#756 Escape the paths used for the --include parameter for gometalinter, which uses RE2

ale_linters/go/gometalinter.vim

@@ -14,7 +14,7 @@ function! ale_linters#go#gometalinter#GetCommand(buffer) abort
     let l:options = ale#Var(a:buffer, 'go_gometalinter_options')
 
     return ale#Escape(l:executable)
-    \   . ' --include=' . ale#Escape(l:filename)
+    \   . ' --include=' . ale#Escape(ale#util#EscapePCRE(l:filename))
     \   . (!empty(l:options) ? ' ' . l:options : '')
     \   . ' ' . ale#Escape(fnamemodify(l:filename, ':h'))
 endfunction

autoload/ale/util.vim

@@ -161,3 +161,9 @@ function! ale#util#FunctionArgCount(function) abort
 
     return l:count
 endfunction
+
+" Escape a string so the characters in it will be safe for use inside of PCRE
+" or RE2 regular expressions without characters having special meanings.
+function! ale#util#EscapePCRE(unsafe_string) abort
+    return substitute(a:unsafe_string, '\([\-\[\]{}()*+?.^$|]\)', '\\\1', 'g')
+endfunction

test/command_callback/test_gometalinter_command_callback.vader

@@ -22,7 +22,7 @@ Execute(The gometalinter callback should return the right defaults):
   \ ale_linters#go#gometalinter#GetExecutable(bufnr(''))
   AssertEqual
   \ ale#Escape('gometalinter')
-  \   . ' --include=' . ale#Escape(expand('%'))
+  \   . ' --include=' . ale#Escape(ale#util#EscapePCRE(expand('%')))
   \   . ' ' . ale#Escape(getcwd()),
   \ ale_linters#go#gometalinter#GetCommand(bufnr(''))
 
@@ -34,7 +34,7 @@ Execute(The gometalinter callback should use a configured executable):
   \ ale_linters#go#gometalinter#GetExecutable(bufnr(''))
   AssertEqual
   \ ale#Escape('something else')
-  \   . ' --include=' . ale#Escape(expand('%'))
+  \   . ' --include=' . ale#Escape(ale#util#EscapePCRE(expand('%')))
   \   . ' ' . ale#Escape(getcwd()),
   \ ale_linters#go#gometalinter#GetCommand(bufnr(''))
 
@@ -43,7 +43,7 @@ Execute(The gometalinter callback should use configured options):
 
   AssertEqual
   \ ale#Escape('gometalinter')
-  \   . ' --include=' . ale#Escape(expand('%'))
+  \   . ' --include=' . ale#Escape(ale#util#EscapePCRE(expand('%')))
   \   . ' --foobar'
   \   . ' ' . ale#Escape(getcwd()),
   \ ale_linters#go#gometalinter#GetCommand(bufnr(''))

test/test_regex_escaping.vader

@@ -0,0 +1,4 @@
+Execute(ale#util#EscapePCRE should escape strings for PCRE or RE2 appropriately):
+  AssertEqual '\\\^\$\*\+\?\.\(\)\|\{\}\[\]', ale#util#EscapePCRE('\^$*+?.()|{}[]')
+  AssertEqual 'abcABC09', ale#util#EscapePCRE('abcABC09')
+  AssertEqual '/', ale#util#EscapePCRE('/')