Flaky SLT test union_by_name.slt:343

[findepi]

This test case

datafusion/datafusion/sqllogictest/test_files/union_by_name.slt

Lines 338 to 423 in 21248fb

	# FIXME: The following should pass without error, but currently it is failing
	# due to differing record batch schemas when the SLT runner collects results.
	# This is due to the following issue: https://github.com/apache/datafusion/issues/15394#issue-2943811768
	#
	# More context can be found here: https://github.com/apache/datafusion/pull/15242#issuecomment-2746563234
	query error
	select x, y, z from t3 union all by name select z, y, x, 'd' as zz from t3;
	----
	DataFusion error: Internal error: Schema mismatch. Previously had
	Schema {
	fields: [
	Field {
	name: "x",
	data_type: Utf8View,
	nullable: true,
	dict_id: 0,
	dict_is_ordered: false,
	metadata: {},
	},
	Field {
	name: "y",
	data_type: Utf8View,
	nullable: true,
	dict_id: 0,
	dict_is_ordered: false,
	metadata: {},
	},
	Field {
	name: "z",
	data_type: Utf8View,
	nullable: true,
	dict_id: 0,
	dict_is_ordered: false,
	metadata: {},
	},
	Field {
	name: "zz",
	data_type: Utf8,
	nullable: false,
	dict_id: 0,
	dict_is_ordered: false,
	metadata: {},
	},
	],
	metadata: {},
	}
	Got:
	Schema {
	fields: [
	Field {
	name: "x",
	data_type: Utf8View,
	nullable: true,
	dict_id: 0,
	dict_is_ordered: false,
	metadata: {},
	},
	Field {
	name: "y",
	data_type: Utf8View,
	nullable: true,
	dict_id: 0,
	dict_is_ordered: false,
	metadata: {},
	},
	Field {
	name: "z",
	data_type: Utf8View,
	nullable: true,
	dict_id: 0,
	dict_is_ordered: false,
	metadata: {},
	},
	Field {
	name: "zz",
	data_type: Utf8,
	nullable: true,
	dict_id: 0,
	dict_is_ordered: false,
	metadata: {},
	},
	],
	metadata: {},
	}.
	This was likely caused by a bug in DataFusion's code and we would welcome that you file an bug report in our issue tracker

failed first

$ cargo test --test sqllogictests --
   Compiling datafusion-sqllogictest v48.0.0 (/Users/findepi/repos/datafusion/datafusion/sqllogictest)
    Finished `test` profile [unoptimized + debuginfo] target(s) in 10.11s
     Running bin/sqllogictests.rs (target/debug/deps/sqllogictests-2e8e67abab0f3489)
Completed 344 test files in 4 seconds                                                                                                                                                                                                                                                                    External error: 1 errors in file /Users/findepi/repos/datafusion/datafusion/sqllogictest/test_files/union_by_name.slt

1. query is expected to fail, but actually succeed:
[SQL] select x, y, z from t3 union all by name select z, y, x, 'd' as zz from t3;
at /Users/findepi/repos/datafusion/datafusion/sqllogictest/test_files/union_by_name.slt:343



Error: Execution("1 failures")
error: test failed, to rerun pass `-p datafusion-sqllogictest --test sqllogictests`

Caused by:
  process didn't exit successfully: `/Users/findepi/repos/datafusion/target/debug/deps/sqllogictests-2e8e67abab0f3489` (exit status: 1)

then succeeded

$ cargo test --test sqllogictests --
    Finished `test` profile [unoptimized + debuginfo] target(s) in 0.19s
     Running bin/sqllogictests.rs (target/debug/deps/sqllogictests-2e8e67abab0f3489)
Completed 344 test files in 4 seconds

Expected

deterministic test results

Observed

insufficient determinism

[findepi]

This makes running cargo test locally less friendly.

[findepi]

This reproduces locally quite well with

for i in `seq 100`; do
    cargo test --test sqllogictests -- union_by_name
done