Source text-patch adapter implementation and remaining acceptance

Read-only source audit against 7338078f8ddd924b8cddee35f512f2286072136d. The connected Unicode/SVN/keyword adapter follows the PatchSave/AutoAdd policy batch and has a separate grouped checkpoint record. This record separates the former missing workflow from implementation and unverified acceptance; it is not a feature completion percentage.

TortoiseMerge/Patch.cpp::ParsePatchFile (49 onward) consumes decoded CFileTextLines records. It splits ordinary ---/+++ file pairs without requiring diff --git, handles SVN revision suffixes and Git quoting, and retains hunk EOL/BOM information. CPatch::PatchFile (425–582) loads the target with its own decoded text/format settings, applies the hunks, preserves output settings, and handles a changed UTF-8 BOM. Its context/remove comparisons recognize expanded keywords through HasExpandedKeyWords (584–605): LastChangedDate, Date, LastChangedRevision, Rev, LastChangedBy, Author, HeadURL, URL and Id.

Before this batch, Review passed original patch bytes to git apply for statistics, validation, simulation and application. Unified Diff codecs could preserve/convert viewer text, but did not supply source decoded patch application. The new immutable SourceTextPatch parser and SourceTextPatchApplication simulator supply that separate format/matching receipt. Target matching and GitPatch.swift integrate it into the existing selected/all review, comparison, recorded-base recovery and checked publication workflow. Normal Git, binary and special-file routes must retain their existing behavior.

Implemented/parser and simulation scope includes UTF-16/UTF-32 patch containers and targets, captured legacy decoding, multi-file GNU/SVN headers, expanded-keyword context/removal matching, bounded source cursor lookahead, Reverse/Strip, original bytes, and BOM/record-ending state. Regular mode and rename/copy metadata are explicit receipts, not permission to drop those changes. Source warnings do not change the preceding newline; missing and zero-byte/BOM-only preimages have distinct source record states. Quoted native Git filename bytes are preserved before SVN annotation handling. Exact rules and adaptations are documented in Unicode and source text patches.

The dated grouped record reports actual checks, failures and unrun cases after implementation freezes. Required acceptance includes actual filesystem output and index behavior for selected/all, new/deleted/moved/copied/executable files, clean recorded-base recovery, target codec/ending/BOM states, original-byte Copy/Save, strict mixed/opaque refusal, stale/path/permission refusal, captured preferences, cancellation and retired native owners. Authored fixture files and this guide do not establish a pass; the dated record provides the actual validation scope.

Explicit future boundaries remain: no invented base for a plain SVN revision, no arbitrary backward/fuzzy search, no binary payload transcoding, and no partial application of a mixed document whose unsupported records would be lost. Metadata-only Git changes remain on the Git route. External patch producer variants outside the pinned source grammar require concrete examples and independent fixtures before an acceptance claim.

Do not treat a .rej viewer as an absent pinned feature: Git/GitPatch.cpp records an error string with the explicit “we do not support reject files ATM” TODO, and MainFrm.cpp::PatchFile's rejected-hunk viewer is under #if 0 (626 onward). Likewise, native binary/symlink/deletion recovery already has separate implemented whole-state choices; it must not be reclassified as wholly unimplemented.

Extended reverse-copy metadata stays on the original Git route. A decoded Unicode container that Git cannot read does not gain invented reverse-copy semantics. The pinned CPatch path does not define such a reverse-copy operation; this additional native format combination remains unsupported and explicitly separate from ordinary Git reverse-copy support.