…on-goals

- Add a "Time Travel and Change Data Feed" section clarifying that Delta time-
  travels and CDFs the reference, not the referenced bytes, which live outside
  the transaction log and may be overwritten or deleted independently.
- Add a "Non-Goals" section scoping out lifecycle/GC of referenced bytes
  (including any Delta-managed notion and its VACUUM interaction) and access
  brokering, keeping the type reference-only and aligned with Parquet/Iceberg.

Co-authored-by: Isaac

Standardize the representation of a file column's storage mode
(MANAGED/EXTERNAL/UNKNOWN) in the __FILE_TYPE_MODE schema-metadata key, a
path-keyed map on the nearest ancestor StructField, mirroring the __COLLATIONS
representation and DBR's FileType mode (databricks-eng/runtime#213587). This
lets the qualifier round-trip through the Delta log without placing it inside
the file value (which must round-trip through the fixed Parquet FILE field set).

Only the representation is standardized; MANAGED vs EXTERNAL carries no Delta
behavior yet, and lifecycle/GC remains a non-goal.

Co-authored-by: Isaac

…a-io#585)

Align with the latest apache/parquet-format#585:
- size must be set whenever offset is set; a self-reference (no path) must set
  offset, and therefore size. Drop the now-invalid [offset, EOF) and [0, size)
  self-reference modes and the external [offset, EOF) mode from the resolution
  table; add explicit invalid rows.
- Define "set" (present, non-null, non-empty for strings) and allow sparse
  group definitions (a group need only define the fields it uses); add an
  inline-only example group.
- Fields matched case-sensitively by name; field IDs "if they exist".
- Readers should ignore unknown checksum algorithms.

Follows the consistent prose intent of PR delta-io#585; note its resolution table still
lists an [offset, EOF) row that contradicts its own validation section (offset
requires size) -- to be raised on the Parquet PR.

Co-authored-by: Isaac

…@ 90147dc)

Align with the latest apache/parquet-format#585 (commit 90147dc):
- path is now a URI-reference per RFC 3986 (absolute or relative), not an
  opaque location string. Resolves the path/uri debate: name stays `path`,
  semantics become URI.
- checksum form changes from <algorithm>:base64(<digest>) to <algorithm>:<digest>
  with per-algorithm encoding (lowercase hex for MD5/CRC32/CRC32C/SHA-256,
  opaque for ETAG); add RFC references and an Encoding column.
- content_type: MIME per RFC 2046, defaults to application/octet-stream when unset.
- offset must not be negative.
- Note that implementations are not expected to treat empty strings as null.

Co-authored-by: Isaac

…@ 92228a1)

Align with the latest apache/parquet-format#585 (commit 92228a1):
- Update checksum RFC citations: MD5 -> RFC 1321, CRC32 -> RFC 2083,
  CRC32C -> RFC 3385 (SHA-256 unchanged at RFC 6234).
- Readers may return a null file value for a row whose reference is invalid.

Co-authored-by: Isaac

…o#585 @ 4223744)

Align with apache/parquet-format#585 (commit 4223744): the FILE locator field
was renamed from `path` to `uri`. Rename the field throughout the field table,
resolution table, Parquet examples, writer/reader requirements, statistics, and
prose. Generic uses of "path" (field path, absolute path) are unchanged, as is
the DBR-specific __FILE_TYPE_MODE storage-mode key.

Co-authored-by: Isaac

…@ f241be8)

Align with apache/parquet-format#585 (commit f241be8): add the modular-encryption
restriction -- data files containing self-references must not use Parquet modular
encryption, since self-referenced byte ranges are not encryption modules and
cannot be encrypted/authenticated independently.

Co-authored-by: Isaac

…rged)

apache/parquet-format#585 is now merged. The FILE spec content is unchanged
from the last sync (commit f241be8), so no semantic updates are needed. Update
references to point at the stable LogicalTypes.md#file spec and drop the
"proposed" framing now that the type is part of the Parquet format.

Co-authored-by: Isaac