feat: one-dimensional arrays tier as Iceberg lists, and tiered tables refuse NaN and infinity

[vyruss]

A one-dimensional array of a supported type tiers as an Iceberg list and reads back as an array on both tiers; an array of timestamptz, jsonb, json, interval or a vector type, and a column declared with more than one dimension, are refused with an error that names the column. A tiered table's hot table gets a coldfront_guard_<column> check constraint that refuses a numeric NaN, an infinity in a date or timestamp column, and an array an Iceberg list cannot hold, where it is written, instead of the archive storing NaN as 0 and stopping on infinity. The archiver reads column types from the extension's type map, so registration, the archive pass, create_iceberg_table() and the DDL hook accept the same types. ci/journey.sh covers this in TC-231 to TC-251.

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⛔ Files ignored due to path filters (1)

• extension/coldfront/test/expected/hot_guard.out is excluded by !**/*.out

📒 Files selected for processing (6)

• ci/journey.sh
• docs/architecture_tiered.md
• docs/usage.md
• extension/coldfront/coldfront--1.0.sql
• extension/coldfront/test/README.md
• extension/coldfront/test/sql/hot_guard.sql

🚧 Files skipped from review as they are similar to previous changes (2)

• extension/coldfront/test/README.md
• docs/usage.md

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📝 Walkthrough

Walkthrough

The change centralizes PostgreSQL-to-Iceberg type mapping, adds support for eligible one-dimensional arrays across cold-tier operations, and installs hot-table guards for values and array shapes that cannot be preserved by the cold tier. Type-mapping errors now identify the affected column when known.

Changes

Cold-tier types and hot-table guards

Layer / File(s)	Summary
Shared type mapping and diagnostics cmd/archiver/..., internal/partcfg/..., extension/coldfront/coldfront--1.0.sql, extension/coldfront/test/sql/type_map.sql, extension/coldfront/test/sql/adopt_type_map.sql, ci/journey.sh, docs/architecture_decoupled.md, docs/usage.md, docs/changelog.md	The extension supplies storage and view-cast mappings used by both modes. Eligible arrays map to Iceberg lists, and adopted lists map to PostgreSQL arrays. Mapping refusals name the column when known.
Array rendering and cold-tier paths extension/coldfront/coldfront--1.0.sql, extension/coldfront/src/coldfront.c, internal/view/..., extension/coldfront/test/sql/array_cold_render.sql, extension/coldfront/test/sql/vector_cold_render.sql, ci/journey.sh, docs/usage.md, docs/changelog.md	Cold-tier array rendering covers values, parameters, and row moves. Numeric arrays use the configured text export cast. Tests and journey coverage exercise array round-trips, shape restrictions, and supported operations.
Hot-table guard lifecycle extension/coldfront/coldfront--1.0.sql, internal/view/..., cmd/archiver/main.go, extension/coldfront/test/sql/hot_guard.sql, ci/journey.sh, docs/architecture_tiered.md, docs/usage.md, docs/changelog.md	Hot-table constraints reject numeric NaN, temporal infinities, and invalid array shapes. Guard creation and validation run during view setup and archive bootstrap. DDL updates guards, and unregistering removes them.

Priority: ➖ Normal

Estimated code review effort: 4 (Complex) | ~60 minutes

Change: Feature

Merge Risk: 🔵 Low · up to bc097

Adding a numeric or eligible array column to a large tiered table can delay reads and writes during guard validation. The remaining risk should be addressed or accepted before merge.

🚥 Pre-merge checks | ✅ 4 | ❓ 1

❌ Failed checks (1 inconclusive)

Check name	Status	Explanation	Resolution
Docstring Coverage	❓ Inconclusive	Docstring coverage is 62.50% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 16 functions across 7 files. (6 skipped: …	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly summarizes the main changes: one-dimensional arrays tier as Iceberg lists, and tiered tables reject NaN and infinity.
Description check	✅ Passed	The description directly explains the array support, rejected types, hot-table guards, shared type mapping, and test coverage.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

Full details: Docstring Coverage

Explanation

Docstring coverage is 62.50% which is insufficient. The required threshold is 80.00%. Docstring coverage is scoped to functions touched by this diff. Analyzed 16 functions across 7 files. (6 skipped: 5 unsupported, 1 too large.)

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🟢 Metrics -17 complexity · 0 duplication

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Actionable comments posted: 1

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• 🪄 Fix CodeRabbit comments on this PR

🤖 Prompt to fix review comments

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Inline comments:
Review comments at @extension/coldfront/coldfront--1.0.sql:
- Around line 4588-4592: Remove the `_validate_hot_guards` call from
`_rebuild_tiered_view` so the DDL hook does not scan guards while the user's
ALTER holds its lock. Keep `_guard_hot_table` to add guards; let the archiver
validate them after the DDL transaction.

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ℹ️ Review info

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• Configuration used: Repository: pgEdge/coldfront/.coderabbit.yaml
• Review profile: CHILL
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📥 Commits

Reviewing files that changed from the base of the PR and between 82e7104 and a8231c5.

⛔ Files ignored due to path filters (12)

• extension/coldfront/test/expected/adopt_iceberg_table.out is excluded by !**/*.out
• extension/coldfront/test/expected/adopt_type_map.out is excluded by !**/*.out
• extension/coldfront/test/expected/array_cold_render.out is excluded by !**/*.out
• extension/coldfront/test/expected/array_cold_render_1.out is excluded by !**/*.out
• extension/coldfront/test/expected/ddl_alter_column.out is excluded by !**/*.out
• extension/coldfront/test/expected/drop_iceberg_table.out is excluded by !**/*.out
• extension/coldfront/test/expected/hot_guard.out is excluded by !**/*.out
• extension/coldfront/test/expected/param_cold_via_plpgsql.out is excluded by !**/*.out
• extension/coldfront/test/expected/param_cold_via_plpgsql_1.out is excluded by !**/*.out
• extension/coldfront/test/expected/type_map.out is excluded by !**/*.out
• extension/coldfront/test/expected/vector_cold_render.out is excluded by !**/*.out
• extension/coldfront/test/expected/vector_type_map.out is excluded by !**/*.out

📒 Files selected for processing (21)

• ci/journey.sh
• cmd/archiver/main.go
• cmd/archiver/main_test.go
• docs/architecture_decoupled.md
• docs/architecture_tiered.md
• docs/changelog.md
• docs/usage.md
• extension/coldfront/Makefile
• extension/coldfront/coldfront--1.0.sql
• extension/coldfront/src/coldfront.c
• extension/coldfront/test/README.md
• extension/coldfront/test/sql/adopt_type_map.sql
• extension/coldfront/test/sql/array_cold_render.sql
• extension/coldfront/test/sql/hot_guard.sql
• extension/coldfront/test/sql/type_map.sql
• extension/coldfront/test/sql/vector_cold_render.sql
• extension/coldfront/test/sql/vector_type_map.sql
• internal/partcfg/commands.go
• internal/partcfg/commands_test.go
• internal/view/view.go
• internal/view/view_test.go

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