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Bug 319378

Summary:

Preferences->Java Compiler-> Errors/Warnings -> switch case fall through enhancement

Product:

[Eclipse Project] JDT

Reporter:

Daniel Holmes <dholmes>

Component:

Doc

Assignee:

Olivier Thomann <Olivier_Thomann>

Status:

VERIFIED FIXED

QA Contact:

Severity:

enhancement

Priority:

CC:

daniel_megert, markus.kell.r, Olivier_Thomann

Version:

3.7

Keywords:

Documentation

Target Milestone:

3.6.1

Hardware:

OS:

Windows XP

Whiteboard:

Attachments:

Description	Flags
Proposed fix	none

Description Daniel Holmes

2010-07-09 08:54:12 EDT

Build Identifier: 20100218-1602

The description for this rules reads "When enabled, the compiler will issue an error or a warning whenever it encounters a switch case without a 'break' statement. Empty switch cases are allowed."

I have created similar with a PMD rule, but it seems that it is not just a break that should be allowed in a case.  A case should be able to have a final statement of a continue (explicit intent to fall through), return or throw (which would also not create an inadvertent fall through).  It would be nice if this rule were expanded for these conditions.

Reproducible: Always

Comment 1 Olivier Thomann

2010-07-15 11:13:26 EDT

I don't see what you expect from us. Updating the description ?
If you have a return, throw or continue, the next statement is not reachable so it is not a fallthrough case.
Did I misunderstand something ?

Comment 2 Daniel Holmes

2010-07-15 11:45:07 EDT

I guess from the description, it was not clear until I tried it that the 'break' as mentioned in the description was inclusive of a case exiting due to return or throw conditions vs just specifically a break statement.  

So I guess the rule does cover this condition and maybe the documentation could be more inclusive of this.

Also, did not realize until I just tested it that continue is not allowed in a switch case construct.  I was taking the word of a co-worker on this :-)

Comment 3 Olivier Thomann

2010-07-15 11:52:50 EDT

You can use continue to a label depending on the context. So you expect the description to be improved ?

Comment 4 Daniel Holmes

2010-07-15 12:00:29 EDT

Yes, I'm suggesting to clarify the description.

I understand your point on continue also is the switch happens to be in a loop.

Comment 5 Olivier Thomann

2010-07-19 09:58:56 EDT

Hi Daniel,

> The description for this rules reads "When enabled, the compiler will issue an
> error or a warning whenever it encounters a switch case without a 'break'
> statement. Empty switch cases are allowed."
Are you referring to the description found in:
org.eclipse.jdt.doc.user/reference/preferences/java/compiler/ref-preferences-errors-warnings.htm ?

In the help, I also found this in JDT/Core options:

"When enabled, the compiler will issue an error or a warning when a case may be entered by falling through a preceding, non empty case."

That seems to be better, doesn't it ?

Comment 6 Daniel Holmes

2010-07-19 11:16:18 EDT

(In reply to comment #5)
Yes, I like that.

Comment 7 Olivier Thomann

2010-07-19 13:15:02 EDT

Released for 3.7M1 and 3.6.1.

Comment 8 Olivier Thomann

2010-07-19 13:24:26 EDT

Created attachment 174651 [details]
Proposed fix

Comment 9 Dani Megert

2010-08-27 03:44:18 EDT

Verified in M20100825-0800.