table.go

     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  // Package godebugs provides a table of known GODEBUG settings,
     6  // for use by a variety of other packages, including internal/godebug,
     7  // runtime, runtime/metrics, and cmd/go/internal/load.
     8  package godebugs
     9  
    10  // An Info describes a single known GODEBUG setting.
    11  type Info struct {
    12  	Name      string // name of the setting ("panicnil")
    13  	Package   string // package that uses the setting ("runtime")
    14  	Changed   int    // minor version when default changed, if any; 21 means Go 1.21
    15  	Old       string // value that restores behavior prior to Changed
    16  	Opaque    bool   // setting does not export information to runtime/metrics using [internal/godebug.Setting.IncNonDefault]
    17  	Immutable bool   // setting cannot be changed after program start
    18  }
    19  
    20  // All is the table of known settings, sorted by Name.
    21  //
    22  // Note: After adding entries to this table, run 'go generate runtime/metrics'
    23  // to update the runtime/metrics doc comment.
    24  // (Otherwise the runtime/metrics test will fail.)
    25  //
    26  // Note: After adding entries to this table, update the list in doc/godebug.md as well.
    27  // (Otherwise the test in this package will fail.)
    28  var All = []Info{
    29  	{Name: "allowmultiplevcs", Package: "cmd/go"},
    30  	{Name: "containermaxprocs", Package: "runtime", Changed: 25, Old: "0"},
    31  	{Name: "cryptocustomrand", Package: "crypto", Changed: 26, Old: "1"},
    32  	{Name: "dataindependenttiming", Package: "crypto/subtle", Opaque: true},
    33  	{Name: "decoratemappings", Package: "runtime", Opaque: true, Changed: 25, Old: "0"},
    34  	{Name: "embedfollowsymlinks", Package: "cmd/go"},
    35  	{Name: "execerrdot", Package: "os/exec"},
    36  	{Name: "fips140", Package: "crypto/fips140", Opaque: true, Immutable: true},
    37  	{Name: "fips140ems", Package: "crypto/tls"},
    38  	{Name: "gocachehash", Package: "cmd/go"},
    39  	{Name: "gocachetest", Package: "cmd/go"},
    40  	{Name: "gocacheverify", Package: "cmd/go"},
    41  	{Name: "gotestjsonbuildtext", Package: "cmd/go", Changed: 24, Old: "1"},
    42  	{Name: "htmlmetacontenturlescape", Package: "html/template"},
    43  	{Name: "http2client", Package: "net/http"},
    44  	{Name: "http2debug", Package: "net/http", Opaque: true},
    45  	{Name: "http2server", Package: "net/http"},
    46  	{Name: "httpcookiemaxnum", Package: "net/http", Changed: 24, Old: "0"},
    47  	{Name: "httplaxcontentlength", Package: "net/http", Changed: 22, Old: "1"},
    48  	{Name: "httpmuxgo121", Package: "net/http", Changed: 22, Old: "1"},
    49  	{Name: "httpservecontentkeepheaders", Package: "net/http", Changed: 23, Old: "1"},
    50  	{Name: "installgoroot", Package: "go/build"},
    51  	{Name: "jstmpllitinterp", Package: "html/template", Opaque: true}, // bug #66217: remove Opaque
    52  	//{Name: "multipartfiles", Package: "mime/multipart"},
    53  	{Name: "multipartmaxheaders", Package: "mime/multipart"},
    54  	{Name: "multipartmaxparts", Package: "mime/multipart"},
    55  	{Name: "multipathtcp", Package: "net", Changed: 24, Old: "0"},
    56  	{Name: "netdns", Package: "net", Opaque: true},
    57  	{Name: "netedns0", Package: "net", Changed: 19, Old: "0"},
    58  	{Name: "netmarshal", Package: "net", Changed: 30, Old: "0"},
    59  	{Name: "panicnil", Package: "runtime", Changed: 21, Old: "1"},
    60  	{Name: "randautoseed", Package: "math/rand"},
    61  	{Name: "randseednop", Package: "math/rand", Changed: 24, Old: "0"},
    62  	{Name: "rsa1024min", Package: "crypto/rsa", Changed: 24, Old: "0"},
    63  	{Name: "tarinsecurepath", Package: "archive/tar"},
    64  	{Name: "tlsmaxrsasize", Package: "crypto/tls"},
    65  	{Name: "tlsmlkem", Package: "crypto/tls", Changed: 24, Old: "0", Opaque: true},
    66  	{Name: "tlssecpmlkem", Package: "crypto/tls", Changed: 26, Old: "0", Opaque: true},
    67  	{Name: "tlssha1", Package: "crypto/tls", Changed: 25, Old: "1"},
    68  	// Mark tracebacklabels as Opaque so we don't generate a metric that we can't increment.
    69  	// IncNonDefault uses a sync.Once, which involves sync.Mutex, and is not safe from a signal handler.
    70  	// (Tracebacks are generated in signal-handlers.)
    71  	{Name: "tracebacklabels", Package: "runtime", Changed: 27, Old: "0", Opaque: true},
    72  	{Name: "updatemaxprocs", Package: "runtime", Changed: 25, Old: "0"},
    73  	{Name: "urlmaxqueryparams", Package: "net/url", Changed: 24, Old: "0"},
    74  	{Name: "urlstrictcolons", Package: "net/url", Changed: 26, Old: "0"},
    75  	{Name: "winreadlinkvolume", Package: "os", Changed: 23, Old: "0"},
    76  	{Name: "winsymlink", Package: "os", Changed: 23, Old: "0"},
    77  	{Name: "x509negativeserial", Package: "crypto/x509", Changed: 23, Old: "1"},
    78  	{Name: "x509rsacrt", Package: "crypto/x509", Changed: 24, Old: "0"},
    79  	{Name: "x509sha256skid", Package: "crypto/x509", Changed: 25, Old: "0"},
    80  	{Name: "x509sslcertoverrideplatform", Package: "crypto/x509", Changed: 27, Old: "0"},
    81  	{Name: "x509usefallbackroots", Package: "crypto/x509"},
    82  	{Name: "x509usepolicies", Package: "crypto/x509", Changed: 24, Old: "0"},
    83  	{Name: "zipinsecurepath", Package: "archive/zip"},
    84  }
    85  
    86  // A RemovedInfo describes a GODEBUG setting that has been removed.
    87  //
    88  // Per the policy for removing GODEBUG settings (go.dev/issue/76163), using any non-"old"
    89  // value for the removed setting is permissible. Using an old value, indicating a non-final
    90  // default value for that setting, leads to a build or vet error.
    91  // To support multiple "old" values (see asynctimerchan), the Old field is a predicate.
    92  type RemovedInfo struct {
    93  	Name    string            // name of the removed GODEBUG setting.
    94  	Removed int               // minor version of Go, when the removal happened
    95  	Old     func(string) bool // reports whether the GODEBUG value (argument) is an old (invalid) value
    96  }
    97  
    98  // Removed contains all GODEBUGs that we have removed.
    99  //
   100  // Every removed GODEBUG must have a corresponding section in doc/godebug.md,
   101  // since cmd/go links to that document when a removed GODEBUG is used.
   102  var Removed = []RemovedInfo{
   103  	{Name: "x509sha1", Removed: 24, Old: one},                                                       // Old: "1"
   104  	{Name: "tlskyber", Removed: 24, Old: zero},                                                      // Old: "0"
   105  	{Name: "gotypesalias", Removed: 27, Old: zero},                                                  // Old: "0"
   106  	{Name: "tlsunsafeekm", Removed: 27, Old: one},                                                   // Old: "1"
   107  	{Name: "tlsrsakex", Removed: 27, Old: one},                                                      // Old: "1"
   108  	{Name: "tls3des", Removed: 27, Old: one},                                                        // Old: "1"
   109  	{Name: "tls10server", Removed: 27, Old: one},                                                    // Old: "1"
   110  	{Name: "x509keypairleaf", Removed: 27, Old: zero},                                               // Old: "0"
   111  	{Name: "asynctimerchan", Removed: 27, Old: func(s string) bool { return s == "1" || s == "2" }}, // Old: "1" or "2"
   112  }
   113  
   114  func zero(s string) bool { return s == "0" }
   115  func one(s string) bool  { return s == "1" }
   116  
   117  // Lookup returns the Info with the given name.
   118  func Lookup(name string) *Info {
   119  	// binary search, avoiding import of sort.
   120  	lo := 0
   121  	hi := len(All)
   122  	for lo < hi {
   123  		m := int(uint(lo+hi) >> 1)
   124  		mid := All[m].Name
   125  		if name == mid {
   126  			return &All[m]
   127  		}
   128  		if name < mid {
   129  			hi = m
   130  		} else {
   131  			lo = m + 1
   132  		}
   133  	}
   134  	return nil
   135  }
   136
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