amend the CidFromReader slice extension math

The append+make slice extension idiom works, but note that append uses
the slice's length as its base. We need to append the number of bytes
required for length to reach cidLength, not the capacity.

The added test case panicked before this change, and works now:

	--- FAIL: TestReadCidsFromBuffer (0.00s)
	panic: runtime error: slice bounds out of range [:73] with capacity 64 [recovered]
		panic: runtime error: slice bounds out of range [:73] with capacity 64

	goroutine 37 [running]:
	testing.tRunner.func1.2({0x570d60, 0xc000016438})
		testing/testing.go:1203 +0x24e
	testing.tRunner.func1()
		testing/testing.go:1206 +0x218
	panic({0x570d60, 0xc000016438})
		runtime/panic.go:1038 +0x215
	github.com/ipfs/go-cid.CidFromReader({0x5b0e20, 0xc000010900})
		github.com/ipfs/go-cid/cid.go:803 +0x75f
	github.com/ipfs/go-cid.TestReadCidsFromBuffer(0xc00014ba00)
		github.com/ipfs/go-cid/cid_test.go:710 +0x625
	testing.tRunner(0xc00014ba00, 0x58af38)
		testing/testing.go:1253 +0x102
	created by testing.(*T).Run
		testing/testing.go:1300 +0x35a
	exit status 2
	FAIL	github.com/ipfs/go-cid	0.004s

.github/workflows/automerge.yml

@@ -1,11 +1,51 @@
 # File managed by web3-bot. DO NOT EDIT.
 # See https://github.com/protocol/.github/ for details.
 
-name: Automerge
+# Automatically merge pull requests opened by web3-bot, as soon as (and only if) all tests pass.
+# This reduces the friction associated with updating with our workflows.
+
 on: [ pull_request ]
+name: Automerge
 
 jobs:
+  automerge-check:
+    if: github.event.pull_request.user.login == 'web3-bot'
+    runs-on: ubuntu-latest
+    outputs:
+      status: ${{ steps.should-automerge.outputs.status }}
+    steps:
+    - uses: actions/checkout@v2
+      with:
+        fetch-depth: 0
+    - name: Check if we should automerge
+      id: should-automerge
+      run: |
+        for commit in $(git rev-list --first-parent origin/${{ github.event.pull_request.base.ref }}..${{ github.event.pull_request.head.sha }}); do
+          committer=$(git show --format=$'%ce' -s $commit)
+          echo "Committer: $committer"
+          if [[ "$committer" != "web3-bot@users.noreply.github.com" ]]; then
+            echo "Commit $commit wasn't committed by web3-bot, but by $committer."
+            echo "::set-output name=status::false"
+            exit
+          fi
+        done
+        echo "::set-output name=status::true"
   automerge:
-    uses: protocol/.github/.github/workflows/automerge.yml@master
+    needs: automerge-check
-    with:
+    runs-on: ubuntu-latest
-      job: 'automerge'
+    if: ${{ needs.automerge-check.outputs.status == 'true' }}
+    steps:
+    - name: Wait on tests
+      uses: lewagon/wait-on-check-action@bafe56a6863672c681c3cf671f5e10b20abf2eaa # v0.2
+      with:
+        ref: ${{ github.event.pull_request.head.sha }}
+        repo-token: ${{ secrets.GITHUB_TOKEN }}
+        wait-interval: 10
+        running-workflow-name: 'automerge' # the name of this job
+    - name: Merge PR
+      uses: pascalgn/automerge-action@741c311a47881be9625932b0a0de1b0937aab1ae # v0.13.1
+      env:
+        GITHUB_TOKEN: "${{ secrets.GITHUB_TOKEN }}"
+        MERGE_LABELS: ""
+        MERGE_METHOD: "squash"
+        MERGE_DELETE_BRANCH: true

.github/workflows/go-check.yml

@@ -8,28 +8,17 @@ jobs:
   unit:
     runs-on: ubuntu-latest
     name: All
-    env:
-      RUNGOGENERATE: false
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v2
         with:
           submodules: recursive
-      - uses: actions/setup-go@v3
+      - uses: actions/setup-go@v2
         with:
-          go-version: "1.19.x"
+          go-version: "1.16.x"
-      - name: Run repo-specific setup
-        uses: ./.github/actions/go-check-setup
-        if: hashFiles('./.github/actions/go-check-setup') != ''
-      - name: Read config
-        if: hashFiles('./.github/workflows/go-check-config.json') != ''
-        run: |
-          if jq -re .gogenerate ./.github/workflows/go-check-config.json; then
-            echo "RUNGOGENERATE=true" >> $GITHUB_ENV
-          fi
       - name: Install staticcheck
-        run: go install honnef.co/go/tools/cmd/staticcheck@376210a89477dedbe6fdc4484b233998650d7b3c # 2022.1.3 (v0.3.3)
+        run: go install honnef.co/go/tools/cmd/staticcheck@434f5f3816b358fe468fa83dcba62d794e7fe04b # 2021.1 (v0.2.0)
       - name: Check that go.mod is tidy
-        uses: protocol/multiple-go-modules@v1.2
+        uses: protocol/multiple-go-modules@v1.0
         with:
           run: |
             go mod tidy
@@ -48,26 +37,14 @@ jobs:
           fi
       - name: go vet
         if: ${{ success() || failure() }} # run this step even if the previous one failed
-        uses: protocol/multiple-go-modules@v1.2
+        uses: protocol/multiple-go-modules@v1.0
         with:
           run: go vet ./...
       - name: staticcheck
         if: ${{ success() || failure() }} # run this step even if the previous one failed
-        uses: protocol/multiple-go-modules@v1.2
+        uses: protocol/multiple-go-modules@v1.0
         with:
           run: |
             set -o pipefail
             staticcheck ./... | sed -e 's@\(.*\)\.go@./\1.go@g'
-      - name: go generate
+
-        uses: protocol/multiple-go-modules@v1.2
-        if: (success() || failure()) && env.RUNGOGENERATE == 'true'
-        with:
-          run: |
-            git clean -fd # make sure there aren't untracked files / directories
-            go generate ./...
-            # check if go generate modified or added any files
-            if ! $(git add . && git diff-index HEAD --exit-code --quiet); then
-              echo "go generated caused changes to the repository:"
-              git status --short
-              exit 1
-            fi

.github/workflows/go-test.yml

@@ -10,59 +10,38 @@ jobs:
       fail-fast: false
       matrix:
         os: [ "ubuntu", "windows", "macos" ]
-        go: [ "1.18.x", "1.19.x" ]
+        go: [ "1.15.x", "1.16.x" ]
-    env:
+    runs-on: ${{ matrix.os }}-latest
-      COVERAGES: ""
+    name: ${{ matrix.os}} (go ${{ matrix.go }})
-    runs-on: ${{ format('{0}-latest', matrix.os) }}
-    name: ${{ matrix.os }} (go ${{ matrix.go }})
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v2
         with:
           submodules: recursive
-      - uses: actions/setup-go@v3
+      - uses: actions/setup-go@v2
         with:
           go-version: ${{ matrix.go }}
       - name: Go information
         run: |
           go version
           go env
-      - name: Use msys2 on windows
-        if: ${{ matrix.os == 'windows' }}
-        shell: bash
-        # The executable for msys2 is also called bash.cmd
-        #   https://github.com/actions/virtual-environments/blob/main/images/win/Windows2019-Readme.md#shells
-        # If we prepend its location to the PATH
-        #   subsequent 'shell: bash' steps will use msys2 instead of gitbash
-        run: echo "C:/msys64/usr/bin" >> $GITHUB_PATH
-      - name: Run repo-specific setup
-        uses: ./.github/actions/go-test-setup
-        if: hashFiles('./.github/actions/go-test-setup') != ''
       - name: Run tests
-        uses: protocol/multiple-go-modules@v1.2
+        uses: protocol/multiple-go-modules@v1.0
         with:
-          # Use -coverpkg=./..., so that we include cross-package coverage.
+          run: go test -v -coverprofile coverage.txt ./...
-          # If package ./A imports ./B, and ./A's tests also cover ./B,
-          # this means ./B's coverage will be significantly higher than 0%.
-          run: go test -v -shuffle=on -coverprofile=module-coverage.txt -coverpkg=./... ./...
       - name: Run tests (32 bit)
         if: ${{ matrix.os != 'macos' }} # can't run 32 bit tests on OSX.
-        uses: protocol/multiple-go-modules@v1.2
+        uses: protocol/multiple-go-modules@v1.0
         env:
           GOARCH: 386
         with:
-          run: |
+          run: go test -v ./...
-            export "PATH=${{ env.PATH_386 }}:$PATH"
-            go test -v -shuffle=on ./...
       - name: Run tests with race detector
         if: ${{ matrix.os == 'ubuntu' }} # speed things up. Windows and OSX VMs are slow
-        uses: protocol/multiple-go-modules@v1.2
+        uses: protocol/multiple-go-modules@v1.0
         with:
           run: go test -v -race ./...
-      - name: Collect coverage files
-        shell: bash
-        run: echo "COVERAGES=$(find . -type f -name 'module-coverage.txt' | tr -s '\n' ',' | sed 's/,$//')" >> $GITHUB_ENV
       - name: Upload coverage to Codecov
-        uses: codecov/codecov-action@81cd2dc8148241f03f5839d295e000b8f761e378 # v3.1.0
+        uses: codecov/codecov-action@a1ed4b322b4b38cb846afb5a0ebfa17086917d27 # v1.5.0
         with:
-          files: '${{ env.COVERAGES }}'
+          file: coverage.txt
           env_vars: OS=${{ matrix.os }}, GO=${{ matrix.go }}

.github/workflows/release-check.yml

@@ -1,11 +0,0 @@
-# File managed by web3-bot. DO NOT EDIT.
-# See https://github.com/protocol/.github/ for details.
-
-name: Release Checker
-on:
-  pull_request:
-    paths: [ 'version.json' ]
-
-jobs:
-  release-check:
-    uses: protocol/.github/.github/workflows/release-check.yml@master

.github/workflows/releaser.yml

@@ -1,11 +0,0 @@
-# File managed by web3-bot. DO NOT EDIT.
-# See https://github.com/protocol/.github/ for details.
-
-name: Releaser
-on:
-  push:
-    paths: [ 'version.json' ]
-
-jobs:
-  releaser:
-    uses: protocol/.github/.github/workflows/releaser.yml@master

.github/workflows/stale.yml

@@ -1,26 +0,0 @@
-name: Close and mark stale issue
-
-on:
-  schedule:
-  - cron: '0 0 * * *'
-
-jobs:
-  stale:
-
-    runs-on: ubuntu-latest
-    permissions:
-      issues: write
-      pull-requests: write
-
-    steps:
-    - uses: actions/stale@v3
-      with:
-        repo-token: ${{ secrets.GITHUB_TOKEN }}
-        stale-issue-message: 'Oops, seems like we needed more information for this issue, please comment with more details or this issue will be closed in 7 days.'
-        close-issue-message: 'This issue was closed because it is missing author input.'
-        stale-issue-label: 'kind/stale'
-        any-of-labels: 'need/author-input'
-        exempt-issue-labels: 'need/triage,need/community-input,need/maintainer-input,need/maintainers-input,need/analysis,status/blocked,status/in-progress,status/ready,status/deferred,status/inactive'
-        days-before-issue-stale: 6
-        days-before-issue-close: 7
-        enable-statistics: true

.github/workflows/tagpush.yml

@@ -1,12 +0,0 @@
-# File managed by web3-bot. DO NOT EDIT.
-# See https://github.com/protocol/.github/ for details.
-
-name: Tag Push Checker
-on:
-  push:
-    tags:
-      - v*
-
-jobs:
-  releaser:
-    uses: protocol/.github/.github/workflows/tagpush.yml@master

README.md

@@ -59,17 +59,10 @@ fmt.Println("Got CID: ", c)
 #### Creating a CID from scratch
 
 ```go
-
-import (
-  cid "github.com/ipfs/go-cid"
-  mc "github.com/multiformats/go-multicodec"
-  mh "github.com/multiformats/go-multihash"
-)
-
 // Create a cid manually by specifying the 'prefix' parameters
 pref := cid.Prefix{
 	Version: 1,
-	Codec: mc.Raw,
+	Codec: cid.Raw,
 	MhType: mh.SHA2_256,
 	MhLength: -1, // default length
 }

_rsrch/cidiface/cid.go

@@ -39,8 +39,7 @@ type Cid interface {
 // and the Multihash length. It does not contains
 // any actual content information.
 // NOTE: The use -1 in MhLength to mean default length is deprecated,
-//
+//   use the V0Builder or V1Builder structures instead
-//	use the V0Builder or V1Builder structures instead
 type Prefix struct {
 	Version  uint64
 	Codec    uint64

_rsrch/cidiface/cidBoxingBench_test.go

@@ -12,14 +12,14 @@ import (
 //
 // Sample results on linux amd64 go1.11beta:
 //
-//	BenchmarkCidMap_CidStr-8          100000             16317 ns/op
+//   BenchmarkCidMap_CidStr-8          100000             16317 ns/op
-//	BenchmarkCidMap_CidIface-8        100000             20516 ns/op
+//   BenchmarkCidMap_CidIface-8        100000             20516 ns/op
 //
 // With benchmem on:
 //
-//	BenchmarkCidMap_CidStr-8          100000             15579 ns/op           11223 B/op        207 allocs/op
+//   BenchmarkCidMap_CidStr-8          100000             15579 ns/op           11223 B/op        207 allocs/op
-//	BenchmarkCidMap_CidIface-8        100000             19500 ns/op           12824 B/op        307 allocs/op
+//   BenchmarkCidMap_CidIface-8        100000             19500 ns/op           12824 B/op        307 allocs/op
-//	BenchmarkCidMap_StrPlusHax-8      200000             10451 ns/op            7589 B/op        202 allocs/op
+//   BenchmarkCidMap_StrPlusHax-8      200000             10451 ns/op            7589 B/op        202 allocs/op
 //
 // We can see here that the impact of interface boxing is significant:
 // it increases the time taken to do the inserts to 133%, largely because
@@ -36,6 +36,7 @@ import (
 // re-arranges itself, it involves more or less an O(n) copy of the content
 // in addition to the alloc itself).  This isn't topical to the question of
 // whether or not interfaces are a good idea; just for contextualizing.
+//
 func BenchmarkCidMap_CidStr(b *testing.B) {
 	for i := 0; i < b.N; i++ {
 		mp := map[CidStr]int{}

_rsrch/cidiface/cidString.go

@@ -114,7 +114,7 @@ func NewCidStr(version uint64, codecType uint64, mhash mh.Multihash) CidStr {
 //
 // For CidV1, the data buffer is in the form:
 //
-//	<version><codec-type><multihash>
+//     <version><codec-type><multihash>
 //
 // CidV0 are also supported. In particular, data buffers starting
 // with length 34 bytes, which starts with bytes [18,32...] are considered

_rsrch/cidiface/cidStruct.go

@@ -110,7 +110,7 @@ func (c CidStruct) Prefix() Prefix {
 //
 // For CidV1, the data buffer is in the form:
 //
-//	<version><codec-type><multihash>
+//     <version><codec-type><multihash>
 //
 // CidV0 are also supported. In particular, data buffers starting
 // with length 34 bytes, which starts with bytes [18,32...] are considered

benchmark_test.go

@@ -1,61 +0,0 @@
-package cid_test
-
-import (
-	"math/rand"
-	"testing"
-
-	"github.com/ipfs/go-cid"
-	"github.com/multiformats/go-multihash"
-)
-
-// BenchmarkIdentityCheck benchmarks two ways of checking whether a CIDv1 has multihash.IDENTITY
-// code:
-//  1. Cid.Prefix(), and
-//  2. decoding the Cid.Hash().
-//
-// This benchmark illustrates that using Cid.Prefix is more efficient than multihash.Decode.
-// Users wishing to perform such a check should use Cid.Prefix.
-//
-// Consider that `Cid.Prefix` is already efficient enough and introducing a dedicated API for
-// performing this check will likely result in small gains.
-func BenchmarkIdentityCheck(b *testing.B) {
-	rng := rand.New(rand.NewSource(1413))
-
-	data := make([]byte, rng.Intn(100)+1024)
-	if _, err := rng.Read(data); err != nil {
-		b.Fatal(err)
-	}
-	mh, err := multihash.Sum(data, multihash.IDENTITY, -1)
-	if err != nil {
-		b.Fatal(err)
-	}
-	cv1 := cid.NewCidV1(cid.Raw, mh)
-
-	b.SetBytes(int64(cv1.ByteLen()))
-	b.ReportAllocs()
-	b.ResetTimer()
-
-	b.Run("Prefix", func(b *testing.B) {
-		b.RunParallel(func(pb *testing.PB) {
-			for pb.Next() {
-				if cv1.Prefix().MhType != multihash.IDENTITY {
-					b.Fatal("expected IDENTITY CID")
-				}
-			}
-		})
-	})
-
-	b.Run("MultihashDecode", func(b *testing.B) {
-		b.RunParallel(func(pb *testing.PB) {
-			for pb.Next() {
-				dmh, err := multihash.Decode(cv1.Hash())
-				if err != nil {
-					b.Fatal(err)
-				}
-				if dmh.Code != multihash.IDENTITY {
-					b.Fatal("expected IDENTITY CID")
-				}
-			}
-		})
-	})
-}

cid.go

@@ -10,7 +10,7 @@
 //
 // A CIDv1 has four parts:
 //
-//	<cidv1> ::= <multibase-prefix><cid-version><multicodec-packed-content-type><multihash-content-address>
+//     <cidv1> ::= <multibase-prefix><cid-version><multicodec-packed-content-type><multihash-content-address>
 //
 // As shown above, the CID implementation relies heavily on Multiformats,
 // particularly Multibase
@@ -22,7 +22,6 @@ package cid
 import (
 	"bytes"
 	"encoding"
-	"encoding/binary"
 	"encoding/json"
 	"errors"
 	"fmt"
@@ -47,21 +46,19 @@ var (
 	ErrInvalidEncoding = errors.New("invalid base encoding")
 )
 
-// Consts below are DEPRECATED and left only for legacy reasons:
+// These are multicodec-packed content types. The should match
-// <https://github.com/ipfs/go-cid/pull/137>
+// the codes described in the authoritative document:
-// Modern code should use consts from go-multicodec instead:
+// https://github.com/multiformats/multicodec/blob/master/table.csv
-// <https://github.com/multiformats/go-multicodec>
 const (
-	// common ones
+	Raw = 0x55
-	Raw         = 0x55
-	DagProtobuf = 0x70   // https://ipld.io/docs/codecs/known/dag-pb/
-	DagCBOR     = 0x71   // https://ipld.io/docs/codecs/known/dag-cbor/
-	DagJSON     = 0x0129 // https://ipld.io/docs/codecs/known/dag-json/
-	Libp2pKey   = 0x72   // https://github.com/libp2p/specs/blob/master/peer-ids/peer-ids.md#peer-ids
 
-	// other
+	DagProtobuf = 0x70
-	GitRaw                = 0x78
+	DagCBOR     = 0x71
-	DagJOSE               = 0x85 // https://ipld.io/specs/codecs/dag-jose/spec/
+	Libp2pKey   = 0x72
+
+	GitRaw = 0x78
+
+	DagJOSE               = 0x85
 	EthBlock              = 0x90
 	EthBlockList          = 0x91
 	EthTxTrie             = 0x92
@@ -83,6 +80,64 @@ const (
 	FilCommitmentSealed   = 0xf102
 )
 
+// Codecs maps the name of a codec to its type
+var Codecs = map[string]uint64{
+	"v0":                      DagProtobuf,
+	"raw":                     Raw,
+	"protobuf":                DagProtobuf,
+	"cbor":                    DagCBOR,
+	"libp2p-key":              Libp2pKey,
+	"git-raw":                 GitRaw,
+	"eth-block":               EthBlock,
+	"eth-block-list":          EthBlockList,
+	"eth-tx-trie":             EthTxTrie,
+	"eth-tx":                  EthTx,
+	"eth-tx-receipt-trie":     EthTxReceiptTrie,
+	"eth-tx-receipt":          EthTxReceipt,
+	"eth-state-trie":          EthStateTrie,
+	"eth-account-snapshot":    EthAccountSnapshot,
+	"eth-storage-trie":        EthStorageTrie,
+	"bitcoin-block":           BitcoinBlock,
+	"bitcoin-tx":              BitcoinTx,
+	"zcash-block":             ZcashBlock,
+	"zcash-tx":                ZcashTx,
+	"decred-block":            DecredBlock,
+	"decred-tx":               DecredTx,
+	"dash-block":              DashBlock,
+	"dash-tx":                 DashTx,
+	"fil-commitment-unsealed": FilCommitmentUnsealed,
+	"fil-commitment-sealed":   FilCommitmentSealed,
+	"dag-jose":                DagJOSE,
+}
+
+// CodecToStr maps the numeric codec to its name
+var CodecToStr = map[uint64]string{
+	Raw:                   "raw",
+	DagProtobuf:           "protobuf",
+	DagCBOR:               "cbor",
+	GitRaw:                "git-raw",
+	EthBlock:              "eth-block",
+	EthBlockList:          "eth-block-list",
+	EthTxTrie:             "eth-tx-trie",
+	EthTx:                 "eth-tx",
+	EthTxReceiptTrie:      "eth-tx-receipt-trie",
+	EthTxReceipt:          "eth-tx-receipt",
+	EthStateTrie:          "eth-state-trie",
+	EthAccountSnapshot:    "eth-account-snapshot",
+	EthStorageTrie:        "eth-storage-trie",
+	BitcoinBlock:          "bitcoin-block",
+	BitcoinTx:             "bitcoin-tx",
+	ZcashBlock:            "zcash-block",
+	ZcashTx:               "zcash-tx",
+	DecredBlock:           "decred-block",
+	DecredTx:              "decred-tx",
+	DashBlock:             "dash-block",
+	DashTx:                "dash-tx",
+	FilCommitmentUnsealed: "fil-commitment-unsealed",
+	FilCommitmentSealed:   "fil-commitment-sealed",
+	DagJOSE:               "dag-jose",
+}
+
 // tryNewCidV0 tries to convert a multihash into a CIDv0 CID and returns an
 // error on failure.
 func tryNewCidV0(mhash mh.Multihash) (Cid, error) {
@@ -118,24 +173,16 @@ func NewCidV0(mhash mh.Multihash) Cid {
 // Panics if the multihash is invalid.
 func NewCidV1(codecType uint64, mhash mh.Multihash) Cid {
 	hashlen := len(mhash)
-
+	// two 8 bytes (max) numbers plus hash
-	// Two 8 bytes (max) numbers plus hash.
+	buf := make([]byte, 1+varint.UvarintSize(codecType)+hashlen)
-	// We use strings.Builder to only allocate once.
+	n := varint.PutUvarint(buf, 1)
-	var b strings.Builder
+	n += varint.PutUvarint(buf[n:], codecType)
-	b.Grow(1 + varint.UvarintSize(codecType) + hashlen)
+	cn := copy(buf[n:], mhash)
-
-	b.WriteByte(1)
-
-	var buf [binary.MaxVarintLen64]byte
-	n := varint.PutUvarint(buf[:], codecType)
-	b.Write(buf[:n])
-
-	cn, _ := b.Write(mhash)
 	if cn != hashlen {
 		panic("copy hash length is inconsistent")
 	}
 
-	return Cid{b.String()}
+	return Cid{string(buf[:n+hashlen])}
 }
 
 var (
@@ -181,19 +228,10 @@ func Parse(v interface{}) (Cid, error) {
 	}
 }
 
-// MustParse calls Parse but will panic on error.
-func MustParse(v interface{}) Cid {
-	c, err := Parse(v)
-	if err != nil {
-		panic(err)
-	}
-	return c
-}
-
 // Decode parses a Cid-encoded string and returns a Cid object.
 // For CidV1, a Cid-encoded string is primarily a multibase string:
 //
-//	<multibase-type-code><base-encoded-string>
+//     <multibase-type-code><base-encoded-string>
 //
 // The base-encoded string represents a:
 //
@@ -249,7 +287,7 @@ func ExtractEncoding(v string) (mbase.Encoding, error) {
 // Cast takes a Cid data slice, parses it and returns a Cid.
 // For CidV1, the data buffer is in the form:
 //
-//	<version><codec-type><multihash>
+//     <version><codec-type><multihash>
 //
 // CidV0 are also supported. In particular, data buffers starting
 // with length 34 bytes, which starts with bytes [18,32...] are considered
@@ -378,13 +416,7 @@ func (c Cid) Hash() mh.Multihash {
 // Bytes returns the byte representation of a Cid.
 // The output of bytes can be parsed back into a Cid
 // with Cast().
-//
-// If c.Defined() == false, it return a nil slice and may not
-// be parsable with Cast().
 func (c Cid) Bytes() []byte {
-	if !c.Defined() {
-		return nil
-	}
 	return []byte(c.str)
 }
 
@@ -465,7 +497,7 @@ func (c *Cid) UnmarshalJSON(b []byte) error {
 
 // MarshalJSON procudes a JSON representation of a Cid, which looks as follows:
 //
-//	{ "/": "<cid-string>" }
+//    { "/": "<cid-string>" }
 //
 // Note that this formatting comes from the IPLD specification
 // (https://github.com/ipld/specs/tree/master/ipld)
@@ -522,8 +554,7 @@ func (c Cid) Prefix() Prefix {
 // and the Multihash length. It does not contains
 // any actual content information.
 // NOTE: The use -1 in MhLength to mean default length is deprecated,
-//
+//   use the V0Builder or V1Builder structures instead
-//	use the V0Builder or V1Builder structures instead
 type Prefix struct {
 	Version  uint64
 	Codec    uint64
@@ -562,7 +593,7 @@ func (p Prefix) Sum(data []byte) (Cid, error) {
 
 // Bytes returns a byte representation of a Prefix. It looks like:
 //
-//	<version><codec><mh-type><mh-length>
+//     <version><codec><mh-type><mh-length>
 func (p Prefix) Bytes() []byte {
 	size := varint.UvarintSize(p.Version)
 	size += varint.UvarintSize(p.Codec)

cid_fuzz.go

@@ -1,4 +1,4 @@
-//go:build gofuzz
+// +build gofuzz
 
 package cid
 

cid_test.go

@@ -15,6 +15,37 @@ import (
 	mh "github.com/multiformats/go-multihash"
 )
 
+// Copying the "silly test" idea from
+// https://github.com/multiformats/go-multihash/blob/7aa9f26a231c6f34f4e9fad52bf580fd36627285/multihash_test.go#L13
+// Makes it so changing the table accidentally has to happen twice.
+var tCodecs = map[uint64]string{
+	Raw:                   "raw",
+	DagProtobuf:           "protobuf",
+	DagCBOR:               "cbor",
+	Libp2pKey:             "libp2p-key",
+	GitRaw:                "git-raw",
+	EthBlock:              "eth-block",
+	EthBlockList:          "eth-block-list",
+	EthTxTrie:             "eth-tx-trie",
+	EthTx:                 "eth-tx",
+	EthTxReceiptTrie:      "eth-tx-receipt-trie",
+	EthTxReceipt:          "eth-tx-receipt",
+	EthStateTrie:          "eth-state-trie",
+	EthAccountSnapshot:    "eth-account-snapshot",
+	EthStorageTrie:        "eth-storage-trie",
+	BitcoinBlock:          "bitcoin-block",
+	BitcoinTx:             "bitcoin-tx",
+	ZcashBlock:            "zcash-block",
+	ZcashTx:               "zcash-tx",
+	DecredBlock:           "decred-block",
+	DecredTx:              "decred-tx",
+	DashBlock:             "dash-block",
+	DashTx:                "dash-tx",
+	FilCommitmentUnsealed: "fil-commitment-unsealed",
+	FilCommitmentSealed:   "fil-commitment-sealed",
+	DagJOSE:               "dag-jose",
+}
+
 func assertEqual(t *testing.T, a, b Cid) {
 	if a.Type() != b.Type() {
 		t.Fatal("mismatch on type")
@@ -29,6 +60,26 @@ func assertEqual(t *testing.T, a, b Cid) {
 	}
 }
 
+func TestTable(t *testing.T) {
+	if len(tCodecs) != len(Codecs)-1 {
+		t.Errorf("Item count mismatch in the Table of Codec. Should be %d, got %d", len(tCodecs)+1, len(Codecs))
+	}
+
+	for k, v := range tCodecs {
+		if Codecs[v] != k {
+			t.Errorf("Table mismatch: 0x%x %s", k, v)
+		}
+	}
+}
+
+// The table returns cid.DagProtobuf for "v0"
+// so we test it apart
+func TestTableForV0(t *testing.T) {
+	if Codecs["v0"] != DagProtobuf {
+		t.Error("Table mismatch: Codecs[\"v0\"] should resolve to DagProtobuf (0x70)")
+	}
+}
+
 func TestPrefixSum(t *testing.T) {
 	// Test creating CIDs both manually and with Prefix.
 	// Tests: https://github.com/ipfs/go-cid/issues/83

go.mod

@@ -4,17 +4,7 @@ require (
 	github.com/multiformats/go-multibase v0.0.3
 	github.com/multiformats/go-multihash v0.0.15
 	github.com/multiformats/go-varint v0.0.6
-)
-
-require (
-	github.com/klauspost/cpuid/v2 v2.0.4 // indirect
-	github.com/minio/blake2b-simd v0.0.0-20160723061019-3f5f724cb5b1 // indirect
-	github.com/minio/sha256-simd v1.0.0 // indirect
-	github.com/mr-tron/base58 v1.2.0 // indirect
-	github.com/multiformats/go-base32 v0.0.3 // indirect
-	github.com/multiformats/go-base36 v0.1.0 // indirect
 	golang.org/x/crypto v0.0.0-20210506145944-38f3c27a63bf // indirect
-	golang.org/x/sys v0.0.0-20210309074719-68d13333faf2 // indirect
 )
 
-go 1.18
+go 1.15

go.sum

@@ -22,9 +22,14 @@ golang.org/x/crypto v0.0.0-20210220033148-5ea612d1eb83/go.mod h1:jdWPYTVW3xRLrWP
 golang.org/x/crypto v0.0.0-20210506145944-38f3c27a63bf h1:B2n+Zi5QeYRDAEodEu72OS36gmTWjgpXr2+cWcBW90o=
 golang.org/x/crypto v0.0.0-20210506145944-38f3c27a63bf/go.mod h1:P+XmwS30IXTQdn5tA2iutPOUgjI07+tq3H3K9MVA1s8=
 golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
+golang.org/x/net v0.0.0-20210226172049-e18ecbb05110/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg=
 golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20191026070338-33540a1f6037/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/sys v0.0.0-20210309074719-68d13333faf2 h1:46ULzRKLh1CwgRq2dC5SlBzEqqNCi8rreOZnNrbqcIY=
 golang.org/x/sys v0.0.0-20210309074719-68d13333faf2/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
 golang.org/x/term v0.0.0-20201117132131-f5c789dd3221/go.mod h1:Nr5EML6q2oocZ2LXRh80K7BxOlk5/8JxuGnuhpl+muw=
+golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
+golang.org/x/text v0.3.3/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
+golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=

version.json

@@ -1,3 +0,0 @@
-{
-  "version": "v0.3.2"
-}