Add fixer for Go modules (#1873)

* Add fixer for Go modules

11 files changed, 80 insertions, 8 deletions

diff --git a/README.md b/README.md
index 93639a0d..b225c9c3 100644
--- a/README.md
+++ b/README.md
@@ -124,7 +124,7 @@ formatting.
 | FusionScript | [fusion-lint](https://github.com/RyanSquared/fusionscript) |
 | Git Commit Messages | [gitlint](https://github.com/jorisroovers/gitlint) |
 | GLSL | [glslang](https://github.com/KhronosGroup/glslang), [glslls](https://github.com/svenstaro/glsl-language-server) |
-| Go | [gofmt](https://golang.org/cmd/gofmt/), [goimports](https://godoc.org/golang.org/x/tools/cmd/goimports), [go vet](https://golang.org/cmd/vet/) !!, [golint](https://godoc.org/github.com/golang/lint), [gotype](https://godoc.org/golang.org/x/tools/cmd/gotype) !!, [gometalinter](https://github.com/alecthomas/gometalinter) !!, [go build](https://golang.org/cmd/go/) !!, [gosimple](https://github.com/dominikh/go-tools/tree/master/cmd/gosimple) !!, [staticcheck](https://github.com/dominikh/go-tools/tree/master/cmd/staticcheck) !!, [golangserver](https://github.com/sourcegraph/go-langserver), [golangci-lint](https://github.com/golangci/golangci-lint) !! |
+| Go | [gofmt](https://golang.org/cmd/gofmt/), [goimports](https://godoc.org/golang.org/x/tools/cmd/goimports), [go mod](https://golang.org/cmd/go/) !!, [go vet](https://golang.org/cmd/vet/) !!, [golint](https://godoc.org/github.com/golang/lint), [gotype](https://godoc.org/golang.org/x/tools/cmd/gotype) !!, [gometalinter](https://github.com/alecthomas/gometalinter) !!, [go build](https://golang.org/cmd/go/) !!, [gosimple](https://github.com/dominikh/go-tools/tree/master/cmd/gosimple) !!, [staticcheck](https://github.com/dominikh/go-tools/tree/master/cmd/staticcheck) !!, [golangserver](https://github.com/sourcegraph/go-langserver), [golangci-lint](https://github.com/golangci/golangci-lint) !! |
 | GraphQL | [eslint](http://eslint.org/), [gqlint](https://github.com/happylinks/gqlint), [prettier](https://github.com/prettier/prettier) |
 | Hack | [hack](http://hacklang.org/), [hackfmt](https://github.com/facebook/hhvm/tree/master/hphp/hack/hackfmt), [hhast](https://github.com/hhvm/hhast) (disabled by default; see `:help ale-integration-hack`) |
 | Haml | [haml-lint](https://github.com/brigade/haml-lint) |
diff --git a/ale_linters/go/gobuild.vim b/ale_linters/go/gobuild.vim
index a44449f1..cef1ff88 100644
--- a/ale_linters/go/gobuild.vim
+++ b/ale_linters/go/gobuild.vim
@@ -3,6 +3,7 @@
 " Description: go build for Go files
 " inspired by work from dzhou121 <dzhou121@gmail.com>
 
+call ale#Set('go_go_executable', 'go')
 call ale#Set('go_gobuild_options', '')
 
 function! ale_linters#go#gobuild#GetCommand(buffer) abort
@@ -10,7 +11,7 @@ function! ale_linters#go#gobuild#GetCommand(buffer) abort
 
     " Run go test in local directory with relative path
     return ale#path#BufferCdString(a:buffer)
-    \   . 'go test'
+    \   . ale#Var(a:buffer, 'go_go_executable') . ' test'
     \   . (!empty(l:options) ? ' ' . l:options : '')
     \   . ' -c -o /dev/null ./'
 endfunction
@@ -47,7 +48,7 @@ endfunction
 call ale#linter#Define('go', {
 \   'name': 'gobuild',
 \   'aliases': ['go build'],
-\   'executable': 'go',
+\   'executable_callback': ale#VarFunc('go_go_executable'),
 \   'command_callback': 'ale_linters#go#gobuild#GetCommand',
 \   'output_stream': 'stderr',
 \   'callback': 'ale_linters#go#gobuild#Handler',
diff --git a/ale_linters/go/govet.vim b/ale_linters/go/govet.vim
index 84c23236..3d0d2adf 100644
--- a/ale_linters/go/govet.vim
+++ b/ale_linters/go/govet.vim
@@ -4,20 +4,23 @@
 " Author: John Eikenberry <jae@zhar.net>
 " Description: updated to work with go1.10
 
+call ale#Set('go_go_executable', 'go')
 call ale#Set('go_govet_options', '')
 
 function! ale_linters#go#govet#GetCommand(buffer) abort
     let l:options = ale#Var(a:buffer, 'go_govet_options')
 
-    return ale#path#BufferCdString(a:buffer) . ' go vet .'
+    return ale#path#BufferCdString(a:buffer) . ' '
+    \   . ale#Var(a:buffer, 'go_go_executable') . ' vet '
     \   . (!empty(l:options) ? ' ' . l:options : '')
+    \   . ' .'
 endfunction
 
 call ale#linter#Define('go', {
 \   'name': 'govet',
 \   'aliases': ['go vet'],
 \   'output_stream': 'stderr',
-\   'executable': 'go',
+\   'executable_callback': ale#VarFunc('go_go_executable'),
 \   'command_callback': 'ale_linters#go#govet#GetCommand',
 \   'callback': 'ale#handlers#go#Handler',
 \   'lint_file': 1,
diff --git a/autoload/ale/fix/registry.vim b/autoload/ale/fix/registry.vim
index eb12f22d..76cce87f 100644
--- a/autoload/ale/fix/registry.vim
+++ b/autoload/ale/fix/registry.vim
@@ -145,6 +145,11 @@ let s:default_registry = {
 \       'suggested_filetypes': ['go'],
 \       'description': 'Fix Go files imports with goimports.',
 \   },
+\   'gomod': {
+\       'function': 'ale#fixers#gomod#Fix',
+\       'suggested_filetypes': ['gomod'],
+\       'description': 'Fix Go module files with go mod edit -fmt.',
+\   },
 \   'tslint': {
 \       'function': 'ale#fixers#tslint#Fix',
 \       'suggested_filetypes': ['typescript'],
diff --git a/autoload/ale/fixers/gomod.vim b/autoload/ale/fixers/gomod.vim
new file mode 100644
index 00000000..68895f9b
--- /dev/null
+++ b/autoload/ale/fixers/gomod.vim
@@ -0,0 +1,10 @@
+call ale#Set('go_go_executable', 'go')
+
+function! ale#fixers#gomod#Fix(buffer) abort
+    let l:executable = ale#Var(a:buffer, 'go_go_executable')
+
+    return {
+    \   'command': ale#Escape(l:executable) . ' mod edit -fmt %t',
+    \   'read_temporary_file': 1,
+    \}
+endfunction
diff --git a/doc/ale-go.txt b/doc/ale-go.txt
index 1d55763e..71b248ee 100644
--- a/doc/ale-go.txt
+++ b/doc/ale-go.txt
@@ -20,6 +20,15 @@ the benefit of running a number of linters, more than ALE would by default,
 while ensuring it doesn't run any linters known to be slow or resource
 intensive.
 
+g:ale_go_go_executable                                    *g:ale_go_go_options*
+                                                          *b:ale_go_go_options*
+
+  Type: |String|
+  Default: `'go'`
+
+  The executable that will be run for the `gobuild` and `govet` linters, and
+  the gomod` fixer.
+
 
 ===============================================================================
 gobuild                                                        *ale-go-gobuild*
diff --git a/doc/ale.txt b/doc/ale.txt
index 9a81b237..46ff08b0 100644
--- a/doc/ale.txt
+++ b/doc/ale.txt
@@ -402,7 +402,7 @@ Notes:
 * FusionScript: `fusion-lint`
 * Git Commit Messages: `gitlint`
 * GLSL: glslang, `glslls`
-* Go: `gofmt`, `goimports`, `go vet`!!, `golint`, `gotype`!!, `gometalinter`!!, `go build`!!, `gosimple`!!, `staticcheck`!!, `golangserver`, `golangci-lint`!!
+* Go: `gofmt`, `goimports`, `go mod`!!, `go vet`!!, `golint`, `gotype`!!, `gometalinter`!!, `go build`!!, `gosimple`!!, `staticcheck`!!, `golangserver`, `golangci-lint`!!
 * GraphQL: `eslint`, `gqlint`, `prettier`
 * Hack: `hack`, `hackfmt`, `hhast`
 * Haml: `haml-lint`
diff --git a/test/command_callback/test_gobuild_command_callback.vader b/test/command_callback/test_gobuild_command_callback.vader
index f9673213..8acbec56 100644
--- a/test/command_callback/test_gobuild_command_callback.vader
+++ b/test/command_callback/test_gobuild_command_callback.vader
@@ -1,9 +1,12 @@
 Before:
+  Save g:ale_go_go_executable
+
   call ale#assert#SetUpLinterTest('go', 'gobuild')
 
   WithChainResults ['/foo/bar', '/foo/baz']
 
 After:
+  Restore
   call ale#assert#TearDownLinterTest()
 
 Execute(The default commands should be correct):
@@ -17,3 +20,12 @@ Execute(Extra options should be supported):
   AssertLinter 'go',
   \ 'cd ' . ale#Escape(expand('%:p:h')) . ' && '
   \   . 'go test --foo-bar -c -o /dev/null ./'
+
+  let g:ale_go_gobuild_options = ''
+
+Execute(The executable should be configurable):
+  let g:ale_go_go_executable = 'foobar'
+
+  AssertLinter 'foobar',
+  \ 'cd ' . ale#Escape(expand('%:p:h')) . ' && '
+  \   . 'foobar test -c -o /dev/null ./'
diff --git a/test/command_callback/test_govet_command_callback.vader b/test/command_callback/test_govet_command_callback.vader
index 3718e0a7..ab93a5cb 100644
--- a/test/command_callback/test_govet_command_callback.vader
+++ b/test/command_callback/test_govet_command_callback.vader
@@ -1,12 +1,19 @@
 Before:
+  Save g:ale_go_go_executable
+  Save g:ale_go_govet_options
   call ale#assert#SetUpLinterTest('go', 'govet')
 
 After:
+  Restore
   call ale#assert#TearDownLinterTest()
 
 Execute(The default command should be correct):
-  AssertLinter 'go', 'cd ' . ale#Escape(expand('%:p:h')) . ' &&  go vet .'
+  AssertLinter 'go', 'cd ' . ale#Escape(expand('%:p:h')) . ' &&  go vet  .'
 
 Execute(Extra options should be supported):
   let g:ale_go_govet_options = '--foo-bar'
-  AssertLinter 'go', 'cd ' . ale#Escape(expand('%:p:h')) . ' &&  go vet . --foo-bar'
+  AssertLinter 'go', 'cd ' . ale#Escape(expand('%:p:h')) . ' &&  go vet  --foo-bar .'
+
+Execute(The executable should be configurable):
+  let g:ale_go_go_executable = 'foobar'
+  AssertLinter 'foobar', 'cd ' . ale#Escape(expand('%:p:h')) . ' &&  foobar vet  .'
diff --git a/test/fixers/test_gomod_fixer_callback.vader b/test/fixers/test_gomod_fixer_callback.vader
new file mode 100644
index 00000000..a378e961
--- /dev/null
+++ b/test/fixers/test_gomod_fixer_callback.vader
@@ -0,0 +1,24 @@
+Before:
+  Save g:ale_go_go_executable
+
+  " Use an invalid global executable, so we don't match it.
+  let g:ale_go_go_executable = 'xxxinvalid'
+  call ale#test#SetDirectory('/testplugin/test/fixers')
+
+After:
+  Restore
+
+  call ale#test#RestoreDirectory()
+
+Execute(The gomod callback should return the correct default values):
+  call ale#test#SetFilename('../go_files/go.mod')
+  setl ft=gomod
+
+  AssertEqual
+  \ {
+  \   'read_temporary_file': 1,
+  \   'command': ale#Escape('xxxinvalid')
+  \     . ' mod edit -fmt'
+  \     . ' %t',
+  \ },
+  \ ale#fixers#gomod#Fix(bufnr(''))
diff --git a/test/go_files/go.mod b/test/go_files/go.mod
new file mode 100644
index 00000000..8b137891
--- /dev/null
+++ b/test/go_files/go.mod
@@ -0,0 +1 @@
+