[release-branch.go1.19] cmd/go: avoid registering AtExit handlers in tests

Ever since 'go build' was added (in CL 5483069), it has used an atexit
handler to clean up working directories.

CL 154109 introduced 'cc' command to the script test framework that
called Init on a builder once per invocation. Unfortunately, since
base.AtExit is unsynchronized, the Init added there caused any script
that invokes that command to be unsafe for concurrent use.

This change fixes the race by having the 'cc' command pass in its
working directory instead of allowing the Builder to allocate one.
Following modern Go best practices, it also replaces the in-place Init
method (which is prone to typestate and aliasing bugs) with a
NewBuilder constructor function.

Updates #54423.
Fixes #54637.

Change-Id: I8fc2127a7d877bb39a1174e398736bb51d03d4d2
Reviewed-on: https://go-review.googlesource.com/c/go/+/425205
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Bryan Mills <bcmills@google.com>
Auto-Submit: Bryan Mills <bcmills@google.com>
Reviewed-by: Than McIntosh <thanm@google.com>
(cherry picked from commit d5aa088d822bc8ef3ceb80c20184f40fcb9b8d2e)
Reviewed-on: https://go-review.googlesource.com/c/go/+/425207

diff --git a/src/cmd/go/internal/envcmd/env.go b/src/cmd/go/internal/envcmd/env.go
index 529351dfbd8a78f93502d8d2a741ddbac013258c..81ee859e66f3e5595e99ac184ee1e52db1569546 100644 (file)
--- a/src/cmd/go/internal/envcmd/env.go
+++ b/src/cmd/go/internal/envcmd/env.go
@@ -174,8 +174,8 @@ func ExtraEnvVars() []cfg.EnvVar {
 // ExtraEnvVarsCostly returns environment variables that should not leak into child processes
 // but are costly to evaluate.
 func ExtraEnvVarsCostly() []cfg.EnvVar {
-       var b work.Builder
-       b.Init()
+       b := work.NewBuilder("")
+
        cppflags, cflags, cxxflags, fflags, ldflags, err := b.CFlags(&load.Package{})
        if err != nil {
                // Should not happen - b.CFlags was given an empty package.

diff --git a/src/cmd/go/internal/list/list.go b/src/cmd/go/internal/list/list.go
index 5f8be6e3c9d9ee3ca310890d5d75e1c5544b211d..0be3d987075290b0d9e57656b42b73253d843386 100644 (file)
--- a/src/cmd/go/internal/list/list.go
+++ b/src/cmd/go/internal/list/list.go
@@ -689,8 +689,7 @@ func runList(ctx context.Context, cmd *base.Command, args []string) {
        // Do we need to run a build to gather information?
        needStale := (listJson && listJsonFields.needAny("Stale", "StaleReason")) || strings.Contains(*listFmt, ".Stale")
        if needStale || *listExport || *listCompiled {
-               var b work.Builder
-               b.Init()
+               b := work.NewBuilder("")
                b.IsCmdList = true
                b.NeedExport = *listExport
                b.NeedCompiledGoFiles = *listCompiled

diff --git a/src/cmd/go/internal/run/run.go b/src/cmd/go/internal/run/run.go
index ebe161181901bb954a7a932e672601ece3d6a89a..6b253a2c9e52e5caff3bfbb197371ff97cf8d695 100644 (file)
--- a/src/cmd/go/internal/run/run.go
+++ b/src/cmd/go/internal/run/run.go
@@ -91,8 +91,7 @@ func runRun(ctx context.Context, cmd *base.Command, args []string) {
        }
 
        work.BuildInit()
-       var b work.Builder
-       b.Init()
+       b := work.NewBuilder("")
        b.Print = printStderr
 
        i := 0

diff --git a/src/cmd/go/internal/test/test.go b/src/cmd/go/internal/test/test.go
index aa5e41e0043801312b1e8bdb42622482772c77fc..028db84cc462bc7a72683c741c7cde0407a1e4cd 100644 (file)
--- a/src/cmd/go/internal/test/test.go
+++ b/src/cmd/go/internal/test/test.go
@@ -744,8 +744,7 @@ func runTest(ctx context.Context, cmd *base.Command, args []string) {
                }
        }
 
-       var b work.Builder
-       b.Init()
+       b := work.NewBuilder("")
 
        if cfg.BuildI {
                fmt.Fprint(os.Stderr, "go: -i flag is deprecated\n")
@@ -800,7 +799,16 @@ func runTest(ctx context.Context, cmd *base.Command, args []string) {
                if !testC || a.Failed {
                        return
                }
-               b.Init()
+
+               // TODO(bcmills): I have no idea why the Builder must be reset here, but
+               // without this reset dance, TestGoTestDashIDashOWritesBinary fails with
+               // lots of "vet config not found" errors. This was added in CL 5699088,
+               // which had almost no public discussion, a very short commit description,
+               // and left no comment in the code to explain what is going on here. 🤯
+               //
+               // Maybe this has the effect of removing actions that were registered by the
+               // call to CompileAction above?
+               b = work.NewBuilder("")
        }
 
        var builds, runs, prints []*work.Action
@@ -916,7 +924,7 @@ func runTest(ctx context.Context, cmd *base.Command, args []string) {
                        ensureImport(p, "sync/atomic")
                }
 
-               buildTest, runTest, printTest, err := builderTest(&b, ctx, pkgOpts, p, allImports[p])
+               buildTest, runTest, printTest, err := builderTest(b, ctx, pkgOpts, p, allImports[p])
                if err != nil {
                        str := err.Error()
                        str = strings.TrimPrefix(str, "\n")

diff --git a/src/cmd/go/internal/vet/vet.go b/src/cmd/go/internal/vet/vet.go
index a0b11fdd3dc5f19990215ad71aebdb7533d383be..085c7d23b246998adf1264985aed0ac0a5b8b4dd 100644 (file)
--- a/src/cmd/go/internal/vet/vet.go
+++ b/src/cmd/go/internal/vet/vet.go
@@ -94,8 +94,7 @@ func runVet(ctx context.Context, cmd *base.Command, args []string) {
                base.Fatalf("no packages to vet")
        }
 
-       var b work.Builder
-       b.Init()
+       b := work.NewBuilder("")
 
        root := &work.Action{Mode: "go vet"}
        for _, p := range pkgs {

diff --git a/src/cmd/go/internal/work/action.go b/src/cmd/go/internal/work/action.go
index c0862c5efe503af8cf6384aebd1468b9d89e024f..4bbd23ab8e43212b10a1303cfec594a16afff59e 100644 (file)
--- a/src/cmd/go/internal/work/action.go
+++ b/src/cmd/go/internal/work/action.go
@@ -240,7 +240,13 @@ const (
        ModeVetOnly = 1 << 8
 )
 
-func (b *Builder) Init() {
+// NewBuilder returns a new Builder ready for use.
+//
+// If workDir is the empty string, NewBuilder creates a WorkDir if needed
+// and arranges for it to be removed in case of an unclean exit.
+func NewBuilder(workDir string) *Builder {
+       b := new(Builder)
+
        b.Print = func(a ...any) (int, error) {
                return fmt.Fprint(os.Stderr, a...)
        }
@@ -249,7 +255,9 @@ func (b *Builder) Init() {
        b.toolIDCache = make(map[string]string)
        b.buildIDCache = make(map[string]string)
 
-       if cfg.BuildN {
+       if workDir != "" {
+               b.WorkDir = workDir
+       } else if cfg.BuildN {
                b.WorkDir = "$WORK"
        } else {
                tmp, err := os.MkdirTemp(cfg.Getenv("GOTMPDIR"), "go-build")
@@ -306,6 +314,8 @@ func (b *Builder) Init() {
                        base.Exit()
                }
        }
+
+       return b
 }
 
 func CheckGOOSARCHPair(goos, goarch string) error {

diff --git a/src/cmd/go/internal/work/build.go b/src/cmd/go/internal/work/build.go
index 42745d992814c918c8b7a8a023d932b88d0f2d98..5f11cdabaf1bc91d51a639e03c1f04e251f3a37f 100644 (file)
--- a/src/cmd/go/internal/work/build.go
+++ b/src/cmd/go/internal/work/build.go
@@ -403,8 +403,7 @@ var RuntimeVersion = runtime.Version()
 func runBuild(ctx context.Context, cmd *base.Command, args []string) {
        modload.InitWorkfile()
        BuildInit()
-       var b Builder
-       b.Init()
+       b := NewBuilder("")
 
        pkgs := load.PackagesAndErrors(ctx, load.PackageOpts{LoadVCS: true}, args)
        load.CheckPackageErrors(pkgs)
@@ -728,8 +727,8 @@ func InstallPackages(ctx context.Context, patterns []string, pkgs []*load.Packag
        }
        base.ExitIfErrors()
 
-       var b Builder
-       b.Init()
+       b := NewBuilder("")
+
        depMode := ModeBuild
        if cfg.BuildI {
                depMode = ModeInstall

diff --git a/src/cmd/go/script_test.go b/src/cmd/go/script_test.go
index 809dfb452f36683ae7b700bb9da045a83141588c..ffdfe12bafc79564d4c1f8d904b3bf378972f1d4 100644 (file)
--- a/src/cmd/go/script_test.go
+++ b/src/cmd/go/script_test.go
@@ -556,10 +556,8 @@ func (ts *testScript) cmdCc(want simpleStatus, args []string) {
                ts.fatalf("usage: cc args... [&]")
        }
 
-       var b work.Builder
-       b.Init()
+       b := work.NewBuilder(ts.workdir)
        ts.cmdExec(want, append(b.GccCmd(".", ""), args...))
-       robustio.RemoveAll(b.WorkDir)
 }
 
 // cd changes to a different directory.