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diff --git a/doc/go1.6.html b/doc/go1.6.html deleted file mode 100644 index c8ec7e7991..0000000000 --- a/doc/go1.6.html +++ /dev/null @@ -1,923 +0,0 @@ -<!--{ - "Title": "Go 1.6 Release Notes", - "Path": "/doc/go1.6", - "Template": true -}--> - -<!-- -Edit .,s;^PKG:([a-z][A-Za-z0-9_/]+);<a href="/pkg/\1/"><code>\1</code></a>;g -Edit .,s;^([a-z][A-Za-z0-9_/]+)\.([A-Z][A-Za-z0-9_]+\.)?([A-Z][A-Za-z0-9_]+)([ .',]|$);<a href="/pkg/\1/#\2\3"><code>\3</code></a>\4;g ---> - -<style> - main ul li { margin: 0.5em 0; } -</style> - -<h2 id="introduction">Introduction to Go 1.6</h2> - -<p> -The latest Go release, version 1.6, arrives six months after 1.5. -Most of its changes are in the implementation of the language, runtime, and libraries. -There are no changes to the language specification. -As always, the release maintains the Go 1 <a href="/doc/go1compat.html">promise of compatibility</a>. -We expect almost all Go programs to continue to compile and run as before. -</p> - -<p> -The release adds new ports to <a href="#ports">Linux on 64-bit MIPS and Android on 32-bit x86</a>; -defined and enforced <a href="#cgo">rules for sharing Go pointers with C</a>; -transparent, automatic <a href="#http2">support for HTTP/2</a>; -and a new mechanism for <a href="#template">template reuse</a>. -</p> - -<h2 id="language">Changes to the language</h2> - -<p> -There are no language changes in this release. -</p> - -<h2 id="ports">Ports</h2> - -<p> -Go 1.6 adds experimental ports to -Linux on 64-bit MIPS (<code>linux/mips64</code> and <code>linux/mips64le</code>). -These ports support <code>cgo</code> but only with internal linking. -</p> - -<p> -Go 1.6 also adds an experimental port to Android on 32-bit x86 (<code>android/386</code>). -</p> - -<p> -On FreeBSD, Go 1.6 defaults to using <code>clang</code>, not <code>gcc</code>, as the external C compiler. -</p> - -<p> -On Linux on little-endian 64-bit PowerPC (<code>linux/ppc64le</code>), -Go 1.6 now supports <code>cgo</code> with external linking and -is roughly feature complete. -</p> - -<p> -On NaCl, Go 1.5 required SDK version pepper-41. -Go 1.6 adds support for later SDK versions. -</p> - -<p> -On 32-bit x86 systems using the <code>-dynlink</code> or <code>-shared</code> compilation modes, -the register CX is now overwritten by certain memory references and should -be avoided in hand-written assembly. -See the <a href="/doc/asm#x86">assembly documentation</a> for details. -</p> - -<h2 id="tools">Tools</h2> - -<h3 id="cgo">Cgo</h3> - -<p> -There is one major change to <a href="/cmd/cgo/"><code>cgo</code></a>, along with one minor change. -</p> - -<p> -The major change is the definition of rules for sharing Go pointers with C code, -to ensure that such C code can coexist with Go's garbage collector. -Briefly, Go and C may share memory allocated by Go -when a pointer to that memory is passed to C as part of a <code>cgo</code> call, -provided that the memory itself contains no pointers to Go-allocated memory, -and provided that C does not retain the pointer after the call returns. -These rules are checked by the runtime during program execution: -if the runtime detects a violation, it prints a diagnosis and crashes the program. -The checks can be disabled by setting the environment variable -<code>GODEBUG=cgocheck=0</code>, but note that the vast majority of -code identified by the checks is subtly incompatible with garbage collection -in one way or another. -Disabling the checks will typically only lead to more mysterious failure modes. -Fixing the code in question should be strongly preferred -over turning off the checks. -See the <a href="/cmd/cgo/#hdr-Passing_pointers"><code>cgo</code> documentation</a> for more details. -</p> - -<p> -The minor change is -the addition of explicit <code>C.complexfloat</code> and <code>C.complexdouble</code> types, -separate from Go's <code>complex64</code> and <code>complex128</code>. -Matching the other numeric types, C's complex types and Go's complex type are -no longer interchangeable. -</p> - -<h3 id="compiler">Compiler Toolchain</h3> - -<p> -The compiler toolchain is mostly unchanged. -Internally, the most significant change is that the parser is now hand-written -instead of generated from <a href="/cmd/yacc/">yacc</a>. -</p> - -<p> -The compiler, linker, and <code>go</code> command have a new flag <code>-msan</code>, -analogous to <code>-race</code> and only available on linux/amd64, -that enables interoperation with the <a href="https://clang.llvm.org/docs/MemorySanitizer.html">Clang MemorySanitizer</a>. -Such interoperation is useful mainly for testing a program containing suspect C or C++ code. -</p> - -<p> -The linker has a new option <code>-libgcc</code> to set the expected location -of the C compiler support library when linking <a href="/cmd/cgo/"><code>cgo</code></a> code. -The option is only consulted when using <code>-linkmode=internal</code>, -and it may be set to <code>none</code> to disable the use of a support library. -</p> - -<p> -The implementation of <a href="/doc/go1.5#link">build modes started in Go 1.5</a> has been expanded to more systems. -This release adds support for the <code>c-shared</code> mode on <code>android/386</code>, <code>android/amd64</code>, -<code>android/arm64</code>, <code>linux/386</code>, and <code>linux/arm64</code>; -for the <code>shared</code> mode on <code>linux/386</code>, <code>linux/arm</code>, <code>linux/amd64</code>, and <code>linux/ppc64le</code>; -and for the new <code>pie</code> mode (generating position-independent executables) on -<code>android/386</code>, <code>android/amd64</code>, <code>android/arm</code>, <code>android/arm64</code>, <code>linux/386</code>, -<code>linux/amd64</code>, <code>linux/arm</code>, <code>linux/arm64</code>, and <code>linux/ppc64le</code>. -See the <a href="https://golang.org/s/execmodes">design document</a> for details. -</p> - -<p> -As a reminder, the linker's <code>-X</code> flag changed in Go 1.5. -In Go 1.4 and earlier, it took two arguments, as in -</p> - -<pre> --X importpath.name value -</pre> - -<p> -Go 1.5 added an alternative syntax using a single argument -that is itself a <code>name=value</code> pair: -</p> - -<pre> --X importpath.name=value -</pre> - -<p> -In Go 1.5 the old syntax was still accepted, after printing a warning -suggesting use of the new syntax instead. -Go 1.6 continues to accept the old syntax and print the warning. -Go 1.7 will remove support for the old syntax. -</p> - -<h3 id="gccgo">Gccgo</h3> - -<p> -The release schedules for the GCC and Go projects do not coincide. -GCC release 5 contains the Go 1.4 version of gccgo. -The next release, GCC 6, will have the Go 1.6.1 version of gccgo. -</p> - -<h3 id="go_command">Go command</h3> - -<p> -The <a href="/cmd/go"><code>go</code></a> command's basic operation -is unchanged, but there are a number of changes worth noting. -</p> - -<p> -Go 1.5 introduced experimental support for vendoring, -enabled by setting the <code>GO15VENDOREXPERIMENT</code> environment variable to <code>1</code>. -Go 1.6 keeps the vendoring support, no longer considered experimental, -and enables it by default. -It can be disabled explicitly by setting -the <code>GO15VENDOREXPERIMENT</code> environment variable to <code>0</code>. -Go 1.7 will remove support for the environment variable. -</p> - -<p> -The most likely problem caused by enabling vendoring by default happens -in source trees containing an existing directory named <code>vendor</code> that -does not expect to be interpreted according to new vendoring semantics. -In this case, the simplest fix is to rename the directory to anything other -than <code>vendor</code> and update any affected import paths. -</p> - -<p> -For details about vendoring, -see the documentation for the <a href="/cmd/go/#hdr-Vendor_Directories"><code>go</code> command</a> -and the <a href="https://golang.org/s/go15vendor">design document</a>. -</p> - -<p> -There is a new build flag, <code>-msan</code>, -that compiles Go with support for the LLVM memory sanitizer. -This is intended mainly for use when linking against C or C++ code -that is being checked with the memory sanitizer. -</p> - -<h3 id="doc_command">Go doc command</h3> - -<p> -Go 1.5 introduced the -<a href="/cmd/go/#hdr-Show_documentation_for_package_or_symbol"><code>go doc</code></a> command, -which allows references to packages using only the package name, as in -<code>go</code> <code>doc</code> <code>http</code>. -In the event of ambiguity, the Go 1.5 behavior was to use the package -with the lexicographically earliest import path. -In Go 1.6, ambiguity is resolved by preferring import paths with -fewer elements, breaking ties using lexicographic comparison. -An important effect of this change is that original copies of packages -are now preferred over vendored copies. -Successful searches also tend to run faster. -</p> - -<h3 id="vet_command">Go vet command</h3> - -<p> -The <a href="/cmd/vet"><code>go vet</code></a> command now diagnoses -passing function or method values as arguments to <code>Printf</code>, -such as when passing <code>f</code> where <code>f()</code> was intended. -</p> - -<h2 id="performance">Performance</h2> - -<p> -As always, the changes are so general and varied that precise statements -about performance are difficult to make. -Some programs may run faster, some slower. -On average the programs in the Go 1 benchmark suite run a few percent faster in Go 1.6 -than they did in Go 1.5. -The garbage collector's pauses are even lower than in Go 1.5, -especially for programs using -a large amount of memory. -</p> - -<p> -There have been significant optimizations bringing more than 10% improvements -to implementations of the -<a href="/pkg/compress/bzip2/"><code>compress/bzip2</code></a>, -<a href="/pkg/compress/gzip/"><code>compress/gzip</code></a>, -<a href="/pkg/crypto/aes/"><code>crypto/aes</code></a>, -<a href="/pkg/crypto/elliptic/"><code>crypto/elliptic</code></a>, -<a href="/pkg/crypto/ecdsa/"><code>crypto/ecdsa</code></a>, and -<a href="/pkg/sort/"><code>sort</code></a> packages. -</p> - -<h2 id="library">Core library</h2> - -<h3 id="http2">HTTP/2</h3> - -<p> -Go 1.6 adds transparent support in the -<a href="/pkg/net/http/"><code>net/http</code></a> package -for the new <a href="https://http2.github.io/">HTTP/2 protocol</a>. -Go clients and servers will automatically use HTTP/2 as appropriate when using HTTPS. -There is no exported API specific to details of the HTTP/2 protocol handling, -just as there is no exported API specific to HTTP/1.1. -</p> - -<p> -Programs that must disable HTTP/2 can do so by setting -<a href="/pkg/net/http/#Transport"><code>Transport.TLSNextProto</code></a> (for clients) -or -<a href="/pkg/net/http/#Server"><code>Server.TLSNextProto</code></a> (for servers) -to a non-nil, empty map. -</p> - -<p> -Programs that must adjust HTTP/2 protocol-specific details can import and use -<a href="https://golang.org/x/net/http2"><code>golang.org/x/net/http2</code></a>, -in particular its -<a href="https://godoc.org/golang.org/x/net/http2/#ConfigureServer">ConfigureServer</a> -and -<a href="https://godoc.org/golang.org/x/net/http2/#ConfigureTransport">ConfigureTransport</a> -functions. -</p> - -<h3 id="runtime">Runtime</h3> - -<p> -The runtime has added lightweight, best-effort detection of concurrent misuse of maps. -As always, if one goroutine is writing to a map, no other goroutine should be -reading or writing the map concurrently. -If the runtime detects this condition, it prints a diagnosis and crashes the program. -The best way to find out more about the problem is to run the program -under the -<a href="https://blog.golang.org/race-detector">race detector</a>, -which will more reliably identify the race -and give more detail. -</p> - -<p> -For program-ending panics, the runtime now by default -prints only the stack of the running goroutine, -not all existing goroutines. -Usually only the current goroutine is relevant to a panic, -so omitting the others significantly reduces irrelevant output -in a crash message. -To see the stacks from all goroutines in crash messages, set the environment variable -<code>GOTRACEBACK</code> to <code>all</code> -or call -<a href="/pkg/runtime/debug/#SetTraceback"><code>debug.SetTraceback</code></a> -before the crash, and rerun the program. -See the <a href="/pkg/runtime/#hdr-Environment_Variables">runtime documentation</a> for details. -</p> - -<p> -<em>Updating</em>: -Uncaught panics intended to dump the state of the entire program, -such as when a timeout is detected or when explicitly handling a received signal, -should now call <code>debug.SetTraceback("all")</code> before panicking. -Searching for uses of -<a href="/pkg/os/signal/#Notify"><code>signal.Notify</code></a> may help identify such code. -</p> - -<p> -On Windows, Go programs in Go 1.5 and earlier forced -the global Windows timer resolution to 1ms at startup -by calling <code>timeBeginPeriod(1)</code>. -Go no longer needs this for good scheduler performance, -and changing the global timer resolution caused problems on some systems, -so the call has been removed. -</p> - -<p> -When using <code>-buildmode=c-archive</code> or -<code>-buildmode=c-shared</code> to build an archive or a shared -library, the handling of signals has changed. -In Go 1.5 the archive or shared library would install a signal handler -for most signals. -In Go 1.6 it will only install a signal handler for the -synchronous signals needed to handle run-time panics in Go code: -SIGBUS, SIGFPE, SIGSEGV. -See the <a href="/pkg/os/signal">os/signal</a> package for more -details. -</p> - -<h3 id="reflect">Reflect</h3> - -<p> -The -<a href="/pkg/reflect/"><code>reflect</code></a> package has -<a href="https://golang.org/issue/12367">resolved a long-standing incompatibility</a> -between the gc and gccgo toolchains -regarding embedded unexported struct types containing exported fields. -Code that walks data structures using reflection, especially to implement -serialization in the spirit -of the -<a href="/pkg/encoding/json/"><code>encoding/json</code></a> and -<a href="/pkg/encoding/xml/"><code>encoding/xml</code></a> packages, -may need to be updated. -</p> - -<p> -The problem arises when using reflection to walk through -an embedded unexported struct-typed field -into an exported field of that struct. -In this case, <code>reflect</code> had incorrectly reported -the embedded field as exported, by returning an empty <code>Field.PkgPath</code>. -Now it correctly reports the field as unexported -but ignores that fact when evaluating access to exported fields -contained within the struct. -</p> - -<p> -<em>Updating</em>: -Typically, code that previously walked over structs and used -</p> - -<pre> -f.PkgPath != "" -</pre> - -<p> -to exclude inaccessible fields -should now use -</p> - -<pre> -f.PkgPath != "" && !f.Anonymous -</pre> - -<p> -For example, see the changes to the implementations of -<a href="https://go-review.googlesource.com/#/c/14011/2/src/encoding/json/encode.go"><code>encoding/json</code></a> and -<a href="https://go-review.googlesource.com/#/c/14012/2/src/encoding/xml/typeinfo.go"><code>encoding/xml</code></a>. -</p> - -<h3 id="sort">Sorting</h3> - -<p> -In the -<a href="/pkg/sort/"><code>sort</code></a> -package, -the implementation of -<a href="/pkg/sort/#Sort"><code>Sort</code></a> -has been rewritten to make about 10% fewer calls to the -<a href="/pkg/sort/#Interface"><code>Interface</code></a>'s -<code>Less</code> and <code>Swap</code> -methods, with a corresponding overall time savings. -The new algorithm does choose a different ordering than before -for values that compare equal (those pairs for which <code>Less(i,</code> <code>j)</code> and <code>Less(j,</code> <code>i)</code> are false). -</p> - -<p> -<em>Updating</em>: -The definition of <code>Sort</code> makes no guarantee about the final order of equal values, -but the new behavior may still break programs that expect a specific order. -Such programs should either refine their <code>Less</code> implementations -to report the desired order -or should switch to -<a href="/pkg/sort/#Stable"><code>Stable</code></a>, -which preserves the original input order -of equal values. -</p> - -<h3 id="template">Templates</h3> - -<p> -In the -<a href="/pkg/text/template/">text/template</a> package, -there are two significant new features to make writing templates easier. -</p> - -<p> -First, it is now possible to <a href="/pkg/text/template/#hdr-Text_and_spaces">trim spaces around template actions</a>, -which can make template definitions more readable. -A minus sign at the beginning of an action says to trim space before the action, -and a minus sign at the end of an action says to trim space after the action. -For example, the template -</p> - -<pre> -{{"{{"}}23 -}} - < -{{"{{"}}- 45}} -</pre> - -<p> -formats as <code>23<45</code>. -</p> - -<p> -Second, the new <a href="/pkg/text/template/#hdr-Actions"><code>{{"{{"}}block}}</code> action</a>, -combined with allowing redefinition of named templates, -provides a simple way to define pieces of a template that -can be replaced in different instantiations. -There is <a href="/pkg/text/template/#example_Template_block">an example</a> -in the <code>text/template</code> package that demonstrates this new feature. -</p> - -<h3 id="minor_library_changes">Minor changes to the library</h3> - -<ul> - -<li> -The <a href="/pkg/archive/tar/"><code>archive/tar</code></a> package's -implementation corrects many bugs in rare corner cases of the file format. -One visible change is that the -<a href="/pkg/archive/tar/#Reader"><code>Reader</code></a> type's -<a href="/pkg/archive/tar/#Reader.Read"><code>Read</code></a> method -now presents the content of special file types as being empty, -returning <code>io.EOF</code> immediately. -</li> - -<li> -In the <a href="/pkg/archive/zip/"><code>archive/zip</code></a> package, the -<a href="/pkg/archive/zip/#Reader"><code>Reader</code></a> type now has a -<a href="/pkg/archive/zip/#Reader.RegisterDecompressor"><code>RegisterDecompressor</code></a> method, -and the -<a href="/pkg/archive/zip/#Writer"><code>Writer</code></a> type now has a -<a href="/pkg/archive/zip/#Writer.RegisterCompressor"><code>RegisterCompressor</code></a> method, -enabling control over compression options for individual zip files. -These take precedence over the pre-existing global -<a href="/pkg/archive/zip/#RegisterDecompressor"><code>RegisterDecompressor</code></a> and -<a href="/pkg/archive/zip/#RegisterCompressor"><code>RegisterCompressor</code></a> functions. -</li> - -<li> -The <a href="/pkg/bufio/"><code>bufio</code></a> package's -<a href="/pkg/bufio/#Scanner"><code>Scanner</code></a> type now has a -<a href="/pkg/bufio/#Scanner.Buffer"><code>Buffer</code></a> method, -to specify an initial buffer and maximum buffer size to use during scanning. -This makes it possible, when needed, to scan tokens larger than -<code>MaxScanTokenSize</code>. -Also for the <code>Scanner</code>, the package now defines the -<a href="/pkg/bufio/#ErrFinalToken"><code>ErrFinalToken</code></a> error value, for use by -<a href="/pkg/bufio/#SplitFunc">split functions</a> to abort processing or to return a final empty token. -</li> - -<li> -The <a href="/pkg/compress/flate/"><code>compress/flate</code></a> package -has deprecated its -<a href="/pkg/compress/flate/#ReadError"><code>ReadError</code></a> and -<a href="/pkg/compress/flate/#WriteError"><code>WriteError</code></a> error implementations. -In Go 1.5 they were only rarely returned when an error was encountered; -now they are never returned, although they remain defined for compatibility. -</li> - -<li> -The <a href="/pkg/compress/flate/"><code>compress/flate</code></a>, -<a href="/pkg/compress/gzip/"><code>compress/gzip</code></a>, and -<a href="/pkg/compress/zlib/"><code>compress/zlib</code></a> packages -now report -<a href="/pkg/io/#ErrUnexpectedEOF"><code>io.ErrUnexpectedEOF</code></a> for truncated input streams, instead of -<a href="/pkg/io/#EOF"><code>io.EOF</code></a>. -</li> - -<li> -The <a href="/pkg/crypto/cipher/"><code>crypto/cipher</code></a> package now -overwrites the destination buffer in the event of a GCM decryption failure. -This is to allow the AESNI code to avoid using a temporary buffer. -</li> - -<li> -The <a href="/pkg/crypto/tls/"><code>crypto/tls</code></a> package -has a variety of minor changes. -It now allows -<a href="/pkg/crypto/tls/#Listen"><code>Listen</code></a> -to succeed when the -<a href="/pkg/crypto/tls/#Config"><code>Config</code></a> -has a nil <code>Certificates</code>, as long as the <code>GetCertificate</code> callback is set, -it adds support for RSA with AES-GCM cipher suites, -and -it adds a -<a href="/pkg/crypto/tls/#RecordHeaderError"><code>RecordHeaderError</code></a> -to allow clients (in particular, the <a href="/pkg/net/http/"><code>net/http</code></a> package) -to report a better error when attempting a TLS connection to a non-TLS server. -</li> - -<li> -The <a href="/pkg/crypto/x509/"><code>crypto/x509</code></a> package -now permits certificates to contain negative serial numbers -(technically an error, but unfortunately common in practice), -and it defines a new -<a href="/pkg/crypto/x509/#InsecureAlgorithmError"><code>InsecureAlgorithmError</code></a> -to give a better error message when rejecting a certificate -signed with an insecure algorithm like MD5. -</li> - -<li> -The <a href="/pkg/debug/dwarf"><code>debug/dwarf</code></a> and -<a href="/pkg/debug/elf/"><code>debug/elf</code></a> packages -together add support for compressed DWARF sections. -User code needs no updating: the sections are decompressed automatically when read. -</li> - -<li> -The <a href="/pkg/debug/elf/"><code>debug/elf</code></a> package -adds support for general compressed ELF sections. -User code needs no updating: the sections are decompressed automatically when read. -However, compressed -<a href="/pkg/debug/elf/#Section"><code>Sections</code></a> do not support random access: -they have a nil <code>ReaderAt</code> field. -</li> - -<li> -The <a href="/pkg/encoding/asn1/"><code>encoding/asn1</code></a> package -now exports -<a href="/pkg/encoding/asn1/#pkg-constants">tag and class constants</a> -useful for advanced parsing of ASN.1 structures. -</li> - -<li> -Also in the <a href="/pkg/encoding/asn1/"><code>encoding/asn1</code></a> package, -<a href="/pkg/encoding/asn1/#Unmarshal"><code>Unmarshal</code></a> now rejects various non-standard integer and length encodings. -</li> - -<li> -The <a href="/pkg/encoding/base64"><code>encoding/base64</code></a> package's -<a href="/pkg/encoding/base64/#Decoder"><code>Decoder</code></a> has been fixed -to process the final bytes of its input. Previously it processed as many four-byte tokens as -possible but ignored the remainder, up to three bytes. -The <code>Decoder</code> therefore now handles inputs in unpadded encodings (like -<a href="/pkg/encoding/base64/#RawURLEncoding">RawURLEncoding</a>) correctly, -but it also rejects inputs in padded encodings that are truncated or end with invalid bytes, -such as trailing spaces. -</li> - -<li> -The <a href="/pkg/encoding/json/"><code>encoding/json</code></a> package -now checks the syntax of a -<a href="/pkg/encoding/json/#Number"><code>Number</code></a> -before marshaling it, requiring that it conforms to the JSON specification for numeric values. -As in previous releases, the zero <code>Number</code> (an empty string) is marshaled as a literal 0 (zero). -</li> - -<li> -The <a href="/pkg/encoding/xml/"><code>encoding/xml</code></a> package's -<a href="/pkg/encoding/xml/#Marshal"><code>Marshal</code></a> -function now supports a <code>cdata</code> attribute, such as <code>chardata</code> -but encoding its argument in one or more <code><![CDATA[ ... ]]></code> tags. -</li> - -<li> -Also in the <a href="/pkg/encoding/xml/"><code>encoding/xml</code></a> package, -<a href="/pkg/encoding/xml/#Decoder"><code>Decoder</code></a>'s -<a href="/pkg/encoding/xml/#Decoder.Token"><code>Token</code></a> method -now reports an error when encountering EOF before seeing all open tags closed, -consistent with its general requirement that tags in the input be properly matched. -To avoid that requirement, use -<a href="/pkg/encoding/xml/#Decoder.RawToken"><code>RawToken</code></a>. -</li> - -<li> -The <a href="/pkg/fmt/"><code>fmt</code></a> package now allows -any integer type as an argument to -<a href="/pkg/fmt/#Printf"><code>Printf</code></a>'s <code>*</code> width and precision specification. -In previous releases, the argument to <code>*</code> was required to have type <code>int</code>. -</li> - -<li> -Also in the <a href="/pkg/fmt/"><code>fmt</code></a> package, -<a href="/pkg/fmt/#Scanf"><code>Scanf</code></a> can now scan hexadecimal strings using %X, as an alias for %x. -Both formats accept any mix of upper- and lower-case hexadecimal. -</li> - -<li> -The <a href="/pkg/image/"><code>image</code></a> -and -<a href="/pkg/image/color/"><code>image/color</code></a> packages -add -<a href="/pkg/image/#NYCbCrA"><code>NYCbCrA</code></a> -and -<a href="/pkg/image/color/#NYCbCrA"><code>NYCbCrA</code></a> -types, to support Y'CbCr images with non-premultiplied alpha. -</li> - -<li> -The <a href="/pkg/io/"><code>io</code></a> package's -<a href="/pkg/io/#MultiWriter"><code>MultiWriter</code></a> -implementation now implements a <code>WriteString</code> method, -for use by -<a href="/pkg/io/#WriteString"><code>WriteString</code></a>. -</li> - -<li> -In the <a href="/pkg/math/big/"><code>math/big</code></a> package, -<a href="/pkg/math/big/#Int"><code>Int</code></a> adds -<a href="/pkg/math/big/#Int.Append"><code>Append</code></a> -and -<a href="/pkg/math/big/#Int.Text"><code>Text</code></a> -methods to give more control over printing. -</li> - -<li> -Also in the <a href="/pkg/math/big/"><code>math/big</code></a> package, -<a href="/pkg/math/big/#Float"><code>Float</code></a> now implements -<a href="/pkg/encoding/#TextMarshaler"><code>encoding.TextMarshaler</code></a> and -<a href="/pkg/encoding/#TextUnmarshaler"><code>encoding.TextUnmarshaler</code></a>, -allowing it to be serialized in a natural form by the -<a href="/pkg/encoding/json/"><code>encoding/json</code></a> and -<a href="/pkg/encoding/xml/"><code>encoding/xml</code></a> packages. -</li> - -<li> -Also in the <a href="/pkg/math/big/"><code>math/big</code></a> package, -<a href="/pkg/math/big/#Float"><code>Float</code></a>'s -<a href="/pkg/math/big/#Float.Append"><code>Append</code></a> method now supports the special precision argument -1. -As in -<a href="/pkg/strconv/#ParseFloat"><code>strconv.ParseFloat</code></a>, -precision -1 means to use the smallest number of digits necessary such that -<a href="/pkg/math/big/#Float.Parse"><code>Parse</code></a> -reading the result into a <code>Float</code> of the same precision -will yield the original value. -</li> - -<li> -The <a href="/pkg/math/rand/"><code>math/rand</code></a> package -adds a -<a href="/pkg/math/rand/#Read"><code>Read</code></a> -function, and likewise -<a href="/pkg/math/rand/#Rand"><code>Rand</code></a> adds a -<a href="/pkg/math/rand/#Rand.Read"><code>Read</code></a> method. -These make it easier to generate pseudorandom test data. -Note that, like the rest of the package, -these should not be used in cryptographic settings; -for such purposes, use the <a href="/pkg/crypto/rand/"><code>crypto/rand</code></a> package instead. -</li> - -<li> -The <a href="/pkg/net/"><code>net</code></a> package's -<a href="/pkg/net/#ParseMAC"><code>ParseMAC</code></a> function now accepts 20-byte IP-over-InfiniBand (IPoIB) link-layer addresses. -</li> - - -<li> -Also in the <a href="/pkg/net/"><code>net</code></a> package, -there have been a few changes to DNS lookups. -First, the -<a href="/pkg/net/#DNSError"><code>DNSError</code></a> error implementation now implements -<a href="/pkg/net/#Error"><code>Error</code></a>, -and in particular its new -<a href="/pkg/net/#DNSError.IsTemporary"><code>IsTemporary</code></a> -method returns true for DNS server errors. -Second, DNS lookup functions such as -<a href="/pkg/net/#LookupAddr"><code>LookupAddr</code></a> -now return rooted domain names (with a trailing dot) -on Plan 9 and Windows, to match the behavior of Go on Unix systems. -</li> - -<li> -The <a href="/pkg/net/http/"><code>net/http</code></a> package has -a number of minor additions beyond the HTTP/2 support already discussed. -First, the -<a href="/pkg/net/http/#FileServer"><code>FileServer</code></a> now sorts its generated directory listings by file name. -Second, the -<a href="/pkg/net/http/#ServeFile"><code>ServeFile</code></a> function now refuses to serve a result -if the request's URL path contains “..” (dot-dot) as a path element. -Programs should typically use <code>FileServer</code> and -<a href="/pkg/net/http/#Dir"><code>Dir</code></a> -instead of calling <code>ServeFile</code> directly. -Programs that need to serve file content in response to requests for URLs containing dot-dot can -still call <a href="/pkg/net/http/#ServeContent"><code>ServeContent</code></a>. -Third, the -<a href="/pkg/net/http/#Client"><code>Client</code></a> now allows user code to set the -<code>Expect:</code> <code>100-continue</code> header (see -<a href="/pkg/net/http/#Transport"><code>Transport.ExpectContinueTimeout</code></a>). -Fourth, there are -<a href="/pkg/net/http/#pkg-constants">five new error codes</a>: -<code>StatusPreconditionRequired</code> (428), -<code>StatusTooManyRequests</code> (429), -<code>StatusRequestHeaderFieldsTooLarge</code> (431), and -<code>StatusNetworkAuthenticationRequired</code> (511) from RFC 6585, -as well as the recently-approved -<code>StatusUnavailableForLegalReasons</code> (451). -Fifth, the implementation and documentation of -<a href="/pkg/net/http/#CloseNotifier"><code>CloseNotifier</code></a> -has been substantially changed. -The <a href="/pkg/net/http/#Hijacker"><code>Hijacker</code></a> -interface now works correctly on connections that have previously -been used with <code>CloseNotifier</code>. -The documentation now describes when <code>CloseNotifier</code> -is expected to work. -</li> - -<li> -Also in the <a href="/pkg/net/http/"><code>net/http</code></a> package, -there are a few changes related to the handling of a -<a href="/pkg/net/http/#Request"><code>Request</code></a> data structure with its <code>Method</code> field set to the empty string. -An empty <code>Method</code> field has always been documented as an alias for <code>"GET"</code> -and it remains so. -However, Go 1.6 fixes a few routines that did not treat an empty -<code>Method</code> the same as an explicit <code>"GET"</code>. -Most notably, in previous releases -<a href="/pkg/net/http/#Client"><code>Client</code></a> followed redirects only with -<code>Method</code> set explicitly to <code>"GET"</code>; -in Go 1.6 <code>Client</code> also follows redirects for the empty <code>Method</code>. -Finally, -<a href="/pkg/net/http/#NewRequest"><code>NewRequest</code></a> accepts a <code>method</code> argument that has not been -documented as allowed to be empty. -In past releases, passing an empty <code>method</code> argument resulted -in a <code>Request</code> with an empty <code>Method</code> field. -In Go 1.6, the resulting <code>Request</code> always has an initialized -<code>Method</code> field: if its argument is an empty string, <code>NewRequest</code> -sets the <code>Method</code> field in the returned <code>Request</code> to <code>"GET"</code>. -</li> - -<li> -The <a href="/pkg/net/http/httptest/"><code>net/http/httptest</code></a> package's -<a href="/pkg/net/http/httptest/#ResponseRecorder"><code>ResponseRecorder</code></a> now initializes a default Content-Type header -using the same content-sniffing algorithm as in -<a href="/pkg/net/http/#Server"><code>http.Server</code></a>. -</li> - -<li> -The <a href="/pkg/net/url/"><code>net/url</code></a> package's -<a href="/pkg/net/url/#Parse"><code>Parse</code></a> is now stricter and more spec-compliant regarding the parsing -of host names. -For example, spaces in the host name are no longer accepted. -</li> - -<li> -Also in the <a href="/pkg/net/url/"><code>net/url</code></a> package, -the <a href="/pkg/net/url/#Error"><code>Error</code></a> type now implements -<a href="/pkg/net/#Error"><code>net.Error</code></a>. -</li> - -<li> -The <a href="/pkg/os/"><code>os</code></a> package's -<a href="/pkg/os/#IsExist"><code>IsExist</code></a>, -<a href="/pkg/os/#IsNotExist"><code>IsNotExist</code></a>, -and -<a href="/pkg/os/#IsPermission"><code>IsPermission</code></a> -now return correct results when inquiring about an -<a href="/pkg/os/#SyscallError"><code>SyscallError</code></a>. -</li> - -<li> -On Unix-like systems, when a write -to <a href="/pkg/os/#pkg-variables"><code>os.Stdout</code> -or <code>os.Stderr</code></a> (more precisely, an <code>os.File</code> -opened for file descriptor 1 or 2) fails due to a broken pipe error, -the program will raise a <code>SIGPIPE</code> signal. -By default this will cause the program to exit; this may be changed by -calling the -<a href="/pkg/os/signal"><code>os/signal</code></a> -<a href="/pkg/os/signal/#Notify"><code>Notify</code></a> function -for <code>syscall.SIGPIPE</code>. -A write to a broken pipe on a file descriptor other 1 or 2 will simply -return <code>syscall.EPIPE</code> (possibly wrapped in -<a href="/pkg/os#PathError"><code>os.PathError</code></a> -and/or <a href="/pkg/os#SyscallError"><code>os.SyscallError</code></a>) -to the caller. -The old behavior of raising an uncatchable <code>SIGPIPE</code> signal -after 10 consecutive writes to a broken pipe no longer occurs. -</li> - -<li> -In the <a href="/pkg/os/exec/"><code>os/exec</code></a> package, -<a href="/pkg/os/exec/#Cmd"><code>Cmd</code></a>'s -<a href="/pkg/os/exec/#Cmd.Output"><code>Output</code></a> method continues to return an -<a href="/pkg/os/exec/#ExitError"><code>ExitError</code></a> when a command exits with an unsuccessful status. -If standard error would otherwise have been discarded, -the returned <code>ExitError</code> now holds a prefix and suffix -(currently 32 kB) of the failed command's standard error output, -for debugging or for inclusion in error messages. -The <code>ExitError</code>'s -<a href="/pkg/os/exec/#ExitError.String"><code>String</code></a> -method does not show the captured standard error; -programs must retrieve it from the data structure -separately. -</li> - -<li> -On Windows, the <a href="/pkg/path/filepath/"><code>path/filepath</code></a> package's -<a href="/pkg/path/filepath/#Join"><code>Join</code></a> function now correctly handles the case when the base is a relative drive path. -For example, <code>Join(`c:`,</code> <code>`a`)</code> now -returns <code>`c:a`</code> instead of <code>`c:\a`</code> as in past releases. -This may affect code that expects the incorrect result. -</li> - -<li> -In the <a href="/pkg/regexp/"><code>regexp</code></a> package, -the -<a href="/pkg/regexp/#Regexp"><code>Regexp</code></a> type has always been safe for use by -concurrent goroutines. -It uses a <a href="/pkg/sync/#Mutex"><code>sync.Mutex</code></a> to protect -a cache of scratch spaces used during regular expression searches. -Some high-concurrency servers using the same <code>Regexp</code> from many goroutines -have seen degraded performance due to contention on that mutex. -To help such servers, <code>Regexp</code> now has a -<a href="/pkg/regexp/#Regexp.Copy"><code>Copy</code></a> method, -which makes a copy of a <code>Regexp</code> that shares most of the structure -of the original but has its own scratch space cache. -Two goroutines can use different copies of a <code>Regexp</code> -without mutex contention. -A copy does have additional space overhead, so <code>Copy</code> -should only be used when contention has been observed. -</li> - -<li> -The <a href="/pkg/strconv/"><code>strconv</code></a> package adds -<a href="/pkg/strconv/#IsGraphic"><code>IsGraphic</code></a>, -similar to <a href="/pkg/strconv/#IsPrint"><code>IsPrint</code></a>. -It also adds -<a href="/pkg/strconv/#QuoteToGraphic"><code>QuoteToGraphic</code></a>, -<a href="/pkg/strconv/#QuoteRuneToGraphic"><code>QuoteRuneToGraphic</code></a>, -<a href="/pkg/strconv/#AppendQuoteToGraphic"><code>AppendQuoteToGraphic</code></a>, -and -<a href="/pkg/strconv/#AppendQuoteRuneToGraphic"><code>AppendQuoteRuneToGraphic</code></a>, -analogous to -<a href="/pkg/strconv/#QuoteToASCII"><code>QuoteToASCII</code></a>, -<a href="/pkg/strconv/#QuoteRuneToASCII"><code>QuoteRuneToASCII</code></a>, -and so on. -The <code>ASCII</code> family escapes all space characters except ASCII space (U+0020). -In contrast, the <code>Graphic</code> family does not escape any Unicode space characters (category Zs). -</li> - -<li> -In the <a href="/pkg/testing/"><code>testing</code></a> package, -when a test calls -<a href="/pkg/testing/#T.Parallel">t.Parallel</a>, -that test is paused until all non-parallel tests complete, and then -that test continues execution with all other parallel tests. -Go 1.6 changes the time reported for such a test: -previously the time counted only the parallel execution, -but now it also counts the time from the start of testing -until the call to <code>t.Parallel</code>. -</li> - -<li> -The <a href="/pkg/text/template/"><code>text/template</code></a> package -contains two minor changes, in addition to the <a href="#template">major changes</a> -described above. -First, it adds a new -<a href="/pkg/text/template/#ExecError"><code>ExecError</code></a> type -returned for any error during -<a href="/pkg/text/template/#Template.Execute"><code>Execute</code></a> -that does not originate in a <code>Write</code> to the underlying writer. -Callers can distinguish template usage errors from I/O errors by checking for -<code>ExecError</code>. -Second, the -<a href="/pkg/text/template/#Template.Funcs"><code>Funcs</code></a> method -now checks that the names used as keys in the -<a href="/pkg/text/template/#FuncMap"><code>FuncMap</code></a> -are identifiers that can appear in a template function invocation. -If not, <code>Funcs</code> panics. -</li> - -<li> -The <a href="/pkg/time/"><code>time</code></a> package's -<a href="/pkg/time/#Parse"><code>Parse</code></a> function has always rejected any day of month larger than 31, -such as January 32. -In Go 1.6, <code>Parse</code> now also rejects February 29 in non-leap years, -February 30, February 31, April 31, June 31, September 31, and November 31. -</li> - -</ul> - |