Fix internal errors when for-loop bodies always exit

[achidlow]

This fixes "internal error" issues with code such as the below:

@subroutine
def silly_for_1() -> None:
    for b in Bytes(b"abc"):
        log(b)
        break


@subroutine
def silly_for_2() -> None:
    for x in (UInt64(0), UInt64(1)):
        log(x)
        break


@subroutine
def silly_for_3() -> None:
    for i in urange(10):
        log(i)
        break

Because the loops above always exit the loop on the first iteration, the IR builder attempts to add unreachable code in the footers.

This fix only adds footers if the block can be activated.

It also restructures the tuple iteration builder to remove the singular use of ignore_predecessor_check.

The refactored iteration code for tuples also produces reduced code sizes across the board.

Testing has been improved, with coverage of each valid combination of iteration type (indexable, range, and tuple) against forwards/reversed items and indexes.

[github-actions]

Coverage Report

File	Stmts	Miss	Cover	Missing
src/puya
__main__.py	31	1	97%	116
arc4_util.py	48	2	96%	61, 63
arc32.py	70	3	96%	77–78, 103
client_gen.py	114	114	0%	1–202
compile.py	211	20	91%	168–171, 183–184, 193–194, 205, 212–213, 230–240, 250–252, 257, 333–334
context.py	40	1	98%	48
errors.py	45	17	62%	43–53, 65–71
log.py	212	30	86%	36–39, 72, 74, 92, 126–127, 169–171, 174–176, 178, 191–200, 222, 292–294, 303–304, 338, 355
parse.py	222	11	95%	96, 108, 133, 227, 318–323, 327, 425–426, 429
utils.py	166	20	88%	52, 56, 90, 96, 111, 114–116, 123, 145, 158–159, 163, 167–170, 199, 201, 224, 254
src/puya/awst
nodes.py	909	50	94%	84, 88–91, 131, 135–138, 304, 481, 497, 515, 562, 589–590, 646, 650, 774, 810, 832, 864, 886, 891, 896, 995, 1143, 1196–1197, 1204–1209, 1251, 1331, 1384, 1388, 1438, 1451, 1496, 1539, 1550, 1552, 1557, 1565, 1570, 1575, 1584, 1589, 1594, 1601
to_code_visitor.py	330	5	98%	112, 296–297, 339, 525
txn_fields.py	98	1	99%	48
wtypes.py	268	26	90%	159–163, 173–176, 191, 206, 234, 270, 294, 299, 340, 368, 370, 470, 497–498, 507–508, 516–517, 536
src/puya/awst_build
arc4_utils.py	316	49	84%	42, 45–46, 48, 80, 92–94, 118, 129–133, 149, 151, 154–155, 178, 216–218, 227, 232, 237–238, 262, 266, 278, 285, 287, 301–302, 305–309, 314–315, 321–324, 332, 350, 362, 370–371, 383, 391, 492, 497, 516
arc32_client_gen.py	69	3	96%	35, 131–132
base_mypy_visitor.py	129	40	69%	70–76, 94, 102–115, 129, 131, 133, 145, 150, 154, 157, 160, 166, 187, 192, 195, 198, 205, 209, 212, 215, 219, 237, 241, 245, 249, 253, 257, 261, 265, 269, 273, 277, 281, 285
context.py	225	47	79%	47, 69, 72, 82–83, 109–110, 206, 211, 217–221, 226, 235, 237, 240–242, 244, 251, 253, 259, 264–265, 270–272, 275, 295, 319–320, 332, 346, 349–361
contract.py	195	34	83%	125–126, 128–131, 139–140, 143, 155, 203, 248, 252, 267–271, 279, 288, 291, 303, 311, 314, 317, 320, 323, 326, 329, 332, 335, 346, 356, 364, 370, 395–401
contract_data.py	58	2	97%	37–38
intrinsic_models.py	40	1	98%	49
main.py	48	3	94%	31, 48, 58
module.py	410	60	85%	53–56, 85, 149, 163–165, 180–181, 188, 197–198, 206–210, 228–232, 239, 263–264, 275, 297–300, 310–312, 318, 341–344, 357, 391, 398, 420–421, 444–449, 503–504, 532, 543, 546, 552, 565, 571, 583, 586, 608, 628, 633, 637, 641–644, 671, 729, 737, 739
pytypes.py	456	51	89%	84–86, 100–101, 141, 157–163, 186, 206, 267, 276, 295, 299, 315–316, 348, 440–442, 456–457, 526–527, 604, 615–616, 664–665, 670, 719–720, 741–742, 870–871, 895, 923, 957–959, 985, 1012, 1022–1023, 1059–1061
subroutine.py	601	52	91%	136, 258, 264, 322–325, 331, 383, 390, 393–399, 464, 579, 581–582, 600, 602, 612–613, 622–623, 627, 648, 718, 725, 745–746, 828, 859–860, 877, 899–900, 905, 993, 1001, 1012–1013, 1037, 1150, 1160, 1167, 1180, 1205, 1208, 1211, 1214, 1217, 1237–1240
utils.py	194	25	87%	38, 55–59, 75, 110–111, 115, 159–160, 234, 242, 247, 260–264, 269–272, 280, 307, 315, 358
src/puya/awst_build/eb
_base.py	125	19	85%	53, 58–60, 65, 72, 77, 82–84, 139, 150, 172, 177, 182, 187, 198, 213, 218–220
_bytes_backed.py	48	2	96%	30–31
_expect.py	125	18	86%	25, 36, 77–80, 92–95, 98, 157–158, 219, 232–235
_literals.py	136	30	78%	42–43, 67, 86, 115, 123, 137, 141, 145–151, 161–175, 180
_utils.py	44	1	98%	95
array.py	27	9	67%	24, 29–34, 44, 50
biguint.py	97	6	94%	57, 99, 136, 151–152, 154
bool.py	51	8	84%	38–42, 58, 69, 84
bytes.py	172	20	88%	72, 105–106, 133–134, 139–140, 146–147, 150–151, 158, 201, 236, 269, 273, 290–291, 306–307
conditional_literal.py	117	35	70%	76, 80, 134, 138–141, 150–152, 161–164, 175–178, 187, 191, 195–198, 213–225, 234–235
contracts.py	84	6	93%	64, 70, 83, 108, 129, 133
ensure_budget.py	33	1	97%	49
interface.py	96	3	97%	296–298, 302
intrinsics.py	99	8	92%	38, 57, 64, 77, 84, 155, 179–180
log.py	43	4	91%	46–47, 52, 61
none.py	25	3	88%	17, 28, 37
string.py	145	13	91%	72, 115–116, 135, 139, 183, 190, 194, 206, 280–282, 302
struct.py	17	5	71%	15–17, 26, 32
subroutine.py	80	18	78%	50, 54–57, 72, 75–83, 97, 105–109, 111–114, 119
template_variables.py	37	3	92%	30, 58, 67
tuple.py	266	11	96%	75, 149, 184–185, 191, 268–269, 394, 405–406, 469
uint64.py	114	5	96%	59, 123–124, 172–173
uint64_enums.py	41	2	95%	42, 47
unsigned_builtins.py	153	20	87%	74, 81, 108, 135, 139, 143, 151, 155, 159, 163, 167, 177, 181, 187, 198, 204, 243, 275, 287, 299
src/puya/awst_build/eb/arc4
_base.py	91	3	97%	187–190, 201
_utils.py	113	9	92%	61–62, 87, 92, 122–125, 165, 169, 183
abi_call.py	159	8	95%	90, 96, 99, 121, 179, 195, 248, 320
address.py	77	3	96%	57, 117–118
bool.py	57	3	95%	44, 86–87
dynamic_array.py	127	10	92%	57, 126–127, 147, 149, 154, 228, 249, 255–258
dynamic_bytes.py	68	3	96%	97–99
emit.py	37	1	97%	39
static_array.py	66	1	98%	41
string.py	100	9	91%	54–55, 103, 126, 131–134, 161–162
struct.py	49	1	98%	49
tuple.py	94	15	84%	50–52, 92–95, 98–99, 135–138, 143, 147–148, 158, 168
ufixed.py	70	2	97%	43, 102
uint.py	75	4	95%	81–83, 135–136
src/puya/awst_build/eb/reference_types
_base.py	52	1	98%	119
account.py	81	2	98%	60, 171
application.py	45	1	98%	35
asset.py	65	1	98%	43
src/puya/awst_build/eb/storage
_common.py	69	3	96%	104, 119–120
_storage.py	96	16	83%	77, 85, 89, 93, 97, 101, 105, 109, 119, 123, 127, 131, 137, 148, 154, 166
value_proxy.py	55	7	87%	39, 43, 51, 55, 92, 100, 104
box_map.py	144	1	99%	183
global_state.py	138	5	96%	108–109, 115, 171–172
local_state.py	148	11	93%	103–104, 108, 157, 161, 165, 175, 179, 203, 290, 314
src/puya/awst_build/eb/transaction
base.py	39	2	95%	23, 43
inner.py	48	2	96%	88–89
inner_params.py	81	5	94%	69, 79, 83, 143, 145
itxn_args.py	60	1	98%	68
src/puya/awst_build/validation
base_invoker.py	29	5	83%	31, 38, 47–52
inner_transactions.py	181	1	99%	160
scratch_slots.py	39	4	90%	19, 33, 49, 51
src/puya/ir
arc4_router.py	329	23	93%	157, 175, 183, 251–252, 341, 520–521, 535, 579–580, 592, 597, 602, 607, 612, 617, 637–641, 672, 871, 904–905
avm_ops.py	315	1	99%	46
avm_ops_models.py	48	3	94%	21, 30, 38
context.py	86	7	92%	72, 94–100, 105, 128, 136
main.py	230	3	99%	438–439, 456
models.py	519	23	96%	67, 176, 183, 313, 383–384, 389, 395–400, 412, 456, 483, 538, 580, 660, 676, 717, 720, 727, 730, 820–821
ssa.py	130	2	98%	51–52
to_text_visitor.py	149	9	94%	93, 98, 182–183, 189–194
types.py	97	12	88%	49–50, 56, 90–95, 103, 140–143
visitor.py	119	15	87%	171, 183, 198, 201, 207, 213, 216, 227, 230, 233, 236, 239, 242, 245, 248
visitor_mutator.py	101	2	98%	152–153
vla.py	72	1	99%	87
src/puya/ir/builder
_utils.py	76	5	93%	78, 204, 240–242
arc4.py	501	27	95%	91, 127–132, 386, 389, 458–461, 725–726, 972, 996, 1085–1102, 1123–1140, 1179–1180, 1232, 1242, 1297, 1342, 1361, 1381, 1445–1452
assignment.py	74	7	91%	49, 90, 163, 174, 192, 208–209
blocks.py	90	2	98%	162, 170
bytes.py	64	14	78%	23–55, 139
callsub.py	57	1	98%	93
flow_control.py	96	1	99%	72
iteration.py	175	4	98%	44, 66, 92, 165
itxn.py	266	13	95%	125–126, 128, 141, 189, 209, 234–235, 563, 587–588, 601–602
main.py	496	37	93%	100, 162, 166, 221, 245, 269–270, 304, 466, 488–491, 507–508, 548, 574, 618–621, 631, 696, 814, 827, 860, 915, 918, 926, 929–930, 937, 968, 1030, 1047, 1097–1098
storage.py	84	4	95%	99–100, 151–152
src/puya/ir/destructure
coalesce_locals.py	102	20	80%	119, 128–129, 132–135, 138–147, 163–166
parcopy.py	84	2	98%	47, 83
src/puya/ir/optimize
collapse_blocks.py	92	5	95%	65–69
control_op_simplification.py	101	10	90%	159–166, 240–247
inner_txn.py	36	1	97%	38
intrinsic_simplification.py	421	26	94%	68, 171, 183, 232–233, 253, 320, 384, 458, 486, 507, 509, 524, 579, 609, 615, 617, 619, 624, 626, 628, 630, 632, 684–685, 692
main.py	86	3	97%	111–112, 128
src/puya/ir/validation
_base.py	30	2	93%	24–25
min_avm_version_validator.py	11	1	91%	15
op_run_mode_validator.py	20	6	70%	19–30
src/puya/mir
annotaters.py	159	2	99%	62, 212
builder.py	136	8	94%	139, 248–249, 302, 305, 308, 311, 314
context.py	39	1	97%	35
models.py	328	16	95%	40, 52, 68, 77, 88, 99, 110, 150, 260, 291, 328, 340, 365–371
output.py	61	2	97%	29, 31
stack.py	250	19	92%	72, 119, 135, 146, 157, 167, 184, 201, 211, 230, 250, 256, 258, 297, 310, 334, 366, 371, 409
src/puya/mir/stack_allocation
baileys.py	205	3	99%	31, 330–334
frame_allocation.py	80	2	98%	21, 68
koopmans.py	61	1	98%	55
peephole.py	100	6	94%	75, 89, 99, 101, 103, 145
src/puya/teal/optimize
peephole.py	112	3	97%	139, 145, 169
repeated_rotations.py	42	1	98%	13
repeated_rotations_search.py	88	6	93%	34, 40–41, 57, 67–68
TOTAL	19136	1420	93%

Tests	Skipped	Failures	Errors	Time
458	3 💤	0 ❌	0 🔥	3m 44s ⏱️