Thread: pgsql: Fix ADD IF NOT EXISTS used in conjunction with ALTER TABLE ONLY

Fix ADD IF NOT EXISTS used in conjunction with ALTER TABLE ONLY

The flag for IF NOT EXISTS was only being passed down in the normal
recursing case. It's been this way since originally added in 9.6 in
commit 2cd40adb85 so backpatch back to 9.6.

Branch
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REL_11_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/128ce8e1a18ed7a83dd0f8dbe7bfb00eb73f200b

Modified Files
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src/backend/commands/tablecmds.c          | 2 +-
src/test/regress/expected/alter_table.out | 6 ++++++
src/test/regress/sql/alter_table.sql      | 4 ++++
3 files changed, 11 insertions(+), 1 deletion(-)