,7 @@ use static_assertions as sa;
 
 // Just the smallest possible version of a runtime assertion-or-panic.
 #[inline(always)]
-pub(crate) fn require(b: bool) {
+fn require(b: bool) {
     if !b {
         core::arch::wasm32::unreachable()
     }