Use Go standard library slices package instead of x/exp/slices

[tklauser]

The former is available since Go 1.21 and the latter is merely a wrapper around it when using Go ≥ 1.21. Use the standard library package directly.

We cannot yet switch out x/exp/maps for the standard library maps package as the maps.Keys function used in statedb code base is only available in Go ≥ 1.23.

[tklauser]

We cannot yet switch out x/exp/maps for the standard library maps package as the maps.Keys function used in statedb code base is only available in Go ≥ 1.23.

Alternatively, we could also bump go.mod to 1.23 and make that switch as well but I'm not sure what the Go version support policy on this repo is. /cc @joamaki

[github-actions]

$ make test
go: downloading github.com/mitchellh/mapstructure v1.5.0
go: downloading golang.org/x/term v0.16.0
go: downloading github.com/spf13/cast v1.6.0
go: downloading github.com/fsnotify/fsnotify v1.7.0
go: downloading github.com/sagikazarmark/slog-shim v0.1.0
go: downloading github.com/spf13/afero v1.11.0
go: downloading golang.org/x/sys v0.17.0
go: downloading github.com/subosito/gotenv v1.6.0
go: downloading github.com/hashicorp/hcl v1.0.0
go: downloading gopkg.in/ini.v1 v1.67.0
go: downloading github.com/magiconair/properties v1.8.7
go: downloading github.com/pelletier/go-toml/v2 v2.1.0
go: downloading golang.org/x/text v0.14.0
	github.com/cilium/statedb/reconciler/benchmark		coverage: 0.0% of statements
	github.com/cilium/statedb/reconciler/example		coverage: 0.0% of statements
ok  	github.com/cilium/statedb	5.627s	coverage: 88.4% of statements
ok  	github.com/cilium/statedb/index	0.005s	coverage: 44.6% of statements
ok  	github.com/cilium/statedb/internal	0.011s	coverage: 93.3% of statements
ok  	github.com/cilium/statedb/part	2.681s	coverage: 82.8% of statements
ok  	github.com/cilium/statedb/reconciler	2.507s	coverage: 92.9% of statements
-----
$ make bench
go test ./... -bench . -benchmem -test.run xxx
goos: linux
goarch: amd64
pkg: github.com/cilium/statedb
cpu: AMD EPYC 7763 64-Core Processor                
BenchmarkDB_WriteTxn_1-4                    	  455200	      2588 ns/op	    386369 objects/sec	    2800 B/op	      32 allocs/op
BenchmarkDB_WriteTxn_10-4                   	 1209490	      1046 ns/op	    955739 objects/sec	     741 B/op	      10 allocs/op
BenchmarkDB_WriteTxn_100-4                  	 1526876	       784.7 ns/op	   1274444 objects/sec	     596 B/op	       7 allocs/op
BenchmarkDB_WriteTxn_1000-4                 	 1475962	       810.6 ns/op	   1233607 objects/sec	     551 B/op	       7 allocs/op
BenchmarkDB_WriteTxn_100_SecondaryIndex-4   	  517376	      2246 ns/op	    445265 objects/sec	    1489 B/op	      37 allocs/op
BenchmarkDB_Modify-4                        	    1311	    934834 ns/op	   1069710 objects/sec	  773480 B/op	    8462 allocs/op
BenchmarkDB_GetInsert-4                     	    1222	   1005693 ns/op	    994340 objects/sec	  755213 B/op	    8459 allocs/op
BenchmarkDB_RandomInsert-4                  	    2389	    494538 ns/op	   2022090 objects/sec	  402092 B/op	    7097 allocs/op
BenchmarkDB_RandomReplace-4                 	     330	   3659913 ns/op	    273231 objects/sec	 2349510 B/op	   48570 allocs/op
BenchmarkDB_SequentialInsert-4              	    1508	    821537 ns/op	   1217230 objects/sec	  551768 B/op	    7287 allocs/op
BenchmarkDB_Changes_Baseline-4              	    1245	    949597 ns/op	   1053079 objects/sec	  553074 B/op	   10252 allocs/op
BenchmarkDB_Changes-4                       	     709	   1696477 ns/op	    589457 objects/sec	  993253 B/op	   14493 allocs/op
BenchmarkDB_RandomLookup-4                  	   21963	     52939 ns/op	  18889698 objects/sec	     144 B/op	       1 allocs/op
BenchmarkDB_SequentialLookup-4              	   27372	     45718 ns/op	  21873165 objects/sec	       0 B/op	       0 allocs/op
BenchmarkDB_FullIteration_All-4             	     982	   1275208 ns/op	  78418738 objects/sec	     464 B/op	      12 allocs/op
BenchmarkDB_FullIteration_Get-4             	     218	   5510466 ns/op	  18147314 objects/sec	       0 B/op	       0 allocs/op
BenchmarkDB_PropagationDelay-4              	  510844	      2314 ns/op	        20.00 50th_µs	        23.00 90th_µs	        86.00 99th_µs	    1585 B/op	      24 allocs/op
PASS
ok  	github.com/cilium/statedb	26.858s
PASS
ok  	github.com/cilium/statedb/index	0.004s
PASS
ok  	github.com/cilium/statedb/internal	0.003s
goos: linux
goarch: amd64
pkg: github.com/cilium/statedb/part
cpu: AMD EPYC 7763 64-Core Processor                
Benchmark_Insert_RootOnlyWatch-4    	    9067	    132492 ns/op	   7547620 objects/sec	  104163 B/op	    2041 allocs/op
Benchmark_Insert-4                  	    6145	    184927 ns/op	   5407549 objects/sec	  219064 B/op	    3065 allocs/op
Benchmark_Modify-4                  	    8134	    142399 ns/op	   7022520 objects/sec	  212303 B/op	    1204 allocs/op
Benchmark_GetInsert-4               	    6615	    177830 ns/op	   5623353 objects/sec	  212351 B/op	    1203 allocs/op
Benchmark_Replace-4                 	27098643	        44.85 ns/op	  22296766 objects/sec	       0 B/op	       0 allocs/op
Benchmark_Replace_RootOnlyWatch-4   	26808273	        44.96 ns/op	  22241443 objects/sec	       0 B/op	       0 allocs/op
Benchmark_txn_1-4                   	 3027760	       405.7 ns/op	   2464726 objects/sec	     448 B/op	       7 allocs/op
Benchmark_txn_10-4                  	 7252398	       163.3 ns/op	   6124082 objects/sec	     154 B/op	       2 allocs/op
Benchmark_txn_100-4                 	 7936075	       152.1 ns/op	   6572923 objects/sec	     224 B/op	       2 allocs/op
Benchmark_txn_1000-4                	 7019612	       173.8 ns/op	   5753185 objects/sec	     216 B/op	       2 allocs/op
Benchmark_txn_delete_1-4            	 3105154	       384.9 ns/op	   2598186 objects/sec	     856 B/op	       6 allocs/op
Benchmark_txn_delete_10-4           	 8487979	       139.4 ns/op	   7174354 objects/sec	     132 B/op	       1 allocs/op
Benchmark_txn_delete_100-4          	10723832	       110.8 ns/op	   9026222 objects/sec	      60 B/op	       1 allocs/op
Benchmark_txn_delete_1000-4         	11331942	       104.8 ns/op	   9544686 objects/sec	      26 B/op	       1 allocs/op
Benchmark_Get-4                     	   38626	     30838 ns/op	  32427940 objects/sec	       0 B/op	       0 allocs/op
Benchmark_Iterate-4                 	  174114	      6934 ns/op	 144211909 objects/sec	      80 B/op	       3 allocs/op
Benchmark_Hashmap_Insert-4          	   15705	     76241 ns/op	  13116400 objects/sec	   86551 B/op	      64 allocs/op
Benchmark_Hashmap_Get_Uint64-4      	  163640	      7382 ns/op	 135460876 objects/sec	       0 B/op	       0 allocs/op
Benchmark_Hashmap_Get_Bytes-4       	  156486	      7674 ns/op	 130314240 objects/sec	       0 B/op	       0 allocs/op
Benchmark_Uint64Map_Random-4        	    1402	    851551 ns/op	   1174329 items/sec	 2702553 B/op	    9022 allocs/op
Benchmark_Uint64Map_Sequential-4    	    1508	    790488 ns/op	   1265041 items/sec	 2492408 B/op	    9749 allocs/op
PASS
ok  	github.com/cilium/statedb/part	28.415s
PASS
ok  	github.com/cilium/statedb/reconciler	0.004s
?   	github.com/cilium/statedb/reconciler/benchmark	[no test files]
?   	github.com/cilium/statedb/reconciler/example	[no test files]
go run ./reconciler/benchmark -quiet
1000000 objects reconciled in 2.95 seconds (batch size 1000)
Throughput 338716.17 objects per second
Allocated 6011279 objects, 424760kB bytes, 517704kB bytes still in use

[joamaki]

Just merged the range-funcs PR, so cilium/statedb is now at Go v1.23. Could you rebase and switch the maps package too?

EDIT: Did this myself.