git/list[1] front-page[2] threads[3] people[4] search[5] about
 

Re: [PATCH v4] userdiff: improve java hunk header regex

From
Johannes Sixt <j6t@kdbg.org>
Date
Aug 11, 2021, 07:34 UTC
Message-ID
<95ebb2cf-2e6e-912e-7d80-3947a8e3d9e4@kdbg.org>
In-Reply-To
<87zgtoh6bm.fsf@gnu.org>
Am 11.08.21 um 07:22 schrieb Tassilo Horn:
Show 9 quoted lines
> Johannes Sixt <j6t@kdbg.org> writes:
>> These new tests are very much appreciated. You do not have to go wild
>> with that many return type tests; IMO, the simple one and the most
>> complicated one should do it. (And btw, s/cart/card/)
> 
> Well, they appeared naturally as a result during development and made it
> easier to spot errors when you know up to which level of complexity it
> still worked.  Is there a stronger reason to remove tests which might
> not be needed, e.g., runtime cost on some CI machines?

I totally understand how the test cases evolved. Having many of them is not a big deal. It's just the disproportion of tests of this new feature vs. the existing tests that your patch creates, in particular, when earlier of the new tests are subsumed by later new tests.

Show 16 quoted lines
> Another thing I've noticed (with my suggested patch) is that I should
> not try to match constructor signatures.  I think that's impossible
> because they are indistinguishable from method calls, e.g., in
> 
>   public class MyClass {
>       MyClass(String RIGHT) {
>           someMethodCall();
>           someOtherMethod(17)
>               .doThat();
>           // Whatever
>           // ChangeMe
>       }
>   }
> 
> there is no regex way to prefer MyClass(String RIGHT) over
> someOtherMethod().
Good find.
Show 18 quoted lines
> So all in all, I'd propose this version in the next patch version:
> 
> --8<---------------cut here---------------start------------->8---
> PATTERNS("java",
> 	 "!^[ \t]*(catch|do|for|if|instanceof|new|return|switch|throw|while)\n"
>          "^[ \t]*("
>          /* Class, enum, and interface declarations */
>          "(([a-z]+[ \t]+)*(class|enum|interface)[ \t]+[A-Za-z][A-Za-z0-9_$]*[ \t]+.*)"
>          /* Method definitions; note that constructor signatures are not */
>          /* matched because they are indistinguishable from method calls. */
>          "|(([A-Za-z_<>&][][?&<>.,A-Za-z_0-9]*[ \t]+)+[A-Za-z_][A-Za-z_0-9]*[ \t]*\\([^;]*)"
>          ")$",
> 	 /* -- */
> 	 "[a-zA-Z_][a-zA-Z0-9_]*"
> 	 "|[-+0-9.e]+[fFlL]?|0[xXbB]?[0-9a-fA-F]+[lL]?"
> 	 "|[-+*/<>%&^|=!]="
> 	 "|--|\\+\\+|<<=?|>>>?=?|&&|\\|\\|"),
> --8<---------------cut here---------------end--------------->8---
That looks fine.

One suggestion, though. You do not have to have all positive patterns ("class, enum, interface" and "method definitions") in a single pattern separated by "|". You can place them on different "lines" (note the "\n" at the end of the first pattern):

	/* Class, enum, and interface declarations */
	"^[ \t]*(...(class|enum|interface)...)$\n"
	/*
	 * Method definitions; note that constructor signatures are not
	 * matched because they are indistinguishable from method calls.
	 */
	"^[ \t]*(...[A-Za-z_][A-Za-z_0-9]*[ \t]*\\([^;]*))$",

I don't think there is a technical difference, but I find this form easier to understand because fewer open parentheses have to be tracked.

-- Hannes
Previous: Tassilo HornNext: Tassilo Horn
Message 8 of 9 in “userdiff: improve java hunk header regex”
  1. userdiff: improve java hunk header regexTassilo Horn, Aug 10, 2021
  2. Johannes SixtAug 10, 2021
  3. Re* [PATCH v4] userdiff: improve java hunk header regexJunio C Hamano, Aug 10, 2021
  4. Johannes SixtAug 11, 2021
  5. Junio C HamanoAug 11, 2021
  6. Johannes SixtAug 11, 2021
  7. Tassilo HornAug 11, 2021
  8. Johannes SixtAug 11, 2021
  9. Tassilo HornAug 11, 2021

Read the whole thread, see it on lore, or plain text.

$ cat FOOTERMessages come from the public archive at lore.kernel.org/git, fetched every hour. The front page is chosen and written each morning by an AI editor and can be wrong; the threads themselves are the record. About and API. For agents: an MCP server at https://gitlist.dev/mcp, and any thread, story or person page as Markdown by adding .md to its URL (or sending Accept: text/markdown). Details in /llms.txt.