fix(profiles): prevent NoneType exception when profiling empty datasets (#3144)

Co-authored-by: Sergio Gómez <sergio.gomez.villamor@adevinta.com>

metadata-ingestion/src/datahub/ingestion/source/ge_data_profiler.py

@@ -218,7 +218,10 @@ class DatahubGEProfiler:
                 column_profile.uniqueProportion = res["observed_value"]
             elif exp == "expect_column_values_to_not_be_null":
                 column_profile.nullCount = res["unexpected_count"]
-                if "unexpected_percent" in res:
+                if (
+                    "unexpected_percent" in res
+                    and res["unexpected_percent"] is not None
+                ):
                     column_profile.nullProportion = res["unexpected_percent"] / 100
             elif exp == "expect_column_values_to_not_match_regex":
                 # ignore; generally used for whitespace checks using regex r"^\s+|\s+$"

metadata-ingestion/tests/integration/mysql/mysql_mces_golden.json

@@ -584,5 +584,80 @@
         "contentType": "application/json"
     },
     "systemMetadata": null
+},
+{
+    "auditHeader": null,
+    "proposedSnapshot": {
+        "com.linkedin.pegasus2avro.metadata.snapshot.DatasetSnapshot": {
+            "urn": "urn:li:dataset:(urn:li:dataPlatform:mysql,test_cases.test_empty,PROD)",
+            "aspects": [
+                {
+                    "com.linkedin.pegasus2avro.schema.SchemaMetadata": {
+                        "schemaName": "test_cases.test_empty",
+                        "platform": "urn:li:dataPlatform:mysql",
+                        "version": 0,
+                        "created": {
+                            "time": 0,
+                            "actor": "urn:li:corpuser:unknown",
+                            "impersonator": null
+                        },
+                        "lastModified": {
+                            "time": 0,
+                            "actor": "urn:li:corpuser:unknown",
+                            "impersonator": null
+                        },
+                        "deleted": null,
+                        "dataset": null,
+                        "cluster": null,
+                        "hash": "",
+                        "platformSchema": {
+                            "com.linkedin.pegasus2avro.schema.MySqlDDL": {
+                                "tableSchema": ""
+                            }
+                        },
+                        "fields": [
+                            {
+                                "fieldPath": "dummy",
+                                "jsonPath": null,
+                                "nullable": true,
+                                "description": null,
+                                "type": {
+                                    "type": {
+                                        "com.linkedin.pegasus2avro.schema.StringType": {}
+                                    }
+                                },
+                                "nativeDataType": "VARCHAR(length=50)",
+                                "recursive": false,
+                                "globalTags": null,
+                                "glossaryTerms": null,
+                                "isPartOfKey": false
+                            }
+                        ],
+                        "primaryKeys": null,
+                        "foreignKeysSpecs": null
+                    }
+                }
+            ]
+        }
+    },
+    "proposedDelta": null,
+    "systemMetadata": {
+        "lastObserved": 1586847600000,
+        "runId": "mysql-test",
+        "properties": null
+    }
+},
+{
+    "auditHeader": null,
+    "entityType": "dataset",
+    "entityUrn": "urn:li:dataset:(urn:li:dataPlatform:mysql,test_cases.test_empty,PROD)",
+    "entityKeyAspect": null,
+    "changeType": "UPSERT",
+    "aspectName": "datasetProfile",
+    "aspect": {
+        "value": "{\"timestampMillis\": 1586847600000, \"rowCount\": 0, \"columnCount\": 1, \"fieldProfiles\": [{\"fieldPath\": \"dummy\", \"uniqueCount\": 0, \"nullCount\": 0, \"sampleValues\": []}]}",
+        "contentType": "application/json"
+    },
+    "systemMetadata": null
 }
-]
+]

metadata-ingestion/tests/integration/mysql/mysql_to_file.yml

@@ -11,9 +11,11 @@ source:
       allow:
         - "^metagalaxy"
         - "^northwind"
+        - "^test_cases"
     profile_pattern:
       allow:
         - "^northwind.*\$"
+        - "^test_cases.*\$"
     profiling:
       enabled: True
 

metadata-ingestion/tests/integration/mysql/setup/setup.sql

@@ -89,5 +89,21 @@ INSERT INTO `customers` (`id`, `company`, `last_name`, `first_name`, `email_addr
 INSERT INTO `customers` (`id`, `company`, `last_name`, `first_name`, `email_address`) VALUES (5, 'Company E', 'Donnell', 'Martin', NULL);
 # 5 records
 
+-- -----------------------------------------------------
+-- Schema for testing different scenarios
+-- -----------------------------------------------------
+
+DROP SCHEMA IF EXISTS `test_cases` ;
+CREATE SCHEMA IF NOT EXISTS `test_cases` DEFAULT CHARACTER SET latin1 ;
+USE `test_cases` ;
+
+-- no data in `test_cases`.`test_empty`
+
+CREATE TABLE IF NOT EXISTS `test_cases`.`test_empty` (
+  `dummy` VARCHAR(50) NULL DEFAULT NULL)
+ENGINE = InnoDB
+DEFAULT CHARACTER SET = utf8;
+
+
 SET FOREIGN_KEY_CHECKS=@OLD_FOREIGN_KEY_CHECKS;
 SET UNIQUE_CHECKS=@OLD_UNIQUE_CHECKS;