Updates #16360

Change-Id: I5927cffa961cd85539a3ba9606b116c5996d1096
Reviewed-on: https://go-review.googlesource.com/26696
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>

The tree's pretty inconsistent about single space vs double space
after a period in documentation. Make it consistently a single space,
per earlier decisions. This means contributors won't be confused by
misleading precedence.

This CL doesn't use go/doc to parse. It only addresses // comments.
It was generated with:

$ perl -i -npe 's,^(\s*// .+[a-z]\.)  +([A-Z]),$1 $2,' $(git grep -l -E '^\s*//(.+\.)  +([A-Z])')
$ go test go/doc -update

Change-Id: Iccdb99c37c797ef1f804a94b22ba5ee4b500c4f7
Reviewed-on: https://go-review.googlesource.com/20022
Reviewed-by: Rob Pike <r@golang.org>
Reviewed-by: Dave Day <djd@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

Applied identical change to cmd/gofmt/internal.go.

Fixes #11275.

Change-Id: Icb4bf0460c94c9e2830dd0d62c69376774cbda30
Reviewed-on: https://go-review.googlesource.com/15154
Reviewed-by: Alan Donovan <adonovan@google.com>

Fixes #11844.

Change-Id: I32edd39e79f7c9bdc132c49bd06081f35dac245d
Reviewed-on: https://go-review.googlesource.com/15114
Reviewed-by: Alan Donovan <adonovan@google.com>

The code formatting mechanism can be applied to partial Go code,
such as a list of statements. The statements are wrapped into a
function definition (to be parsed fine), and unwrapped after formatting.

When the statements contain //line annotations, it may fail,
because not all comments are flushed by the printer before the final '}'.
Formatting "\ta()\n//line :1" results in "\ta() }\n\n//line", which
is wrong.

Tweaked the wrapping/unwrapping code to make sure comments are flushed
before the '}'.

Fixes #11276

Change-Id: Id15c80279b0382ee9ed939cca1647f525c4929f5
Reviewed-on: https://go-review.googlesource.com/11282
Run-TryBot: Robert Griesemer <gri@golang.org>
Reviewed-by: Robert Griesemer <gri@golang.org>

cmd/gofmt and go/format had 3 functions (parse, format and isSpace)
that had to be kept in-sync.

This CL extracts these 3 functions and refactors them into a new
internal/format package.
This CL is just code reorganization with no behavior nor semantic
change.

Change-Id: I593f24e9d3cadbbd9559a67e3b1d2ff190b4fd90
Reviewed-on: https://go-review.googlesource.com/6760
Reviewed-by: Robert Griesemer <gri@golang.org>

This is a minor cleanup following CL 142360043:

The internal parse and format functions in both packages
were almost identical - made them identical by adding an
extra parameter, and documented them as identical.

Eventually we should find a nice way to factor these functions
out, but we cannot do this now while in prep for 1.4.

No functionality change.

LGTM=adonovan
R=adonovan
CC=golang-codereviews
https://golang.org/cl/146520043

Fixes #5551.
Fixes #4449.

Adds tests for both issues.

Note that the two issues occur only when formatting partial Go code
with indent.

The best way to understand the change is as follows: I took the code
of cmd/gofmt and go/format, combined it into one unified code that
does not suffer from either 4449 nor 5551, and then applied that code
to both cmd/gofmt and go/format.

As a result, there is now much more identical code between the two
packages, making future code deduplication easier (it was not possible
to do that now without adding public APIs, which I was advised not to
do at this time).

More specifically, I took the parse() of cmd/gofmt which correctly
preserves comments (issue 5551) and modified it to fix issue where
it would sometimes modify literal values (issue 4449).

I ended up removing the matchSpace() function because it no longer
needed to do some of its work (insert indent), and a part of its work
had to be done in advance (determining the indentation of first code
line), because that calculation is required for cfg.Fprint() to run.

adjustIndent is used to adjust the indent of cfg.Fprint() to compensate
for the body of wrapper func being indented by one level. This allows
to get rid of the bytes.Replace text manipulation of inner content,
which was problematic and sometimes altered raw string literals (issue
4449). This means that sometimes the value of cfg.Indent is negative,
but that works as expected.

So now the algorithm for formatting partial Go code is:

1. Determine and prepend leading space of original source.
2. Determine and prepend indentation of first code line.
3. Format and write partial Go code (with all of its leading &
   trailing space trimmed).
4. Determine and append trailing space of original source.

LGTM=gri
R=golang-codereviews, bradfitz, gri
CC=golang-codereviews
https://golang.org/cl/142360043

Preparation was in CL 134570043.
This CL contains only the effect of 'hg mv src/pkg/* src'.
For more about the move, see golang.org/s/go14nopkg.