[SPARK-12580][SQL] Remove string concatenations from usage and extended in @ExpressionDescription

[kiszk]

Use multi-line string literals for @ExpressionDescription with // scalastyle:off line.size.limit and // scalastyle:on line.size.limit

The policy is here, as describe at #10488

Let's use multi-line string literals. If we have to have a line with more than 100 characters, let's use // scalastyle:off line.size.limit and // scalastyle:on line.size.limit to just bypass the line number requirement.

[kiszk]

@yhuai, are these changes fine with the policy that you proposed? I would appreciate it if you would check them.

[rxin]

Actually this line length makes it pretty annoying to view. Can't we wrap them, and just require two newlines for a real newline?

[SparkQA]

Test build #48462 has finished for PR 10524 at commit acb422c.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[SparkQA]

Test build #48466 has finished for PR 10524 at commit 193568c.

• This patch fails from timeout after a configured wait of 250m.
• This patch merges cleanly.
• This patch adds no public classes.

[kiszk]

On jenkins with scala-2.11, we can wrap once in a source file (i.e. only one string concatenation). To use more than one concatenation causes compilation error.
Is it OK to use only one string concatenation?

[kiszk]

Jenkins, retest this please.

[SparkQA]

Test build #48490 has finished for PR 10524 at commit 193568c.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[yhuai]

@kiszk Can you try

"""
1st line

2nd line

3rd line
"""

and see if it works?

[kiszk]

@yhuai, I think that I will work. Do you think how many characters are preferable to all at a line?

[yhuai]

How about 80 characters? Let's make sure it is easy to read by users (who use describe function command) and developers (who read code).

[kiszk]

I see. Sounds good. I will reformat them.

[SparkQA]

Test build #48670 has finished for PR 10524 at commit 19bb151.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[SparkQA]

Test build #48671 has finished for PR 10524 at commit f2c1094.

• This patch fails Spark unit tests.
• This patch merges cleanly.
• This patch adds no public classes.

[kiszk]

Jenkins, retest this please

[SparkQA]

Test build #48717 has finished for PR 10524 at commit f2c1094.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[yhuai]

Should we keep this unchanged? The indentation looks weird.

[SparkQA]

Test build #48941 has finished for PR 10524 at commit 4649202.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[yhuai]

thanks! Merging to master.