Native writer predecessor-test mapping

This maps every registered CPIO/TAR test and the shared-helper tests at Abuild revision 136ca84f0f5c49acae5fdd22f43359a32ca26e70 to Arca checks. It records equivalent assertions rather than requiring identical method names, fixtures or Ahven grouping. Normal checks use only committed Arca inputs.

The source units are tests-abuild_transformations_cpio, tests-abuild_file_formats_tar and tests-abuild_file_formats_binary_io. Their mixed transformation cases are classified explicitly below. Ahven checks package contracts; the independent Python suites own byte-format and external-reader assertions. A case marked adapter-only must remain tested in Abuild when its backend later changes.

CPIO

cpio_scenarios.adb supplies the shared direct checks and archive inputs. check-cpio.py independently decodes fields, layout and payloads and uses GNU cpio and bsdtar.

Original registered case	Arca assertion or scope disposition
Create_Simple_CPIO	check_entries and test_external_readers cover native entry types, metadata and contents. Full transformation .hex/.list snapshots are replaced by the independent native matrix and short raw-record check; fileset assembly remains in Abuild.
Create_CPIO_Directory_Tree	Nested native names and external extraction are covered. Automatically adding parent directories from a fileset is adapter-only.
Check_CPIO_Block_Device_Header	check_entries: permission-only input 006 must emit mode 060006, including writer-supplied type bits.
Check_CPIO_Raw_Record_Layout	test_short_raw_records: five-byte file/symlink data, original field values and offsets, uppercase hex, link count, zero regular rdev fields, NUL names, 1/2/3-byte padding, trailer fields and exact 512-byte size. The general decoder also rejects extra zero blocks.
Reject_Uninitialized_CPIO_Close	Shared Check_Errors, Ahven CPIO/error contracts: exception/message before Create and after Close.
Check_CPIO_Content	Complete patterned payload equality in check_entries and after extraction with both readers. Transform creation remains in Abuild.
Check_CPIO_Hardlinks_From_Source_Path	Explicit writer hardlink headers, one payload and extracted inode identity are covered. Automatic grouping by source path is adapter-only.
Check_CPIO_Hardlinks_From_Inodes	The same native output contract is covered. Discovering shared source inodes is adapter-only.
Check_CPIO_Hardlink_Metadata	check_entries: equal inode/NLink/mode/UID/GID/mtime, first payload empty and last payload complete. Choosing canonical metadata from contradictory fileset entries is adapter-only.
Create_CPIO_With_Larger_File	A patterned payload exceeding two copy buffers is independently decoded and extracted with both readers. Transform wiring is adapter-only.
Reject_Pre_Epoch_CPIO_Directory	The underlying native timestamp rejection is covered. Translation to a contextual CPIO_Generic_Error is adapter-only.
Reject_Pre_Epoch_CPIO_Writer_MTime	Shared Check_Errors: UTC epoch minus one second and first timestamp above Unsigned_32, with exception/message checks.
Reject_Oversized_CPIO_Writer_File	The Python fixture supplies exactly 2**32 sparse bytes; shared errors require File_Too_Big and its size diagnostic. Ahven also tests a larger rejected source.
Reject_Unopened_CPIO_Add	All native entry operations are checked before Create. The original Images.Add_Object exception translation and message are adapter-only.
Create_CPIO_With_Larger_Than_4GB_File	The native size boundary is covered as above. Transformation diagnostics containing the entry path are adapter-only.

The short raw check preserves the assertions formerly hidden by broad thematic matching. Corruption controls change single-link/rdev fields, hexadecimal case, three-byte payload padding and total padding. The changed field values retain a valid record layout, so the value assertions must fail.

TAR

tar_scenarios.adb supplies the shared checks and inputs. check-tar.py uses its own field map and checksum calculation, the retained GNU fixture, GNU tar and bsdtar.

Original registered case	Arca assertion or scope disposition
Create_Simple_Tarball	check_entries and test_reference_readers: every supported type, metadata, device values, payload and links. Fileset assembly stays in Abuild.
Create_Tarball_Parallel	Ahven and Python compare eight independent complete outputs on 128-KiB worker stacks; the predecessor used twenty workers.
Create_Tarball_With_Longnames	check_edges pins a deep multipart path with several legal splits and a long multipart hardlink target. test_legacy_reader_edges lists and extracts both with both readers. Adapter path assembly is excluded.
Create_Tarball_With_Longnames_101	Exactly 100-byte names and 101-byte GNU fallback are checked independently. The original declared path is actually 100 characters despite the case name. Fileset tree construction stays in Abuild.
Create_Tarball_With_Prefix_Split_Path	The unchanged GNU fixture pins the original middle/leaf.txt split path; both readers list it.
Check_Tar_Header_Format	header_fields, check_entries and the complete GNU fixture pin magic/version, fields, checksums, payloads and padding.
Check_Tar_GNU_Ustar_Golden_Master	test_gnu_ustar_fixture compares all bytes to the original unchanged, hash-checked reference fixture.
Check_Tar_Prefix_Header_Fields	GNU fixture plus explicit 155/100-byte prefix/name checks. The deep-path check also pins the rightmost eligible split.
Check_Tar_Exact_Fit_Header_Fields	Exact 100-byte name/link and 155-byte prefix fields, no unnecessary GNU metadata, and explicit final types including symlink 2.
Check_Tar_Long_Directory_Header	check_edges pins L, complete name, directory type 5, truncated fallback name and empty prefix; both readers reconstruct and extract the directory.
Check_Tar_Leading_Slash_Longname	The original leading-slash long-directory condition requires GNU L and preserves the complete name. Absolute-path extraction is not needed by this raw-header assertion.
Check_Tar_End_Of_Archive_Marker	Empty output is exactly two zero blocks; both readers accept it with an empty listing. Nonempty archives require exactly two end blocks too.
Check_Tar_Directory_Name_Normalization	already/ remains unchanged and has final type 5; existing repeated trailing separators retain the predecessor's actual behavior.
Extract_Tarball_Content	Both readers extract patterned and empty regular files with exact content.
Extract_Multi_Buffer_Tarball_Content	test_aligned_multi_buffer_readers uses 1 MiB + 512, checks exact archive length with no payload padding, and compares both extracted files byte for byte. The size matrix also covers unaligned and exact-buffer inputs.
Create_Tarball_With_Long_Link_Target	Type 2, full GNU K target and raw ././@LongLink marker are pinned, with actual symlink targets checked after extraction by both readers.
Check_Tar_Long_Name_And_Link	Combined L,K ordering, full metadata, final hardlink type 1, 100-byte fallback name and target marker. Both readers produce a regular hardlink verified with lstat, not a followed symlink.
Check_Tar_Empty_User_Group_Numeric_Fallback	Empty raw uname/gname plus test_numeric_owner_fallback: GNU tar -tvf must display 65432/65431 without forced numeric-owner output.
Reject_Missing_Source_File	Shared Check_Errors and decoded recovery output.
Reject_Uninitialized_Archive	Shared Check_Errors: all entry operations and Close.
Reject_Pre_Epoch_Timestamp	Shared header-time path rejects UTC epoch minus one second; the direct case now uses a device entry.
Reject_Too_Large_Mtime	First unrepresentable value 2**33, rather than a date further beyond the boundary.
Accept_Max_Mtime	check_entries pins 2**33 - 1 in the header.
Reject_Too_Large_File	Sparse 2**33-byte source and exact exception identity.
Reject_Too_Large_Metadata_Field	UID, GID, major and minor independently reject their first overflowing value.
Accept_Max_Metadata_Field	All four seven-octal-digit fields accept 2**21 - 1; raw values and reader acceptance are checked.
Check_Tarball_Hardlinks_From_Source_Path	Native explicit hardlinks are covered. Automatic grouping of identical source paths is adapter-only.
Check_Tarball_Hardlinks_From_Inodes	Native explicit hardlinks are covered. Source inode discovery/grouping is adapter-only.

TAR corruption controls repair the checksum after changing final types, fallback names/targets or the selected prefix split. The generic decoder must first accept the modified layout; only the intended value assertion then rejects it. External-reader checks use the real archives too.

Shared copy helper

Original registered case	Arca assertion or scope disposition
Reject_Zero_Size_Copy_Growth	Private-copy Ahven/shared scenarios reject a nonempty source after a zero-size snapshot, source growth and short reads, and check messages and descriptor cleanup.
Encode_Little_Endian_Fields	Excluded: these endian operations were not imported into Arca.
Reject_Out_Of_Bounds_Field	Excluded: this concerns the same non-imported endian operations.

This mapping covers the relevant original writer assertions. It does not claim every possible future boundary, exhaustive I/O faults, active-I/O task abort safety or completion of maximum multi-gigabyte payloads. Arca adds scope-exit ownership, failed-Create/closed-instance reuse, decoder sensitivity and reproducibility checks beyond this predecessor mapping.