code review 4786041: goinstall: write to goinstall.log in respective GOPATH

goinstall: write to goinstall.log in respective GOPATH
goinstall: report every newly installed package to the dashboard

This makes "goinstall -a" work on systems with GOROOTs that are
not user-writable, as is the case with Debian's Go packages.

This also makes goinstall.log the canonical list of installed
packages, in that only packages new to goinstall.log are reported to
the dashboard.

A side-effect is that writing to goinstall.log is now mandatory.
(A bug in the original implementation meant this was the case, anyway.)

The principal benefit of this change is that multiple packages from the
same repository can now be reported to the dashboard.  It is also less
likely for a user to report multiple installations of the same package
to the dashboard (they would need to remove the package from
goinstall.log first).

[adg, 2011-07-19 11:16:52]

Hello golang-dev@googlegroups.com,

I'd like you to review this change to
https://go.googlecode.com/hg/

[rsc, 2011-07-19 15:54:33]

http://codereview.appspot.com/4786041/diff/6001/src/cmd/goinstall/main.go
File src/cmd/goinstall/main.go (right):

http://codereview.appspot.com/4786041/diff/6001/src/cmd/goinstall/main.go#new...
src/cmd/goinstall/main.go:151: for _, t := range build.Path {
This isn't right.  The behavior of the tool should not change
depending on whether a permission bit is or isn't set.

Alternatives:

1. Always write to the first element of $GOPATH.
2. Write to the element where code was just installed.

#2 sounds like the right thing to me.

[niemeyer, 2011-07-20 00:50:15]

> 2. Write to the element where code was just installed.
> 
> #2 sounds like the right thing to me.

Agreed, and the same is true for reading as well.  If it
writes on the first writable or to where it was installed,
but reads from the first entry which isn't writable, the
goinstall -a won't be very useful.

[adg, 2011-07-20 01:42:53]

Hello rsc@golang.org, n13m3y3r@gmail.com (cc: golang-dev@googlegroups.com),

Please take another look.

[adg, 2011-07-20 01:43:24]

http://codereview.appspot.com/4786041/diff/6001/src/cmd/goinstall/main.go
File src/cmd/goinstall/main.go (right):

http://codereview.appspot.com/4786041/diff/6001/src/cmd/goinstall/main.go#new...
src/cmd/goinstall/main.go:151: for _, t := range build.Path {
On 2011/07/19 15:54:34, rsc wrote:
> 2. Write to the element where code was just installed.

Done.

[rsc, 2011-07-20 15:02:55]

http://codereview.appspot.com/4786041/diff/11001/src/cmd/goinstall/main.go
File src/cmd/goinstall/main.go (right):

http://codereview.appspot.com/4786041/diff/11001/src/cmd/goinstall/main.go#ne...
src/cmd/goinstall/main.go:146: // in the given tree, if the package is not
already in any goinstall.log file.
I'm not sure about this.  I think it should be specific to the tree.
That may mean you need a separate installedPkgs for each tree.

[adg, 2011-07-21 01:43:45]

http://codereview.appspot.com/4786041/diff/11001/src/cmd/goinstall/main.go
File src/cmd/goinstall/main.go (right):

http://codereview.appspot.com/4786041/diff/11001/src/cmd/goinstall/main.go#ne...
src/cmd/goinstall/main.go:146: // in the given tree, if the package is not
already in any goinstall.log file.
On 2011/07/20 15:02:55, rsc wrote:
> I'm not sure about this.  I think it should be specific to the tree.
> That may mean you need a separate installedPkgs for each tree.

Done.

The only advantage I can see to this is that we can make -a smarter so that it
re-installs packages in a specific GOPATH. This might be a valuable feature, but
it's outside the scope of this CL.

[rsc, 2011-07-24 02:12:45]

> The only advantage I can see to this is that we can make -a smarter so that it
> re-installs packages in a specific GOPATH. This might be a valuable feature,
but
> it's outside the scope of this CL.

The main advantage is that if I rm -rf some directory from my $GOPATH,
everything else is still consistent.

[rsc, 2011-07-24 02:14:12]

LGTM

[adg, 2011-07-24 03:43:12]

*** Submitted as http://code.google.com/p/go/source/detail?r=7b7b7ef3e147 ***

goinstall: write to goinstall.log in respective GOPATH
goinstall: report every newly installed package to the dashboard

This makes "goinstall -a" work on systems with GOROOTs that are
not user-writable, as is the case with Debian's Go packages.

This also makes goinstall.log the canonical list of installed
packages, in that only packages new to goinstall.log are reported to
the dashboard.

A side-effect is that writing to goinstall.log is now mandatory.
(A bug in the original implementation meant this was the case, anyway.)

The principal benefit of this change is that multiple packages from the
same repository can now be reported to the dashboard.  It is also less
likely for a user to report multiple installations of the same package
to the dashboard (they would need to remove the package from
goinstall.log first).

R=rsc, n13m3y3r
CC=golang-dev
http://codereview.appspot.com/4786041