Previously when a printer had a large buffer we dropped both
the buffer and the printer. There is no need to drop the printer
in this case, as a printer with a nil buffer is valid. So we
just drop the buffer and recycle the printer anyway.
This saves one allocation in case the buffer is over the limit.
Also tighten some of the tests for other unrelated cases.
Change-Id: Iba1b6a71ca4691464b8c68ab0b6ab0d4d5d6168c
Reviewed-on: https://go-review.googlesource.com/c/go/+/427395
Reviewed-by: Ian Lance Taylor <iant@google.com>
Run-TryBot: Rob Pike <r@golang.org>
Reviewed-by: Heschi Kreinick <heschi@google.com>
Reviewed-by: Rob Pike <r@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Sometimes when implementing a Formatter it's helpful to use the fmt
package without invoking the formatter. This new function, FormatString,
makes that easier in some cases by recreating the original formatting
directive (such as "%3.2f") that caused Formatter.Format to be
called.
The original Formatter interface is probably not what we would
design today, but we're stuck with it. FormatString, although it
takes a State as an argument, compensates by making Formatter a
little more flexible.
The State does not include the verb so (unlike in the issue), we
must provide it explicitly in the call to FormatString. Doing it there
minimizes allocations by returning the complete format string.
Fixes#51668
Updates #51195
Change-Id: Ie31c8256515864b2f460df45fbd231286b8b7a28
Reviewed-on: https://go-review.googlesource.com/c/go/+/400875
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>
Run-TryBot: Russ Cox <rsc@golang.org>
These are straightforward variants of the existing Sprintf etc.,
but append the resulting bytes to a provided buffer rather than
returning a string.
Internally, there is potentially some allocation because the package
uses a pool of buffers to build its output. We make no attempt to
override that, so the result is first printed into the pool and
then copied to the output. Since it is a managed pool, asymptotically
there should be no extra allocation.
Fixes#47579
RELNOTE=yes
Change-Id: Icef797f9b6f0c84d03e7035d95c06cdb819e2649
Reviewed-on: https://go-review.googlesource.com/c/go/+/406177
Reviewed-by: Ian Lance Taylor <iant@google.com>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Michael Knyszek <mknyszek@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
[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>
go/doc in all its forms applies this replacement when rendering
the comments. We are considering formatting doc comments,
including doing this replacement as part of the formatting.
Apply it to our source files ahead of time.
For #51082.
Change-Id: Ifcc1f5861abb57c5d14e7d8c2102dfb31b7a3a19
Reviewed-on: https://go-review.googlesource.com/c/go/+/384262
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>
A run of lines that are indented with any number of spaces or tabs
format as a <pre> block. This commit fixes various doc comments
that format badly according to that (standard) rule.
For example, consider:
// - List item.
// Second line.
// - Another item.
Because the - lines are unindented, this is actually two paragraphs
separated by a one-line <pre> block. This CL rewrites it to:
// - List item.
// Second line.
// - Another item.
Today, that will format as a single <pre> block.
In a future release, we hope to format it as a bulleted list.
Various other minor fixes as well, all in preparation for reformatting.
For #51082.
Change-Id: I95cf06040d4186830e571cd50148be3bf8daf189
Reviewed-on: https://go-review.googlesource.com/c/go/+/384257
Trust: Russ Cox <rsc@golang.org>
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gopher Robot <gobot@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>
Replace 24 spaces added in CL 389434 with 3 tabs,
so the new line is indented like other lines around it.
Updates #51419.
Change-Id: Ic3e50023a01f233c52dda53c36de2c461222d95c
Reviewed-on: https://go-review.googlesource.com/c/go/+/390674
Trust: Dmitri Shuralyov <dmitshur@golang.org>
Run-TryBot: Dmitri Shuralyov <dmitshur@golang.org>
Auto-Submit: Dmitri Shuralyov <dmitshur@golang.org>
TryBot-Result: Gopher Robot <gobot@golang.org>
Reviewed-by: Adam Shannon <adamkshannon@gmail.com>
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>
The package-level documentation on fmt previously had only two formal
sections, for printing and scanning. Because of this, the section on
printing was very long, including some pseudo-sections describing
particular features. This feature makes those pseudo-sections into
proper sections, both to improve readability and so that those sections
have hyperlinks on documentation sites.
Fixes#46522
Change-Id: I38b7bc3447610faca446051da235edcbbd063f61
Reviewed-on: https://go-review.googlesource.com/c/go/+/324349
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
Run-TryBot: Dmitri Shuralyov <dmitshur@golang.org>
TryBot-Result: Go Bot <gobot@golang.org>
Trust: Tobias Klauser <tobias.klauser@gmail.com>
Formatter is mentioned further down, but it's helpful
to add it amongst the verbs and flags.
Background: I spent a while puzzling how "%+v" prints
a stack trace for github.com/pkg/errors when this isn't
documented under 'flags'.
Change-Id: Ic70145902a36780147dedca568b3cf482974fc38
GitHub-Last-Rev: 6571b499f2
GitHub-Pull-Request: golang/go#39860
Reviewed-on: https://go-review.googlesource.com/c/go/+/240000
Reviewed-by: Rob Pike <r@golang.org>
Trust: Rob Pike <r@golang.org>
Trust: Ian Lance Taylor <iant@golang.org>
Instead of returning a bad verb error format for runes above
utf8.Maxrune return a quoted utf8.RuneError rune (\ufffd).
This makes the behaviour consistent with the "c" verb and
aligns behaviour to not return bad verb error format when
a verb is applied to the correct argument type.
Fixes#14569
Change-Id: I679485f6bb90ebe408423ab68af16cce38816cd0
Reviewed-on: https://go-review.googlesource.com/c/go/+/248759
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
Instead use string(r) where r has type rune.
This is in preparation for a vet warning for string(i).
Updates #32479
Change-Id: Ic205269bba1bd41723950219ecfb67ce17a7aa79
Reviewed-on: https://go-review.googlesource.com/c/go/+/220844
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Akhil Indurti <aindurti@gmail.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Toshihiro Shiino <shiino.toshihiro@gmail.com>
There were a couple of bugs, including not requiring a percent and
returning the wrong error for a bad format containing %%.
Both are addressed by fixing the first.
Fixes#34180.
Change-Id: If96c0c0258bcb95eec49871437d719cb9d399d9b
Reviewed-on: https://go-review.googlesource.com/c/go/+/202879
Run-TryBot: Emmanuel Odeke <emm.odeke@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>
As mentioned in https://golang.org/issue/34062#issuecomment-529692313
src/cmd refers to older version of golang.org/x/tools.
Hence, not checking if multiple errors are used in the same fmt.Errorf.
Updating golang.org/x/tools version to latest in src/cmd.
Fixes#34062
Change-Id: I358dec2c3d3af2b19add766b8488b919109b81d6
Reviewed-on: https://go-review.googlesource.com/c/go/+/196843
Run-TryBot: Michael Matloob <matloob@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Michael Matloob <matloob@golang.org>
Like panicking and erroring - wrapErrs should always be reset to
the default false. wrapErrs should only be true when set by Errorf.
Change-Id: I4d51cc2f0905109e232b0983dc5331bd34f138bc
Reviewed-on: https://go-review.googlesource.com/c/go/+/178517
Run-TryBot: Martin Möhrmann <moehrmann@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Damien Neil <dneil@google.com>
When fmt.Errorf is provided with a %w verb with an error operand,
return an error implementing an Unwrap method returning that operand.
It is invalid to use %w with other formatting functions, to use %w
multiple times in a format string, or to use %w with a non-error
operand. When the Errorf format string contains an invalid use of %w,
the returned error does not implement Unwrap.
Change-Id: I534e20d3b163ab22c2b137b1c9095906dc243221
Reviewed-on: https://go-review.googlesource.com/c/go/+/176998
Reviewed-by: Marcel van Lohuizen <mpvl@golang.org>
Renaming the method makes clear, both to readers and to vet,
that this method is not the implementation of io.ByteWriter.
Working toward making the tree vet-safe instead of having
so many exceptions in cmd/vet/all/whitelist.
For #31916.
Change-Id: I79da062ca6469b62a6b9e284c6cf2413c7425249
Reviewed-on: https://go-review.googlesource.com/c/go/+/176109
Run-TryBot: Russ Cox <rsc@golang.org>
Reviewed-by: Austin Clements <austin@google.com>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
As proposed in Issue #29934, update errors produced by the os package to
work with errors.Is sentinel tests. For example,
errors.Is(err, os.ErrPermission) is equivalent to os.IsPermission(err)
with added unwrapping support.
Move the definition for os.ErrPermission and others into the syscall
package. Add an Is method to syscall.Errno and others. Add an Unwrap
method to os.PathError and others.
Updates #30322
Updates #29934
Change-Id: I95727d26c18a5354c720de316dff0bffc04dd926
Reviewed-on: https://go-review.googlesource.com/c/go/+/163058
Reviewed-by: Marcel van Lohuizen <mpvl@golang.org>
The name change init -> init.ializers was initially required for
initialization code.
With CL 161337 there's no wrapper code any more, there's a data
structure instead (named .inittask). So we can go back to just
plain init appearing in tracebacks.
RELNOTE=yes
Update #29919. Followon to CL 161337.
Change-Id: I5a4a49d286df24b53b2baa193dfda482f3ea82a5
Reviewed-on: https://go-review.googlesource.com/c/go/+/167780
Run-TryBot: Keith Randall <khr@golang.org>
Reviewed-by: Josh Bleecher Snyder <josharian@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
This applies only for cases where %w is not used.
The purpose of this change is to reduce test failures where tests
depend on these two being the same type, as they previously were.
Change-Id: I2dd28b93fe1d59f3cfbb4eb0875d1fb8ee699746
Reviewed-on: https://go-review.googlesource.com/c/go/+/167402
Run-TryBot: Marcel van Lohuizen <mpvl@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Damien Neil <dneil@google.com>
This is a refinement of CL 164557.
Make it explicit in tests that using a non-string verb with
fmtError does not result in falling back to using fmt.Formatter.
Change-Id: I6d090f31818eb7cc7668d7565b1449c91cd03a23
Reviewed-on: https://go-review.googlesource.com/c/go/+/164701
Run-TryBot: Marcel van Lohuizen <mpvl@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Damien Neil <dneil@google.com>
CL 165619 removed these names when it removed
the use of the plain 'return'. But the names help for
documentation purposes even without being mentioned
directly in the function, so removing them makes the
code less readable. Put them back. I renamed found
to zeroFound to make the meaning clearer.
Change-Id: I1010931f08290af0b0ede7d21b1404c2eea196a0
Reviewed-on: https://go-review.googlesource.com/c/go/+/165899
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
When formatting an error with a non-string formatting verb such as %d,
use the default formatting behavior rather than treating this as a bad
verb.
For example, this should print 42, not %!d(main.E=42):
var E int
func (E) Error() string { return "error" }
fmt.Printf("%d", E(42))
Fixes#30472
Change-Id: I62fd309c8ee9839a69052b0ec7f1808449dcee8e
Reviewed-on: https://go-review.googlesource.com/c/164557
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Original Printf("%d", hi) obviously doesn't produce
%!d(string=hi) unless somewhere before this code
block you have hi := "hi" somewhere, also this change
maintains consistency with the rest of it
Change-Id: I40d8cca623176dcad66374ba74e3a1f8f975ac9e
GitHub-Last-Rev: 242e9ee6af
GitHub-Pull-Request: golang/go#30223
Reviewed-on: https://go-review.googlesource.com/c/162541
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
This CL updates fmt's scanner to accept the new number syntaxes:
- Hexadecimal floating-point values.
- Digit-separating underscores.
- Leading 0b and 0o prefixes.
See golang.org/design/19308-number-literals for background.
For #12711.
For #19308.
For #28493.
For #29008.
Change-Id: I5582af5c94059c781e6cf4e862441d3df3006adf
Reviewed-on: https://go-review.googlesource.com/c/160247
Reviewed-by: Robert Griesemer <gri@golang.org>
This CL modifies fmt's printer to implement %#b and %O
to emit leading 0b and 0o prefixes on binary and octal.
(%#o is already taken and emits "0377"; %O emits "0o377".)
See golang.org/design/19308-number-literals for background.
For #19308.
For #12711.
Vet update is #29986.
Change-Id: I7c38a4484c48a03abe9f6d45c7d981c7c314f583
Reviewed-on: https://go-review.googlesource.com/c/160246
Reviewed-by: Robert Griesemer <gri@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
This CL modifies fmt's printer to implement %x and %X
for formatting floating-point data (floats and complexes)
in standard hexadecimal notation.
See golang.org/design/19308-number-literals for background.
For #29008.
Vet update is #29986.
Change-Id: If2842a11631bc393a1ebcf6914ed07658652af5a
Reviewed-on: https://go-review.googlesource.com/c/160245
Reviewed-by: Robert Griesemer <gri@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
Now that maps are printed in deterministic order, the map example
can have multiple keys without breaking the build.
Change-Id: Iccec0cd76a3d41c75d8d4eb768ec0ac09ad9f2ad
Reviewed-on: https://go-review.googlesource.com/c/151218
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
fmtBytes is in the top 10 callers of runtime.slicebytetostring according
to Google wide profiling data.
Avoid the string conversion of the input byte slice in fmtBytes by calling
a newly added specialized fmtS function for byte slices.
Expand tests for verb s with widths to test strings and byte slice arguments.
SprintfTruncateString 157ns ± 4% 156ns ± 3% ~ (p=0.122 n=20+20)
SprintfTruncateBytes 188ns ± 2% 155ns ± 3% -18.00% (p=0.000 n=20+19)
name old alloc/op new alloc/op delta
SprintfTruncateString 16.0B ± 0% 16.0B ± 0% ~ (all equal)
SprintfTruncateBytes 64.0B ± 0% 16.0B ± 0% -75.00% (p=0.000 n=20+20)
name old allocs/op new allocs/op delta
SprintfTruncateString 1.00 ± 0% 1.00 ± 0% ~ (all equal)
SprintfTruncateBytes 2.00 ± 0% 1.00 ± 0% -50.00% (p=0.000 n=20+20)
Change-Id: I461bf514d4232b39bd9c812f7faa4e5ef693a03b
Reviewed-on: https://go-review.googlesource.com/c/145284
Run-TryBot: Martin Möhrmann <martisch@uos.de>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
For easier testing, change the way maps are printed so they
appear in a consistent order between runs. Do this by printing
them in key-sorted order.
To do this, we add a package at the root, internal/fmtsort,
that implements a general mechanism for sorting map keys
regardless of their type. This is a little messy and probably
slow, but formatted printing of maps has never been fast and
is already always reflection-driven.
The rules are:
The ordering rules are more general than with Go's < operator:
- when applicable, nil compares low
- ints, floats, and strings order by <
- NaN compares less than non-NaN floats
- bool compares false before true
- complex compares real, then imag
- pointers compare by machine address
- channel values compare by machine address
- structs compare each field in turn
- arrays compare each element in turn.
- interface values compare first by reflect.Type describing the concrete type
and then by concrete value as described in the previous rules.
The new package is internal because we really do not want
everyone using this to sort things. It is slow, not general, and
only suitable for the subset of types that can be map keys.
Also use the package in text/template, which already had a
weaker version of this mechanism.
This change requires adding a dependency on sort to the fmt
package, but that isn't disruptive to the dependency tree.
Fixes#21095
Change-Id: Ia602115c7de5d95993dbd609611d8bd96e054157
Reviewed-on: https://go-review.googlesource.com/c/142737
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>
Numbers without decimals are valid Go representations of whole-number
floats. That is, "var x float64 = 5" is valid Go. Avoid breakage in
tests that expect a certain output from %#v by reverting to it.
To guarantee the right type is generated by a print use %T(%#v) instead.
Added a test to lock in this behavior.
This reverts commit 7c7cecc184.
Fixes#27634
Updates #26363
Change-Id: I544c400a0903777dd216452a7e86dfe60b0b0283
Reviewed-on: https://go-review.googlesource.com/c/142597
Run-TryBot: Filippo Valsorda <filippo@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Bryan C. Mills <bcmills@google.com>
And start using it elsewhere in the standard library, removing the
copies in the process.
While at it, rewrite the io.WriteString godoc to be more clear, since it
can now make reference to the defined interface.
Fixes#27946.
Change-Id: Id5ba223c09c19e5fb49815bd3b1bd3254fc786f3
Reviewed-on: https://go-review.googlesource.com/c/139457
Run-TryBot: Daniel Martí <mvdan@mvdan.cc>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Provide an example for each of the printing functions (Print,
Sprintf, Fprintln etc.), and make them all produce the same output
so their usage can be compared.
Also add a package-level example explaining the difference between
how Printf, Println, and Print behave.
There are more examples to come.
Update #27554.
Change-Id: Ide03e5233f3762a9ee2ac0269f534ab927562ce2
Reviewed-on: https://go-review.googlesource.com/136615
Reviewed-by: Ian Lance Taylor <iant@golang.org>
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
There is much left out here—the space of possibilities is very
large—but this example shows all that most programmers will need
to know for most printing problems.
Update #27554.
Change-Id: Ib6ae651d5c3720cf7fe1a05ffd0859a5b56a9157
Reviewed-on: https://go-review.googlesource.com/136616
Reviewed-by: Ian Lance Taylor <iant@golang.org>
The current usage of sync.Pool is leaky because it stores an arbitrary
sized buffer into the pool. However, sync.Pool assumes that all items in the
pool are interchangeable from a memory cost perspective. Due to the unbounded
size of a buffer that may be added, it is possible for the pool to eventually
pin arbitrarily large amounts of memory in a live-lock situation.
As a simple fix, we just set a maximum size that we permit back into the pool.
We do not need to fix the use of a sync.Pool in scan.go since the free method
has always enforced a maximum capacity since the first commit of the scan logic.
Fixes#27740
Updates #23199
Change-Id: I875278f7dba42625405df36df3e9b028252ce5e3
Reviewed-on: https://go-review.googlesource.com/136116
Reviewed-by: Bryan C. Mills <bcmills@google.com>
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Updates #27376
Change-Id: I9ce6541a95b5ecd13f3932558427de1f597df07a
Reviewed-on: https://go-review.googlesource.com/134036
Run-TryBot: Ian Lance Taylor <iant@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>
