etl::span checks

[mike919192]

This add the optional assert checks to etl::span. Several of the span checks needed to throw from C++11 constexpr so the ternary operation was used where needed.

Adding macros ETL_CHECKING_XXX and ETL_NOT_CHECKING_XXX for the optional index operator checks and extra checks. This makes the macro usage a little simpler compared to checking if the right macro is defined.

Added span_out_of_range exception. Fixed the at functions were using the wrong exception (array_out_of_range).

Some of the static asserts in the static span class where unessesarily checking that Extent != etl::dynamic_extent.

[mike919192]

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Walkthrough

• Added explicit checking-state macros in include/etl/error_handler.h: ETL_CHECKING_INDEX_OPERATOR/ETL_NOT_CHECKING_INDEX_OPERATOR and ETL_CHECKING_EXTRA/ETL_NOT_CHECKING_EXTRA.
• Updated include/etl/array.h to use ETL_NOT_USING_CPP14 and ETL_CHECKING_INDEX_OPERATOR in the operator[] const-correctness conditional.
• Introduced etl::span_out_of_range in include/etl/span.h and replaced previous range errors with this type across at(), operator[], front(), back(), and subview methods, with static assertions and throw/assert paths gated by macros, for both fixed and dynamic extents.
• Adjusted tests to expect etl::span_out_of_range and expanded out-of-range coverage.

Pre-merge checks and finishing touches

❌ Failed checks (1 warning, 1 inconclusive)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 70.59% which is insufficient. The required threshold is 80.00%.	You can run @coderabbitai generate docstrings to improve docstring coverage.
Title Check	❓ Inconclusive	The title “etl::span checks” is too generic and does not clearly summarise the primary changes such as adding optional assert checks, new checking macros, and the span_out_of_range exception, making it difficult for reviewers to understand the main focus at a glance.	Consider clarifying the title to explicitly mention the addition of optional assert checks, the new span_out_of_range exception, and enhancements to checking macros for etl::span to better convey the main changes.

✅ Passed checks (1 passed)

Check name	Status	Explanation
Description Check	✅ Passed	The description accurately outlines the key modifications including optional assert checks, new ETL_CHECKING_XXX macros, the span_out_of_range exception, and fixes to at() and static asserts, all of which directly correspond to the changes in the pull request.

✨ Finishing touches

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🧪 Generate unit tests (beta)

• Create PR with unit tests
• Post copyable unit tests in a comment

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Actionable comments posted: 0

🧹 Nitpick comments (2)

test/test_span_fixed_extent.cpp (1)

431-439: Tests updated for span_out_of_range and extra checks — looks good

Runtime OOB checks now expect etl::span_out_of_range and static-assert cases are left commented. This aligns with the new span behaviour and checking macros.

Consider pruning or moving the commented static-assert demos to a dedicated compile-time test block to keep the runtime suite concise.

Also applies to: 463-465, 479-481, 564-567, 589-591, 615-618, 640-642, 697-705, 706-711

test/test_span_dynamic_extent.cpp (1)

714-718: Undef helper macros after use to avoid leakage across the TU

Define/undef within the test to prevent unintended reuse later in the file.

Apply this small cleanup:

-      #define SPAN6_EXPR { auto span6 = view.subspan<2, 7>(); (void)span6; }
+      #define SPAN6_EXPR { auto span6 = view.subspan<2, 7>(); (void)span6; }
       CHECK_THROW(SPAN6_EXPR, etl::span_out_of_range);
-      #define CSPAN6_EXPR { auto cspan6 = cview.subspan<2, 7>(); (void)cspan6; }
+      #define CSPAN6_EXPR { auto cspan6 = cview.subspan<2, 7>(); (void)cspan6; }
       CHECK_THROW(CSPAN6_EXPR, etl::span_out_of_range);
+      #undef SPAN6_EXPR
+      #undef CSPAN6_EXPR

📜 Review details

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📥 Commits

Reviewing files that changed from the base of the PR and between 2c17011 and b2d0bbb.

📒 Files selected for processing (5)

• include/etl/array.h (1 hunks)
• include/etl/error_handler.h (1 hunks)
• include/etl/span.h (18 hunks)
• test/test_span_dynamic_extent.cpp (8 hunks)
• test/test_span_fixed_extent.cpp (8 hunks)

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📓 Path-based instructions (1)

include/etl/*.h

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Files:

• include/etl/array.h
• include/etl/error_handler.h
• include/etl/span.h

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🔇 Additional comments (6)

include/etl/array.h (1)

162-168: Operator[] C++11 throw path correctly gated by new checking-state macro

Condition switch to ETL_NOT_USING_CPP14 and ETL_CHECKING_INDEX_OPERATOR is correct and consistent with new error handler macros.

include/etl/error_handler.h (1)

378-385: State macros for index/extra checks are well introduced

ETL_CHECKING_INDEX_OPERATOR / ETL_CHECKING_EXTRA (and complements) are correctly defined in both branches, enabling clear downstream conditionals.

Also applies to: 389-396

test/test_span_dynamic_extent.cpp (1)

442-449: Runtime OOB tests updated to span_out_of_range — good coverage

Checks for front/back on empty, at(), operator[], first/last, and subspan now expect etl::span_out_of_range. Matches new error paths.

Also applies to: 473-475, 489-491, 574-576, 598-600, 624-626, 648-650, 711-724

include/etl/span.h (3)

105-117: New exception type span_out_of_range

Dedicated out-of-range exception for span is a clean separation from array exceptions.

---

256-270: Fixed-extent accessors/subviews: static asserts + conditional throw/assert paths

• front/back guarded by ETL_STATIC_ASSERT (Extent > 0).
• at()/operator[] now use span_out_of_range and follow the C++11 ternary-throw pattern when needed.
• first/last/subspan enforce COUNT/OFFSET at compile-time; runtime-count variants gate throw/assert and noexcept via the new macros.

Also applies to: 405-419, 425-434, 441-446, 451-460, 466-472, 477-488, 494-506, 534-548

---

718-741: Dynamic-extent accessors/subviews: exception/assert gating and noexcept toggling look correct

Runtime bounds checks now consistently throw span_out_of_range when exceptions and EXTRA checks are enabled, otherwise assert; noexcept reflects that state. Operator[] follows the C++11 ternary-throw approach for constexpr contexts.

Also applies to: 876-889, 896-905, 911-934, 940-963, 971-985, 1010-1017