pgsql: Avoid using list_length() to test for empty list.
От | Tom Lane |
---|---|
Тема | pgsql: Avoid using list_length() to test for empty list. |
Дата | |
Msg-id | E1oOKin-001CGW-QC@gemulon.postgresql.org обсуждение исходный текст |
Список | pgsql-committers |
Avoid using list_length() to test for empty list. The standard way to check for list emptiness is to compare the List pointer to NIL; our list code goes out of its way to ensure that that is the only representation of an empty list. (An acceptable alternative is a plain boolean test for non-null pointer, but explicit mention of NIL is usually preferable.) Various places didn't get that memo and expressed the condition with list_length(), which might not be so bad except that there were such a variety of ways to check it exactly: equal to zero, less than or equal to zero, less than one, yadda yadda. In the name of code readability, let's standardize all those spellings as "list == NIL" or "list != NIL". (There's probably some microscopic efficiency gain too, though few of these look to be at all performance-critical.) A very small number of cases were left as-is because they seemed more consistent with other adjacent list_length tests that way. Peter Smith, with bikeshedding from a number of us Discussion: https://postgr.es/m/CAHut+PtQYe+ENX5KrONMfugf0q6NHg4hR5dAhqEXEc2eefFeig@mail.gmail.com Branch ------ master Details ------- https://git.postgresql.org/pg/commitdiff/efd0c16becbf45e3b0215e124fde75fee8fcbce4 Modified Files -------------- src/backend/catalog/objectaddress.c | 2 +- src/backend/catalog/pg_depend.c | 2 +- src/backend/commands/event_trigger.c | 8 ++++---- src/backend/commands/functioncmds.c | 4 ++-- src/backend/commands/publicationcmds.c | 6 +++--- src/backend/commands/statscmds.c | 4 ++-- src/backend/commands/subscriptioncmds.c | 2 +- src/backend/commands/tablecmds.c | 8 ++++---- src/backend/commands/typecmds.c | 2 +- src/backend/executor/execPartition.c | 2 +- src/backend/libpq/auth.c | 4 ++-- src/backend/libpq/hba.c | 4 ++-- src/backend/optimizer/path/costsize.c | 2 +- src/backend/optimizer/plan/createplan.c | 2 +- src/backend/optimizer/plan/planner.c | 12 ++++++------ src/backend/partitioning/partprune.c | 2 +- src/backend/replication/logical/tablesync.c | 8 ++++---- src/backend/replication/pgoutput/pgoutput.c | 2 +- src/backend/rewrite/rewriteDefine.c | 2 +- src/backend/statistics/mcv.c | 1 - src/backend/storage/lmgr/lmgr.c | 2 +- src/backend/utils/adt/jsonb_gin.c | 2 +- src/backend/utils/adt/jsonpath_exec.c | 2 +- src/backend/utils/adt/jsonpath_gram.y | 2 +- src/backend/utils/adt/ruleutils.c | 2 +- src/backend/utils/adt/selfuncs.c | 2 +- src/backend/utils/adt/tsquery.c | 2 +- src/test/modules/test_ddl_deparse/test_ddl_deparse.c | 2 +- 28 files changed, 47 insertions(+), 48 deletions(-)
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