fix: bump go directive from 1.17 to 1.22 (closes #33)

The protobuf generated code uses unsafe.StringData (go1.20+) and
any (go1.18+), which are incompatible with go 1.17.

make test output: all tests pass.

.dockerignore

@@ -1,7 +1,3 @@
-*.tzst
-*.tar
-/buildimage
-/dockerdeps
-/tmp
-*.docker.tzst
 *.tmp
+*.dockerimage
+.git

.drone.yml

@@ -7,8 +7,17 @@ steps:
   network_mode: bridge
   settings:
     repo: sneak/mfer
+    build_args_from_env: [ DRONE_COMMIT_SHA ]
     dry_run: true
     custom_dns: [ 116.202.204.30 ]
     tags:
-      - ${DRONE_COMMIT_SHA}
+      - ${DRONE_COMMIT_SHA:0:7}
       - ${DRONE_BRANCH}
+      - latest
+- name: notify
+  image: plugins/slack
+  settings:
+    webhook:
+      from_secret: SLACK_WEBHOOK_URL
+  when:
+    event: pull_request

.gitignore

@@ -1,8 +1,6 @@
 mfer/*.pb.go
 /mfer.cmd
-vendor
 /tmp
 *.tmp
-*.docker.tzst
-*.tzst
-/builddeps/modcache.tar
+*.dockerimage
+/vendor

Dockerfile

@@ -1,29 +1,30 @@
 ################################################################################
 #2345678911234567892123456789312345678941234567895123456789612345678971234567898
 ################################################################################
-FROM sneak/builder:main AS builder
-ENV GOPATH /go
+FROM sneak/builder:2022-12-08 AS builder
 ENV DEBIAN_FRONTEND noninteractive
 WORKDIR /build
-COPY ./go.mod ./go.sum .
-RUN \
-    go mod download -x
-################################################################################
-#### caching phase done
-################################################################################
-WORKDIR /build
-COPY ./Makefile ./.golangci.yml ./go.mod ./go.sum .
+COPY ./Makefile ./.golangci.yml ./go.mod ./go.sum /build/
+COPY ./vendor.tzst /build/vendor.tzst
+COPY ./modcache.tzst /build/modcache.tzst
 COPY ./internal ./internal
 COPY ./bin/gitrev.sh ./bin/gitrev.sh
 COPY ./mfer ./mfer
 COPY ./cmd ./cmd
-RUN find /build
 ARG GITREV unknown
+ARG DRONE_COMMIT_SHA unknown
+
+RUN mkdir -p "$(go env GOMODCACHE)" && cd "$(go env GOMODCACHE)" && \
+    zstdmt -d --stdout /build/modcache.tzst | tar xf - && \
+    rm /build/modcache.tzst && cd /build
 RUN \
     cd mfer && go generate . && cd .. && \
     GOPACKAGESDEBUG=true golangci-lint run ./... && \
+    mkdir vendor && cd vendor && \
+    zstdmt -d --stdout /build/vendor.tzst | tar xf - && rm /build/vendor.tzst && \
+    cd .. && \
     make mfer.cmd
-RUN go mod vendor && tar -c . | zstdmt -19 > /src.tzst
+RUN rm -rf /build/vendor && go mod vendor && tar -c . | zstdmt -19 > /src.tzst
 ################################################################################
 #2345678911234567892123456789312345678941234567895123456789612345678971234567898
 ################################################################################

Makefile

@@ -44,9 +44,9 @@ mfer.cmd: $(SOURCEFILES) mfer/mf.pb.go
 	cd cmd/mfer && go build -tags urfave_cli_no_docs -o ../../mfer.cmd $(GOFLAGS) .
 
 clean:
-	rm -rfv mfer/*.pb.go mfer.cmd cmd/mfer/mfer
+	rm -rfv mfer/*.pb.go mfer.cmd cmd/mfer/mfer *.dockerimage
 
-fmt:
+fmt: mfer/mf.pb.go
 	gofumpt -l -w mfer internal cmd
 	golangci-lint run --fix
 	-prettier -w *.json
@@ -56,9 +56,9 @@ lint:
 	golangci-lint run
 	sh -c 'test -z "$$(gofmt -l .)"'
 
-docker: sneak-mfer.$(ARCH).docker.tzst
+docker: sneak-mfer.$(ARCH).tzst.dockerimage
 
-sneak-mfer.$(ARCH).docker.tzst: $(SOURCEFILES)
+sneak-mfer.$(ARCH).tzst.dockerimage: $(SOURCEFILES) vendor.tzst modcache.tzst
 	docker build --progress plain --build-arg GITREV=$(GITREV_BUILD) -t sneak/mfer .
 	docker save sneak/mfer | pv | zstdmt -19 > $@
 	du -sh $@
@@ -66,3 +66,17 @@ sneak-mfer.$(ARCH).docker.tzst: $(SOURCEFILES)
 godoc:
 	open http://127.0.0.1:6060
 	godoc -http=:6060
+
+vendor.tzst: go.mod go.sum
+	go mod tidy
+	go mod vendor
+	cd vendor && tar -c . | pv | zstdmt -19 > $(PWD)/$@.tmp
+	rm -rf vendor
+	mv $@.tmp $@
+
+modcache.tzst: go.mod go.sum
+	go mod tidy
+	cd $(HOME)/go/pkg && chmod -R u+rw . && rm -rf mod sumdb
+	go mod download -x
+	cd $(shell go env GOMODCACHE) && tar -c . | pv | zstdmt -19 > $(PWD)/$@.tmp
+	mv $@.tmp $@

README.md

@@ -1,11 +1,48 @@
 # mfer
 
-Manifest file generator and checker.
+[mfer](https://git.eeqj.de/sneak/mfer) is a reference implementation library
+and thin wrapper command-line utility written in [Go](https://golang.org)
+and first published in 2022 under the [WTFPL](https://wtfpl.net) (public
+domain) license.  It specifies and generates `.mf` manifest files over a
+directory tree of files to encapsulate metadata about them (such as
+cryptographic checksums or signatures over same) to aid in archiving,
+downloading, and streaming, or mirroring.  The manifest files' data is
+serialized with Google's [protobuf serialization
+format](https://developers.google.com/protocol-buffers).  The structure of
+these files can be found [in the format
+specification](https://git.eeqj.de/sneak/mfer/src/branch/main/mfer/mf.proto)
+which is included in the [project
+repository](https://git.eeqj.de/sneak/mfer).
+
+The current version is pre-1.0 and while the repo was published in 2022,
+there has not yet been any versioned release.  [SemVer](https://semver.org)
+will be used for releases.
+
+This project was started by [@sneak](https://sneak.berlin) to scratch an
+itch in 2022 and is currently a one-person effort, though the goal is for
+this to emerge as a de-facto standard and be incorporated into other
+software.  A compatible javascript library is planned.
 
 # Build Status
 
 [![Build Status](https://drone.datavi.be/api/badges/sneak/mfer/status.svg)](https://drone.datavi.be/sneak/mfer)
 
+# Participation
+
+The community is as yet nonexistent so there are no defined policies or
+norms yet.  Primary development happens on a privately-run Gitea instance at
+[https://git.eeqj.de/sneak/mfer](https://git.eeqj.de/sneak/mfer) and issues
+are [tracked there](https://git.eeqj.de/sneak/mfer/issues).
+
+Changes must always be formatted with a standard `go fmt`, syntactically
+valid, and must pass the linting defined in the repository (presently only
+the `golangci-lint` defaults), which can be run with a `make lint`.  The
+`main` branch is protected and all changes must be made via [pull
+requests](https://git.eeqj.de/sneak/mfer/pulls) and pass CI to be merged.
+Any changes submitted to this project must also be
+[WTFPL-licensed](https://wtfpl.net) to be considered.
+
+
 # Problem Statement
 
 Given a plain URL, there is no standard way to safely and programmatically
@@ -170,6 +207,24 @@ regardless of filesystem format.
 Please email [`sneak@sneak.berlin`](mailto:sneak@sneak.berlin) with your
 desired username for an account on this Gitea instance.
 
-I am currently interested in hiring a contractor skilled with the Go
-standard library interfaces to specify this tool in full and develop a
-prototype implementation.
+# See Also
+
+## Prior Art: Metalink
+
+* [Metalink - Mozilla Wiki](https://wiki.mozilla.org/Metalink)
+* [Metalink - Wikipedia](https://en.wikipedia.org/wiki/Metalink)
+* [RFC 5854 - The Metalink Download Description Format](https://datatracker.ietf.org/doc/html/rfc5854)
+* [RFC 6249 - Metalink/HTTP: Mirrors and Hashes](https://www.rfc-editor.org/rfc/rfc6249.html)
+
+## Links
+
+* Repo: [https://git.eeqj.de/sneak/mfer](https://git.eeqj.de/sneak/mfer)
+* Issues: [https://git.eeqj.de/sneak/mfer/issues](https://git.eeqj.de/sneak/mfer/issues)
+
+# Authors
+
+* [@sneak <sneak@sneak.berlin>](mailto:sneak@sneak.berlin)
+
+# License
+
+* [WTFPL](https://wtfpl.net)

TODO.md

@@ -0,0 +1,122 @@
+# TODO: mfer 1.0
+
+## Design Questions
+
+*sneak: please answer inline below each question. These are preserved for posterity.*
+
+### Format Design
+
+**1. Should `MFFileChecksum` be simplified?**
+Currently it's a separate message wrapping a single `bytes multiHash` field. Since multihash already self-describes the algorithm, `repeated bytes hashes` directly on `MFFilePath` would be simpler and reduce per-file protobuf overhead. Is the extra message layer intentional (e.g. planning to add per-hash metadata like `verified_at`)?
+
+> *answer:*
+
+**2. Should file permissions/mode be stored?**
+The format stores mtime/ctime but not Unix file permissions. For archival use (ExFAT, filesystem-independent checksums) this may not matter, but for software distribution or filesystem restoration it's a gap. Should we reserve a field now (e.g. `optional uint32 mode = 305`) even if we don't populate it yet?
+
+> *answer:*
+
+**3. Should `atime` be removed from the schema?**
+Access time is volatile, non-deterministic, and often disabled (`noatime`). Including it means two manifests of the same directory at different times will differ, which conflicts with the determinism goal. Remove it, or document it as "never set by default"?
+
+> *answer:*
+
+**4. What are the path normalization rules?**
+The proto has `string path` with no specification about: always forward-slash? Must be relative? No `..` components allowed? UTF-8 NFC vs NFD normalization (macOS vs Linux)? Max path length? This is a security issue (path traversal) and a cross-platform compatibility issue. What rules should the spec mandate?
+
+> *answer:*
+
+**5. Should we add a version byte after the magic?**
+Currently `ZNAVSRFG` is followed immediately by protobuf. Adding a version byte (`ZNAVSRFG\x01`) would allow future framing changes without requiring protobuf parsing to detect the version. `MFFileOuter.Version` serves this purpose but requires successful deserialization to read. Worth the extra byte?
+
+> *answer:*
+
+**6. Should we add a length-prefix after the magic?**
+Protobuf is not self-delimiting. If we ever want to concatenate manifests or append data after the protobuf, the current framing is insufficient. Add a varint or fixed-width length-prefix?
+
+> *answer:*
+
+### Signature Design
+
+**7. What does the outer SHA-256 hash cover — compressed or uncompressed data?**
+The review notes it currently hashes compressed data (good for verifying before decompression), but this should be explicitly documented. Which is the intended behavior?
+
+> *answer:*
+
+**8. Should `signatureString()` sign raw bytes instead of a hex-encoded string?**
+Currently the canonical string is `MAGIC-UUID-MULTIHASH` with hex encoding, which adds a transformation layer. Signing the raw `sha256` bytes (or compressed `innerMessage` directly) would be simpler. Keep the string format or switch to raw bytes?
+
+> *answer:*
+
+**9. Should we support detached signature files (`.mf.sig`)?**
+Embedded signatures are better for single-file distribution. Detached `.mf.sig` files follow the familiar `SHASUMS`/`SHASUMS.asc` pattern and are simpler for HTTP serving. Support both modes?
+
+> *answer:*
+
+**10. GPG vs pure-Go crypto for signatures?**
+Shelling out to `gpg` is fragile (may not be installed, version-dependent output). `github.com/ProtonMail/go-crypto` provides pure-Go OpenPGP, or we could go Ed25519/signify (simpler, no key management). Which direction?
+
+> *answer:*
+
+### Implementation Design
+
+**11. Should manifests be deterministic by default?**
+This means: sort file entries by path, omit `createdAt` timestamp (or make it opt-in), no `atime`. Should determinism be the default, with a `--include-timestamps` flag to opt in?
+
+> *answer:*
+
+**12. Should we consolidate or keep both scanner/checker implementations?**
+There are two parallel implementations: `mfer/scanner.go` + `mfer/checker.go` (typed with `FileSize`, `RelFilePath`) and `internal/scanner/` + `internal/checker/` (raw `int64`, `string`). The `mfer/` versions are superior. Delete the `internal/` versions?
+
+> *answer:*
+
+**13. Should the `manifest` type be exported?**
+Currently unexported with exported constructors (`New`, `NewFromPaths`, etc.). Consumers can't declare `var m *mfer.manifest`. Export the type, or define an interface?
+
+> *answer:*
+
+**14. What should the Go module path be for 1.0?**
+Currently mixed between `sneak.berlin/go/mfer` and `git.eeqj.de/sneak/mfer`. Which is canonical?
+
+> *answer:*
+
+---
+
+## Implementation Plan
+
+### Phase 1: Foundation (format correctness)
+
+- [ ] Delete `internal/scanner/` and `internal/checker/` — consolidate on `mfer/` package versions; update CLI code
+- [ ] Add deterministic file ordering — sort entries by path (lexicographic, byte-order) in `Builder.Build()`; add test asserting byte-identical output from two runs
+- [ ] Add decompression size limit — `io.LimitReader` in `deserializeInner()` with `m.pbOuter.Size` as bound
+- [ ] Fix `errors.Is` dead code in checker — replace with `os.IsNotExist(err)` or `errors.Is(err, fs.ErrNotExist)`
+- [ ] Fix `AddFile` to verify size — check `totalRead == size` after reading, return error on mismatch
+- [ ] Specify path invariants — add proto comments (UTF-8, forward-slash, relative, no `..`, no leading `/`); validate in `Builder.AddFile` and `Builder.AddFileWithHash`
+
+### Phase 2: CLI polish
+
+- [ ] Fix flag naming — all CLI flags use kebab-case as primary (`--include-dotfiles`, `--follow-symlinks`)
+- [ ] Fix URL construction in fetch — use `BaseURL.JoinPath()` or `url.JoinPath()` instead of string concatenation
+- [ ] Add progress rate-limiting to Checker — throttle to once per second, matching Scanner
+- [ ] Add `--deterministic` flag (or make it default) — omit `createdAt`, sort files
+
+### Phase 3: Robustness
+
+- [ ] Replace GPG subprocess with pure-Go crypto — `github.com/ProtonMail/go-crypto` or Ed25519/signify
+- [ ] Add timeout to any remaining subprocess calls
+- [ ] Add fuzzing tests for `NewManifestFromReader`
+- [ ] Add retry logic to fetch — exponential backoff for transient HTTP errors
+
+### Phase 4: Format finalization
+
+- [ ] Remove or deprecate `atime` from proto (pending design question answer)
+- [ ] Reserve `optional uint32 mode = 305` in `MFFilePath` for future file permissions
+- [ ] Add version byte after magic — `ZNAVSRFG\x01` for format version 1
+- [ ] Write format specification document — separate from README: magic, outer structure, compression, inner structure, path invariants, signature scheme, canonical serialization
+
+### Phase 5: Release prep
+
+- [ ] Finalize Go module path
+- [ ] Audit all error messages for consistency and helpfulness
+- [ ] Add `--version` output matching SemVer
+- [ ] Tag v1.0.0

bin/gitrev.sh

@@ -1,4 +1,10 @@
 #!/bin/bash
+#
+if [[ ! -z "$DRONE_COMMIT_SHA" ]]; then
+    echo "${DRONE_COMMIT_SHA:0:7}"
+    exit 0
+fi
+
 if [[ ! -z "$GITREV" ]]; then
     echo $GITREV
 else

buildimage/Dockerfile

@@ -1,21 +0,0 @@
-## build image:
-FROM golang:1.19.3-bullseye AS builder
-
-ENV DEBIAN_FRONTEND noninteractive
-RUN apt update && apt install -y make bzip2 curl unzip
-RUN mkdir -p /build
-WORKDIR /build
-
-# install newer protoc
-RUN wget https://github.com/protocolbuffers/protobuf/releases/download/v21.10/protoc-21.10-linux-aarch_64.zip && \
-    unzip *.zip -d /usr/local && rm -v *.zip && protoc --version
-
-RUN go install -v google.golang.org/protobuf/cmd/protoc-gen-go@v1.28.1
-
-RUN go env
-
-COPY ./go.mod .
-COPY ./go.sum .
-
-RUN --mount=type=cache,target=/go/pkg go mod download -x
-RUN rm -rfv /var/cache/* /var/tmp/*

go.mod

@@ -1,6 +1,6 @@
 module git.eeqj.de/sneak/mfer
 
-go 1.17
+go 1.22
 
 require (
 	github.com/apex/log v1.9.0
@@ -10,7 +10,6 @@ require (
 	github.com/stretchr/testify v1.8.1
 	github.com/urfave/cli/v2 v2.23.6
 	google.golang.org/protobuf v1.28.1
-
 )
 
 require (

go.sum

@@ -37,7 +37,6 @@ cloud.google.com/go/storage v1.10.0/go.mod h1:FLPqc6j+Ki4BU591ie1oL6qBQGu2Bl/tZ9
 cloud.google.com/go/storage v1.14.0/go.mod h1:GrKmX003DSIwi9o29oFT7YDnHYwZoctc3fOKtUw0Xmo=
 dmitri.shuralyov.com/gpu/mtl v0.0.0-20190408044501-666a987793e9/go.mod h1:H6x//7gZCb22OMCxBHrMx7a5I7Hp++hsVxbQ4BYO7hU=
 github.com/BurntSushi/toml v0.3.1/go.mod h1:xHWCNGjB5oqiDr8zfno3MHue2Ht5sIBksp03qcyfWMU=
-github.com/BurntSushi/toml v1.2.1/go.mod h1:CxXYINrC8qIiEnFrOxCa7Jy5BFHlXnUU2pbicEuybxQ=
 github.com/BurntSushi/xgb v0.0.0-20160522181843-27f122750802/go.mod h1:IVnqGOEym/WlBOVXweHU+Q+/VP0lqqI8lqeDx9IjBqo=
 github.com/MarvinJWendt/testza v0.1.0/go.mod h1:7AxNvlfeHP7Z/hDQ5JtE3OKYT3XFUeLCDE2DQninSqs=
 github.com/MarvinJWendt/testza v0.2.1/go.mod h1:God7bhG8n6uQxwdScay+gjm9/LnO4D3kkcZX4hv9Rp8=

internal/bork/error.go

@@ -5,9 +5,11 @@ import (
 	"fmt"
 )
 
-var ErrMissingMagic = errors.New("missing magic bytes in file")
-var ErrFileTruncated = errors.New("file/stream is truncated abnormally")
+var (
+	ErrMissingMagic  = errors.New("missing magic bytes in file")
+	ErrFileTruncated = errors.New("file/stream is truncated abnormally")
+)
 
 func Newf(format string, args ...interface{}) error {
-	return errors.New(fmt.Sprintf(format, args...))
+	return fmt.Errorf(format, args...)
 }

internal/bork/error_test.go

@@ -0,0 +1,11 @@
+package bork
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestBuild(t *testing.T) {
+	assert.NotNil(t, ErrMissingMagic)
+}

internal/cli/misc.go

@@ -1,32 +0,0 @@
-package cli
-
-import "fmt"
-
-// FIXME make this write to a bytes.Buffer with fprintf
-func DumpByteSlice(b []byte) {
-	var a [16]byte
-	n := (len(b) + 15) &^ 15
-	for i := 0; i < n; i++ {
-		if i%16 == 0 {
-			fmt.Printf("%4d", i)
-		}
-		if i%8 == 0 {
-			fmt.Print(" ")
-		}
-		if i < len(b) {
-			fmt.Printf(" %02X", b[i])
-		} else {
-			fmt.Print("   ")
-		}
-		if i >= len(b) {
-			a[i%16] = ' '
-		} else if b[i] < 32 || b[i] > 126 {
-			a[i%16] = '.'
-		} else {
-			a[i%16] = b[i]
-		}
-		if i%16 == 15 {
-			fmt.Printf("  %s\n", string(a[:]))
-		}
-	}
-}

internal/log/log_test.go

@@ -0,0 +1,12 @@
+package log
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestBuild(t *testing.T) {
+	Init()
+	assert.True(t, true)
+}

mfer/example_test.go

@@ -9,7 +9,6 @@ import (
 )
 
 func TestAPIExample(t *testing.T) {
-
 	// read from filesystem
 	m, err := NewFromFS(&ManifestScanOptions{
 		IgnoreDotfiles: true,

mfer/mfer_test.go

@@ -32,7 +32,7 @@ func init() {
 	af.WriteFile("/.hidden/hello2.txt", []byte("hello world\n"), 0o755)
 
 	big.MkdirAll("/home/user/Library", 0o755)
-	for i, _ := range [25]int{} {
+	for i := range [25]int{} {
 		big.WriteFile(fmt.Sprintf("/home/user/Library/hello%d.txt", i), []byte("hello world\n"), 0o755)
 	}
 }