From 9f3ed7bb01af308b955e5d024bf734dc1a52bb61 Mon Sep 17 00:00:00 2001
From: callebtc <93376500+callebtc@users.noreply.github.com>
Date: Sat, 16 Mar 2024 10:51:37 +0100
Subject: [PATCH] migrate: only if data exists

---
 cashu/mint/migrations.py | 80 +++++++++++++++++++++-------------------
 1 file changed, 42 insertions(+), 38 deletions(-)

diff --git a/cashu/mint/migrations.py b/cashu/mint/migrations.py
index e82a2a66..2291288c 100644
--- a/cashu/mint/migrations.py
+++ b/cashu/mint/migrations.py
@@ -561,44 +561,48 @@ async def m016_recompute_Y_with_new_h2c(db: Database):
 
     # Perform batch update in a single transaction
     async with db.connect() as conn:
-        # For proofs_used
-        await conn.execute(
-            "CREATE TABLE IF NOT EXISTS tmp_proofs_used (Y TEXT, secret TEXT)"
-        )
-        values_placeholder = ", ".join(
-            f"('{y}', '{secret}')" for y, secret in proofs_used_data
-        )
-        await conn.execute(
-            f"INSERT INTO tmp_proofs_used (Y, secret) VALUES {values_placeholder}",
-        )
-        await conn.execute(
-            f"""
-            UPDATE {table_with_schema(db, 'proofs_used')}
-            SET Y = tmp_proofs_used.Y
-            FROM tmp_proofs_used
-            WHERE {table_with_schema(db, 'proofs_used')}.secret = tmp_proofs_used.secret
-            """
-        )
+        if len(proofs_used_data):
+            # For proofs_used
+            await conn.execute(
+                "CREATE TABLE IF NOT EXISTS tmp_proofs_used (Y TEXT, secret TEXT)"
+            )
+            values_placeholder = ", ".join(
+                f"('{y}', '{secret}')" for y, secret in proofs_used_data
+            )
+            await conn.execute(
+                f"INSERT INTO tmp_proofs_used (Y, secret) VALUES {values_placeholder}",
+            )
+            await conn.execute(
+                f"""
+                UPDATE {table_with_schema(db, 'proofs_used')}
+                SET Y = tmp_proofs_used.Y
+                FROM tmp_proofs_used
+                WHERE {table_with_schema(db, 'proofs_used')}.secret = tmp_proofs_used.secret
+                """
+            )
 
-        # For proofs_pending
-        await conn.execute(
-            "CREATE TABLE IF NOT EXISTS tmp_proofs_pending (Y TEXT, secret TEXT)"
-        )
-        values_placeholder = ", ".join(
-            f"('{y}', '{secret}')" for y, secret in proofs_pending_data
-        )
-        await conn.execute(
-            f"INSERT INTO tmp_proofs_used (Y, secret) VALUES {values_placeholder}",
-        )
-        await conn.execute(
-            f"""
-            UPDATE {table_with_schema(db, 'proofs_pending')}
-            SET Y = tmp_proofs_pending.Y
-            FROM tmp_proofs_pending
-            WHERE {table_with_schema(db, 'proofs_pending')}.secret = tmp_proofs_pending.secret
-            """
-        )
+        if len(proofs_pending_data):
+            # For proofs_pending
+            await conn.execute(
+                "CREATE TABLE IF NOT EXISTS tmp_proofs_pending (Y TEXT, secret TEXT)"
+            )
+            values_placeholder = ", ".join(
+                f"('{y}', '{secret}')" for y, secret in proofs_pending_data
+            )
+            await conn.execute(
+                f"INSERT INTO tmp_proofs_used (Y, secret) VALUES {values_placeholder}",
+            )
+            await conn.execute(
+                f"""
+                UPDATE {table_with_schema(db, 'proofs_pending')}
+                SET Y = tmp_proofs_pending.Y
+                FROM tmp_proofs_pending
+                WHERE {table_with_schema(db, 'proofs_pending')}.secret = tmp_proofs_pending.secret
+                """
+            )
 
     async with db.connect() as conn:
-        await conn.execute("DROP TABLE tmp_proofs_used")
-        await conn.execute("DROP TABLE tmp_proofs_pending")
+        if len(proofs_used_data):
+            await conn.execute("DROP TABLE tmp_proofs_used")
+        if len(proofs_pending_data):
+            await conn.execute("DROP TABLE tmp_proofs_pending")