v0.4.0

The fidelity write tier arrives: surgical, byte-preserving edits that change only the bytes a filter targets and leave every other byte -- comments, indentation, quoting, key order -- untouched, or refuse. In the same release, byte-preserving reads become the default and the re-serializing pipeline moves behind --normalize.

Added

• Write tier: surgical value edits. yqr can now mutate a document through the fidelity engine, changing only the targeted bytes: assignment .a.b = <rhs> (scalar literal or a .-rooted path), append .xs += <item>, new-key assign .a.new = <rhs>, and del(.a.b). Each edit passes through the engine's re-parse guard -- an edit that would restructure the document is refused (exit 5) rather than emitted, and scalar writes are quoted to match the neighbouring style. A filter is either a read-only query or a single mutation; mixing them is a parse error.
• -i / --in-place flag writes the mutated document back to the input file atomically (temp file + rename, fsync before rename, symlinks followed, owner-only temp permissions). Using -i with stdin or with a read-only filter is an error, diagnosed before any input is read. Without -i, the mutated document is printed to stdout (byte-exact except the edit).
• Structural delete of multi-line and nested block entries (e.g. del(.spec.template)), which the single-line delete path rejects. Flow-style and sole-entry deletes remain refused with a clear message.
• --normalize / -N flag for the re-serializing pipeline: it drops comments and canonicalizes scalars (e.g. 007 becomes 7).

Changed

• Byte-preserving reads are now the default. yqr '.' file.yaml reproduces the input byte-for-byte -- comments, quoting, indentation, scalar spellings, and line endings survive -- with no flag. Untouched nodes are emitted as their original source bytes; computed, absent, and unaddressable nodes fall back to typed rendering per node.
• --engine now selects the backend for the default (byte-preserving) read. Under --normalize the re-serializing pipeline runs and the engine choice has no observable effect beyond the up-front name validation.

Breaking

• --preserve / -p removed. Byte preservation is now the default, so the flag is gone. Replace yqr -p '.' f with yqr '.' f; use yqr --normalize '.' f for the re-serializing behaviour.

Security

• Bumped the transitive crossbeam-epoch pin 0.9.18 -> 0.9.20 to clear RUSTSEC-2026-0204. It reaches the build only through the criterion dev-dependency (benchmarks), so released binaries were never affected; the change is lockfile-only.

Full changelog: https://github.com/zoosky/yqr/blob/v0.4.0/CHANGELOG.md