Rethink blocking annotations in detach-partition-concurrently-[34].

In 741d7f10, I tried to make the reports from canceled steps come out
after the pg_cancel_backend() steps, since that was the most common
ordering before.  However, that doesn't ensure that a canceled step
doesn't report even later, as shown in a recent failure on buildfarm
member idiacanthus.  Rather than complicating things even more with
additional annotations, let's just force the cancel's effect to be
reported first.  It's not *that* unnatural-looking.

Back-patch to v14 where these test cases appeared.

Report: https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=idiacanthus&dt=2021-07-02%2001%3A40%3A04

src/test/isolation/expected/detach-partition-concurrently-4.out

@@ -11,14 +11,15 @@ a
 (2 rows)
 
 step s2detach: alter table d4_primary detach partition d4_primary1 concurrently; <waiting ...>
-step s1cancel: select pg_cancel_backend(pid) from d4_pid;
+step s1cancel: select pg_cancel_backend(pid) from d4_pid; <waiting ...>
+step s2detach: <... completed>
+ERROR:  canceling statement due to user request
+step s1cancel: <... completed>
 pg_cancel_backend
 -----------------
 t                
 (1 row)
 
-step s2detach: <... completed>
-ERROR:  canceling statement due to user request
 step s1insert: insert into d4_fk values (1);
 ERROR:  insert or update on table "d4_fk" violates foreign key constraint "d4_fk_a_fkey"
 step s1c: commit;
@@ -50,14 +51,15 @@ a
 (2 rows)
 
 step s2detach: alter table d4_primary detach partition d4_primary1 concurrently; <waiting ...>
-step s1cancel: select pg_cancel_backend(pid) from d4_pid;
+step s1cancel: select pg_cancel_backend(pid) from d4_pid; <waiting ...>
+step s2detach: <... completed>
+ERROR:  canceling statement due to user request
+step s1cancel: <... completed>
 pg_cancel_backend
 -----------------
 t                
 (1 row)
 
-step s2detach: <... completed>
-ERROR:  canceling statement due to user request
 step s1insert: insert into d4_fk values (1);
 ERROR:  insert or update on table "d4_fk" violates foreign key constraint "d4_fk_a_fkey"
 step s1c: commit;
@@ -83,14 +85,15 @@ step s2snitch: insert into d4_pid select pg_backend_pid();
 step s1b: begin;
 step s1declare: declare f cursor for select * from d4_primary;
 step s2detach: alter table d4_primary detach partition d4_primary1 concurrently; <waiting ...>
-step s1cancel: select pg_cancel_backend(pid) from d4_pid;
+step s1cancel: select pg_cancel_backend(pid) from d4_pid; <waiting ...>
+step s2detach: <... completed>
+ERROR:  canceling statement due to user request
+step s1cancel: <... completed>
 pg_cancel_backend
 -----------------
 t                
 (1 row)
 
-step s2detach: <... completed>
-ERROR:  canceling statement due to user request
 step s1fetchall: fetch all from f;
 a
 -
@@ -124,14 +127,15 @@ step s2snitch: insert into d4_pid select pg_backend_pid();
 step s1b: begin;
 step s1declare: declare f cursor for select * from d4_primary;
 step s2detach: alter table d4_primary detach partition d4_primary1 concurrently; <waiting ...>
-step s1cancel: select pg_cancel_backend(pid) from d4_pid;
+step s1cancel: select pg_cancel_backend(pid) from d4_pid; <waiting ...>
+step s2detach: <... completed>
+ERROR:  canceling statement due to user request
+step s1cancel: <... completed>
 pg_cancel_backend
 -----------------
 t                
 (1 row)
 
-step s2detach: <... completed>
-ERROR:  canceling statement due to user request
 step s1svpt: savepoint f;
 step s1insert: insert into d4_fk values (1);
 ERROR:  insert or update on table "d4_fk" violates foreign key constraint "d4_fk_a_fkey"
@@ -251,14 +255,15 @@ a
 (1 row)
 
 step s2detach: alter table d4_primary detach partition d4_primary1 concurrently; <waiting ...>
-step s1cancel: select pg_cancel_backend(pid) from d4_pid;
+step s1cancel: select pg_cancel_backend(pid) from d4_pid; <waiting ...>
+step s2detach: <... completed>
+ERROR:  canceling statement due to user request
+step s1cancel: <... completed>
 pg_cancel_backend
 -----------------
 t                
 (1 row)
 
-step s2detach: <... completed>
-ERROR:  canceling statement due to user request
 step s1updcur: update d4_fk set a = 1 where current of f;
 ERROR:  insert or update on table "d4_fk" violates foreign key constraint "d4_fk_a_fkey"
 step s1c: commit;
@@ -326,14 +331,15 @@ step s3brr: begin isolation level repeatable read;
 step s3insert: insert into d4_fk values (1);
 ERROR:  insert or update on table "d4_fk" violates foreign key constraint "d4_fk_a_fkey"
 step s3commit: commit;
-step s1cancel: select pg_cancel_backend(pid) from d4_pid;
+step s1cancel: select pg_cancel_backend(pid) from d4_pid; <waiting ...>
+step s2detach: <... completed>
+ERROR:  canceling statement due to user request
+step s1cancel: <... completed>
 pg_cancel_backend
 -----------------
 t                
 (1 row)
 
-step s2detach: <... completed>
-ERROR:  canceling statement due to user request
 step s1c: commit;
 
 starting permutation: s2snitch s1b s1s s2detach s3brr s3insert s3commit s1c
@@ -365,14 +371,15 @@ a
 (2 rows)
 
 step s2detach: alter table d4_primary detach partition d4_primary1 concurrently; <waiting ...>
-step s1cancel: select pg_cancel_backend(pid) from d4_pid;
+step s1cancel: select pg_cancel_backend(pid) from d4_pid; <waiting ...>
+step s2detach: <... completed>
+ERROR:  canceling statement due to user request
+step s1cancel: <... completed>
 pg_cancel_backend
 -----------------
 t                
 (1 row)
 
-step s2detach: <... completed>
-ERROR:  canceling statement due to user request
 step s1noop: 
 step s3vacfreeze: vacuum freeze pg_catalog.pg_inherits;
 step s1s: select * from d4_primary;
@@ -397,14 +404,15 @@ a
 (2 rows)
 
 step s2detach: alter table d4_primary detach partition d4_primary1 concurrently; <waiting ...>
-step s1cancel: select pg_cancel_backend(pid) from d4_pid;
+step s1cancel: select pg_cancel_backend(pid) from d4_pid; <waiting ...>
+step s2detach: <... completed>
+ERROR:  canceling statement due to user request
+step s1cancel: <... completed>
 pg_cancel_backend
 -----------------
 t                
 (1 row)
 
-step s2detach: <... completed>
-ERROR:  canceling statement due to user request
 step s1noop: 
 step s3vacfreeze: vacuum freeze pg_catalog.pg_inherits;
 step s1s: select * from d4_primary;

src/test/isolation/specs/detach-partition-concurrently-3.spec

 # Try various things to happen to a partition with an incomplete detach
 #
 # Note: When using "s1cancel", mark the target step (the one to be canceled)
-# as being blocked by "s1cancel".  This ensures consistent reporting regardless
-# of whether "s1cancel" returns before or after the other step reports failure.
+# as blocking "s1cancel".  This ensures consistent reporting regardless of
+# whether "s1cancel" finishes before or after the other step reports failure.
 # Also, ensure the step after "s1cancel" is also an s1 step (use "s1noop" if
 # necessary).  This ensures we won't move on to the next step until the cancel
 # is complete.
@@ -50,37 +50,37 @@ step s2commit		{ COMMIT; }
 
 # Try various things while the partition is in "being detached" state, with
 # no session waiting.
-permutation s2snitch s1b s1s s2detach(s1cancel) s1cancel s1c s1describe s1alter
-permutation s2snitch s1b s1s s2detach(s1cancel) s1cancel s1insert s1c
-permutation s2snitch s1brr s1s s2detach(s1cancel) s1cancel s1insert s1c s1spart
-permutation s2snitch s1b s1s s2detach(s1cancel) s1cancel s1c s1insertpart
+permutation s2snitch s1b s1s s2detach s1cancel(s2detach) s1c s1describe s1alter
+permutation s2snitch s1b s1s s2detach s1cancel(s2detach) s1insert s1c
+permutation s2snitch s1brr s1s s2detach s1cancel(s2detach) s1insert s1c s1spart
+permutation s2snitch s1b s1s s2detach s1cancel(s2detach) s1c s1insertpart
 
 # Test partition descriptor caching
-permutation s2snitch s1b s1s s2detach2(s1cancel) s1cancel s1c s1brr s1insert s1s s1insert s1c
-permutation s2snitch s1b s1s s2detach2(s1cancel) s1cancel s1c s1brr s1s s1insert s1s s1c
+permutation s2snitch s1b s1s s2detach2 s1cancel(s2detach2) s1c s1brr s1insert s1s s1insert s1c
+permutation s2snitch s1b s1s s2detach2 s1cancel(s2detach2) s1c s1brr s1s s1insert s1s s1c
 
 # "drop" here does both tables
-permutation s2snitch s1b s1s s2detach(s1cancel) s1cancel s1c s1drop s1list
+permutation s2snitch s1b s1s s2detach s1cancel(s2detach) s1c s1drop s1list
 # "truncate" only does parent, not partition
-permutation s2snitch s1b s1s s2detach(s1cancel) s1cancel s1c s1trunc s1spart
+permutation s2snitch s1b s1s s2detach s1cancel(s2detach) s1c s1trunc s1spart
 
 # If a partition pending detach exists, we cannot drop another one
-permutation s2snitch s1b s1s s2detach(s1cancel) s1cancel s1noop s2detach2 s1c
-permutation s2snitch s1b s1s s2detach(s1cancel) s1cancel s1noop s2detachfinal s1c s2detach2
-permutation s2snitch s1b s1s s2detach(s1cancel) s1cancel s1c s1droppart s2detach2
+permutation s2snitch s1b s1s s2detach s1cancel(s2detach) s1noop s2detach2 s1c
+permutation s2snitch s1b s1s s2detach s1cancel(s2detach) s1noop s2detachfinal s1c s2detach2
+permutation s2snitch s1b s1s s2detach s1cancel(s2detach) s1c s1droppart s2detach2
 
 # When a partition with incomplete detach is dropped, we grab lock on parent too.
-permutation s2snitch s1b s1s s2detach(s1cancel) s1cancel s1c s2begin s2drop s1s s2commit
+permutation s2snitch s1b s1s s2detach s1cancel(s2detach) s1c s2begin s2drop s1s s2commit
 
 # Partially detach, then select and try to complete the detach.  Reading
 # from partition blocks (AEL is required on partition); reading from parent
 # does not block.
-permutation s2snitch s1b s1s s2detach(s1cancel) s1cancel s1c s1b s1spart s2detachfinal s1c
-permutation s2snitch s1b s1s s2detach(s1cancel) s1cancel s1c s1b s1s s2detachfinal s1c
+permutation s2snitch s1b s1s s2detach s1cancel(s2detach) s1c s1b s1spart s2detachfinal s1c
+permutation s2snitch s1b s1s s2detach s1cancel(s2detach) s1c s1b s1s s2detachfinal s1c
 
 # DETACH FINALIZE in a transaction block. No insert/select on the partition
 # is allowed concurrently with that.
-permutation s2snitch s1b s1s s2detach(s1cancel) s1cancel s1c s1b s1spart s2detachfinal s1c
-permutation s2snitch s1b s1s s2detach(s1cancel) s1cancel s1c s2begin s2detachfinal s2commit
-permutation s2snitch s1b s1s s2detach(s1cancel) s1cancel s1c s2begin s2detachfinal s1spart s2commit
-permutation s2snitch s1b s1s s2detach(s1cancel) s1cancel s1c s2begin s2detachfinal s1insertpart s2commit
+permutation s2snitch s1b s1s s2detach s1cancel(s2detach) s1c s1b s1spart s2detachfinal s1c
+permutation s2snitch s1b s1s s2detach s1cancel(s2detach) s1c s2begin s2detachfinal s2commit
+permutation s2snitch s1b s1s s2detach s1cancel(s2detach) s1c s2begin s2detachfinal s1spart s2commit
+permutation s2snitch s1b s1s s2detach s1cancel(s2detach) s1c s2begin s2detachfinal s1insertpart s2commit

src/test/isolation/specs/detach-partition-concurrently-4.spec

@@ -5,8 +5,8 @@
 # that keeping both variants adds any extra coverage.)
 #
 # Note: When using "s1cancel", mark the target step (the one to be canceled)
-# as being blocked by "s1cancel".  This ensures consistent reporting regardless
-# of whether "s1cancel" returns before or after the other step reports failure.
+# as blocking "s1cancel".  This ensures consistent reporting regardless of
+# whether "s1cancel" finishes before or after the other step reports failure.
 # Also, ensure the step after "s1cancel" is also an s1 step (use "s1noop" if
 # necessary).  This ensures we won't move on to the next step until the cancel
 # is complete.
@@ -50,34 +50,34 @@ step s3commit		{ commit; }
 step s3vacfreeze	{ vacuum freeze pg_catalog.pg_inherits; }
 
 # Trying to insert into a partially detached partition is rejected
-permutation s2snitch s1b   s1s s2detach(s1cancel) s1cancel s1insert s1c
+permutation s2snitch s1b   s1s s2detach s1cancel(s2detach) s1insert s1c
 permutation s2snitch s1b   s1s s2detach                    s1insert s1c
 # ... even under REPEATABLE READ mode.
-permutation s2snitch s1brr s1s s2detach(s1cancel) s1cancel s1insert s1c
+permutation s2snitch s1brr s1s s2detach s1cancel(s2detach) s1insert s1c
 permutation s2snitch s1brr s1s s2detach                    s1insert s1c
 
 # If you read the referenced table using a cursor, you can see a row that the
 # RI query does not see.
-permutation s2snitch s1b s1declare s2detach(s1cancel) s1cancel s1fetchall s1insert s1c
+permutation s2snitch s1b s1declare s2detach s1cancel(s2detach) s1fetchall s1insert s1c
 permutation s2snitch s1b s1declare s2detach                    s1fetchall s1insert s1c
-permutation s2snitch s1b s1declare s2detach(s1cancel) s1cancel s1svpt s1insert s1rollback s1fetchall s1c
+permutation s2snitch s1b s1declare s2detach s1cancel(s2detach) s1svpt s1insert s1rollback s1fetchall s1c
 permutation s2snitch s1b s1declare s2detach                    s1svpt s1insert s1rollback s1fetchall s1c
-permutation s2snitch s1b s2detach(s1cancel) s1declare s1cancel s1fetchall s1insert s1c
+permutation s2snitch s1b s2detach s1declare s1cancel(s2detach) s1fetchall s1insert s1c
 permutation s2snitch s1b s2detach s1declare                    s1fetchall s1insert s1c
-permutation s2snitch s1b s2detach(s1cancel) s1declare s1cancel s1svpt s1insert s1rollback s1fetchall s1c
+permutation s2snitch s1b s2detach s1declare s1cancel(s2detach) s1svpt s1insert s1rollback s1fetchall s1c
 permutation s2snitch s1b s2detach s1declare                    s1svpt s1insert s1rollback s1fetchall s1c
 
 # Creating the referencing row using a cursor
-permutation s2snitch s1brr s1declare2 s1fetchone s2detach(s1cancel) s1cancel s1updcur s1c
+permutation s2snitch s1brr s1declare2 s1fetchone s2detach s1cancel(s2detach) s1updcur s1c
 permutation s2snitch s1brr s1declare2 s1fetchone s2detach                    s1updcur s1c
 permutation s2snitch s1brr s1declare2 s1fetchone s1updcur s2detach s1c
 
 # Try reading the table from an independent session.
 permutation s2snitch s1b s1s s2detach s3insert s1c
-permutation s2snitch s1b s1s s2detach(s1cancel) s3brr s3insert s3commit s1cancel s1c
+permutation s2snitch s1b s1s s2detach s3brr s3insert s3commit s1cancel(s2detach) s1c
 permutation s2snitch s1b s1s s2detach s3brr s3insert s3commit s1c
 
 # Try one where we VACUUM FREEZE pg_inherits (to verify that xmin change is
 # handled correctly).
-permutation s2snitch s1brr s1s s2detach(s1cancel) s1cancel s1noop s3vacfreeze s1s s1insert s1c
-permutation s2snitch s1b s1s s2detach(s1cancel) s1cancel s1noop s3vacfreeze s1s s1insert s1c
+permutation s2snitch s1brr s1s s2detach s1cancel(s2detach) s1noop s3vacfreeze s1s s1insert s1c
+permutation s2snitch s1b s1s s2detach s1cancel(s2detach) s1noop s3vacfreeze s1s s1insert s1c