docs: add direct contract storage reading example

testnet/examples/reading-contract-storage.md

@@ -0,0 +1,176 @@
+# Reading Contract Storage Directly
+
+When debugging an `EphemeralAccount`, it can be useful to inspect the contract's persistent storage directly through Soroban RPC instead of relying only on a contract read-only method.
+
+This is useful when investigating a problem where the contract's own reporting method may itself be incorrect or affected by the issue being investigated.
+
+## Why read storage directly?
+
+`EphemeralAccount` stores its status in persistent instance storage under `DataKey::Status`:
+
+```rust
+env.storage().instance().set(&DataKey::Status, &status);
+```
+
+The contract also exposes `get_status()`, which reads the same storage value.
+
+For normal application use, calling `get_status()` is simpler. For debugging, however, querying the ledger entry directly provides an independent view of the stored value without executing the contract's `get_status()` method.
+
+## Prerequisites
+
+You need:
+
+* Stellar CLI installed
+* Access to the target Stellar network
+* An `EphemeralAccount` contract ID
+* A contract instance that has been initialized and has a persistent `Status` entry
+
+Set the contract ID:
+
+```bash
+export EPHEMERAL_ACCOUNT_ID="YOUR_EPHEMERAL_ACCOUNT_CONTRACT_ID"
+```
+
+## Read the Status storage entry
+
+`DataKey::Status` is a unit variant of a `#[contracttype]` enum. Soroban encodes this as a one-element vector containing the `Status` symbol.
+
+The base64-encoded SCVal for the storage key is:
+
+```text
+AAAAEAAAAAEAAAAPAAAABlN0YXR1cwAA
+```
+
+Fetch the persistent contract-data entry directly:
+
+```bash
+stellar ledger entry fetch contract-data \
+  --contract "$EPHEMERAL_ACCOUNT_ID" \
+  --key-xdr "AAAAEAAAAAEAAAAPAAAABlN0YXR1cwAA" \
+  --durability persistent \
+  --network testnet \
+  --output json-formatted
+```
+
+This command reads the contract-data ledger entry through Stellar RPC rather than invoking `EphemeralAccount::get_status()`.
+
+## Example response
+
+A response will contain the ledger entry and its stored value. Depending on the CLI version and output format, the value will be represented as decoded XDR/JSON similar to:
+
+```json
+{
+  "contractData": {
+    "contract": "...",
+    "key": {
+      "vec": [
+        {
+          "symbol": "Status"
+        }
+      ]
+    },
+    "durability": "persistent",
+    "val": {
+      "vec": [
+        {
+          "symbol": "Active"
+        }
+      ]
+    }
+  }
+}
+```
+
+The exact JSON shape may vary between Stellar CLI/RPC versions. The important fields are:
+
+* the contract ID matches the `EphemeralAccount` being investigated;
+* the key represents `DataKey::Status`;
+* the durability is `persistent`;
+* the stored value contains the current `AccountStatus`.
+
+The current `AccountStatus` values used by `EphemeralAccount` include:
+
+```text
+Active
+PaymentReceived
+Swept
+Expired
+```
+
+## Compare with the contract read-only method
+
+The normal application-level read is:
+
+```bash
+stellar contract invoke \
+  --id "$EPHEMERAL_ACCOUNT_ID" \
+  --network testnet \
+  -- \
+  get_status
+```
+
+This executes the contract's `get_status()` function.
+
+The direct storage query is different:
+
+```bash
+stellar ledger entry fetch contract-data \
+  --contract "$EPHEMERAL_ACCOUNT_ID" \
+  --key-xdr "AAAAEAAAAAEAAAAPAAAABlN0YXR1cwAA" \
+  --durability persistent \
+  --network testnet \
+  --output json-formatted
+```
+
+The first command asks the contract to report its status.
+
+The second asks the RPC service for the current ledger entry containing the stored status.
+
+## Debugging workflow
+
+When investigating a suspected status-reporting problem:
+
+1. Record the `EphemeralAccount` contract ID.
+2. Call `get_status()`.
+3. Fetch the `Status` storage entry directly through RPC.
+4. Compare the two results.
+5. If they differ, investigate the contract code, deployed WASM version, or storage interpretation.
+6. If they agree, continue investigating the surrounding application or RPC usage.
+
+For example:
+
+```text
+get_status()
+    ↓
+PaymentReceived
+
+Direct persistent storage
+    ↓
+PaymentReceived
+
+Both agree
+```
+
+If the results disagree:
+
+```text
+get_status()
+    ↓
+Active
+
+Direct persistent storage
+    ↓
+PaymentReceived
+
+Investigate contract code/deployment or decoding
+```
+
+## Important limitations
+
+Direct storage inspection is a debugging technique, not a replacement for the contract API.
+
+The storage key encoding depends on the contract's `DataKey` definition. If the contract changes its storage key type or layout, the XDR used to query the entry must also change.
+
+Also, `getLedgerEntries` reads current live ledger state. It is not a historical state query. If the entry is archived or no longer available through the RPC state retained by the network, the query may not return the expected value.
+
+For general RPC details, see Stellar's `getLedgerEntries` documentation.