read_test.go

     1  // Copyright 2022 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package cov_test
     6  
     7  import (
     8  	"cmd/internal/cov"
     9  	"fmt"
    10  	"internal/coverage"
    11  	"internal/coverage/decodecounter"
    12  	"internal/coverage/decodemeta"
    13  	"internal/coverage/pods"
    14  	"internal/testenv"
    15  	"os"
    16  	"path/filepath"
    17  	"testing"
    18  )
    19  
    20  // visitor implements the CovDataVisitor interface in a very stripped
    21  // down way, just keeps track of interesting events.
    22  type visitor struct {
    23  	metaFileCount    int
    24  	counterFileCount int
    25  	funcCounterData  int
    26  	metaFuncCount    int
    27  }
    28  
    29  func (v *visitor) BeginPod(p pods.Pod) {}
    30  func (v *visitor) EndPod(p pods.Pod)   {}
    31  func (v *visitor) VisitMetaDataFile(mdf string, mfr *decodemeta.CoverageMetaFileReader) {
    32  	v.metaFileCount++
    33  }
    34  func (v *visitor) BeginCounterDataFile(cdf string, cdr *decodecounter.CounterDataReader, dirIdx int) {
    35  	v.counterFileCount++
    36  }
    37  func (v *visitor) EndCounterDataFile(cdf string, cdr *decodecounter.CounterDataReader, dirIdx int) {}
    38  func (v *visitor) VisitFuncCounterData(payload decodecounter.FuncPayload)                          { v.funcCounterData++ }
    39  func (v *visitor) EndCounters()                                                                    {}
    40  func (v *visitor) BeginPackage(pd *decodemeta.CoverageMetaDataDecoder, pkgIdx uint32)              {}
    41  func (v *visitor) EndPackage(pd *decodemeta.CoverageMetaDataDecoder, pkgIdx uint32)                {}
    42  func (v *visitor) VisitFunc(pkgIdx uint32, fnIdx uint32, fd *coverage.FuncDesc)                    { v.metaFuncCount++ }
    43  func (v *visitor) Finish()                                                                         {}
    44  
    45  func TestIssue58411(t *testing.T) {
    46  	testenv.MustHaveGoBuild(t)
    47  
    48  	// Build a tiny test program with -cover. Smallness is important;
    49  	// it is one of the factors that triggers issue 58411.
    50  	d := t.TempDir()
    51  	exepath := filepath.Join(d, "small.exe")
    52  	path := filepath.Join("testdata", "small.go")
    53  	cmd := testenv.Command(t, testenv.GoToolPath(t), "build",
    54  		"-o", exepath, "-cover", path)
    55  	b, err := cmd.CombinedOutput()
    56  	if len(b) != 0 {
    57  		t.Logf("## build output:\n%s", b)
    58  	}
    59  	if err != nil {
    60  		t.Fatalf("build error: %v", err)
    61  	}
    62  
    63  	// Run to produce coverage data. Note the large argument; we need a large
    64  	// argument (more than 4k) to trigger the bug, but the overall file
    65  	// has to remain small (since large files will be read with mmap).
    66  	covdir := filepath.Join(d, "covdata")
    67  	if err = os.Mkdir(covdir, 0777); err != nil {
    68  		t.Fatalf("creating covdir: %v", err)
    69  	}
    70  	large := fmt.Sprintf("%07999d", 0)
    71  	cmd = testenv.Command(t, exepath, "1", "2", "3", large)
    72  	cmd.Dir = covdir
    73  	cmd.Env = append(os.Environ(), "GOCOVERDIR="+covdir)
    74  	b, err = cmd.CombinedOutput()
    75  	if err != nil {
    76  		t.Logf("## run output:\n%s", b)
    77  		t.Fatalf("build error: %v", err)
    78  	}
    79  
    80  	vis := &visitor{}
    81  
    82  	// Read resulting coverage data. Without the fix, this would
    83  	// yield a "short read" error.
    84  	const verbosityLevel = 0
    85  	const flags = 0
    86  	cdr := cov.MakeCovDataReader(vis, []string{covdir}, verbosityLevel, flags, nil)
    87  	err = cdr.Visit()
    88  	if err != nil {
    89  		t.Fatalf("visit failed: %v", err)
    90  	}
    91  
    92  	// make sure we saw a few things just for grins
    93  	const want = "{metaFileCount:1 counterFileCount:1 funcCounterData:1 metaFuncCount:1}"
    94  	got := fmt.Sprintf("%+v", *vis)
    95  	if want != got {
    96  		t.Errorf("visitor contents: want %v got %v\n", want, got)
    97  	}
    98  }
    99
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