[Daniel-B-Smith]

The iteration ordered of HashMap is not stable, so the encoding can happen in a different order leading to a different hash. This was first noticed across x86_64 vs aarch64. This PR changes the HashMaps on the encoder table to be IndexMaps.

There isn't a test because I don't know how to inject randomness in the iteration order within a single test run.

I made the type change by hand and AI assisted in getting everything to type check (eg changing the types in the query).

Fixes #164379

[Kobzol]

@bors try @rust-timer queue

[rust-bors]

☀️ Try build successful (CI)
Build commit: 0674054 (06740546cfaf1f4efec338d45578021361fe6a56)
Base parent: 15c1044 (15c10447a46529b68e38c7f138aeb95240e4d7d6)

[rust-timer]

Finished benchmarking commit (0674054): comparison URL.

Overall result: ❌ regressions - no action needed

Benchmarking means the PR may be perf-sensitive. Consider adding rollup=never if this change is not fit for rolling up.

@rustbot label: -S-waiting-on-perf -perf-regression

Instruction count

Our most reliable metric. Used to determine the overall result above. However, even this metric can be noisy.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	0.2%	[0.2%, 0.2%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Max RSS (memory usage)

Results (secondary -3.9%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-3.9%	[-3.9%, -3.9%]	1
All ❌✅ (primary)	-	-	0

Cycles

Results (primary 2.9%, secondary -2.9%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	2.9%	[2.9%, 2.9%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-2.9%	[-2.9%, -2.9%]	1
All ❌✅ (primary)	2.9%	[2.9%, 2.9%]	1

Binary size

This perf run didn't have relevant results for this metric.

Bootstrap: 490.17s -> 489.887s (-0.06%)
Artifact size: 408.94 MiB -> 409.05 MiB (0.03%)

[rust-bors]

☔ The latest upstream changes (presumably #164788) made this pull request unmergeable. Please resolve the merge conflicts by rebasing.

[Daniel-B-Smith]

Closing since the proper fix has landed.