Asset Hub was using the native token for benchmarking xcm instructions.
This is not the best since it's cheaper than using something in
`pallet-assets` for example.
Had to remove some restrictive checks from `pallet-xcm-benchmarks`.

I'll bring back the checks with a better framework in the future that
allows for handling multiple assets (`fungibles::*` traits).

---------

Co-authored-by: cmd[bot] <41898282+github-actions[bot]@users.noreply.github.com>

# Description

It is difficult to spot changes to umbrella features when reviewing,
when defined on a long line, so made sure tomls formatting will be
applied to long array lines by splitting them on multiple lines. This
will be applied to any tomls in the monorepo that is not excluded from
taplo.

## Integration

N/A

## Review Notes

Set global taplo config `array_auto_expand` to true.

---------

Signed-off-by: Iulian Barbu <[email protected]>

The xcm-executor will not support `ExecuteWithOrigin` from the start. It
might be implemented again in the future when more time can be spent on
it.

---------

Co-authored-by: cmd[bot] <41898282+github-actions[bot]@users.noreply.github.com>

This PR includes:

- deduplicating some XCM decoding logic
- making use of `decode_with_depth_limit` consistently for
`VersionedXcm`
- some cleanup

Closes #6851 

This PR adds an `EventEmitter` trait to the XCM Executor configuration,
enabling event emission for XCM handling. The implementation introduces
three dedicated functions to emit relevant events:

- `emit_sent_event`: Emits a `Sent` event when an XCM is successfully
sent.
- `emit_send_failure_event`: Emits a `SendFailed` event when an XCM
fails to send.
- `emit_process_failure_event`: Emits a `ProcessXcmError` event when an
XCM fails during processing.

Kusama address: FkB6QEo8VnV3oifugNj5NeVG3Mvq1zFbrUu4P5YwRoe5mQN

---------

Co-authored-by: Raymond Cheung <[email protected]>
Co-authored-by: Adrian Catangiu <[email protected]>
Co-authored-by: cmd[bot] <41898282+github-actions[bot]@users.noreply.github.com>

This PR enhances **`test_log_capture`**, ensuring logs are **captured
for assertions** and **printed to the console** during test execution.

## **Motivation**  

- Partially addresses #6119 and #6125, to improves developer **tracing
and debugging** in XCM-related tests.
- Builds on #7594, improving **log visibility** while maintaining test
**log capture capabilities**.
- While writing tests for #7234, I noticed this function was missing.
This PR adds it to streamline log handling in unit tests.

## **Changes**  

- Ensures logs up to `TRACE` level are **captured** (for assertions) and
**printed** (for visibility).
- Refines documentation to clearly specify **when to use** each
function.
- **Removes ANSI escape codes** from captured logs to ensure clean,
readable assertions.

## **When to Use?**  

| Usage | Captures Logs? | Prints Logs? | Example |

|----------------------------------------------|-----------------|--------------|-----------------------------------------------|
| `init_log_capture(LevelFilter::INFO, false)` | ✅ Yes | ❌ No | Capture
logs for assertions without printing. |
| `init_log_capture(LevelFilter::TRACE, true)` | ✅ Yes | ✅ Yes | Capture
logs and print them in test output. |
| `sp_tracing::init_for_tests()` | ❌ No | ✅

 Yes | Print logs to the
console without capturing. |

---------

Co-authored-by: cmd[bot] <41898282+github-actions[bot]@users.noreply.github.com>

I added a new `ExternalConsensusLocationsConverterFor` struct to handle
external global consensus locations and their child locations.
This struct extends the functionality of existing converters
(`GlobalConsensusParachainConvertsFor` and
`EthereumLocationsConverterFor`) while maintaining backward
compatibility.

Fixes https://github.com/paritytech/polkadot-sdk/issues/7129

Polkadot address: 121HJWZtD13GJQPD82oEj3gSeHqsRYm1mFgRALu4L96kfPD1

---------

Co-authored-by: Adrian Catangiu <[email protected]>
Co-authored-by: ndk <[email protected]>

Related to https://github.com/paritytech/polkadot-sdk/issues/7360

This PR adds `DecodeWithMemTracking` as a trait bound for `Header`,
`Block` and `TransactionExtension` and
derives it for all the types that implement these traits in
`polkadot-sdk`.

A follow-up PR to simplify event assertions by introducing
`contains_event`, allowing event checks without needing exact field
matches. This reduces redundancy and makes tests more flexible.

Partially addresses #6119 by providing an alternative way to assert
events.

Reference: [PR #7594 -
Discussion](https://github.com/paritytech/polkadot-sdk/pull/7594#discussion_r1965566349)

---------

Co-authored-by: cmd[bot] <41898282+github-actions[bot]@users.noreply.github.com>
Co-authored-by: Branislav Kontur <[email protected]>
Co-authored-by: Bastian Köcher <[email protected]>

The `PayFees` instruction should only ever be used once. If it's used
more than once, it's just a noop.

---------

Co-authored-by: cmd[bot] <41898282+github-actions[bot]@users.noreply.github.com>
Co-authored-by: Adrian Catangiu <[email protected]>

# Description

Fixes #7413

## Integration

This PR updates the `DryRunApi`. The signature of the `dry_run_call` is
changed, and the XCM version of the return values of `dry_run_xcm` now
follows the version of the input XCM program.

## Review Notes

* **The `DryRunApi` is modified**
* **Added the `Router::clear_messages` to `dry_run_xcm` common
implementation**
* **Fixed the xcmp-queue's Router's clear_messages: channels details'
first_index and last_index are reset when clearing**
* **The MIN_XCM_VERSION is added**
* The common implementation in the `pallet-xcm` is modified accordingly
* The `DryRunApi` tests are modified to account for testing old XCM
versions
* The implementation from the `pallet-xcm` is used where it was not used
(including the `DryRunApi` tests)
* All the runtime implementations are modified according to the Runtime
API change

---------

Co-authored-by: Adrian Catangiu <[email protected]>

# Description

This PR introduces a lightweight log-capturing mechanism for XCM unit
tests, simplifying debugging by enabling structured log assertions. It
partially addresses #6119 and #6125, offering an optional way to verify
logs in tests while remaining unobtrusive in normal execution.

# Key Changes

* [x] Introduces a log capture utility in `sp_tracing`.
* [x] Adds XCM test examples demonstrating how and when to use log
capturing.

# Review Notes:

* The log capture mechanism is opt-in and does not affect existing tests
unless explicitly used.
* The implementation is minimal and does not add complexity to existing
test setups.
* It provides a structured alternative to
[`sp_tracing::init_for_tests()`](https://paritytech.github.io/polkadot-sdk/master/sp_tracing/fn.init_for_tests.html)
for log verification in automated tests.

---------

Co-authored-by: cmd[bot] <41898282+github-actions[bot]@users.noreply.github.com>

# Description

Added logs in pallet-xcm to help in debugging, fixes #2408, and in
continuation of #4982

# Checklist

- [x]
https://github.com/paritytech/polkadot-sdk/blob/master/polkadot/xcm/xcm-builder/src/
- [x]
https://github.com/paritytech/polkadot-sdk/tree/master/cumulus/parachains/runtimes/assets/common/src
- [x] runtime-defined XCM filters/converters (just [one
example](https://github.com/paritytech/polkadot-sdk/blob/183b55aa

/cumulus/parachains/runtimes/bridge-hubs/bridge-hub-westend/src/xcm_config.rs#L284))

Polkadot Address: 1Gz5aLtEu2n4jsfA6XwtZnuaRymJrDDw4kEGdNHTdxrpzrc

---------

Co-authored-by: Ayevbeosa Iyamu <[email protected]>
Co-authored-by: Bastian Köcher <[email protected]>
Co-authored-by: Adrian Catangiu <[email protected]>
Co-authored-by: Raymond Cheung <[email protected]>
Co-authored-by: cmd[bot] <41898282+github-actions[bot]@users.noreply.github.com>

Ref https://github.com/paritytech/ci_cd/issues/1107

We mainly need that so that we can finally compile the `pallet_revive`
fixtures on stable. I did my best to keep the commits focused on one
thing to make review easier.

All the changes are needed because rustc introduced more warnings or is
more strict about existing ones. Most of the stuff could just be fixed
and the commits should be pretty self explanatory. However, there are a
few this that are notable:

## `non_local_definitions `

A lot of runtimes to write `impl` blocks inside functions. This makes
sense to reduce the amount of conditional compilation. I guess I could
have moved them into a module instead. But I think allowing it here
makes sense to avoid the code churn.

## `unexpected_cfgs`

The FRAME macros emit code that references various features like `std`,
`runtime-benchmarks` or `try-runtime`. If a create that uses those
macros does not have those features we get this warning. Those were
mostly when defining a `mock` runtime. I opted for silencing the warning
in this case rather than adding not needed features.

For the benchmarking ui tests I opted for adding the `runtime-benchmark`
feature to the `Cargo.toml`.

## Failing UI test

I am bumping the `trybuild` version and regenerating the ui tests. The
old version seems to be incompatible. This requires us to pass
`deny_warnings` in `CARGO_ENCODED_RUSTFLAGS` as `RUSTFLAGS` is ignored
in the new version.

## Removing toolchain file from the pallet revive fixtures

This is no longer needed since the latest stable will compile them fine
using the `RUSTC_BOOTSTRAP=1`.

---------

Co-authored-by: cmd[bot] <41898282+github-actions[bot]@users.noreply.github.com>

Just deriving `DecodeWithMemTracking` for the types used by the bridge,
snowbridge and xcm pallets

XCM: Deny barrier checks for nested XCMs with specific instructions to be executed on the local chain (#7200)

Resolves (partially):
https://github.com/paritytech/polkadot-sdk/issues/7148
Depends on: https://github.com/paritytech/polkadot-sdk/pull/7169

# Description

This PR addresses partially #7148 (Problem 2) and ensures the proper
checking of nested local instructions. It introduces a new barrier -
`DenyRecursively` - to provide more refined control over instruction
denial. The main change is the replacement of `DenyThenTry<Deny, Allow>`
with `DenyThenTry<DenyRecursively<Deny>, Allow>` which handles both
top-level and nested local instructions by applying allow condition
after denial.

For context and additional information, please refer to [_Problem 2 -
Barrier vs nested XCM
validation_](https://github.com/paritytech/polkadot-sdk/issues/7148).

# TODO
- [x] Evaluate PoC, more details at #7351:
    - **DenyNestedXcmInstructions**: Keep it as it is and be explicit:
        1. Name the Deny barriers for the top level.
2. Name the Deny barrier for nested with `DenyInstructionsWithXcm`.
- **DenyThenTry<DenyInstructionsWithXcm<Deny>, Allow>**: Alternatively,
hard-code those three instructions in `DenyThenTry`, so we wouldn’t need
`DenyInstructionsWithXcm`. However, this approach wouldn’t be as
general.
- **DenyInstructionsWithXcmFor**: Another possibility is to check
`DenyInstructionsWithXcm::Inner` for the actual `message`, so we don’t
need duplication for top-level and nested (not sure, maybe be explicit
is good thing) - see _Problem2 - example_. Instead of this:
   ```
  DenyThenTry<
                (
                               // Deny for top level XCM program 
                               DenyReserveTransferToRelayChain,
// Dedicated barrier for nested XCM programs
                               DenyInstructionsWithXcmFor<
// Repeat all Deny filters here
DenyReserveTransferToRelayChain,
                                >
                ),
   ```
  we could just use:
   ```
  DenyThenTry<
                (
                               // Dedicated barrier for XCM programs
                               DenyInstructionsWithXcmFor<
// Add all `Deny` filters here
DenyReserveTransferToRelayChain,
                                                ...
                                >
                ),
   ```
- [POC
Evaluation](https://github.com/paritytech/polkadot-sdk/pull/7200#discussion_r1939288792)
- [x] Consider better name `DenyInstructionsWithXcm` =>
`DenyRecursively`, more details at
[here](https://github.com/paritytech/polkadot-sdk/pull/7200#discussion_r1958588973)
- [x] Clean-up and docs
- [x] Merge https://github.com/paritytech/polkadot-sdk/pull/7169 or
rebase this branch on the top of `yrong:fix-for-deny-then-try`
- [x] Set for the runtimes where we use `DenyThenTry<Deny, Allow>` =>
`DenyThenTry<DenyRecursively<Deny>, Allow>`
- [ ] Schedule sec.audit

---------

Co-authored-by: Raymond Cheung <[email protected]>
Co-authored-by: cmd[bot] <41898282+github-actions[bot]@users.noreply.github.com>
Co-authored-by: ron <[email protected]>
Co-authored-by: Francisco Aguirre <[email protected]>
Co-authored-by: Clara van Staden <[email protected]>
Co-authored-by: Adrian Catangiu <[email protected]>

Fix issue where setting the `remote_fees` field of `InitiateTransfer` to
`None` could lead to unintended bypassing of fees in certain conditions.

Changes made to fix this:
- `remote_fees: None` now results in the `UnpaidExecution` instruction
being appended *after* the origin altering instruction, be it
`AliasOrigin` or `ClearOrigin`. This means `preserve_origin: true` must
be set if you want to have any chance of not paying for fees.
- The `AliasOrigin` instruction is not appended if the executor is
called with the root location (`Here`) since it would alias to itself.
Although this self-aliasing could be done, it needs the ecosystem to add
a new aliasing instruction, so we just skip it.
- Tweaked the `AllowExplicitUnpaidExecutionFrom` barrier to allow
receiving assets (via teleport or reserve asset transfer) and altering
the origin before actually using `UnpaidExecution`. This is to allow
unpaid teleports to work with `InitiateTransfer`.
- For this, the barrier now executes origin altering instructions and
keeps track of the modified origin. It then checks if this final origin
has enough permissions to not pay for fees. In order to follow the
`AliasOrigin` instruction it now takes a new generic `Aliasers` that
should be set to the XCM config item of the same name. This new generic
has a default value of `()`, effectively disallowing the use of
`AliasOrigin`.

---------

Co-authored-by: cmd[bot] <41898282+github-actions[bot]@users.noreply.github.com>
Co-authored-by: Adrian Catangiu <[email protected]>

Preparation for AHM and making stuff public.

---------

Signed-off-by: Oliver Tale-Yazdi <[email protected]>
Co-authored-by: cmd[bot] <41898282+github-actions[bot]@users.noreply.github.com>
Co-authored-by: Dónal Murray <[email protected]>

Closes #4315

---------

Co-authored-by: Guillaume Thiolliere <[email protected]>

# Description

Fixes #7039

The Preservation of transfer method of fungible and fungibles adapters
is changed from Preserve to Expendable. So the behavior of the
TransferAsset will be consistent with the WithdrawAsset function, as in
[fungible](https://github.com/paritytech/polkadot-sdk/blob/f3ab3854

/polkadot/xcm/xcm-builder/src/fungible_adapter.rs#L217)
and [fungibles](https://github.com/paritytech/polkadot-sdk/issues/url)
adapter.

This pull request includes changes to the `fungible_adapter.rs` and
`fungibles_adapter.rs` files in the `polkadot/xcm/xcm-builder`
directory. The main change involves modifying the transfer method to use
the `Expendable` strategy instead of the `Preserve` strategy.

Changes to transfer strategy:

*
[`polkadot/xcm/xcm-builder/src/fungible_adapter.rs`](diffhunk://#diff-6ebd77385441f2c8b023c480e818a01c4b43ae892c73ca30144cd64ee960bd66L67-R67):
Changed the transfer method to use `Expendable` instead of `Preserve`.
*
[`polkadot/xcm/xcm-builder/src/fungibles_adapter.rs`](diffhunk://#diff-82221429de4c4c88be3d2976ece6475ef4fa56a32abc70290911bd47191f8e17L61-R61):
Changed the transfer method to use `Expendable` instead of `Preserve`.

---------

Co-authored-by: Francisco Aguirre <[email protected]>
Co-authored-by: Adrian Catangiu <[email protected]>

- Closes https://github.com/paritytech/license-scanner/issues/44
- Silent because only comments are changed in the crates.

## What's inside

First, we change the file traversal mechanism from shell globbing to
walking through files which happens inside the `license-scanner` - so it
has knowledge about directory structure and can correlate files with
corresponding Cargo manifest.

Next, added `MIT-0` and `Unlicense` to the allowed list of licenses.
`Unlicense` appears only once across {Substrate,Cumulus,Polkadot} - in
`penpal-runtime`.

Finally, updated headers in files that do not match the corresponding
manifest license.

---------

Co-authored-by: cornholio <[email protected]>

# Description

Close #7122.

This PR replaces the unmaintained `derivative` dependency with
`derive-where`.

## Integration

This PR doesn't change the public interfaces.

## Review Notes

The `derivative` crate, previously used to derive basic traits for
structs with generics or enums, is no longer actively maintained. It has
been replaced with the `derive-where` crate, which offers a more
straightforward syntax while providing the same features as
`derivative`.

---------

Co-authored-by: Guillaume Thiolliere <[email protected]>

Resolves (partially):
https://github.com/paritytech/polkadot-sdk/issues/7148 (see _Problem 1 -
`ShouldExecute` tuple implementation and `Deny` filter tuple_)

This PR changes the behavior of `DenyThenTry` from the pattern
`DenyIfAllMatch` to `DenyIfAnyMatch` for the tuple.

I would expect the latter is the right behavior so make the fix in
place, but we can also add a dedicated Impl with the legacy one
untouched.

## TODO
- [x] add unit-test for `DenyReserveTransferToRelayChain`
- [x] add test and investigate/check `DenyThenTry` as discussed
[here](https://github.com/paritytech/polkadot-sdk/pull/6838#discussion_r1914553990)
and update documentation if needed

---------

Co-authored-by: Branislav Kontur <[email protected]>
Co-authored-by: Francisco Aguirre <[email protected]>
Co-authored-by: command-bot <>
Co-authored-by: Clara van Staden <[email protected]>
Co-authored-by: Adrian Catangiu <[email protected]>

Part of: https://github.com/paritytech/polkadot-sdk/issues/6906

This PR contains small fixes identified during work on the larger PR:
https://github.com/paritytech/polkadot-sdk/issues/6906.

---------

Co-authored-by: command-bot <>

# Derived Dev Accounts

Resolves https://github.com/paritytech/polkadot-sdk/issues/6040

## Description
This update introduces support for creating an arbitrary number of
developer accounts at the genesis block based on a specified derivation
path. This functionality is gated by the runtime-benchmarks feature,
ensuring it is only enabled during benchmarking scenarios.

### Key Features
- Arbitrary Dev Accounts at Genesis: Developers can now specify any
number of accounts to be generated at genesis using a hard derivation
path.

- Default Derivation Path: If no derivation path is provided (i.e., when
`Option<dev_accounts: (..., None)>` is set to `Some` at genesis), the
system will default to the path `//Sender//{}`.

- No Impact on Total Token Issuance: Developer accounts are excluded
from the total issuance of the token supply at genesis, ensuring they do
not affect the overall balance or token distribution.

polkadot address: 14SRqZTC1d8rfxL8W1tBTnfUBPU23ACFVPzp61FyGf4ftUFg

---------

Co-authored-by: Sebastian Kunert <[email protected]>

We already use it for lots of pallet.

Keeping it feature gated by experimental means we lose the information
of which pallet was using experimental before the migration to frame
crate usage.

We can consider `polkadot-sdk-frame` crate unstable but let's not use
the feature `experimental`.

---------

Co-authored-by: command-bot <>

## Description

This PR deprecates `UnpaidLocalExporter` in favor of the new
`LocalExporter`. First, the name is misleading, as it can be used in
both paid and unpaid scenarios. Second, it contains a hard-coded channel
0, whereas `LocalExporter` uses the same algorithm as `xcm-exporter`.

## Future Improvements  

Remove the `channel` argument and slightly modify the
`ExportXcm::validate` signature as part of [this
issue](https://github.com/orgs/paritytech/projects/145/views/8?pane=issue&itemId=84899273).

---------

Co-authored-by: command-bot <>

Implement cumulus StorageWeightReclaim as wrapping transaction extension + frame system ReclaimWeight (#6140)

(rebasing of https://github.com/paritytech/polkadot-sdk/pull/5234)

## Issues:

* Transaction extensions have weights and refund weight. So the
reclaiming of unused weight must happen last in the transaction
extension pipeline. Currently it is inside `CheckWeight`.
* cumulus storage weight reclaim transaction extension misses the proof
size of logic happening prior to itself.

## Done:

* a new storage `ExtrinsicWeightReclaimed` in frame-system. Any logic
which attempts to do some reclaim must use this storage to avoid double
reclaim.
* a new function `reclaim_weight` in frame-system pallet: info and post
info in arguments, read the already reclaimed weight, calculate the new
unused weight from info and post info. do the more accurate reclaim if
higher.
* `CheckWeight` is unchanged and still reclaim the weight in post
dispatch
* `ReclaimWeight` is a new transaction extension in frame system. For
s...

It doesn't make sense to only reorder the features array.

For example:

This makes it hard for me to compare the dependencies and features,
especially some crates have a really really long dependencies list.
```toml​
[dependencies]
c = "*"
a = "*"
b = "*"

[features]
std = [
  "a",
  "b",
  "c",
]
```

This makes my life easier.
```toml​
[dependencies]
a = "*"
b = "*"
c = "*"

[features]
std = [
  "a",
  "b",
  "c",
]
```

---------

Co-authored-by: Bastian Köcher <[email protected]>
Co-authored-by: command-bot <>

Migrates pallet-xcm benchmarks to benchmark v2 syntax

* Part of #6202

Co-authored-by: GitHub Action <[email protected]>
Co-authored-by: Branislav Kontur <[email protected]>
Co-authored-by: command-bot <>

`InitiateTransfer`, the new instruction introduced in XCMv5, allows
preserving the origin after a cross-chain transfer via the usage of the
`AliasOrigin` instruction. The receiving chain needs to be configured to
allow such this instruction to have its intended effect and not just
throw an error.

In this PR, I add the alias rules specified in the [RFC for origin
preservation](https://github.com/polkadot-fellows/RFCs/blob/main/text/0122-alias-origin-on-asset-transfers.md)
to westend chains so we can test these scenarios in the testnet.

The new scenarios include:
- Sending a cross-chain transfer from one system chain to another and
doing a Transact on the same message (1 hop)
- Sending a reserve asset transfer from one chain to another going
through asset hub and doing Transact on the same message (2 hops)

The updated chains are:
- Relay: added `AliasChildLocation`
- Collectives: added `AliasChildLocation` and
`AliasOriginRootUsingFilter<AssetHubLocation, Everything>`
- People: added `AliasChildLocation` and
`AliasOriginRootUsingFilter<AssetHubLocation, Everything>`
- Coretime: added `AliasChildLocation` and
`AliasOriginRootUsingFilter<AssetHubLocation, Everything>`

AssetHub already has `AliasChildLocation` and doesn't need the other
config item.
BridgeHub is not intended to be used by end users so I didn't add any
config item.
Only added `AliasChildOrigin` to the relay since we intend for it to be
used less.

---------

Co-authored-by: GitHub Action <[email protected]>
Co-authored-by: command-bot <>

## Description

Our smoke tests transfer `WETH` from Sepolia to Westend-AssetHub breaks,
try to reregister `WETH` on AH but fails as following:


https://bridgehub-westend.subscan.io/xcm_message/westend-4796d6b3600aca32ef63b9953acf6a456cfd2fbe

https://assethub-westend.subscan.io/extrinsic/9731267-0?event=9731267-2

The reason is that the transact call encoded on BH to register the asset

https://github.com/paritytech/polkadot-sdk/blob/a77940ba

/bridges/snowbridge/primitives/router/src/inbound/mod.rs#L282-L289
```
0x3500020209079edaa8020300fff9976782d46cc05630d1f6ebab18b2324d6b1400ce796ae65569a670d0c1cc1ac12515a3ce21b5fbf729d63d7b289baad070139d01000000000000000000000000000000
```

the `asset_id` which is the xcm location can't be decoded on AH in V5

Issue initial post in
https://matrix.to/#/!qUtSTcfMJzBdPmpFKa:parity.io/$RNMAxIIOKGtBAqkgwiFuQf4eNaYpmOK-Pfw4d6vv1aU?via=parity.io&via=matrix.org&via=web3.foundation

---------

Co-authored-by: Adrian Catangiu <[email protected]>
Co-authored-by: Francisco Aguirre <[email protected]>

Co-authored-by: Francisco Aguirre <[email protected]>

# Description

Sending XCM messages to other chains requires paying a "transport fee".
This can be paid either:
- from `origin` local account if `jit_withdraw = true`,
- taken from Holding register otherwise.

This currently works for following hops/scenarios:
1. On destination no transport fee needed (only sending costs, not
receiving),
2. Local/originating chain: just set JIT=true and fee will be paid from
signed account,
3. Intermediary hops - only if intermediary is acting as reserve between
two untrusted chains (aka only for `DepositReserveAsset` instruction) -
this was fixed in https://github.com/paritytech/polkadot-sdk/pull/3142

But now we're seeing more complex asset transfers that are mixing
reserve transfers with teleports depending on the involved chains.

# Example

E.g. transferring DOT between Relay and parachain, but through AH (using
AH instead of the Relay chain as parachain's DOT reserve).

In the `Parachain --1--> AssetHub --2--> Relay` scenario, DOT has to be
reserve-withdrawn in leg `1`, then teleported in leg `2`.
On the intermediary hop (AssetHub), `InitiateTeleport` fails to send
onward message because of missing transport fees. We also can't rely on
`jit_withdraw` because the original origin is lost on the way, and even
if it weren't we can't rely on the user having funded accounts on each
hop along the way.

# Solution/Changes

- Charge the transport fee in the executor from the transferred assets
(if available),
- Only charge from transferred assets if JIT_WITHDRAW was not set,
- Only charge from transferred assets if unless using XCMv5 `PayFees`
where we do not have this problem.

# Testing

Added regression tests in emulated transfers.

Fixes https://github.com/paritytech/polkadot-sdk/issues/4832
Fixes https://github.com/paritytech/polkadot-sdk/issues/6637

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Signed-off-by: Adrian Catangiu <[email protected]>
Co-authored-by: Francisco Aguirre <[email protected]>

Last feature we wanted for V5, changing `SetAssetClaimer` to be just one
of many possible "hints" that you can specify at the beginning of your
program to change its behaviour.

This makes it easier to add new hints in the future and have barriers
accept them.

---------

Co-authored-by: GitHub Action <[email protected]>

Closes: https://github.com/paritytech/polkadot-sdk/issues/6585

Removing the `require_weight_at_most` parameter in V5 Transact had only
one problem. Converting a message from V5 to V4 to send to chains that
didn't upgrade yet. The conversion would not know what weight to give to
the Transact, since V4 and below require it.

To fix this, I added back the weight in the form of an `Option<Weight>`
called `fallback_max_weight`. This can be set to `None` if you don't
intend to deal with a chain that hasn't upgraded yet. If you set it to
`Some(_)`, the behaviour is the same. The plan is to totally remove this
in V6 since there will be a good conversion path from V6 to V5.

---------

Co-authored-by: GitHub Action <[email protected]>
Co-authored-by: Adrian Catangiu <[email protected]>