docs: mark --ignore-missing-args / --delete-missing-args implemented

Precise Notes on the arg model (files-from entries), implies-relationships
(delete-missing implies ignore, independent of --delete), delete/timing/force/
exclude-protection interplay, the third manifest section and the 2.9.0 -> 2.10.0
wire bump, and the divergences (empty-list hard error, no negation, max-delete
not applied to explicit deletions). The files-from row now references the flags.
The Summary count line is intentionally left for a recount commit.

RSYNC_COMPAT.md

@@ -54,7 +54,7 @@ This document maps rsync's full feature set to FastSync's current implementation
 | `--exclude-from=FILE` | Read exclude patterns from file | ✅ Implemented | Reads patterns from file |
 | `--include-from=FILE` | Read include patterns from file | ✅ Implemented | Reads patterns from file |
 | `--filter=RULE` | Add file-filtering rule | ✅ Implemented | Long option only: rsync's short `-f` conflicts with FastSync sendfile (see FastSync-specific list), so `-f` is not reassigned. Supported subset: `+`/`-` include/exclude, implicit-exclude patterns, `include`/`exclude` word forms, a leading `/` anchor (to the transfer root, or to a `.rsync-filter` file's directory), and a trailing `/` for dir-only rules; first match wins with a default of include inside the filter layer. Filters are an independent layer from `--exclude`/`--include` (an entry must pass both). Rejected with a clear error (no silent no-ops): `merge`/`dir-merge`/`hide`/`show`/`protect`/`risk`/`clear` words, rules that begin with `:`/`.`/`!` (merge/dir-merge/list-clear shorthands), and include/exclude modifiers other than `/` (`! C s r p x`) |
-| `--files-from=FILE` | Read source file list from file | ✅ Implemented | Entries are paths relative to the source root (leading `./` stripped, `..`/absolute entries rejected at parse time, blank lines ignored; NUL-delimited with `-0`). A listed regular file is transferred; a listed directory transfers its whole subtree (FastSync recursion is always on, unlike rsync's non-recursive default). Non-listed paths and their subtrees are pruned by the scanner. A listed entry that does not exist under the source (and an empty list) is a hard error reported before any transfer; listing `.` (whole tree) and empty listed directories are fine. Scalability note: `file_list_affects` is O(list size) per scanned entry, so a very large `--files-from` list against a huge tree is quadratic; lists are typically small enough that this is acceptable, but it is the documented bound. The delete manifest still derives from what was actually sent, so `--delete` stays consistent with the subset |
+| `--files-from=FILE` | Read source file list from file | ✅ Implemented | Entries are paths relative to the source root (leading `./` stripped, `..`/absolute entries rejected at parse time, blank lines ignored; NUL-delimited with `-0`). A listed regular file is transferred; a listed directory transfers its whole subtree (FastSync recursion is always on, unlike rsync's non-recursive default). Non-listed paths and their subtrees are pruned by the scanner. A listed entry that does not exist under the source (and an empty list) is a hard error reported before any transfer, unless `--ignore-missing-args` / `--delete-missing-args` is given (see the Safety & Security rows): those flags downgrade the listed-but-missing case to a skip and, for `--delete-missing-args`, a destination deletion; an empty list stays a hard error in every mode. Listing `.` (whole tree) and empty listed directories are fine. Scalability note: `file_list_affects` is O(list size) per scanned entry, so a very large `--files-from` list against a huge tree is quadratic; lists are typically small enough that this is acceptable, but it is the documented bound. The delete manifest still derives from what was actually sent, so `--delete` stays consistent with the subset |
 | `-0`, `--from0` | Delimit *-from files with NULs | ✅ Implemented | `--files-from` entries become NUL-delimited; the flag may appear before or after `--files-from` on the command line. NUL mode preserves entry bytes exactly (trailing CR/LF are part of the name; only newline mode trims them) |
 | `--max-size=SIZE` | Skip files larger than SIZE | ✅ Implemented | `max_size` in scanner |
 | `--min-size=SIZE` | Skip files smaller than SIZE | ✅ Implemented | `min_size` in scanner |
@@ -144,6 +144,24 @@ limit"). These wire/layout changes bumped `PROTOCOL_VERSION` **2.8.0 → 2.9.0**
 `delete_excluded`, `prune_empty_dirs`, `max_delete` — round-trip unchanged and
 are validated on receive.
 
+**Missing-args note (Phase 3, missing-args wave):** `--ignore-missing-args` and
+`--delete-missing-args` are implemented as described in the Safety & Security
+rows. Wire impact: the `STATUS_MANIFEST` frame now carries a **third section** —
+a list of destination-relative **exact-delete paths** (the missing entries'
+mirrors) — and the config frame gained a `delete_missing_args` boolean
+(`ignore_missing_args` stays client-only, exactly like `ignore_errors`). These
+wire/layout changes bumped `PROTOCOL_VERSION` **2.9.0 → 2.10.0** (peers must
+match). The receiver validates the third section identically to the keep-set
+(non-empty, relative, traversal-free; `MAX_MANIFEST_ENTRIES` per section, a
+single `MAX_MANIFEST_BYTES` budget shared across all three). On commit the
+receiver runs the exact-path deletions FIRST (`manifest_delete_missing_args`:
+confined per-path unlink/rmdir, deep removal only under `--force`/`--delete`,
+staging/basis protected, never blocked by the protected-prefix list) and then
+the ordinary extras walk when `--delete` is active (`manifest_delete_all`). A
+client may request the exact-path deletions without `--delete`; the server's
+`--allow-delete` policy gates them exactly like `--delete`, so an unauthorized
+server ignores the request while the missing entries are still skipped.
+
 The deletion walker is now **all-or-nothing**: before any unlink it rehearses
 the deletion (an fd-relative walk identical to the delete pass, counting every
 regular file it would unlink and every directory it would remove) and refuses to
@@ -299,8 +317,8 @@ do NOT imply `--delete`; without `--delete` they are inert (matching rsync).
 | `--max-alloc=SIZE` | Limit a single memory allocation | ✅ Implemented | Caps the largest single allocation; binary units, default 1G |
 | `--trust-sender` | Trust remote sender's file list | ❌ Not Implemented | |
 | `--old-args` | Disable modern arg protection | ✅ Implemented | SSH-only legacy mode; restores raw remote command construction and permits shell interpretation of the configured server path |
-| `--ignore-missing-args` | Ignore missing source args | ❌ Not Implemented | |
+| `--ignore-missing-args` | Ignore missing source args | ✅ Implemented | FastSync has a single source-root argument (which always exists), so the "explicitly requested source arguments" are the `--files-from` entries and the flags only ever apply there (inert without `--files-from`, like `-R`). Without the flag a listed-but-missing entry stays a hard pre-transfer error (nothing is transferred). With it each missing entry is skipped: nothing is sent for it, it never enters the keep-set, and the run succeeds for the rest — an all-missing non-empty list succeeds transferring nothing, matching rsync. `--dirs` + `--files-from` missing entries are skipped the same way. Every skipped entry is logged and a per-run warning names the count, so the handling is never a silent no-op. Divergences: an EMPTY `--files-from` file stays a hard error in every mode (no argument was requested at all; rsync likewise reports "no source files specified"); missing-arg skipping only applies to the pre-transfer list validation, so an entry that is present at preflight and vanishes mid-transfer still fails (matching rsync, whose flag "does not affect subsequent vanished-file errors"); `--no-ignore-missing-args` is not a supported negation |
-| `--delete-missing-args` | Delete missing source args | ❌ Not Implemented | |
+| `--delete-missing-args` | Delete missing source args | ✅ Implemented | Implies `--ignore-missing-args` (order-independent) and additionally removes each missing entry's destination mirror receiver-side. The mirror is computed exactly like a present sibling's wire path: the bare relative entry under `-R`, otherwise the full source-mirror path below the destination root. rsync parity, verified against the man page: it does **not** imply `--delete` generally and is "independent of any other type of delete processing" — unrelated destination extras are untouched unless `--delete` is also present. Composition with `--delete` + timing: the exact-path deletions commit with the manifest, early for `--delete-before`/`--delete-during`, else only after a fully-successful transfer (delete-after/commit). A non-empty directory mirror is removed only when `--force` or `--delete` is in effect (otherwise it is left with a warning and the run continues, like rsync); an absent mirror is a no-op. An explicitly listed missing arg is a user request, not an excluded file: its deletion is never blocked by the filter-exclusion protection of excluded destination mirrors (a mirror sitting inside a filter-excluded directory is still removed). Safety/policy: gated by the server `--allow-delete` policy like `--delete`; the request paths cross the wire only in the delete-manifest frame and are confined by the same receiver validation as the keep-set (non-empty, relative, traversal-free, bounded by the per-section/per-frame manifest caps); the `--delay-updates` staging directory and basis snapshots are protected exactly as in the extras walker. Divergence: the missing-args deletions are not counted toward `--max-delete` (they are explicit per-path requests, not discovered extras). See the Phase-3 wire note below for the `PROTOCOL_VERSION` bump |
 
 ## 16. Batch Operations