diff options
| -rw-r--r-- | Makefile | 7 | ||||
| -rw-r--r-- | contrib/coccinelle/README | 41 |
2 files changed, 46 insertions, 2 deletions
@@ -2742,9 +2742,12 @@ endif then \ echo ' ' SPATCH result: $@; \ fi -coccicheck: $(addsuffix .patch,$(wildcard contrib/coccinelle/*.cocci)) +coccicheck: $(addsuffix .patch,$(filter-out %.pending.cocci,$(wildcard contrib/coccinelle/*.cocci))) -.PHONY: coccicheck +# See contrib/coccinelle/README +coccicheck-pending: $(addsuffix .patch,$(wildcard contrib/coccinelle/*.pending.cocci)) + +.PHONY: coccicheck coccicheck-pending ### Installation rules diff --git a/contrib/coccinelle/README b/contrib/coccinelle/README index 9c2f8879c2..f0e80bd7f0 100644 --- a/contrib/coccinelle/README +++ b/contrib/coccinelle/README @@ -1,2 +1,43 @@ This directory provides examples of Coccinelle (http://coccinelle.lip6.fr/) semantic patches that might be useful to developers. + +There are two types of semantic patches: + + * Using the semantic transformation to check for bad patterns in the code; + The target 'make coccicheck' is designed to check for these patterns and + it is expected that any resulting patch indicates a regression. + The patches resulting from 'make coccicheck' are small and infrequent, + so once they are found, they can be sent to the mailing list as per usual. + + Example for introducing new patterns: + 67947c34ae (convert "hashcmp() != 0" to "!hasheq()", 2018-08-28) + b84c783882 (fsck: s/++i > 1/i++/, 2018-10-24) + + Example of fixes using this approach: + 248f66ed8e (run-command: use strbuf_addstr() for adding a string to + a strbuf, 2018-03-25) + f919ffebed (Use MOVE_ARRAY, 2018-01-22) + + These types of semantic patches are usually part of testing, c.f. + 0860a7641b (travis-ci: fail if Coccinelle static analysis found something + to transform, 2018-07-23) + + * Using semantic transformations in large scale refactorings throughout + the code base. + + When applying the semantic patch into a real patch, sending it to the + mailing list in the usual way, such a patch would be expected to have a + lot of textual and semantic conflicts as such large scale refactorings + change function signatures that are used widely in the code base. + A textual conflict would arise if surrounding code near any call of such + function changes. A semantic conflict arises when other patch series in + flight introduce calls to such functions. + + So to aid these large scale refactorings, semantic patches can be used. + However we do not want to store them in the same place as the checks for + bad patterns, as then automated builds would fail. + That is why semantic patches 'contrib/coccinelle/*.pending.cocci' + are ignored for checks, and can be applied using 'make coccicheck-pending'. + + This allows to expose plans of pending large scale refactorings without + impacting the bad pattern checks. |