go122-task-across-generations.go

Documentation: internal/trace/v2/testdata/generators

     1  // Copyright 2023 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  // Regression test for an issue found in development.
     6  //
     7  // The issue is that EvUserTaskEnd events don't carry the
     8  // task type with them, so the parser needs to track that
     9  // information. But if the parser just tracks the string ID
    10  // and not the string itself, that string ID may not be valid
    11  // for use in future generations.
    12  
    13  package main
    14  
    15  import (
    16  	"internal/trace/v2"
    17  	"internal/trace/v2/event/go122"
    18  	testgen "internal/trace/v2/internal/testgen/go122"
    19  )
    20  
    21  func main() {
    22  	testgen.Main(gen)
    23  }
    24  
    25  func gen(t *testgen.Trace) {
    26  	g1 := t.Generation(1)
    27  
    28  	// A running goroutine emits a task begin.
    29  	b1 := g1.Batch(trace.ThreadID(0), 0)
    30  	b1.Event("ProcStatus", trace.ProcID(0), go122.ProcRunning)
    31  	b1.Event("GoStatus", trace.GoID(1), trace.ThreadID(0), go122.GoRunning)
    32  	b1.Event("UserTaskBegin", trace.TaskID(2), trace.TaskID(0) /* 0 means no parent, not background */, "my task", testgen.NoStack)
    33  
    34  	g2 := t.Generation(2)
    35  
    36  	// That same goroutine emits a task end in the following generation.
    37  	b2 := g2.Batch(trace.ThreadID(0), 5)
    38  	b2.Event("ProcStatus", trace.ProcID(0), go122.ProcRunning)
    39  	b2.Event("GoStatus", trace.GoID(1), trace.ThreadID(0), go122.GoRunning)
    40  	b2.Event("UserTaskEnd", trace.TaskID(2), testgen.NoStack)
    41  }
    42
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