dev: sync internal with x/tools (#6076)

Author: ldez

internal/x/tools/analysisflags/readme.md

@@ -5,4 +5,7 @@ This is just a copy of the code without any changes.
 
 ## History
 
-- sync with https://github.com/golang/tools/blob/v0.28.0
+- https://github.com/golangci/golangci-lint/pull/6076
+  - sync with https://github.com/golang/tools/blob/v0.37.0/go/analysis/internal/analysisflags
+- https://github.com/golangci/golangci-lint/pull/5576
+  - sync with https://github.com/golang/tools/blob/v0.28.0/go/analysis/internal/analysisflags

internal/x/tools/analysisinternal/analysis.go

@@ -8,25 +8,30 @@ package analysisinternal
 
 import (
 	"fmt"
-	"os"
+	"slices"
 
 	"golang.org/x/tools/go/analysis"
 )
 
-// MakeReadFile returns a simple implementation of the Pass.ReadFile function.
-func MakeReadFile(pass *analysis.Pass) func(filename string) ([]byte, error) {
+// A ReadFileFunc is a function that returns the
+// contents of a file, such as [os.ReadFile].
+type ReadFileFunc = func(filename string) ([]byte, error)
+
+// CheckedReadFile returns a wrapper around a Pass.ReadFile
+// function that performs the appropriate checks.
+func CheckedReadFile(pass *analysis.Pass, readFile ReadFileFunc) ReadFileFunc {
 	return func(filename string) ([]byte, error) {
 		if err := CheckReadable(pass, filename); err != nil {
 			return nil, err
 		}
-		return os.ReadFile(filename)
+		return readFile(filename)
 	}
 }
 
 // CheckReadable enforces the access policy defined by the ReadFile field of [analysis.Pass].
 func CheckReadable(pass *analysis.Pass, filename string) error {
-	if slicesContains(pass.OtherFiles, filename) ||
-		slicesContains(pass.IgnoredFiles, filename) {
+	if slices.Contains(pass.OtherFiles, filename) ||
+		slices.Contains(pass.IgnoredFiles, filename) {
 		return nil
 	}
 	for _, f := range pass.Files {
@@ -36,13 +41,3 @@ func CheckReadable(pass *analysis.Pass, filename string) error {
 	}
 	return fmt.Errorf("Pass.ReadFile: %s is not among OtherFiles, IgnoredFiles, or names of Files", filename)
 }
-
-// TODO(adonovan): use go1.21 slices.Contains.
-func slicesContains[S ~[]E, E comparable](slice S, x E) bool {
-	for _, elem := range slice {
-		if elem == x {
-			return true
-		}
-	}
-	return false
-}

internal/x/tools/analysisinternal/readme.md

@@ -5,4 +5,7 @@ This is just a copy of the code without any changes.
 
 ## History
 
-- sync with https://github.com/golang/tools/blob/v0.28.0
+- https://github.com/golangci/golangci-lint/pull/6076
+  - sync with https://github.com/golang/tools/blob/v0.37.0/internal/analysisinternal/
+- https://github.com/golangci/golangci-lint/pull/5576
+  - sync with https://github.com/golang/tools/blob/v0.28.0/internal/analysisinternal/

internal/x/tools/diff/diff.go

@@ -7,6 +7,7 @@ package diff
 
 import (
 	"fmt"
+	"slices"
 	"sort"
 	"strings"
 )
@@ -64,7 +65,7 @@ func ApplyBytes(src []byte, edits []Edit) ([]byte, error) {
 // It may return a different slice.
 func validate(src string, edits []Edit) ([]Edit, int, error) {
 	if !sort.IsSorted(editsSort(edits)) {
-		edits = append([]Edit(nil), edits...)
+		edits = slices.Clone(edits)
 		SortEdits(edits)
 	}
 

internal/x/tools/diff/lcs/common.go

@@ -51,7 +51,7 @@ func (l lcs) fix() lcs {
 	// from the set of diagonals in l, find a maximal non-conflicting set
 	// this problem may be NP-complete, but we use a greedy heuristic,
 	// which is quadratic, but with a better data structure, could be D log D.
-	// indepedent is not enough: {0,3,1} and {3,0,2} can't both occur in an lcs
+	// independent is not enough: {0,3,1} and {3,0,2} can't both occur in an lcs
 	// which has to have monotone x and y
 	if len(l) == 0 {
 		return nil

internal/x/tools/diff/lcs/common_test.go

@@ -6,7 +6,8 @@ package lcs
 
 import (
 	"log"
-	"math/rand"
+	"math/rand/v2"
+	"slices"
 	"strings"
 	"testing"
 )
@@ -72,10 +73,8 @@ func check(t *testing.T, str string, lcs lcs, want []string) {
 		got.WriteString(str[dd.X : dd.X+dd.Len])
 	}
 	ans := got.String()
-	for _, w := range want {
-		if ans == w {
-			return
-		}
+	if slices.Contains(want, ans) {
+		return
 	}
 	t.Fatalf("str=%q lcs=%v want=%q got=%q", str, lcs, want, ans)
 }
@@ -106,11 +105,11 @@ func lcslen(l lcs) int {
 }
 
 // return a random string of length n made of characters from s
-func randstr(s string, n int) string {
+func randstr(rng *rand.Rand, s string, n int) string {
 	src := []rune(s)
 	x := make([]rune, n)
-	for i := 0; i < n; i++ {
-		x[i] = src[rand.Intn(len(src))]
+	for i := range n {
+		x[i] = src[rng.Int64N(int64(len(src)))]
 	}
 	return string(x)
 }

internal/x/tools/diff/lcs/doc.go

@@ -139,7 +139,7 @@ computed labels. That is the worst case. Had the code noticed (x,y)=(u,v)=(3,3)
 from the edgegraph. The implementation looks for a number of special cases to try to avoid computing an extra forward path.
 
 If the two-sided algorithm has stop early (because D has become too large) it will have found a forward LCS and a
-backwards LCS. Ideally these go with disjoint prefixes and suffixes of A and B, but disjointness may fail and the two
+backwards LCS. Ideally these go with disjoint prefixes and suffixes of A and B, but disjointedness may fail and the two
 computed LCS may conflict. (An easy example is where A is a suffix of B, and shares a short prefix. The backwards LCS
 is all of A, and the forward LCS is a prefix of A.) The algorithm combines the two
 to form a best-effort LCS. In the worst case the forward partial LCS may have to

internal/x/tools/diff/lcs/old.go

@@ -105,7 +105,7 @@ func forward(e *editGraph) lcs {
 		return ans
 	}
 	// from D to D+1
-	for D := 0; D < e.limit; D++ {
+	for D := range e.limit {
 		e.setForward(D+1, -(D + 1), e.getForward(D, -D))
 		if ok, ans := e.fdone(D+1, -(D + 1)); ok {
 			return ans
@@ -199,13 +199,14 @@ func (e *editGraph) bdone(D, k int) (bool, lcs) {
 }
 
 // run the backward algorithm, until success or up to the limit on D.
+// (used only by tests)
 func backward(e *editGraph) lcs {
 	e.setBackward(0, 0, e.ux)
 	if ok, ans := e.bdone(0, 0); ok {
 		return ans
 	}
 	// from D to D+1
-	for D := 0; D < e.limit; D++ {
+	for D := range e.limit {
 		e.setBackward(D+1, -(D + 1), e.getBackward(D, -D)-1)
 		if ok, ans := e.bdone(D+1, -(D + 1)); ok {
 			return ans
@@ -299,7 +300,7 @@ func twosided(e *editGraph) lcs {
 	e.setBackward(0, 0, e.ux)
 
 	// from D to D+1
-	for D := 0; D < e.limit; D++ {
+	for D := range e.limit {
 		// just finished a backwards pass, so check
 		if got, ok := e.twoDone(D, D); ok {
 			return e.twolcs(D, D, got)
@@ -376,10 +377,7 @@ func (e *editGraph) twoDone(df, db int) (int, bool) {
 	if (df+db+e.delta)%2 != 0 {
 		return 0, false // diagonals cannot overlap
 	}
-	kmin := -db + e.delta
-	if -df > kmin {
-		kmin = -df
-	}
+	kmin := max(-df, -db+e.delta)
 	kmax := db + e.delta
 	if df < kmax {
 		kmax = df

internal/x/tools/diff/lcs/old_test.go

@@ -7,7 +7,7 @@ package lcs
 import (
 	"fmt"
 	"log"
-	"math/rand"
+	"math/rand/v2"
 	"os"
 	"strings"
 	"testing"
@@ -106,15 +106,16 @@ func TestRegressionOld003(t *testing.T) {
 }
 
 func TestRandOld(t *testing.T) {
-	rand.Seed(1)
-	for i := 0; i < 1000; i++ {
+	rng := rng(t)
+
+	for i := range 1000 {
 		// TODO(adonovan): use ASCII and bytesSeqs here? The use of
 		// non-ASCII isn't relevant to the property exercised by the test.
-		a := []rune(randstr("abω", 16))
-		b := []rune(randstr("abωc", 16))
+		a := []rune(randstr(rng, "abω", 16))
+		b := []rune(randstr(rng, "abωc", 16))
 		seq := runesSeqs{a, b}
 
-		const lim = 24 // large enough to get true lcs
+		const lim = 0 // make sure we get the lcs (24 was too small)
 		_, forw := compute(seq, forward, lim)
 		_, back := compute(seq, backward, lim)
 		_, two := compute(seq, twosided, lim)
@@ -158,7 +159,7 @@ func TestDiffAPI(t *testing.T) {
 }
 
 func BenchmarkTwoOld(b *testing.B) {
-	tests := genBench("abc", 96)
+	tests := genBench(rng(b), "abc", 96)
 	for i := 0; i < b.N; i++ {
 		for _, tt := range tests {
 			_, two := compute(stringSeqs{tt.before, tt.after}, twosided, 100)
@@ -170,7 +171,7 @@ func BenchmarkTwoOld(b *testing.B) {
 }
 
 func BenchmarkForwOld(b *testing.B) {
-	tests := genBench("abc", 96)
+	tests := genBench(rng(b), "abc", 96)
 	for i := 0; i < b.N; i++ {
 		for _, tt := range tests {
 			_, two := compute(stringSeqs{tt.before, tt.after}, forward, 100)
@@ -181,14 +182,21 @@ func BenchmarkForwOld(b *testing.B) {
 	}
 }
 
-func genBench(set string, n int) []struct{ before, after string } {
+// rng returns a randomly initialized PRNG whose seeds are logged so
+// that occasional test failures can be deterministically replayed.
+func rng(tb testing.TB) *rand.Rand {
+	seed1, seed2 := rand.Uint64(), rand.Uint64()
+	tb.Logf("PRNG seeds: %d, %d", seed1, seed2)
+	return rand.New(rand.NewPCG(seed1, seed2))
+}
+
+func genBench(rng *rand.Rand, set string, n int) []struct{ before, after string } {
 	// before and after for benchmarks. 24 strings of length n with
 	// before and after differing at least once, and about 5%
-	rand.Seed(3)
 	var ans []struct{ before, after string }
-	for i := 0; i < 24; i++ {
+	for range 24 {
 		// maybe b should have an approximately known number of diffs
-		a := randstr(set, n)
+		a := randstr(rng, set, n)
 		cnt := 0
 		bb := make([]rune, 0, n)
 		for _, r := range a {

internal/x/tools/diff/ndiff.go

@@ -72,7 +72,7 @@ func diffRunes(before, after []rune) []Edit {
 func runes(bytes []byte) []rune {
 	n := utf8.RuneCount(bytes)
 	runes := make([]rune, n)
-	for i := 0; i < n; i++ {
+	for i := range n {
 		r, sz := utf8.DecodeRune(bytes)
 		bytes = bytes[sz:]
 		runes[i] = r