[SPARK-37906][SQL] spark-sql should not pass last comment to backend

[AngersZhuuuu]

What changes were proposed in this pull request?

In #34815 we change back support unclosed bracketed comment to backend.

But miss the case such as

SELECT 1; --comment

SELECT 1; /* comment */

It's a common use case in sql job. We should ignore the comment at end of SQL script.

Need to clarify that when use -e, we directly pass SQL to splitSemiColon, when use -f, CliDriver will add a \n for query.

 public int processReader(BufferedReader r) throws IOException {
StringBuilder qsb = new StringBuilder();
String line;
while((line = r.readLine()) != null) {
if (!line.startsWith("--")) {
qsb.append(line + "\n");
}
}
return this.processLine(qsb.toString());
}

So in splitSemiColon, we should consider both case.

In this pr, the final behavior like below

For -e

Query	Behavior before	Behavior now
SELECT 1; --comment	Will pass both SELECT 1 and --comment to backend engine and throw exception since --comment can't be executed	Only pass SELECT 1 to backend engine and will ignore the simple comment
SELECT 1; /* comment */	Will pass both SELECT 1 and /* comment */ to backend engine and throw exception since /* comment */ can't be executed	Only pass SELECT 1 to backend engine
SELECT 1; /* comment	Will pass SELECT 1 and /* comment to backend engine	Will pass SELECT 1 and /* comment to backend engine
SELECT 1; /* comment SELECT 1	Will pass SELECT 1 and /* comment SELECT 1 to backend engine	Will pass SELECT 1 and /* comment SELECT 1 to backend engine
/ * comment SELECT 1;	Will pass / * comment SELECT 1; to back end engine and throw unclose bracketed comment exception	Will pass / * comment SELECT 1; to back end engine and throw unclose bracketed comment exception

For -f, since -f will add a \n at the end line if it's not started as --

Query	Behavior before	Behavior now
SELECT 1; --comment\n	Will pass both SELECT 1 and --comment to backend engine and throw exception since --comment can't be executed	Only pass SELECT 1 to backend engine and will ignore the simple comment
SELECT 1; /* comment */ \n	Will pass both SELECT 1 and /* comment */ to backend engine and throw exception since /* comment */ can't be executed	Only pass SELECT 1 to backend engine
SELECT 1; /* comment \n	Will pass SELECT 1 and /* comment\n to backend engine	Will pass SELECT 1 and /* comment\n to backend engine
SELECT 1; /* comment SELECT 1\n	Will pass SELECT 1 and /* comment SELECT 1\n to backend engine	Will pass SELECT 1 and /* comment SELECT 1\n to backend engine
/ * comment SELECT 1;\n	Will pass / * comment SELECT 1;\n to back end engine and throw unclose bracketed comment exception	Will pass / * comment SELECT 1;\n to back end engine and throw unclose bracketed comment exception

Why are the changes needed?

Spark sql should not pass last entire comment to backend

Does this PR introduce any user-facing change?

Use can write SQL script end with a comment

SELECT 1; --comment

SELECT 1; /* comment */

How was this patch tested?

Added UT

[AngersZhuuuu]

ping @cloud-fan

[cloud-fan]

is it possible to add a test?

[AngersZhuuuu]

is it possible to add a test?

Added

[AngersZhuuuu]

How about current?

[cloud-fan]

thanks, merging to master!