lint: fix issues in examples (mmcloughlin#49)

.golangci.yml

@@ -21,3 +21,5 @@ issues:
   exclude:
     # errcheck: Almost all programs ignore errors on these functions and in most cases it's ok
     - Error return value of .((os\.)?std(out|err)\..*|.*Close|.*Flush|os\.Remove(All)?|.*printf?|os\.(Un)?Setenv). is not checked
+    # gocritic: unlambda with builtins is invalid.
+    - ' with `(len|cap|real|imag)`'

examples/args/args.go

@@ -1,5 +1,6 @@
 package args
 
+// Struct is a struct containing various datatypes, to help demonstrate struct field access.
 type Struct struct {
 	Byte       byte
 	Int8       int8
@@ -15,6 +16,7 @@ type Struct struct {
 	Complex128 complex128
 }
 
+// Sub is a sub-struct of Struct, to demonstrate nested datastructure accesses.
 type Sub struct {
 	A uint64
 	B [3]byte

examples/fnv1a/fnv_test.go

@@ -11,7 +11,9 @@ import (
 func TestHash64(t *testing.T) {
 	expect := func(data []byte) uint64 {
 		h := fnv.New64a()
-		h.Write(data)
+		if _, err := h.Write(data); err != nil {
+			t.Fatal(err)
+		}
 		return h.Sum64()
 	}
 	if err := quick.CheckEqual(Hash64, expect, nil); err != nil {

examples/returns/returns.go

@@ -1,5 +1,6 @@
 package returns
 
+// Struct is used to deomonstrate writing struct return values.
 type Struct struct {
 	Word  uint16
 	Point [2]float64

examples/sha1/sha1.go

@@ -4,11 +4,13 @@ import (
 	"encoding/binary"
 )
 
-const (
-	Size      = 20
-	BlockSize = 64
-)
+// Size of a SHA-1 checksum in bytes.
+const Size = 20
+
+// BlockSize is the block size of SHA-1 in bytes.
+const BlockSize = 64
 
+// Sum returns the SHA-1 checksum of data.
 func Sum(data []byte) [Size]byte {
 	n := len(data)
 	h := [5]uint32{0x67452301, 0xefcdab89, 0x98badcfe, 0x10325476, 0xc3d2e1f0}
@@ -21,7 +23,7 @@ func Sum(data []byte) [Size]byte {
 
 	// Final block.
 	tmp := make([]byte, BlockSize)
-	copy(tmp[:], data)
+	copy(tmp, data)
 	tmp[len(data)] = 0x80
 
 	if len(data) >= 56 {

examples/stadtx/LICENSE

@@ -1,4 +1,4 @@
-// Downloaded from https://raw.githubusercontent.com/demerphq/BeagleHash/5f8620b953230e5b16171b745155fc3b0ef8f75e/LICENSE
+// Code generated by downloading from https://raw.githubusercontent.com/demerphq/BeagleHash/5f8620b953230e5b16171b745155fc3b0ef8f75e/LICENSE. DO NOT EDIT.
 
                    GNU LESSER GENERAL PUBLIC LICENSE
                        Version 3, 29 June 2007

examples/stadtx/fork.sh

@@ -4,7 +4,7 @@ dl() {
     url=$1
     filename=$(basename $1)
     {
-        echo "// Downloaded from ${url}"
+        echo "// Code generated by downloading from ${url}. DO NOT EDIT."
         echo
         curl -L ${url}
     } > ${filename}

script/generate

@@ -8,7 +8,7 @@ post=$(go list ./... | grep -E  'avo/(examples|tests)')
 go install ./internal/cmd/avogen
 
 # Attempt to delete generated files, to prove we can recreate them.
-grep -REl 'Code generated.*DO NOT EDIT\.$' . | grep -v '.md$' | xargs rm -v
+grep -RE '^// Code generated.*DO NOT EDIT\.$' . | grep -v download | cut -d: -f1 | grep -v '.md$' | xargs rm -v
 
 # Generate once.
 go generate -v -x ${core}

script/lint

@@ -10,4 +10,5 @@ find . -name '*.s' | xargs asmfmt -w
 test -z "$(git status --porcelain)"
 
 # Run suite of golangci-lint checks.
-golangci-lint run
+# (Provide examples directory explicitly since it is skipped by default.)
+golangci-lint run ./... ./examples/...