diff --git a/doc/go1.19.html b/doc/go1.19.html index d73f635344..4276e9ffea 100644 --- a/doc/go1.19.html +++ b/doc/go1.19.html @@ -20,12 +20,26 @@ Do not send CLs removing the interior tags from such phrases.
- TODO: complete this section -
- TODO: https://go.dev/issue/52038: adjust scope of type parameters declared by method receivers + There is only one small change to the language, + a very small correction + to the scope of type parameters in method declarations. + Existing programs are unaffected. +
+ +
+ The Go memory model has been revised to align Go with
+ the memory model used by C, C++, Java, JavaScript, Rust, and Swift.
+ Go only provides sequentially consistent atomics, not any of the more relaxed forms found in other languages.
+ Along with the memory model update,
+ Go 1.19 introduces new types in the sync/atomic
package
+ that make it easier to use atomic values, such as
+ atomic.Int64
+ and
+ atomic.Pointer[T].
- TODO: complete this section, or delete if not needed -
-: - TODO: https://go.dev/issue/47528 warn when errors.As target has type *error -
- TODO: complete this section. + +
+Go 1.19 adds support for links, lists, and clearer headings in doc comments.
+As part of this change, gofmt
+now reformats doc comments to make their rendered meaning clearer.
+See “Go Doc Comments”
+for syntax details and descriptions of common mistakes now highlighted by gofmt
.
+As another part of this change, the new package go/doc/comment
+provides parsing and reformatting of doc comments
+as well as support for rendering them to HTML, Markdown, and text.
+
unix
build constraint
+
+
+ The build constraint unix
is now recognized
+ in //go:build
lines. The constraint is satisfied
+ if the target operating system, also known as GOOS
, is
+ a Unix or Unix-like system. For the 1.19 release it is satisfied
+ if GOOS
is one of
+ aix
, android
, darwin
,
+ dragonfly
, freebsd
, hurd
,
+ illumos
, ios
, linux
,
+ netbsd
, openbsd
, or solaris
.
+ In future releases the unix
constraint may match
+ additional newly supported operating systems.
GOGCCFLAGS
variables it reports.
+unix
build constraint
- The build constraint unix
is now recognized
- in //go:build
lines. The constraint is satisfied
- if the target operating system, also known as GOOS
, is
- a Unix or Unix-like system. For the 1.19 release it is satisfied
- if GOOS
is one of
- aix
, android
, darwin
,
- dragonfly
, freebsd
, hurd
,
- illumos
, ios
, linux
,
- netbsd
, openbsd
, or solaris
.
- In future releases the unix
constraint may match
- additional newly supported operating systems.
+
:
+ The vet
checker “errorsas” now reports when
+ errors.As
is called
+ with a second argument of type *error
,
+ a common mistake.
+
On Unix operating systems, Go programs that import package
os now automatically increase the open file limit
- (RLIMIT_NOFILE
) to the maximum allowed value. Programs that need
- a lower limit (for compatibility with select
, for example) can
- set the limit back as needed, or lower the hard limit prior to starting the
- Go program.
+ (RLIMIT_NOFILE
) to the maximum allowed value;
+ that is, they change the soft limit to match the hard limit.
+ This corrects artificially low limits set on some systems for compatibility with very old C programs using the
+ select system call.
+ Go programs are not helped by that limit, and instead even simple programs like gofmt
+ often ran out of file descriptors on such systems when processing many files in parallel.
+ One impact of this change is that Go programs that in turn execute very old C programs in child processes
+ may run those programs with too high a limit.
+ This can be corrected by setting the hard limit before invoking the Go program.
@@ -174,7 +203,8 @@ Do not send CLs removing the interior tags from such phrases.
- TODO: https://go.dev/issue/44853: enable address sanitizer in Go + The address sanitizer support added in Go 1.18 + now handles function arguments and global variables more precisely.
- TODO: complete this section -
-
The sync/atomic
package defines new atomic types
Bool
,
@@ -238,46 +265,46 @@ Do not send CLs removing the interior tags from such phrases.
the need to convert to
unsafe.Pointer
at call sites.
Int64
and
- Uint64
automatically
- receive 64-bit alignment on ARM, 386, and 32-bit MIPS required for 64-bit
- atomics on these systems.
-
- TODO: https://go.dev/cl/384265: go/doc: use go/doc/comment; modified api/next/51082.txt
- TODO: https://go.dev/cl/397276: go/doc/comment: add data structures; modified api/next/51082.txt
- TODO: https://go.dev/cl/397278: go/doc/comment: add paragraph parsing and test framework; modified api/next/51082.txt
- TODO: https://go.dev/cl/397279: go/doc/comment: add Printer and basic comment printing; modified api/next/51082.txt
- TODO: https://go.dev/cl/397281: go/doc/comment: parse and print doc links; modified api/next/51082.txt
- TODO: https://go.dev/cl/397284: go/doc/comment: parse and print headings; modified api/next/51082.txt
+ Uint64
are
+ automatically aligned to 64-bit boundaries in structs and allocated data,
+ even on 32-bit systems.
- TODO: https://go.dev/issue/43724: return error when PATH lookup would use current directory -
-- TODO: https://go.dev/issue/43947: on Windows use NeedCurrentDirectoryForExePathW for LookPath behavior +
+
+ Command
and
+ LookPath
no longer
+ allow results from a PATH search to be found relative to the current directory.
+ This removes a common source of security problems
+ but may also break existing programs that depend on using, say, exec.Command("prog")
+ to run a binary named prog
(or, on Windows, prog.exe
) in the current directory.
+ See the os/exec
package documentation for
+ information about how best to update such programs.
+ On Windows, Command
and LookPath
now respect the
+ NoDefaultCurrentDirectoryInExePath
+ environment variable, making it possible to disable
+ the default implicit search of “.
” in PATH lookups on Windows systems.
+
As always, there are various minor changes and updates to the library, made with the Go 1 promise of compatibility in mind. -
-- TODO: complete this section + There are also various performance improvements, not enumerated here.
- TODO: https://go.dev/cl/387976: permit zip files to have prefixes
+ Reader
+ now ignores non-ZIP data at the start of a ZIP file, matching most other implementations.
+ This is necessary to read some Java JAR files, among other uses.
- CreateCertificate
- no longer supports creating certificates with SignatureAlgorithm
+ CreateCertificate
+ no longer supports creating certificates with SignatureAlgorithm
set to MD5WithRSA
.
RevocationList
adds new fields
RawIssuer
, Signature
,
AuthorityKeyId
, and Extensions
.
-
- The new method RevocationList.CheckSignatureFrom
+
+ The new method RevocationList.CheckSignatureFrom
checks that the signature on a CRL is a valid signature from a
Certificate.
@@ -358,7 +385,7 @@ Do not send CLs removing the interior tags from such phrases.
When building paths, Certificate.Verify
- now considers certificates to be equal when the subjects, public keys, and SANs
+ now considers certificates to be equal when the subjects, public keys, and SANs
are all equal. Before, it required byte-for-byte equality.
- TODO: https://go.dev/cl/396735: debug: define ELF relocation for loong64; modified api/next/46229.txt
+ The new EM_LONGARCH
and R_LARCH_*
constants
+ support the loong64 port.
- TODO: https://go.dev/issue/51868: add APIs to support reading COMDAT info for sections -
- -- TODO: https://go.dev/cl/394534: debug/pe: add APIs for reading section def aux info; modified api/next/51868.txt +
+ The new File.COFFSymbolReadSectionDefAux
+ method, which returns a COFFSymbolAuxFormat5
,
+ provides access to COMDAT information in PE file sections.
+ These are supported by new IMAGE_COMDAT_*
and IMAGE_SCN_*
constants.
- TODO: https://go.dev/cl/386017: add AppendByteOrder
+ The new interface
+ AppendByteOrder
+ provides efficient methods for appending a uint16
, uint32
, or uint64
+ to a byte slice.
+ BigEndian
and
+ LittleEndian
now implement this interface.
- TODO: https://go.dev/issue/51644: add AppendUvarint and AppendVarint
+ Similarly, the new functions
+ AppendUvarint
and
+ AppendVarint
+ are efficient appending versions of
+ PutUvarint
and
+ PutVarint
.
- TODO: https://go.dev/cl/405675: add Reader.InputOffset method
+ The new method
+ Reader.InputOffset
+ reports the reader's current input position as a byte offset,
+ analogous to encoding/json
's
+ Decoder.InputOffset
.
- TODO: https://go.dev/issue/45628: add Decoder.InputPos
- TODO: https://go.dev/cl/311270: encoding/xml: expose decoder line and column; modified api/next/45628.txt
+ The new method
+ Decoder.InputPos
+ reports the reader's current input position as a line and column,
+ analogous to encoding/csv
's
+ Decoder.FieldPos
.
- TODO: https://go.dev/cl/313329: add TextVar function
+ The new function
+ TextVar
+ defines a flag with a value implementing
+ encoding.TextUnmarshaler
,
+ allowing command-line flag variables to have types such as
+ big.Int
,
+ netip.Addr
, and
+ time.Time
.
- TODO: https://go.dev/cl/406177: add Append, Appendln, Appendf
+ The new functions
+ Append
,
+ Appendf
, and
+ Appendln
+ append formatted data to byte slices.
- TODO: https://go.dev/cl/403696: parser to accept ~x as unary expression
+ The parser now recognizes ~x
as a unary expression with operator
+ token.TILDE,
+ allowing better error recovery when a type constraint such as ~int
is used in an incorrect context.
- TODO: https://go.dev/cl/392494: hash/maphash: add Bytes and String; modified api/next/42710.txt
- TODO: https://go.dev/issue/42710: add Bytes and String
+ The new functions
+ Bytes
+ and
+ String
+ provide an efficient way hash a single byte slice or string.
+ They are equivalent to using the more general
+ Hash
+ with a single write, but they avoid setup overhead for small inputs.
- TODO: https://go.dev/issue/46121: make FuncMap an alias for text/template.FuncMap
- TODO: https://go.dev/cl/389156: html/template: make FuncMap a type alias of text/template.FuncMap; modified api/except.txt, api/next/46121.txt
+ The type FuncMap
+ is now an alias for
+ text/template
's FuncMap
+ instead of its own named type.
+ This allows writing code that operates on a FuncMap
from either setting.
- Draw
with the Src
operator preserves
+ Draw
with the
+ Src
operator preserves
non-premultiplied-alpha colors when destination and source images are
- both *image.NRGBA
(or both *image.NRGBA64
).
+ both image.NRGBA
+ or both image.NRGBA64
.
This reverts a behavior change accidentally introduced by a Go 1.18
- library optimization, to match the behavior in Go 1.17 and earlier.
+ library optimization; the code now matches the behavior in Go 1.17 and earlier.
- TODO: https://go.dev/cl/400236: NopCloser forward WriterTo implementations if the reader supports it
+ NopCloser
's result now implements
+ WriterTo
+ whenever its input does.
- TODO: https://go.dev/issue/50842: implement WriterTo on result of MultiReader
+ MultiReader
's result now implements
+ WriterTo
unconditionally.
+ If any underlying reader does not implement WriterTo
,
+ it is simulated appropriately.
text/javascript; charset=utf-8
.
Applications that expect text/plain
on Windows must
now explicitly call
- AddExtensionType
.
+ AddExtensionType
.
Resolver.PreferGo
is now implemented on Windows and Plan 9. It previously only worked on Unix
@@ -578,6 +651,7 @@ Do not send CLs removing the interior tags from such phrases.
possible to write portable programs and be in control of all DNS name lookups
when dialing.
The net
package now has initial support for the netgo
build tag on Windows. When used, the package uses the Go DNS client (as used
@@ -636,26 +710,17 @@ Do not send CLs removing the interior tags from such phrases.
-
- TODO: https://go.dev/cl/392415: raise open file rlimit at startup -
-
- An exec.Cmd
with a non-empty Dir
and a
- nil Env
now implicitly sets the PWD
environment
+ A Cmd
with a non-empty Dir
field
+ and nil Env
now implicitly sets the PWD
environment
variable for the subprocess to match Dir
.
- The new method (*exec.Cmd).Environ
reports the
+ The new method Cmd.Environ
reports the
environment that would be used to run the command, including the
- aforementioned PWD
variable.
+ implicitly set PWD
variable.
- The method Value.Bytes
now accepts addressable arrays in addition to slices.
+ The method Value.Bytes
+ now accepts addressable arrays in addition to slices.
- The methods Value.Len
and Value.Cap
now successfully operate on a pointer to an array and return the length of that array, to match what the builtin len
and cap
functions do.
+ The methods Value.Len
+ and Value.Cap
+ now successfully operate on a pointer to an array and return the length of that array,
+ to match what the builtin
+ len
and cap
functions do.
- TODO: https://go.dev/issue/51684: add ErrNestingDepth error
- TODO: https://go.dev/cl/401076: regexp: change ErrInvalidDepth message to match proposal; modified api/next/51684.txt, api/next/regexpdepth.txt
+ Go 1.18 release candidate 1, Go 1.17.8, and Go 1.16.15 included a security fix
+ to the regular expression parser, making it reject very deeply nested expressions.
+ Because Go patch releases do not introduce new API,
+ the parser returned syntax.ErrInternalError
in this case.
+ Go 1.19 adds a more specific error, syntax.ErrNestingDepth
,
+ which the parser now returns instead.
- TODO: https://go.dev/cl/384617: regexp/syntax: add and use ErrInvalidDepth; modified api/next/regexpdepth.txt - TODO: https://go.dev/cl/401854: regexp/syntax: rename ErrInvalidDepth to ErrNestingDepth; modified api/next/51684.txt -
-
- The GOROOT
function now returns the empty string
+ The GOROOT
function now returns the empty string
(instead of "go"
) when the binary was built with
the -trimpath
flag set and the GOROOT
variable is not set in the process environment.
@@ -797,8 +861,11 @@ Do not send CLs removing the interior tags from such phrases.
is faster for several common scenarios.
- TODO: https://go.dev/issue/50340: add Find - TODO: https://go.dev/cl/396514: sort: add Find function; modified api/next/50340.txt + The new function + Find + is like + Search + but often easier to use: it returns an additional boolean reporting whether an equal value was found.
Quote
- and related functions now quote the rune 007F as \x7f
,
- not \u007f
.
+ and related functions now quote the rune U+007F as \x7f
,
+ not \u007f
,
+ for consistency with other ASCII values.
- TODO: https://go.dev/cl/393515: add Duration.Abs
- TODO: https://go.dev/issue/51414: add Duration.Abs
+ The new method
+ Duration.Abs
+ provides a convenient and safe way to take the absolute value of a duration,
+ converting −2⁶³ to 2⁶³−1.
+ (This boundary case can happen as the result of subtracting a recent time from the zero time.)
- TODO: https://go.dev/issue/50062: add Time.ZoneBounds
- TODO: https://go.dev/cl/405374: time: add Time.ZoneBounds; modified api/next/50062.txt
+ The new method
+ Time.ZoneBounds
+ returns the start and end times of the time zone in effect at a given time.
+ It can be used in a loop to enumerate all the known time zone transitions at a given location.