[wgtmac]

Summary

Preserve the caller's CMAKE_MODULE_PATH when dependency discovery fails in the installed Iceberg CMake package.

iceberg_find_dependencies currently saves and replaces the module path, then restores it after find_dependency() calls. However, find_dependency() returns from the package config on failure, skipping that restoration. The surrounding macro does not introduce a return boundary, so a non-required find_package(iceberg) can leave the caller's subsequent package discovery using Iceberg's module path.

Replace the manual save/restore logic with block(SCOPE_FOR VARIABLES PROPAGATE iceberg_FOUND iceberg_NOT_FOUND_MESSAGE). This preserves both the caller's module path (including its defined/undefined state) and the package failure diagnostic, while retaining imported dependency targets and existing per-dependency extra arguments.

This is the same underlying issue addressed in apache/orc#2735 and worked around by apache/arrow#55415.

The patch only changes src/iceberg/iceberg-config.cmake.in; no test files, CMakeLists files, or unrelated dependency-search policies are changed.

Testing

• pre-commit run --files src/iceberg/iceberg-config.cmake.in passed all applicable checks; file-type-inapplicable hooks were skipped.
• Used temporary, out-of-tree configure projects with CMake 3.25.2 and 4.3.1. For each version, all six combinations of dependency success/failure and module path initially undefined/empty/multiple directories passed with the fix.
• The same checks reproduced the leak in all three missing-dependency scenarios against the original template. They also checked package/component discovery, failure diagnostics, imported dependency targets, subsequent caller module discovery, and forwarding of AWS SDK COMPONENTS arguments.
• No full Iceberg build or C++ tests were run for this CMake-package-only change.

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[Copilot]

🟢 Approval recommended

No active review issues were identified for the dependency-discovery scoping change.

No open issues 🎉

What changed in this PR

This PR prevents failed dependency discovery in the installed Iceberg CMake package from altering the caller’s CMAKE_MODULE_PATH.

Changes:

• Replaces manual save/restore logic with a variable-scoped block, preserving the module path even on early return.
• Propagates package failure status and diagnostics while retaining imported dependency targets and extra dependency arguments.

File	Description
src/​iceberg/​iceberg-config.cmake.in	Scopes dependency discovery to preserve the caller’s module path on success and failure.

_{Review effort: Balanced}

[zhjwpku]

This looks cleaner. I also confirmed that block was introduced in CMake 3.25, which matches our minimum supported version.

[zhjwpku]

The PROPAGATE list hard-codes iceberg_FOUND / iceberg_NOT_FOUND_MESSAGE, but find_dependency() sets ${CMAKE_FIND_PACKAGE_NAME}_FOUND / _NOT_FOUND_MESSAGE before return(). CMAKE_FIND_PACKAGE_NAME is the name the caller passed to find_package(). With find_package(Iceberg), Iceberg_FOUND is set inside the block and never reaches the caller. When a dependency is missing, the package is then reported as found with no targets.

Suggested change

	block(SCOPE_FOR VARIABLES PROPAGATE iceberg_FOUND iceberg_NOT_FOUND_MESSAGE)
	block(SCOPE_FOR VARIABLES
	PROPAGATE ${CMAKE_FIND_PACKAGE_NAME}_FOUND
	${CMAKE_FIND_PACKAGE_NAME}_NOT_FOUND_MESSAGE)