.github/workflows/test.yml

@@ -1,16 +1,28 @@
 # Based on https://github.com/mvdan/github-actions-golang
-on: [push, pull_request]
+on: [push, pull_request, workflow_dispatch]
 name: Tests
 jobs:
   test:
     strategy:
       matrix:
-        go-version: [1.19.x, 1.20.x]
+        go-version: ['stable', 'oldstable']
         os: [ubuntu-latest, macos-latest, windows-latest]
     runs-on: ${{ matrix.os }}
     steps:
-      - uses: actions/setup-go@v3
+      - uses: actions/setup-go@v4
         with:
           go-version: ${{ matrix.go-version }}
       - uses: actions/checkout@v3
       - run: go test ./...
+  govulncheck:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: golang/govulncheck-action@v1
+  gocritic:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/setup-go@v4
+      - uses: actions/checkout@v3
+      - run: |
+          go install github.com/go-critic/go-critic/cmd/gocritic@latest
+          gocritic check .

README.md

@@ -313,7 +313,7 @@ Filters are methods on an existing pipe that also return a pipe, allowing you to
 | [`SHA256Sums`](https://pkg.go.dev/github.com/bitfield/script#Pipe.SHA256Sums) | SHA-256 hashes of each listed file |
 | [`Tee`](https://pkg.go.dev/github.com/bitfield/script#Pipe.Tee) | input copied to supplied writers |
 
-Note that filters run concurrently, rather than producing nothing until each stage has fully read its input. This is convenient for executing long-running comands, for example. If you do need to wait for the pipeline to complete, call [`Wait`](https://pkg.go.dev/github.com/bitfield/script#Pipe.Wait).
+Note that filters run concurrently, rather than producing nothing until each stage has fully read its input. This is convenient for executing long-running commands, for example. If you do need to wait for the pipeline to complete, call [`Wait`](https://pkg.go.dev/github.com/bitfield/script#Pipe.Wait).
 
 ## Sinks
 

go.mod

@@ -1,10 +1,16 @@
 module github.com/bitfield/script
 
-go 1.12
+go 1.18
 
 require (
 	github.com/google/go-cmp v0.5.9
-	github.com/itchyny/gojq v0.12.12
-	github.com/rogpeppe/go-internal v1.10.0
-	mvdan.cc/sh/v3 v3.6.0
+	github.com/itchyny/gojq v0.12.13
+	github.com/rogpeppe/go-internal v1.11.0
+	mvdan.cc/sh/v3 v3.7.0
+)
+
+require (
+	github.com/itchyny/timefmt-go v0.1.5 // indirect
+	golang.org/x/sys v0.10.0 // indirect
+	golang.org/x/tools v0.11.0 // indirect
 )

go.sum

@@ -1,35 +1,24 @@
-github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=
-github.com/creack/pty v1.1.18/go.mod h1:MOBLtS5ELjhRRrroQr9kyvTxUAFNvYEK993ew/Vr4O4=
 github.com/frankban/quicktest v1.14.4 h1:g2rn0vABPOOXmZUj+vbmUp0lPoXEMuhTpIluN0XL9UY=
-github.com/frankban/quicktest v1.14.4/go.mod h1:4ptaffx2x8+WTWXmUCuVU6aPUX1/Mz7zb5vbUoiM6w0=
-github.com/google/go-cmp v0.5.4/go.mod h1:v8dTdLbMG2kIc/vJvl+f65V22dbkXbowE6jgT/gNBxE=
+github.com/frankban/quicktest v1.14.5 h1:dfYrrRyLtiqT9GyKXgdh+k4inNeTvmGbuSgZ3lx3GhA=
 github.com/google/go-cmp v0.5.9 h1:O2Tfq5qg4qc4AmwVlvv0oLiVAGB7enBSJ2x2DqQFi38=
 github.com/google/go-cmp v0.5.9/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
-github.com/google/renameio/v2 v2.0.0/go.mod h1:BtmJXm5YlszgC+TD4HOEEUFgkJP3nLxehU6hfe7jRt4=
 github.com/itchyny/gojq v0.12.12 h1:x+xGI9BXqKoJQZkr95ibpe3cdrTbY8D9lonrK433rcA=
 github.com/itchyny/gojq v0.12.12/go.mod h1:j+3sVkjxwd7A7Z5jrbKibgOLn0ZfLWkV+Awxr/pyzJE=
+github.com/itchyny/gojq v0.12.13 h1:IxyYlHYIlspQHHTE0f3cJF0NKDMfajxViuhBLnHd/QU=
+github.com/itchyny/gojq v0.12.13/go.mod h1:JzwzAqenfhrPUuwbmEz3nu3JQmFLlQTQMUcOdnu/Sf4=
 github.com/itchyny/timefmt-go v0.1.5 h1:G0INE2la8S6ru/ZI5JecgyzbbJNs5lG1RcBqa7Jm6GE=
 github.com/itchyny/timefmt-go v0.1.5/go.mod h1:nEP7L+2YmAbT2kZ2HfSs1d8Xtw9LY8D2stDBckWakZ8=
 github.com/kr/pretty v0.3.1 h1:flRD4NNwYAUpkphVc1HcthR4KEIFJ65n8Mw5qdRn3LE=
-github.com/kr/pretty v0.3.1/go.mod h1:hoEshYVHaxMs3cyo3Yncou5ZscifuDolrwPKZanG3xk=
 github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
-github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
-github.com/mattn/go-isatty v0.0.17/go.mod h1:kYGgaQfpe5nmfYZH+SKPsOc2e4SrIfOl2e/yFXSvRLM=
-github.com/mattn/go-runewidth v0.0.14/go.mod h1:Jdepj2loyihRzMpdS35Xk/zdY8IAYHsh153qUoGf23w=
-github.com/pkg/diff v0.0.0-20210226163009-20ebb0f2a09e/go.mod h1:pJLUxLENpZxwdsKMEsNbx1VGcRFpLqf3715MtcvvzbA=
-github.com/rivo/uniseg v0.2.0/go.mod h1:J6wj4VEh+S6ZtnVlnTBMWIodfgj8LQOQFoIToxlJtxc=
-github.com/rivo/uniseg v0.4.4/go.mod h1:FN3SvrM+Zdj16jyLfmOkMNblXMcoc8DfTHruCPUcx88=
-github.com/rogpeppe/go-internal v1.9.0/go.mod h1:WtVeX8xhTBvf0smdhujwtBcq4Qrzq/fJaraNFVN+nFs=
 github.com/rogpeppe/go-internal v1.10.0 h1:TMyTOH3F/DB16zRVcYyreMH6GnZZrwQVAoYjRBZyWFQ=
 github.com/rogpeppe/go-internal v1.10.0/go.mod h1:UQnix2H7Ngw/k4C5ijL5+65zddjncjaFoBhdsK/akog=
-golang.org/x/sync v0.1.0/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
-golang.org/x/sys v0.0.0-20220811171246-fbc7d0a398ab/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.3.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.5.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/term v0.3.0/go.mod h1:q750SLmJuPmVoN1blW3UFBPREJfb1KmY3vwxfr+nFDA=
-golang.org/x/xerrors v0.0.0-20191204190536-9bdfabe68543/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
-gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
-gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
-mvdan.cc/editorconfig v0.2.0/go.mod h1:lvnnD3BNdBYkhq+B4uBuFFKatfp02eB6HixDvEz91C0=
+github.com/rogpeppe/go-internal v1.11.0 h1:cWPaGQEPrBb5/AsnsZesgZZ9yb1OQ+GOISoDNXVBh4M=
+github.com/rogpeppe/go-internal v1.11.0/go.mod h1:ddIwULY96R17DhadqLgMfk9H9tvdUzkipdSkR5nkCZA=
+golang.org/x/sys v0.10.0 h1:SqMFp9UcQJZa+pmYuAKjd9xq1f0j5rLcDIk0mj4qAsA=
+golang.org/x/sys v0.10.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/tools v0.11.0 h1:EMCa6U9S2LtZXLAMoWiR/R8dAQFRqbAitmbJ2UKhoi8=
+golang.org/x/tools v0.11.0/go.mod h1:anzJrxPjNtfgiYQYirP2CPGzGLxrH2u2QBhn6Bf3qY8=
 mvdan.cc/sh/v3 v3.6.0 h1:gtva4EXJ0dFNvl5bHjcUEvws+KRcDslT8VKheTYkbGU=
 mvdan.cc/sh/v3 v3.6.0/go.mod h1:U4mhtBLZ32iWhif5/lD+ygy1zrgaQhUu+XFy7C8+TTA=
+mvdan.cc/sh/v3 v3.7.0 h1:lSTjdP/1xsddtaKfGg7Myu7DnlHItd3/M2tomOcNNBg=
+mvdan.cc/sh/v3 v3.7.0/go.mod h1:K2gwkaesF/D7av7Kxl0HbF5kGOd2ArupNTX3X44+8l8=

script.go

@@ -104,10 +104,10 @@ func FindFiles(dir string) *Pipe {
 	return Slice(paths)
 }
 
-// Get creates a pipe that makes an HTTP GET request to URL, and produces the
+// Get creates a pipe that makes an HTTP GET request to url, and produces the
 // response. See [Pipe.Do] for how the HTTP response status is interpreted.
-func Get(URL string) *Pipe {
-	return NewPipe().Get(URL)
+func Get(url string) *Pipe {
+	return NewPipe().Get(url)
 }
 
 // IfExists tests whether path exists, and creates a pipe whose error status
@@ -169,11 +169,11 @@ func NewPipe() *Pipe {
 	}
 }
 
-// Post creates a pipe that makes an HTTP POST request to URL, with an empty
+// Post creates a pipe that makes an HTTP POST request to url, with an empty
 // body, and produces the response. See [Pipe.Do] for how the HTTP response
 // status is interpreted.
-func Post(URL string) *Pipe {
-	return NewPipe().Post(URL)
+func Post(url string) *Pipe {
+	return NewPipe().Post(url)
 }
 
 // Slice creates a pipe containing each element of s, one per line.
@@ -514,21 +514,24 @@ func (p *Pipe) FilterScan(filter func(string, io.Writer)) *Pipe {
 
 // First produces only the first n lines of the pipe's contents, or all the
 // lines if there are less than n. If n is zero or negative, there is no output
-// at all.
+// at all. When n lines have been produced, First stops reading its input and
+// sends EOF to its output.
 func (p *Pipe) First(n int) *Pipe {
 	if p.Error() != nil {
 		return p
 	}
 	if n <= 0 {
 		return NewPipe()
 	}
-	i := 0
-	return p.FilterScan(func(line string, w io.Writer) {
-		if i >= n {
-			return
+	return p.Filter(func(r io.Reader, w io.Writer) error {
+		scanner := newScanner(r)
+		for i := 0; i < n && scanner.Scan(); i++ {
+			_, err := fmt.Fprintln(w, scanner.Text())
+			if err != nil {
+				return err
+			}
 		}
-		fmt.Fprintln(w, line)
-		i++
+		return scanner.Err()
 	})
 }
 
@@ -584,11 +587,11 @@ func (p *Pipe) Freq() *Pipe {
 	})
 }
 
-// Get makes an HTTP GET request to URL, sending the contents of the pipe as
+// Get makes an HTTP GET request to url, sending the contents of the pipe as
 // the request body, and produces the server's response. See [Pipe.Do] for how
 // the HTTP response status is interpreted.
-func (p *Pipe) Get(URL string) *Pipe {
-	req, err := http.NewRequest(http.MethodGet, URL, p.Reader)
+func (p *Pipe) Get(url string) *Pipe {
+	req, err := http.NewRequest(http.MethodGet, url, p.Reader)
 	if err != nil {
 		return p.WithError(err)
 	}
@@ -693,11 +696,11 @@ func (p *Pipe) MatchRegexp(re *regexp.Regexp) *Pipe {
 	})
 }
 
-// Post makes an HTTP POST request to URL, using the contents of the pipe as
+// Post makes an HTTP POST request to url, using the contents of the pipe as
 // the request body, and produces the server's response. See [Pipe.Do] for how
 // the HTTP response status is interpreted.
-func (p *Pipe) Post(URL string) *Pipe {
-	req, err := http.NewRequest(http.MethodPost, URL, p.Reader)
+func (p *Pipe) Post(url string) *Pipe {
+	req, err := http.NewRequest(http.MethodPost, url, p.Reader)
 	if err != nil {
 		return p.WithError(err)
 	}
@@ -731,8 +734,8 @@ func (p *Pipe) Replace(search, replace string) *Pipe {
 }
 
 // ReplaceRegexp replaces all matches of the compiled regexp re with the string
-// re. $x variables in the replace string are interpreted as by
-// [regexp.Expand]; for example, $1 represents the text of the first submatch.
+// replace. $x variables in the replace string are interpreted as by
+// [regexp#Regexp.Expand]; for example, $1 represents the text of the first submatch.
 func (p *Pipe) ReplaceRegexp(re *regexp.Regexp, replace string) *Pipe {
 	return p.FilterLine(func(line string) string {
 		return re.ReplaceAllString(line, replace)
@@ -849,7 +852,7 @@ func (p *Pipe) Tee(writers ...io.Writer) *Pipe {
 // useful for waiting until concurrent filters have completed (see
 // [Pipe.Filter]).
 func (p *Pipe) Wait() {
-	_, err := io.ReadAll(p)
+	_, err := io.Copy(io.Discard, p)
 	if err != nil {
 		p.SetError(err)
 	}
@@ -905,7 +908,7 @@ func (p *Pipe) writeOrAppendFile(path string, mode int) (int64, error) {
 	if p.Error() != nil {
 		return 0, p.Error()
 	}
-	out, err := os.OpenFile(path, mode, 0666)
+	out, err := os.OpenFile(path, mode, 0o666)
 	if err != nil {
 		p.SetError(err)
 		return 0, err
@@ -942,7 +945,7 @@ func (ra ReadAutoCloser) Close() error {
 	if ra.r == nil {
 		return nil
 	}
-	return ra.r.(io.Closer).Close()
+	return ra.r.Close()
 }
 
 // Read reads up to len(b) bytes from ra's reader into b. It returns the number

script_test.go

@@ -244,7 +244,7 @@ func TestDoPerformsSuppliedHTTPRequest(t *testing.T) {
 		fmt.Fprintln(w, "some data")
 	}))
 	defer ts.Close()
-	req, err := http.NewRequest(http.MethodGet, ts.URL, nil)
+	req, err := http.NewRequest(http.MethodGet, ts.URL, http.NoBody)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -573,6 +573,24 @@ func TestFirstHasNoEffectGivenLessThanNInputLines(t *testing.T) {
 	}
 }
 
+func TestFirstDoesNotConsumeUnnecessaryData(t *testing.T) {
+	t.Parallel()
+	// First uses a 4096-byte buffer, so will always read at least
+	// that much, but no more (once N lines have been read).
+	r := strings.NewReader(strings.Repeat("line\n", 1000))
+	got, err := script.NewPipe().WithReader(r).First(1).String()
+	if err != nil {
+		t.Fatal(err)
+	}
+	want := "line\n"
+	if want != got {
+		t.Errorf("want output %q, got %q", want, got)
+	}
+	if r.Len() == 0 {
+		t.Errorf("no data left in reader")
+	}
+}
+
 func TestFreqHandlesLongLines(t *testing.T) {
 	t.Parallel()
 	got, err := script.Echo(longLine).Freq().Slice()
@@ -1669,7 +1687,7 @@ func TestWriteFile_TruncatesExistingFile(t *testing.T) {
 	path := t.TempDir() + "/" + t.Name()
 	// write some data first so we can check for truncation
 	data := make([]byte, 15)
-	err := os.WriteFile(path, data, 0600)
+	err := os.WriteFile(path, data, 0o600)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -1698,7 +1716,7 @@ func TestWithHTTPClient_SetsSuppliedClientOnPipe(t *testing.T) {
 		fmt.Fprintln(w, "some data")
 	}))
 	defer ts.Close()
-	req, err := http.NewRequest(http.MethodGet, ts.URL, nil)
+	req, err := http.NewRequest(http.MethodGet, ts.URL, http.NoBody)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -1842,9 +1860,10 @@ func ExampleDo() {
 		fmt.Fprintln(w, "some data")
 	}))
 	defer ts.Close()
-	req, err := http.NewRequest(http.MethodGet, ts.URL, nil)
+	req, err := http.NewRequest(http.MethodGet, ts.URL, http.NoBody)
 	if err != nil {
-		log.Fatal(err)
+		log.Println(err)
+		return
 	}
 	script.Do(req).Stdout()
 	// Output:
@@ -1961,7 +1980,8 @@ func ExamplePipe_Do() {
 	defer ts.Close()
 	req, err := http.NewRequest(http.MethodGet, ts.URL, strings.NewReader("hello"))
 	if err != nil {
-		log.Fatal(err)
+		log.Println(err)
+		return
 	}
 	script.NewPipe().Do(req).Stdout()
 	// Output: