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diff --git a/doc/go1.12.html b/doc/go1.12.html deleted file mode 100644 index a8b0c87fe5..0000000000 --- a/doc/go1.12.html +++ /dev/null @@ -1,949 +0,0 @@ -<!--{ - "Title": "Go 1.12 Release Notes", - "Path": "/doc/go1.12", - "Template": true -}--> - -<!-- -NOTE: In this document and others in this directory, the convention is to -set fixed-width phrases with non-fixed-width spaces, as in -<code>hello</code> <code>world</code>. -Do not send CLs removing the interior tags from such phrases. ---> - -<style> - main ul li { margin: 0.5em 0; } -</style> - -<h2 id="introduction">Introduction to Go 1.12</h2> - -<p> - The latest Go release, version 1.12, arrives six months after <a href="go1.11">Go 1.11</a>. - Most of its changes are in the implementation of the toolchain, runtime, and libraries. - As always, the release maintains the Go 1 <a href="/doc/go1compat">promise of compatibility</a>. - We expect almost all Go programs to continue to compile and run as before. -</p> - -<h2 id="language">Changes to the language</h2> - -<p> - There are no changes to the language specification. -</p> - -<h2 id="ports">Ports</h2> - -<p><!-- CL 138675 --> - The race detector is now supported on <code>linux/arm64</code>. -</p> - -<p id="freebsd"> - Go 1.12 is the last release that is supported on FreeBSD 10.x, which has - already reached end-of-life. Go 1.13 will require FreeBSD 11.2+ or FreeBSD - 12.0+. - FreeBSD 12.0+ requires a kernel with the COMPAT_FREEBSD11 option set (this is the default). -</p> - -<p><!-- CL 146898 --> - cgo is now supported on <code>linux/ppc64</code>. -</p> - -<p id="hurd"><!-- CL 146023 --> - <code>hurd</code> is now a recognized value for <code>GOOS</code>, reserved - for the GNU/Hurd system for use with <code>gccgo</code>. -</p> - -<h3 id="windows">Windows</h3> - -<p> - Go's new <code>windows/arm</code> port supports running Go on Windows 10 - IoT Core on 32-bit ARM chips such as the Raspberry Pi 3. -</p> - -<h3 id="aix">AIX</h3> - -<p> - Go now supports AIX 7.2 and later on POWER8 architectures (<code>aix/ppc64</code>). External linking, cgo, pprof and the race detector aren't yet supported. -</p> - -<h3 id="darwin">Darwin</h3> - -<p> - Go 1.12 is the last release that will run on macOS 10.10 Yosemite. - Go 1.13 will require macOS 10.11 El Capitan or later. -</p> - -<p><!-- CL 141639 --> - <code>libSystem</code> is now used when making syscalls on Darwin, - ensuring forward-compatibility with future versions of macOS and iOS. - <!-- CL 153338 --> - The switch to <code>libSystem</code> triggered additional App Store - checks for private API usage. Since it is considered private, - <code>syscall.Getdirentries</code> now always fails with - <code>ENOSYS</code> on iOS. - Additionally, <a href="/pkg/syscall/#Setrlimit"><code>syscall.Setrlimit</code></a> - reports <code>invalid</code> <code>argument</code> in places where it historically - succeeded. These consequences are not specific to Go and users should expect - behavioral parity with <code>libSystem</code>'s implementation going forward. -</p> - -<h2 id="tools">Tools</h2> - -<h3 id="vet"><code>go tool vet</code> no longer supported</h3> - -<p> - The <code>go vet</code> command has been rewritten to serve as the - base for a range of different source code analysis tools. See - the <a href="https://godoc.org/golang.org/x/tools/go/analysis">golang.org/x/tools/go/analysis</a> - package for details. A side-effect is that <code>go tool vet</code> - is no longer supported. External tools that use <code>go tool - vet</code> must be changed to use <code>go - vet</code>. Using <code>go vet</code> instead of <code>go tool - vet</code> should work with all supported versions of Go. -</p> - -<p> - As part of this change, the experimental <code>-shadow</code> option - is no longer available with <code>go vet</code>. Checking for - variable shadowing may now be done using -<pre> -go get -u golang.org/x/tools/go/analysis/passes/shadow/cmd/shadow -go vet -vettool=$(which shadow) -</pre> -</p> - -<h3 id="tour">Tour</h3> - -<p> <!-- CL 152657 --> -The Go tour is no longer included in the main binary distribution. To -run the tour locally, instead of running <code>go</code> <code>tool</code> <code>tour</code>, -manually install it: -<pre> -go get -u golang.org/x/tour -tour -</pre> -</p> - -<h3 id="gocache">Build cache requirement</h3> - -<p> - The <a href="/cmd/go/#hdr-Build_and_test_caching">build cache</a> is now - required as a step toward eliminating - <code>$GOPATH/pkg</code>. Setting the environment variable - <code>GOCACHE=off</code> will cause <code>go</code> commands that write to the - cache to fail. -</p> - -<h3 id="binary-only">Binary-only packages</h3> - -<p> - Go 1.12 is the last release that will support binary-only packages. -</p> - -<h3 id="cgo">Cgo</h3> - -<p> - Go 1.12 will translate the C type <code>EGLDisplay</code> to the Go type <code>uintptr</code>. - This change is similar to how Go 1.10 and newer treats Darwin's CoreFoundation - and Java's JNI types. See the - <a href="/cmd/cgo/#hdr-Special_cases">cgo documentation</a> - for more information. -</p> - -<p><!-- CL 152657 --> - Mangled C names are no longer accepted in packages that use Cgo. Use the Cgo - names instead. For example, use the documented cgo name <code>C.char</code> - rather than the mangled name <code>_Ctype_char</code> that cgo generates. -</p> - -<h3 id="modules">Modules</h3> - -<p><!-- CL 148517 --> - When <code>GO111MODULE</code> is set to <code>on</code>, the <code>go</code> - command now supports module-aware operations outside of a module directory, - provided that those operations do not need to resolve import paths relative to - the current directory or explicitly edit the <code>go.mod</code> file. - Commands such as <code>go</code> <code>get</code>, - <code>go</code> <code>list</code>, and - <code>go</code> <code>mod</code> <code>download</code> behave as if in a - module with initially-empty requirements. - In this mode, <code>go</code> <code>env</code> <code>GOMOD</code> reports - the system's null device (<code>/dev/null</code> or <code>NUL</code>). -</p> - -<p><!-- CL 146382 --> - <code>go</code> commands that download and extract modules are now safe to - invoke concurrently. - The module cache (<code>GOPATH/pkg/mod</code>) must reside in a filesystem that - supports file locking. -</p> - -<p><!-- CL 147282, 147281 --> - The <code>go</code> directive in a <code>go.mod</code> file now indicates the - version of the language used by the files within that module. - It will be set to the current release - (<code>go</code> <code>1.12</code>) if no existing version is - present. - If the <code>go</code> directive for a module specifies a - version <em>newer</em> than the toolchain in use, the <code>go</code> command - will attempt to build the packages regardless, and will note the mismatch only if - that build fails. -</p> - -<p><!-- CL 147282, 147281 --> - This changed use of the <code>go</code> directive means that if you - use Go 1.12 to build a module, thus recording <code>go 1.12</code> - in the <code>go.mod</code> file, you will get an error when - attempting to build the same module with Go 1.11 through Go 1.11.3. - Go 1.11.4 or later will work fine, as will releases older than Go 1.11. - If you must use Go 1.11 through 1.11.3, you can avoid the problem by - setting the language version to 1.11, using the Go 1.12 go tool, - via <code>go mod edit -go=1.11</code>. -</p> - -<p><!-- CL 152739 --> - When an import cannot be resolved using the active modules, - the <code>go</code> command will now try to use the modules mentioned in the - main module's <code>replace</code> directives before consulting the module - cache and the usual network sources. - If a matching replacement is found but the <code>replace</code> directive does - not specify a version, the <code>go</code> command uses a pseudo-version - derived from the zero <code>time.Time</code> (such - as <code>v0.0.0-00010101000000-000000000000</code>). -</p> - -<h3 id="compiler">Compiler toolchain</h3> - -<p><!-- CL 134155, 134156 --> - The compiler's live variable analysis has improved. This may mean that - finalizers will be executed sooner in this release than in previous - releases. If that is a problem, consider the appropriate addition of a - <a href="/pkg/runtime/#KeepAlive"><code>runtime.KeepAlive</code></a> call. -</p> - -<p><!-- CL 147361 --> - More functions are now eligible for inlining by default, including - functions that do nothing but call another function. - This extra inlining makes it additionally important to use - <a href="/pkg/runtime/#CallersFrames"><code>runtime.CallersFrames</code></a> - instead of iterating over the result of - <a href="/pkg/runtime/#Callers"><code>runtime.Callers</code></a> directly. -<pre> -// Old code which no longer works correctly (it will miss inlined call frames). -var pcs [10]uintptr -n := runtime.Callers(1, pcs[:]) -for _, pc := range pcs[:n] { - f := runtime.FuncForPC(pc) - if f != nil { - fmt.Println(f.Name()) - } -} -</pre> -<pre> -// New code which will work correctly. -var pcs [10]uintptr -n := runtime.Callers(1, pcs[:]) -frames := runtime.CallersFrames(pcs[:n]) -for { - frame, more := frames.Next() - fmt.Println(frame.Function) - if !more { - break - } -} -</pre> -</p> - -<p><!-- CL 153477 --> - Wrappers generated by the compiler to implement method expressions - are no longer reported - by <a href="/pkg/runtime/#CallersFrames"><code>runtime.CallersFrames</code></a> - and <a href="/pkg/runtime/#Stack"><code>runtime.Stack</code></a>. They - are also not printed in panic stack traces. - - This change aligns the <code>gc</code> toolchain to match - the <code>gccgo</code> toolchain, which already elided such wrappers - from stack traces. - - Clients of these APIs might need to adjust for the missing - frames. For code that must interoperate between 1.11 and 1.12 - releases, you can replace the method expression <code>x.M</code> - with the function literal <code>func (...) { x.M(...) } </code>. -</p> - -<p><!-- CL 144340 --> - The compiler now accepts a <code>-lang</code> flag to set the Go language - version to use. For example, <code>-lang=go1.8</code> causes the compiler to - emit an error if the program uses type aliases, which were added in Go 1.9. - Language changes made before Go 1.12 are not consistently enforced. -</p> - -<p><!-- CL 147160 --> - The compiler toolchain now uses different conventions to call Go - functions and assembly functions. This should be invisible to users, - except for calls that simultaneously cross between Go and - assembly <em>and</em> cross a package boundary. If linking results - in an error like "relocation target not defined for ABIInternal (but - is defined for ABI0)", please refer to the - <a href="https://github.com/golang/proposal/blob/master/design/27539-internal-abi.md#compatibility">compatibility section</a> - of the ABI design document. -</p> - -<p><!-- CL 145179 --> - There have been many improvements to the DWARF debug information - produced by the compiler, including improvements to argument - printing and variable location information. -</p> - -<p><!-- CL 61511 --> - Go programs now also maintain stack frame pointers on <code>linux/arm64</code> - for the benefit of profiling tools like <code>perf</code>. The frame pointer - maintenance has a small run-time overhead that varies but averages around 3%. - To build a toolchain that does not use frame pointers, set - <code>GOEXPERIMENT=noframepointer</code> when running <code>make.bash</code>. -</p> - -<p><!-- CL 142717 --> - The obsolete "safe" compiler mode (enabled by the <code>-u</code> gcflag) has been removed. -</p> - -<h3 id="godoc"><code>godoc</code> and <code>go</code> <code>doc</code></h3> - -<p> - In Go 1.12, <code>godoc</code> no longer has a command-line interface and - is only a web server. Users should use <code>go</code> <code>doc</code> - for command-line help output instead. Go 1.12 is the last release that will - include the <code>godoc</code> webserver; in Go 1.13 it will be available - via <code>go</code> <code>get</code>. -</p> - -<p><!-- CL 141977 --> - <code>go</code> <code>doc</code> now supports the <code>-all</code> flag, - which will cause it to print all exported APIs and their documentation, - as the <code>godoc</code> command line used to do. -</p> - -<p><!-- CL 140959 --> - <code>go</code> <code>doc</code> also now includes the <code>-src</code> flag, - which will show the target's source code. -</p> - -<h3 id="trace">Trace</h3> - -<p><!-- CL 60790 --> - The trace tool now supports plotting mutator utilization curves, - including cross-references to the execution trace. These are useful - for analyzing the impact of the garbage collector on application - latency and throughput. -</p> - -<h3 id="assembler">Assembler</h3> - -<p><!-- CL 147218 --> - On <code>arm64</code>, the platform register was renamed from - <code>R18</code> to <code>R18_PLATFORM</code> to prevent accidental - use, as the OS could choose to reserve this register. -</p> - -<h2 id="runtime">Runtime</h2> - -<p><!-- CL 138959 --> - Go 1.12 significantly improves the performance of sweeping when a - large fraction of the heap remains live. This reduces allocation - latency immediately following a garbage collection. -</p> - -<p><!-- CL 139719 --> - The Go runtime now releases memory back to the operating system more - aggressively, particularly in response to large allocations that - can't reuse existing heap space. -</p> - -<p><!-- CL 146342, CL 146340, CL 146345, CL 146339, CL 146343, CL 146337, CL 146341, CL 146338 --> - The Go runtime's timer and deadline code is faster and scales better - with higher numbers of CPUs. In particular, this improves the - performance of manipulating network connection deadlines. -</p> - -<p><!-- CL 135395 --> - On Linux, the runtime now uses <code>MADV_FREE</code> to release unused - memory. This is more efficient but may result in higher reported - RSS. The kernel will reclaim the unused data when it is needed. - To revert to the Go 1.11 behavior (<code>MADV_DONTNEED</code>), set the - environment variable <code>GODEBUG=madvdontneed=1</code>. -</p> - -<p><!-- CL 149578 --> - Adding cpu.<em>extension</em>=off to the - <a href="/doc/diagnostics.html#godebug">GODEBUG</a> environment - variable now disables the use of optional CPU instruction - set extensions in the standard library and runtime. This is not - yet supported on Windows. -</p> - -<p><!-- CL 158337 --> - Go 1.12 improves the accuracy of memory profiles by fixing - overcounting of large heap allocations. -</p> - -<p><!-- CL 159717 --> - Tracebacks, <code>runtime.Caller</code>, - and <code>runtime.Callers</code> no longer include - compiler-generated initialization functions. Doing a traceback - during the initialization of a global variable will now show a - function named <code>PKG.init.ializers</code>. -</p> - -<h2 id="library">Core library</h2> - -<h3 id="tls_1_3">TLS 1.3</h3> - -<p> - Go 1.12 adds opt-in support for TLS 1.3 in the <code>crypto/tls</code> package as - specified by <a href="https://www.rfc-editor.org/info/rfc8446">RFC 8446</a>. It can - be enabled by adding the value <code>tls13=1</code> to the <code>GODEBUG</code> - environment variable. It will be enabled by default in Go 1.13. -</p> - -<p> - To negotiate TLS 1.3, make sure you do not set an explicit <code>MaxVersion</code> in - <a href="/pkg/crypto/tls/#Config"><code>Config</code></a> and run your program with - the environment variable <code>GODEBUG=tls13=1</code> set. -</p> - -<p> - All TLS 1.2 features except <code>TLSUnique</code> in - <a href="/pkg/crypto/tls/#ConnectionState"><code>ConnectionState</code></a> - and renegotiation are available in TLS 1.3 and provide equivalent or - better security and performance. Note that even though TLS 1.3 is backwards - compatible with previous versions, certain legacy systems might not work - correctly when attempting to negotiate it. RSA certificate keys too small - to be secure (including 512-bit keys) will not work with TLS 1.3. -</p> - -<p> - TLS 1.3 cipher suites are not configurable. All supported cipher suites are - safe, and if <code>PreferServerCipherSuites</code> is set in - <a href="/pkg/crypto/tls/#Config"><code>Config</code></a> the preference order - is based on the available hardware. -</p> - -<p> - Early data (also called "0-RTT mode") is not currently supported as a - client or server. Additionally, a Go 1.12 server does not support skipping - unexpected early data if a client sends it. Since TLS 1.3 0-RTT mode - involves clients keeping state regarding which servers support 0-RTT, - a Go 1.12 server cannot be part of a load-balancing pool where some other - servers do support 0-RTT. If switching a domain from a server that supported - 0-RTT to a Go 1.12 server, 0-RTT would have to be disabled for at least the - lifetime of the issued session tickets before the switch to ensure - uninterrupted operation. -</p> - -<p> - In TLS 1.3 the client is the last one to speak in the handshake, so if it causes - an error to occur on the server, it will be returned on the client by the first - <a href="/pkg/crypto/tls/#Conn.Read"><code>Read</code></a>, not by - <a href="/pkg/crypto/tls/#Conn.Handshake"><code>Handshake</code></a>. For - example, that will be the case if the server rejects the client certificate. - Similarly, session tickets are now post-handshake messages, so are only - received by the client upon its first - <a href="/pkg/crypto/tls/#Conn.Read"><code>Read</code></a>. -</p> - -<h3 id="minor_library_changes">Minor changes to the library</h3> - -<p> - As always, there are various minor changes and updates to the library, - made with the Go 1 <a href="/doc/go1compat">promise of compatibility</a> - in mind. -</p> - -<!-- TODO: CL 115677: https://golang.org/cl/115677: cmd/vet: check embedded field tags too --> - -<dl id="bufio"><dt><a href="/pkg/bufio/">bufio</a></dt> - <dd> - <p><!-- CL 149297 --> - <code>Reader</code>'s <a href="/pkg/bufio/#Reader.UnreadRune"><code>UnreadRune</code></a> and - <a href="/pkg/bufio/#Reader.UnreadByte"><code>UnreadByte</code></a> methods will now return an error - if they are called after <a href="/pkg/bufio/#Reader.Peek"><code>Peek</code></a>. - </p> - -</dl><!-- bufio --> - -<dl id="bytes"><dt><a href="/pkg/bytes/">bytes</a></dt> - <dd> - <p><!-- CL 137855 --> - The new function <a href="/pkg/bytes/#ReplaceAll"><code>ReplaceAll</code></a> returns a copy of - a byte slice with all non-overlapping instances of a value replaced by another. - </p> - - <p><!-- CL 145098 --> - A pointer to a zero-value <a href="/pkg/bytes/#Reader"><code>Reader</code></a> is now - functionally equivalent to <a href="/pkg/bytes/#NewReader"><code>NewReader</code></a><code>(nil)</code>. - Prior to Go 1.12, the former could not be used as a substitute for the latter in all cases. - </p> - -</dl><!-- bytes --> - -<dl id="crypto/rand"><dt><a href="/pkg/crypto/rand/">crypto/rand</a></dt> - <dd> - <p><!-- CL 139419 --> - A warning will now be printed to standard error the first time - <code>Reader.Read</code> is blocked for more than 60 seconds waiting - to read entropy from the kernel. - </p> - - <p><!-- CL 120055 --> - On FreeBSD, <code>Reader</code> now uses the <code>getrandom</code> - system call if available, <code>/dev/urandom</code> otherwise. - </p> - -</dl><!-- crypto/rand --> - -<dl id="crypto/rc4"><dt><a href="/pkg/crypto/rc4/">crypto/rc4</a></dt> - <dd> - <p><!-- CL 130397 --> - This release removes the assembly implementations, leaving only - the pure Go version. The Go compiler generates code that is - either slightly better or slightly worse, depending on the exact - CPU. RC4 is insecure and should only be used for compatibility - with legacy systems. - </p> - -</dl><!-- crypto/rc4 --> - -<dl id="crypto/tls"><dt><a href="/pkg/crypto/tls/">crypto/tls</a></dt> - <dd> - <p><!-- CL 143177 --> - If a client sends an initial message that does not look like TLS, the server - will no longer reply with an alert, and it will expose the underlying - <code>net.Conn</code> in the new field <code>Conn</code> of - <a href="/pkg/crypto/tls/#RecordHeaderError"><code>RecordHeaderError</code></a>. - </p> - -</dl><!-- crypto/tls --> - -<dl id="database/sql"><dt><a href="/pkg/database/sql/">database/sql</a></dt> - <dd> - <p><!-- CL 145738 --> - A query cursor can now be obtained by passing a - <a href="/pkg/database/sql/#Rows"><code>*Rows</code></a> - value to the <a href="/pkg/database/sql/#Row.Scan"><code>Row.Scan</code></a> method. - </p> - -</dl><!-- database/sql --> - -<dl id="expvar"><dt><a href="/pkg/expvar/">expvar</a></dt> - <dd> - <p><!-- CL 139537 --> - The new <a href="/pkg/expvar/#Map.Delete"><code>Delete</code></a> method allows - for deletion of key/value pairs from a <a href="/pkg/expvar/#Map"><code>Map</code></a>. - </p> - -</dl><!-- expvar --> - -<dl id="fmt"><dt><a href="/pkg/fmt/">fmt</a></dt> - <dd> - <p><!-- CL 142737 --> - Maps are now printed in key-sorted order to ease testing. The ordering rules are: - <ul> - <li>When applicable, nil compares low - <li>ints, floats, and strings order by < - <li>NaN compares less than non-NaN floats - <li>bool compares false before true - <li>Complex compares real, then imaginary - <li>Pointers compare by machine address - <li>Channel values compare by machine address - <li>Structs compare each field in turn - <li>Arrays compare each element in turn - <li>Interface values compare first by <code>reflect.Type</code> describing the concrete type - and then by concrete value as described in the previous rules. - </ul> - </p> - - <p><!-- CL 129777 --> - When printing maps, non-reflexive key values like <code>NaN</code> were previously - displayed as <code><nil></code>. As of this release, the correct values are printed. - </p> - -</dl><!-- fmt --> - -<dl id="go/doc"><dt><a href="/pkg/go/doc/">go/doc</a></dt> - <dd> - <p><!-- CL 140958 --> - To address some outstanding issues in <a href="/cmd/doc/"><code>cmd/doc</code></a>, - this package has a new <a href="/pkg/go/doc/#Mode"><code>Mode</code></a> bit, - <code>PreserveAST</code>, which controls whether AST data is cleared. - </p> - -</dl><!-- go/doc --> - -<dl id="go/token"><dt><a href="/pkg/go/token/">go/token</a></dt> - <dd> - <p><!-- CL 134075 --> - The <a href="/pkg/go/token#File"><code>File</code></a> type has a new - <a href="/pkg/go/token#File.LineStart"><code>LineStart</code></a> field, - which returns the position of the start of a given line. This is especially useful - in programs that occasionally handle non-Go files, such as assembly, but wish to use - the <code>token.Pos</code> mechanism to identify file positions. - </p> - -</dl><!-- go/token --> - -<dl id="image"><dt><a href="/pkg/image/">image</a></dt> - <dd> - <p><!-- CL 118755 --> - The <a href="/pkg/image/#RegisterFormat"><code>RegisterFormat</code></a> function is now safe for concurrent use. - </p> - -</dl><!-- image --> - -<dl id="image/png"><dt><a href="/pkg/image/png/">image/png</a></dt> - <dd> - <p><!-- CL 134235 --> - Paletted images with fewer than 16 colors now encode to smaller outputs. - </p> - -</dl><!-- image/png --> - -<dl id="io"><dt><a href="/pkg/io/">io</a></dt> - <dd> - <p><!-- CL 139457 --> - The new <a href="/pkg/io#StringWriter"><code>StringWriter</code></a> interface wraps the - <a href="/pkg/io/#WriteString"><code>WriteString</code></a> function. - </p> - -</dl><!-- io --> - -<dl id="math"><dt><a href="/pkg/math/">math</a></dt> - <dd> - <p><!-- CL 153059 --> - The functions - <a href="/pkg/math/#Sin"><code>Sin</code></a>, - <a href="/pkg/math/#Cos"><code>Cos</code></a>, - <a href="/pkg/math/#Tan"><code>Tan</code></a>, - and <a href="/pkg/math/#Sincos"><code>Sincos</code></a> now - apply Payne-Hanek range reduction to huge arguments. This - produces more accurate answers, but they will not be bit-for-bit - identical with the results in earlier releases. - </p> -</dl><!-- math --> - -<dl id="math/bits"><dt><a href="/pkg/math/bits/">math/bits</a></dt> - <dd> - <p><!-- CL 123157 --> - New extended precision operations <a href="/pkg/math/bits/#Add"><code>Add</code></a>, <a href="/pkg/math/bits/#Sub"><code>Sub</code></a>, <a href="/pkg/math/bits/#Mul"><code>Mul</code></a>, and <a href="/pkg/math/bits/#Div"><code>Div</code></a> are available in <code>uint</code>, <code>uint32</code>, and <code>uint64</code> versions. - </p> - -</dl><!-- math/bits --> - -<dl id="net"><dt><a href="/pkg/net/">net</a></dt> - <dd> - <p><!-- CL 146659 --> - The - <a href="/pkg/net/#Dialer.DualStack"><code>Dialer.DualStack</code></a> setting is now ignored and deprecated; - RFC 6555 Fast Fallback ("Happy Eyeballs") is now enabled by default. To disable, set - <a href="/pkg/net/#Dialer.FallbackDelay"><code>Dialer.FallbackDelay</code></a> to a negative value. - </p> - - <p><!-- CL 107196 --> - Similarly, TCP keep-alives are now enabled by default if - <a href="/pkg/net/#Dialer.KeepAlive"><code>Dialer.KeepAlive</code></a> is zero. - To disable, set it to a negative value. - </p> - - <p><!-- CL 113997 --> - On Linux, the <a href="http://man7.org/linux/man-pages/man2/splice.2.html"><code>splice</code> system call</a> is now used when copying from a - <a href="/pkg/net/#UnixConn"><code>UnixConn</code></a> to a - <a href="/pkg/net/#TCPConn"><code>TCPConn</code></a>. - </p> -</dl><!-- net --> - -<dl id="net/http"><dt><a href="/pkg/net/http/">net/http</a></dt> - <dd> - <p><!-- CL 143177 --> - The HTTP server now rejects misdirected HTTP requests to HTTPS servers with a plaintext "400 Bad Request" response. - </p> - - <p><!-- CL 130115 --> - The new <a href="/pkg/net/http/#Client.CloseIdleConnections"><code>Client.CloseIdleConnections</code></a> - method calls the <code>Client</code>'s underlying <code>Transport</code>'s <code>CloseIdleConnections</code> - if it has one. - </p> - - <p><!-- CL 145398 --> - The <a href="/pkg/net/http/#Transport"><code>Transport</code></a> no longer rejects HTTP responses which declare - HTTP Trailers but don't use chunked encoding. Instead, the declared trailers are now just ignored. - </p> - - <p><!-- CL 152080 --> <!-- CL 151857 --> - The <a href="/pkg/net/http/#Transport"><code>Transport</code></a> no longer handles <code>MAX_CONCURRENT_STREAMS</code> values - advertised from HTTP/2 servers as strictly as it did during Go 1.10 and Go 1.11. The default behavior is now back - to how it was in Go 1.9: each connection to a server can have up to <code>MAX_CONCURRENT_STREAMS</code> requests - active and then new TCP connections are created as needed. In Go 1.10 and Go 1.11 the <code>http2</code> package - would block and wait for requests to finish instead of creating new connections. - To get the stricter behavior back, import the - <a href="https://godoc.org/golang.org/x/net/http2"><code>golang.org/x/net/http2</code></a> package - directly and set - <a href="https://godoc.org/golang.org/x/net/http2#Transport.StrictMaxConcurrentStreams"><code>Transport.StrictMaxConcurrentStreams</code></a> to - <code>true</code>. - </p> - -</dl><!-- net/http --> - -<dl id="net/url"><dt><a href="/pkg/net/url/">net/url</a></dt> - <dd> - <p><!-- CL 159157, CL 160178 --> - <a href="/pkg/net/url/#Parse"><code>Parse</code></a>, - <a href="/pkg/net/url/#ParseRequestURI"><code>ParseRequestURI</code></a>, - and - <a href="/pkg/net/url/#URL.Parse"><code>URL.Parse</code></a> - now return an - error for URLs containing ASCII control characters, which includes NULL, - tab, and newlines. - </p> - -</dl><!-- net/url --> - -<dl id="net/http/httputil"><dt><a href="/pkg/net/http/httputil/">net/http/httputil</a></dt> - <dd> - <p><!-- CL 146437 --> - The <a href="/pkg/net/http/httputil/#ReverseProxy"><code>ReverseProxy</code></a> now automatically - proxies WebSocket requests. - </p> - -</dl><!-- net/http/httputil --> - -<dl id="os"><dt><a href="/pkg/os/">os</a></dt> - <dd> - <p><!-- CL 125443 --> - The new <a href="/pkg/os/#ProcessState.ExitCode"><code>ProcessState.ExitCode</code></a> method - returns the process's exit code. - </p> - - <p><!-- CL 135075 --> - <code>ModeCharDevice</code> has been added to the <code>ModeType</code> bitmask, allowing for - <code>ModeDevice | ModeCharDevice</code> to be recovered when masking a - <a href="/pkg/os/#FileMode"><code>FileMode</code></a> with <code>ModeType</code>. - </p> - - <p><!-- CL 139418 --> - The new function <a href="/pkg/os/#UserHomeDir"><code>UserHomeDir</code></a> returns the - current user's home directory. - </p> - - <p><!-- CL 146020 --> - <a href="/pkg/os/#RemoveAll"><code>RemoveAll</code></a> now supports paths longer than 4096 characters - on most Unix systems. - </p> - - <p><!-- CL 130676 --> - <a href="/pkg/os/#File.Sync"><code>File.Sync</code></a> now uses <code>F_FULLFSYNC</code> on macOS - to correctly flush the file contents to permanent storage. - This may cause the method to run more slowly than in previous releases. - </p> - - <p><!--CL 155517 --> - <a href="/pkg/os/#File"><code>File</code></a> now supports - a <a href="/pkg/os/#File.SyscallConn"><code>SyscallConn</code></a> - method returning - a <a href="/pkg/syscall/#RawConn"><code>syscall.RawConn</code></a> - interface value. This may be used to invoke system-specific - operations on the underlying file descriptor. - </p> - -</dl><!-- os --> - -<dl id="path/filepath"><dt><a href="/pkg/path/filepath/">path/filepath</a></dt> - <dd> - <p><!-- CL 145220 --> - The <a href="/pkg/path/filepath/#IsAbs"><code>IsAbs</code></a> function now returns true when passed - a reserved filename on Windows such as <code>NUL</code>. - <a href="https://docs.microsoft.com/en-us/windows/desktop/fileio/naming-a-file#naming-conventions">List of reserved names.</a> - </p> - -</dl><!-- path/filepath --> - -<dl id="reflect"><dt><a href="/pkg/reflect/">reflect</a></dt> - <dd> - <p><!-- CL 33572 --> - A new <a href="/pkg/reflect#MapIter"><code>MapIter</code></a> type is - an iterator for ranging over a map. This type is exposed through the - <a href="/pkg/reflect#Value"><code>Value</code></a> type's new - <a href="/pkg/reflect#Value.MapRange"><code>MapRange</code></a> method. - This follows the same iteration semantics as a range statement, with <code>Next</code> - to advance the iterator, and <code>Key</code>/<code>Value</code> to access each entry. - </p> - -</dl><!-- reflect --> - -<dl id="regexp"><dt><a href="/pkg/regexp/">regexp</a></dt> - <dd> - <p><!-- CL 139784 --> - <a href="/pkg/regexp/#Regexp.Copy"><code>Copy</code></a> is no longer necessary - to avoid lock contention, so it has been given a partial deprecation comment. - <a href="/pkg/regexp/#Regexp.Copy"><code>Copy</code></a> - may still be appropriate if the reason for its use is to make two copies with - different <a href="/pkg/regexp/#Regexp.Longest"><code>Longest</code></a> settings. - </p> - -</dl><!-- regexp --> - -<dl id="runtime/debug"><dt><a href="/pkg/runtime/debug/">runtime/debug</a></dt> - <dd> - <p><!-- CL 144220 --> - A new <a href="/pkg/runtime/debug/#BuildInfo"><code>BuildInfo</code></a> type - exposes the build information read from the running binary, available only in - binaries built with module support. This includes the main package path, main - module information, and the module dependencies. This type is given through the - <a href="/pkg/runtime/debug/#ReadBuildInfo"><code>ReadBuildInfo</code></a> function - on <a href="/pkg/runtime/debug/#BuildInfo"><code>BuildInfo</code></a>. - </p> - -</dl><!-- runtime/debug --> - -<dl id="strings"><dt><a href="/pkg/strings/">strings</a></dt> - <dd> - <p><!-- CL 137855 --> - The new function <a href="/pkg/strings/#ReplaceAll"><code>ReplaceAll</code></a> returns a copy of - a string with all non-overlapping instances of a value replaced by another. - </p> - - <p><!-- CL 145098 --> - A pointer to a zero-value <a href="/pkg/strings/#Reader"><code>Reader</code></a> is now - functionally equivalent to <a href="/pkg/strings/#NewReader"><code>NewReader</code></a><code>(nil)</code>. - Prior to Go 1.12, the former could not be used as a substitute for the latter in all cases. - </p> - - <p><!-- CL 122835 --> - The new <a href="/pkg/strings/#Builder.Cap"><code>Builder.Cap</code></a> method returns the capacity of the builder's underlying byte slice. - </p> - - <p><!-- CL 131495 --> - The character mapping functions <a href="/pkg/strings/#Map"><code>Map</code></a>, - <a href="/pkg/strings/#Title"><code>Title</code></a>, - <a href="/pkg/strings/#ToLower"><code>ToLower</code></a>, - <a href="/pkg/strings/#ToLowerSpecial"><code>ToLowerSpecial</code></a>, - <a href="/pkg/strings/#ToTitle"><code>ToTitle</code></a>, - <a href="/pkg/strings/#ToTitleSpecial"><code>ToTitleSpecial</code></a>, - <a href="/pkg/strings/#ToUpper"><code>ToUpper</code></a>, and - <a href="/pkg/strings/#ToUpperSpecial"><code>ToUpperSpecial</code></a> - now always guarantee to return valid UTF-8. In earlier releases, if the input was invalid UTF-8 but no character replacements - needed to be applied, these routines incorrectly returned the invalid UTF-8 unmodified. - </p> - -</dl><!-- strings --> - -<dl id="syscall"><dt><a href="/pkg/syscall/">syscall</a></dt> - <dd> - <p><!-- CL 138595 --> - 64-bit inodes are now supported on FreeBSD 12. Some types have been adjusted accordingly. - </p> - - <p><!-- CL 125456 --> - The Unix socket - (<a href="https://blogs.msdn.microsoft.com/commandline/2017/12/19/af_unix-comes-to-windows/"><code>AF_UNIX</code></a>) - address family is now supported for compatible versions of Windows. - </p> - - <p><!-- CL 147117 --> - The new function <a href="/pkg/syscall/?GOOS=windows&GOARCH=amd64#Syscall18"><code>Syscall18</code></a> - has been introduced for Windows, allowing for calls with up to 18 arguments. - </p> - -</dl><!-- syscall --> - -<dl id="syscall/js"><dt><a href="/pkg/syscall/js/">syscall/js</a></dt> - <dd> - <p><!-- CL 153559 --> - <p> - The <code>Callback</code> type and <code>NewCallback</code> function have been renamed; - they are now called - <a href="/pkg/syscall/js/?GOOS=js&GOARCH=wasm#Func"><code>Func</code></a> and - <a href="/pkg/syscall/js/?GOOS=js&GOARCH=wasm#FuncOf"><code>FuncOf</code></a>, respectively. - This is a breaking change, but WebAssembly support is still experimental - and not yet subject to the - <a href="/doc/go1compat">Go 1 compatibility promise</a>. Any code using the - old names will need to be updated. - </p> - - <p><!-- CL 141644 --> - If a type implements the new - <a href="/pkg/syscall/js/?GOOS=js&GOARCH=wasm#Wrapper"><code>Wrapper</code></a> - interface, - <a href="/pkg/syscall/js/?GOOS=js&GOARCH=wasm#ValueOf"><code>ValueOf</code></a> - will use it to return the JavaScript value for that type. - </p> - - <p><!-- CL 143137 --> - The meaning of the zero - <a href="/pkg/syscall/js/?GOOS=js&GOARCH=wasm#Value"><code>Value</code></a> - has changed. It now represents the JavaScript <code>undefined</code> value - instead of the number zero. - This is a breaking change, but WebAssembly support is still experimental - and not yet subject to the - <a href="/doc/go1compat">Go 1 compatibility promise</a>. Any code relying on - the zero <a href="/pkg/syscall/js/?GOOS=js&GOARCH=wasm#Value"><code>Value</code></a> - to mean the number zero will need to be updated. - </p> - - <p><!-- CL 144384 --> - The new - <a href="/pkg/syscall/js/?GOOS=js&GOARCH=wasm#Value.Truthy"><code>Value.Truthy</code></a> - method reports the - <a href="https://developer.mozilla.org/en-US/docs/Glossary/Truthy">JavaScript "truthiness"</a> - of a given value. - </p> - -</dl><!-- syscall/js --> - -<dl id="testing"><dt><a href="/pkg/testing/">testing</a></dt> - <dd> - <p><!-- CL 139258 --> - The <a href="/cmd/go/#hdr-Testing_flags"><code>-benchtime</code></a> flag now supports setting an explicit iteration count instead of a time when the value ends with an "<code>x</code>". For example, <code>-benchtime=100x</code> runs the benchmark 100 times. - </p> - -</dl><!-- testing --> - -<dl id="text/template"><dt><a href="/pkg/text/template/">text/template</a></dt> - <dd> - <p><!-- CL 142217 --> - When executing a template, long context values are no longer truncated in errors. - </p> - <p> - <code>executing "tmpl" at <.very.deep.context.v...>: map has no entry for key "notpresent"</code> - </p> - <p> - is now - </p> - <p> - <code>executing "tmpl" at <.very.deep.context.value.notpresent>: map has no entry for key "notpresent"</code> - </p> - - <dd> - <p><!-- CL 143097 --> - If a user-defined function called by a template panics, the - panic is now caught and returned as an error by - the <code>Execute</code> or <code>ExecuteTemplate</code> method. - </p> -</dl><!-- text/template --> - -<dl id="time"><dt><a href="/pkg/time/">time</a></dt> - <dd> - <p><!-- CL 151299 --> - The time zone database in <code>$GOROOT/lib/time/zoneinfo.zip</code> - has been updated to version 2018i. Note that this ZIP file is - only used if a time zone database is not provided by the operating - system. - </p> - -</dl><!-- time --> - -<dl id="unsafe"><dt><a href="/pkg/unsafe/">unsafe</a></dt> - <dd> - <p><!-- CL 146058 --> - It is invalid to convert a nil <code>unsafe.Pointer</code> to <code>uintptr</code> and back with arithmetic. - (This was already invalid, but will now cause the compiler to misbehave.) - </p> - -</dl><!-- unsafe --> |