feat: lookup_or_create_adhoc_group(): Add context to SQL errors (#7554)

STYLE.md

@@ -16,7 +16,8 @@ id INTEGER PRIMARY KEY AUTOINCREMENT,
 text TEXT DEFAULT '' NOT NULL -- message text
 ) STRICT",
     )
-    .await?;
+    .await
+    .context("CREATE TABLE messages")?;
 ```
 
 Do not use macros like [`concat!`](https://doc.rust-lang.org/std/macro.concat.html)
@@ -29,7 +30,8 @@ id INTEGER PRIMARY KEY AUTOINCREMENT, \
 text TEXT DEFAULT '' NOT NULL \
 ) STRICT",
     )
-    .await?;
+    .await
+    .context("CREATE TABLE messages")?;
 ```
 Escaping newlines
 is prone to errors like this if space before backslash is missing:
@@ -63,6 +65,9 @@ an older version. Also don't change the column type, consider adding a new colum
 instead. Finally, never change column semantics, this is especially dangerous because the `STRICT`
 keyword doesn't help here.
 
+Consider adding context to `anyhow` errors for SQL statements using `.context()` so that it's
+possible to understand from logs which statement failed. See [Errors](#errors) for more info.
+
 ## Errors
 
 Delta Chat core mostly uses [`anyhow`](https://docs.rs/anyhow/) errors.

src/receive_imf.rs

@@ -2506,10 +2506,11 @@ async fn lookup_or_create_adhoc_group(
                 id INTEGER PRIMARY KEY
             ) STRICT",
             (),
-        )?;
+        )
+        .context("CREATE TEMP TABLE temp.contacts")?;
         let mut stmt = t.prepare("INSERT INTO temp.contacts(id) VALUES (?)")?;
         for &id in &contact_ids {
-            stmt.execute((id,))?;
+            stmt.execute((id,)).context("INSERT INTO temp.contacts")?;
         }
         let val = t
             .query_row(
@@ -2531,8 +2532,10 @@ async fn lookup_or_create_adhoc_group(
                     Ok((id, blocked))
                 },
             )
-            .optional()?;
-        t.execute("DROP TABLE temp.contacts", ())?;
+            .optional()
+            .context("Select chat with matching name and members")?;
+        t.execute("DROP TABLE temp.contacts", ())
+            .context("DROP TABLE temp.contacts")?;
         Ok(val)
     };
     let query_only = true;