Change-Id: I874f0c0399cb09de4fe4dd2097602c5fa0512b12
GitHub-Last-Rev: 73be01ae2a
GitHub-Pull-Request: golang/go#67223
Reviewed-on: https://go-review.googlesource.com/c/go/+/583735
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Change-Id: I00d49ded65801ab12322f711d1ac6131d69aea34
Reviewed-on: https://go-review.googlesource.com/c/go/+/535081
Reviewed-by: Carlos Amedee <carlos@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: shuang cui <imcusg@gmail.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
Use ^ and $ in the -run flag regular expression value when the intention
is to invoke a single named test. This removes the reliance on there not
being another similarly named test to achieve the intended result.
In particular, package syscall has tests named TestUnshareMountNameSpace
and TestUnshareMountNameSpaceChroot that both trigger themselves setting
GO_WANT_HELPER_PROCESS=1 to run alternate code in a helper process. As a
consequence of overlap in their test names, the former was inadvertently
triggering one too many helpers.
Spotted while reviewing CL 525196. Apply the same change in other places
to make it easier for code readers to see that said tests aren't running
extraneous tests. The unlikely cases of -run=TestSomething intentionally
being used to run all tests that have the TestSomething substring in the
name can be better written as -run=^.*TestSomething.*$ or with a comment
so it is clear it wasn't an oversight.
Change-Id: Iba208aba3998acdbf8c6708e5d23ab88938bfc1e
Reviewed-on: https://go-review.googlesource.com/c/go/+/524948
Reviewed-by: Tobias Klauser <tobias.klauser@gmail.com>
Auto-Submit: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: Kirill Kolyshkin <kolyshkin@gmail.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
As part of developing #57411, we ran into cases where a flag was
defined in one package init and Set in another package init, and there
was no init ordering implied by the spec between those two
packages. Changes in initialization ordering as part of #57411 caused
a Set to happen before the definition, which makes the Set silently
fail.
This CL makes the Set fail loudly in that situation.
Currently Set *does* fail kinda quietly in that situation, in that it
returns an error. (It seems that no one checks the error from Set,
at least for string flags.) Ian suggsted that instead we panic at
the definition site if there was previously a Set called on that
(at the time undefined) flag.
So Set on an undefined flag is ok and returns an error (as before),
but defining a flag which has already been Set causes a panic. (The
API for flag definition has no way to return an error, and does
already panic in some situations like a duplicate definition.)
Update #57411
Change-Id: I39b5a49006f9469de0b7f3fe092afe3a352e4fcb
Reviewed-on: https://go-review.googlesource.com/c/go/+/480215
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@google.com>
Fixes#53747
Based on CL 416514
Change-Id: I1ff79c6290b06dfa8672a473045e8fe80c22afcf
GitHub-Last-Rev: 74fba9b309
GitHub-Pull-Request: golang/go#59013
Reviewed-on: https://go-review.googlesource.com/c/go/+/476015
Run-TryBot: Ian Lance Taylor <iant@google.com>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: Cherry Mui <cherryyz@google.com>
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
flag.Example() has this comment:
... one must execute, typically at the start of main (not init!):
flag.Parse()
We don't run it here because this is not a main function
This example function will be renamed to "main" at pkg.go.dev, which
makes the comment confusing.
See https://pkg.go.dev/flag#example-package.
This change modify the comment to clarify this situation.
Change-Id: I17357fdaaefe54791fff8fbbf6a33003af207f88
GitHub-Last-Rev: eeea8ce39c
GitHub-Pull-Request: golang/go#56411
Reviewed-on: https://go-review.googlesource.com/c/go/+/445315
Run-TryBot: Ian Lance Taylor <iant@google.com>
Run-TryBot: Rob Pike <r@golang.org>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: Rob Pike <r@golang.org>
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: Heschi Kreinick <heschi@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Remove a vestigial " // BUG" comment as there is no bug in the relevant code section and comment predated other changes. Also removed a needless allocation and conformed to the "v, ok := a[x]" standard convention. Tests are passing.
Change-Id: Id28ad1baf77447052b54b341f018e573bac0c11a
GitHub-Last-Rev: 26084698bf
GitHub-Pull-Request: golang/go#56210
Reviewed-on: https://go-review.googlesource.com/c/go/+/442815
Reviewed-by: Ian Lance Taylor <iant@google.com>
Reviewed-by: David Chase <drchase@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
Run-TryBot: Ian Lance Taylor <iant@google.com>
Reviewed-by: Rob Pike <r@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Although I can't think of any reason to do this, it is possible for
a user-defined flag to implement IsBoolFlag but return "false".
This is nuts because checking the interface is satisfied should
obviously be sufficient, but the documentation kinda implies it's
not. And if you try this, you'll discover that the usage message
ignores the return value even though the rest of the package plays
nice. Bother.
So we fix it, as the fix is trivial: call the method when creating
the usage message.
Fixes#53473
Change-Id: I1ac80a876ad5626eebfc5ef6cb972cd3007afaad
Reviewed-on: https://go-review.googlesource.com/c/go/+/431102
Reviewed-by: Cherry Mui <cherryyz@google.com>
Run-TryBot: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Change-Id: Iee846c4ac0f111ff97aa618dd42f6b2d14aa4342
Reviewed-on: https://go-review.googlesource.com/c/go/+/428259
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
Run-TryBot: Ian Lance Taylor <iant@google.com>
Updating examples, to show that double dashes are also permitted. This has been easy to miss previously.
Change-Id: Ib67b4e39fea90ef4cb9e894709c53baedfc18fc2
GitHub-Last-Rev: f7df57b646
GitHub-Pull-Request: golang/go#53628
Reviewed-on: https://go-review.googlesource.com/c/go/+/415374
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Ian Lance Taylor <iant@google.com>
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: David Chase <drchase@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Run-TryBot: Ian Lance Taylor <iant@google.com>
[This CL is part of a sequence implementing the proposal #51082.
The design doc is at https://go.dev/s/godocfmt-design.]
Run the updated gofmt, which reformats doc comments,
on the main repository. Vendored files are excluded.
For #51082.
Change-Id: I7332f099b60f716295fb34719c98c04eb1a85407
Reviewed-on: https://go-review.googlesource.com/c/go/+/384268
Reviewed-by: Jonathan Amsterdam <jba@google.com>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
When printing the usage message, recover panics when calling String
methods on reflect-constructed flag.Value zero values. Collect the panic
messages and include them at the end of the PrintDefaults output so that
the programmer knows to fix the panic.
Fixes#28667
Change-Id: Ic4378a5813a2e26f063d5580d678add65ece8f97
Reviewed-on: https://go-review.googlesource.com/c/go/+/396574
Run-TryBot: Andrew Gerrand <adg@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Auto-Submit: Ian Lance Taylor <iant@golang.org>
Trust: Andrew Gerrand <adg@golang.org>
A long time ago, gofmt insisted on inserting tabs in /* */ comments
at the top level of the file, like this:
/*
Package doc comment.
*/
package p
Gofmt still insists on the tab for comments not at top level,
but it has relaxed the rules about top-level comments.
A few very old doc comments are indented, left over from the old rule.
We are considering formatting doc comments, and so to make
everything consistent, standardize on unindented doc comments
by removing tabs in the few doc comments that are still indented this way.
Also update some cmd/gofmt testdata to match.
Change-Id: I293742e39b52f8a48ec41f72ca4acdafa7ce43bc
Reviewed-on: https://go-review.googlesource.com/c/go/+/384261
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
The TextVar function makes it easier to integrate the flag package
with any Go type that implements encoding.Text{Marshaler,Unmarshaler}.
Fixes#45754
Change-Id: Id23c37d59cf8c9699a7943a22ce27a45eb685c0f
Reviewed-on: https://go-review.googlesource.com/c/go/+/313329
Trust: Joseph Tsai <joetsai@digital-static.net>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Joseph Tsai <joetsai@digital-static.net>
TryBot-Result: Gopher Robot <gobot@golang.org>
A few of the tests were printing garbage to stderr,
since FlagSet's default Output is os.Stderr:
$ go test
flag provided but not defined: -x
invalid value "1" for flag -v: test error
Usage of test:
flag needs an argument: -b
Usage of test:
-b usage
PASS
ok flag 0.008s
Add the remaining SetOutput(io.Discard) method calls.
Note that TestUserDefinedFunc was a tricky one.
Even with the added SetOutput calls,
the last part of the test would still print usage text to stderr.
It took me a while to figure out the problem was copying FlagSet.
I've filed go.dev/issue/51507 to record this particular sharp edge,
and the test code now avoids making FlagSet copies to avoid the bug.
Change-Id: I323f24091b98386312aa72df3eb890af6625628d
Reviewed-on: https://go-review.googlesource.com/c/go/+/390234
Trust: Daniel Martí <mvdan@mvdan.cc>
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
And then revert the bootstrap cmd directories and certain testdata.
And adjust tests as needed.
Not reverting the changes in std that are bootstrapped,
because some of those changes would appear in API docs,
and we want to use any consistently.
Instead, rewrite 'any' to 'interface{}' in cmd/dist for those directories
when preparing the bootstrap copy.
A few files changed as a result of running gofmt -w
not because of interface{} -> any but because they
hadn't been updated for the new //go:build lines.
Fixes#49884.
Change-Id: Ie8045cba995f65bd79c694ec77a1b3d1fe01bb09
Reviewed-on: https://go-review.googlesource.com/c/go/+/368254
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
There is a single function in the flag package whose implementation
uses string concatenation instead of the recommended strings.Builder.
The function was last touched before strings.Builder was introduced
in Go 1.10, which explains the old style code. This PR updates
the implementation.
Fixes#45392
Change-Id: Id2d8f1788765a0c4faaeb1e6870914f72b3c8442
GitHub-Last-Rev: 0e12fe3045
GitHub-Pull-Request: golang/go#45393
Reviewed-on: https://go-review.googlesource.com/c/go/+/307329
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Trust: Josh Bleecher Snyder <josharian@gmail.com>
The old ioutil references are still valid, but update our code
to reflect best practices and get used to the new locations.
Code compiled with the bootstrap toolchain
(cmd/asm, cmd/dist, cmd/compile, debug/elf)
must remain Go 1.4-compatible and is excluded.
Also excluded vendored code.
For #41190.
Change-Id: I6d86f2bf7bc37a9d904b6cee3fe0c7af6d94d5b1
Reviewed-on: https://go-review.googlesource.com/c/go/+/263142
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
CL 221427 added TestExitCode. This test is failing
on Plan 9 because ExitCode is always equal to 1
on error since Plan 9 use error strings.
This change fixes TestExitCode by checking that
ExitCode is equal to 1 on error instead of the
specific value.
Fixes#38237.
Change-Id: Ie269722e731e275e5bfc51644c1fa6be76525f1f
Reviewed-on: https://go-review.googlesource.com/c/go/+/227158
Run-TryBot: David du Colombier <0intro@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
flag treats -h or -help as a special case to print a nice help
message, but exit with a status code of 2. This update makes
that status code 0.
Fixes#37533
Change-Id: I7e0bd29944ce46607fb7cfc6740734f7444a151a
GitHub-Last-Rev: 83f64d757b
GitHub-Pull-Request: golang/go#37530
Reviewed-on: https://go-review.googlesource.com/c/go/+/221427
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Changed the flag variable name to nFlag instead of flagname,
because flagname was confusing.
Change-Id: I20dd4c4b4f605395d427a125ba4fd14580e5d766
Reviewed-on: https://go-review.googlesource.com/c/go/+/221678
Reviewed-by: Rob Pike <r@golang.org>
The out method was renamed to Output in CL 70391 for #17628 and #21888.
Fixes#37514
Change-Id: I99be47b5030ccbbf10a056df9fcc3c97cb99b015
Reviewed-on: https://go-review.googlesource.com/c/go/+/221383
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
The first biggest offender was crypto/des.init at ~1%. It's
cryptographically broken and the init function is relatively expensive,
which is unfortunate as both crypto/tls and crypto/x509 (and by
extension, cmd/go) import it. Hide the work behind sync.Once.
The second biggest offender was flag.sortFlags at just under 1%, used by
the Visit flagset methods. It allocated two slices, which made a
difference as cmd/go iterates over multiple flagsets during init.
Use a single slice with a direct sort.Interface implementation.
Another big offender is initializing global maps. Reducing this work in
cmd/go/internal/imports and net/textproto gives us close to another
whole 1% in saved work. The former can use map literals, and the latter
can hide the work behind sync.Once.
Finally, compress/flate used newHuffmanBitWriter as part of init, which
allocates many objects and slices. Yet it only used one of the slice
fields. Allocating just that slice saves a surprising ~0.3%, since we
generated a lot of unnecessary garbage.
All in all, these little pieces amount to just over 3% saved CPU time.
name old time/op new time/op delta
ExecGoEnv-8 3.61ms ± 1% 3.50ms ± 0% -3.02% (p=0.000 n=10+10)
Updates #26775.
Updates #29382.
Change-Id: I915416e88a874c63235ba512617c8aef35c0ca8b
Reviewed-on: https://go-review.googlesource.com/c/go/+/166459
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
The existing docs only mention that it is possible to change the output
destination of PrintDefaults from the default of standard error, but fail to
mention how to actually do so. This change fixes this lack by directing users
to CommandLine.SetOutput.
Fixes#15024
Change-Id: Ieaa7edbebd23d4ea6fa7e53d97a87143d590bdb3
Reviewed-on: https://go-review.googlesource.com/c/145203
Reviewed-by: Rob Pike <r@golang.org>
Return a consistently formatted error string that reports either
a parse error or a range error.
Before:
invalid boolean value "3" for -debug: strconv.ParseBool: parsing "3": invalid syntax
After:
invalid boolean value "3" for -debug: parse error
Fixes#26822
Change-Id: I60992bf23da32a4c0cf32472a8af486a3c9674ad
Reviewed-on: https://go-review.googlesource.com/c/143257
Reviewed-by: Ian Lance Taylor <iant@golang.org>
I omitted vendor directories and anything necessary for bootstrapping.
(Tested by bootstrapping with Go 1.4)
Updates #27864
Change-Id: I7d9b68d0372d3a34dee22966cca323513ece7e8a
Reviewed-on: https://go-review.googlesource.com/137856
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Change-Id: I579cc9f4f8e5be5fd6447a99614797ab7bc53611
Reviewed-on: https://go-review.googlesource.com/120175
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Godoc expects text after a header, not code.
Change-Id: I99f412ad15e10bf9cea0dbd19019ed6ce477736c
Reviewed-on: https://go-review.googlesource.com/117595
Reviewed-by: Rob Pike <r@golang.org>
Removing the colon will make the "Usage" and "Command line flag syntax" in the docs, a header when interpreted by godoc.
Fixes#25749
Change-Id: Ifc5572e171db1aaef9775b1d6c86091a8f2528fd
GitHub-Last-Rev: 1b57973430
GitHub-Pull-Request: golang/go#25750
Reviewed-on: https://go-review.googlesource.com/116555
Reviewed-by: Rob Pike <r@golang.org>
When the flag package first begin printing nonzero defaults, the test
was against a fixed set of string representations of zero values.
This worked until the string representation of a time.Duration
changed from "0" to "0s", causing the zero Duration to register as
nonzero. The flag package then added reflect-based code that fell back
to the old test. This failed to work when a nonzero default for a flag
happened to be the string representation of one the original fixed set
of zero values in the original test. This change removes the original
test, allowing the reflect-based code to be the only deciding factor.
Fixes#23543
Change-Id: I582ce554d6729e336fdd96fb27340674c15350d8
Reviewed-on: https://go-review.googlesource.com/103867
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Allows code that operates on a FlagSet to know the name and error
handling behavior of the FlagSet without having to call FlagSet.Init.
Fixes#17628Fixes#21888
Change-Id: Ib0fe4c8885f9ccdacf5a7fb761d5ecb23f3bb055
Reviewed-on: https://go-review.googlesource.com/70391
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Simplifies the switch statement in the isZeroValue function by merging
the case branches.
Change-Id: I5b27939b62808dadac0cef632567b17e0e2b9a1d
Reviewed-on: https://go-review.googlesource.com/71390
Run-TryBot: Gabriel Aszalos <gabriel.aszalos@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Previously, a multi-line flag usage string would not be indented with the
rest of the usage strings. This made long usage strings difficult to read.
For example, the usage for flag.String("A", "", "1\n2\n3") would be printed
as:
-A 1
2
3
But will now be printed as:
-A 1
2
3
Also fixes a slight error in the FlagSet.PrintDefaults documentation.
Fixes#20799
Change-Id: I4379c6b7590fdb93a2809a01046a0f6ae32c3e5d
Reviewed-on: https://go-review.googlesource.com/66711
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
Some custom usage functions call it for clarity; others rely on the default
behavior, which makes an explicit call redundant. Document that it's
safe to be explicit.
Fixes#21671.
Change-Id: I08e9f47265582821cfd35995dff0c589cd85809d
Reviewed-on: https://go-review.googlesource.com/59792
Reviewed-by: Dominik Honnef <dominik@honnef.co>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Went mainly for the ones that make no sense, such as the ones
mid-sentence or after commas.
Change-Id: Ie245d2c19cc7428a06295635cf6a9482ade25ff0
Reviewed-on: https://go-review.googlesource.com/57293
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
TryBot-Result: Gobot Gobot <gobot@golang.org>
CommandLine (exported in Go 1.2) has default output of os.Stderr.
Before it was exported, it made sense to have the global Usage func
(the implicit usage func if CommandLine.Usage is nil) hard-code
os.Stderr has its output. But once CommandLine was exported, Usage
should use it if provided.
Fixes#20998
Change-Id: I9e1c0415a563a982634b9808199c9ee175d72f4c
Reviewed-on: https://go-review.googlesource.com/48390
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
This allows callers to invoke f.Usage() themselves and get the default
usage handler instead of a panic (from calling a nil function).
Fixes#16955.
Change-Id: Ie337fd9e1f85daf78c5eae7b5c41d5ad8c1f89bf
Reviewed-on: https://go-review.googlesource.com/31576
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
The existing implementation of flag values with fmt package uses
more memory and works slower than the implementation with strconv
package.
Change-Id: I9e749179f66d5c50cafe98186641bcdbc546d2db
Reviewed-on: https://go-review.googlesource.com/28914
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Otherwise flag.PrintDefaults will fail when it tries to determine
whether the default is the zero value.
Fixes#16694.
Change-Id: I253fbf11ffc0a9069fd48c2c3cf3074df53e3a03
Reviewed-on: https://go-review.googlesource.com/27003
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Implemented by using a reflect-based approach to recognize the zero
value of any non-interface type that implements flag.Value. Interface
types will fall back to the old code.
Fixes#15904.
Change-Id: I594c3bfb30e9ab1aca3e008ef7f70be20aa41a0b
Reviewed-on: https://go-review.googlesource.com/23581
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
