#3299 Merge gcc and clang into a cc linter

Users can easily be confused when they set some options for a C or C++
compiler, and another compiler is run with different options, which
still reports errors. To remedy this, the existing `gcc` and `clang`
linters have been replaced with a `cc` linter that will run either
compiler.

This is a breaking change for ALE v3.0.0.

2 files changed, 24 insertions, 41 deletions

diff --git a/ale_linters/c/gcc.vim b/ale_linters/c/cc.vim
index 252285a3..6d920ab0 100644
--- a/ale_linters/c/gcc.vim
+++ b/ale_linters/c/cc.vim
@@ -1,12 +1,27 @@
 " Author: w0rp <devw0rp@gmail.com>
-" Description: gcc linter for c files
+" Description: A C compiler linter for C files with gcc/clang, etc.
 
-call ale#Set('c_gcc_executable', 'gcc')
-call ale#Set('c_gcc_options', '-std=c11 -Wall')
+call ale#Set('c_cc_executable', '<auto>')
+call ale#Set('c_cc_options', '-std=c11 -Wall')
 
-function! ale_linters#c#gcc#GetCommand(buffer, output) abort
+function! ale_linters#c#cc#GetExecutable(buffer) abort
+    let l:executable = ale#Var(a:buffer, 'c_cc_executable')
+
+    " Default to either clang or gcc.
+    if l:executable is# '<auto>'
+        if ale#engine#IsExecutable(a:buffer, 'clang')
+            let l:executable = 'clang'
+        else
+            let l:executable = 'gcc'
+        endif
+    endif
+
+    return l:executable
+endfunction
+
+function! ale_linters#c#cc#GetCommand(buffer, output) abort
     let l:cflags = ale#c#GetCFlags(a:buffer, a:output)
-    let l:ale_flags = ale#Var(a:buffer, 'c_gcc_options')
+    let l:ale_flags = ale#Var(a:buffer, 'c_cc_options')
 
     if l:cflags =~# '-std='
         let l:ale_flags = substitute(
@@ -29,9 +44,10 @@ function! ale_linters#c#gcc#GetCommand(buffer, output) abort
 endfunction
 
 call ale#linter#Define('c', {
-\   'name': 'gcc',
+\   'name': 'cc',
+\   'aliases': ['gcc', 'clang'],
 \   'output_stream': 'stderr',
-\   'executable': {b -> ale#Var(b, 'c_gcc_executable')},
-\   'command': {b -> ale#c#RunMakeCommand(b, function('ale_linters#c#gcc#GetCommand'))},
+\   'executable': function('ale_linters#c#cc#GetExecutable'),
+\   'command': {b -> ale#c#RunMakeCommand(b, function('ale_linters#c#cc#GetCommand'))},
 \   'callback': 'ale#handlers#gcc#HandleGCCFormatWithIncludes',
 \})
diff --git a/ale_linters/c/clang.vim b/ale_linters/c/clang.vim
deleted file mode 100644
index 84c105de..00000000
--- a/ale_linters/c/clang.vim
+++ /dev/null
@@ -1,33 +0,0 @@
-" Author: Masahiro H https://github.com/mshr-h
-" Description: clang linter for c files
-
-call ale#Set('c_clang_executable', 'clang')
-call ale#Set('c_clang_options', '-std=c11 -Wall')
-
-function! ale_linters#c#clang#GetCommand(buffer, output) abort
-    let l:cflags = ale#c#GetCFlags(a:buffer, a:output)
-    let l:ale_flags = ale#Var(a:buffer, 'c_clang_options')
-
-    if l:cflags =~# '-std='
-        let l:ale_flags = substitute(
-        \   l:ale_flags,
-        \   '-std=\(c\|gnu\)[0-9]\{2\}',
-        \   '',
-        \   'g')
-    endif
-
-    " -iquote with the directory the file is in makes #include work for
-    "  headers in the same directory.
-    return '%e -S -x c -fsyntax-only'
-    \   . ' -iquote ' . ale#Escape(fnamemodify(bufname(a:buffer), ':p:h'))
-    \   . ale#Pad(l:cflags)
-    \   . ale#Pad(l:ale_flags) . ' -'
-endfunction
-
-call ale#linter#Define('c', {
-\   'name': 'clang',
-\   'output_stream': 'stderr',
-\   'executable': {b -> ale#Var(b, 'c_clang_executable')},
-\   'command': {b -> ale#c#RunMakeCommand(b, function('ale_linters#c#clang#GetCommand'))},
-\   'callback': 'ale#handlers#gcc#HandleGCCFormatWithIncludes',
-\})