fix(rust): Trim trailing backslash in url storage options (delta-io#2656

)

This trims trailing backslash if present in a storage option's
value if it's key ends with `_URL` (e.g. HOST_URL) or if the value
itself seems to be a url (i.e. if it contains `://`).

This also adds supporting test for this fix.

crates/core/src/table/builder.rs

@@ -261,7 +261,23 @@ impl DeltaTableBuilder {
     /// - [S3 options](https://docs.rs/object_store/latest/object_store/aws/enum.AmazonS3ConfigKey.html#variants)
     /// - [Google options](https://docs.rs/object_store/latest/object_store/gcp/enum.GoogleConfigKey.html#variants)
     pub fn with_storage_options(mut self, storage_options: HashMap<String, String>) -> Self {
-        self.storage_options = Some(storage_options);
+        self.storage_options = Some(
+            storage_options
+            .clone()
+            .into_iter()
+            .map(
+                |(k, v)| {
+                    let needs_trim = v.contains("://") ||
+                        k.to_lowercase().ends_with("_url");
+                    if needs_trim {
+                        (k.to_owned(), v.trim_end_matches('/').to_owned())
+                    } else {
+                        (k, v)
+                    }
+                }
+            )
+            .collect()
+        );
         self
     }
 
@@ -561,4 +577,41 @@ mod tests {
         DeltaTableBuilder::from_valid_uri("this://is.nonsense")
             .expect_err("this should be an error");
     }
+
+    #[test]
+    fn test_writer_storage_opts_url_trim() {
+        let cases = [
+            // Trim Case 1 - Key indicating a url
+            ("SOMETHING_URL", "something://else/", "something://else"),
+            // Trim Case 2 - Value https url ending with slash
+            ("SOMETHING", "http://something:port/", "http://something:port"),
+            // Trim Case 3 - Value https url ending with slash
+            ("SOMETHING", "https://something:port/", "https://something:port"),
+            // Trim Case 4 - JDBC MySQL url with slash
+            (
+                "SOME_JDBC_PREFIX",
+                "jdbc:mysql://mysql.db.server:3306/",
+                "jdbc:mysql://mysql.db.server:3306"),
+            // Trim Case 5 - S3A file system link
+            ("SOME_S3_LINK", "s3a://bucket-name/", "s3a://bucket-name"),
+            // No Trim Case 6 - Not a url but ending with slash
+            ("SOME_RANDOM_STRING", "a1b2c3d4e5f#/", "a1b2c3d4e5f#/"),
+            // No Trim Case 7 - Some value not a url
+            (
+                "SOME_VALUE",
+                "/ This is some value 123 /",
+                "/ This is some value 123 /"
+            ),
+        ];
+        for (key, val, expected) in cases {
+            let table_uri = Url::parse("memory:///test/tests/data/delta-0.8.0").unwrap();
+            let mut storage_opts = HashMap::<String, String>::new();
+            storage_opts.insert(key.to_owned(), val.to_owned());
+
+            let table = DeltaTableBuilder::from_uri(table_uri)
+                .with_storage_options(storage_opts);
+            let found_opts = table.storage_options();
+            assert_eq!(expected, found_opts.0.get(key).unwrap());
+        }
+    }
 }