#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.

5 files changed, 75 insertions, 202 deletions

diff --git a/test/command_callback/test_c_gcc_command_callbacks.vader b/test/command_callback/test_c_cc_command_callbacks.vader
index ee5d9030..9d71d941 100644
--- a/test/command_callback/test_c_gcc_command_callbacks.vader
+++ b/test/command_callback/test_c_cc_command_callbacks.vader
@@ -1,16 +1,25 @@
 Before:
   Save g:ale_c_parse_makefile
+  Save g:ale_history_enabled
+
+  let g:ale_c_parse_makefile = 0
+  let g:ale_history_enabled = 0
+
   let g:get_cflags_return_value = ''
+  let g:executable_map = {}
 
   runtime autoload/ale/c.vim
+  runtime autoload/ale/engine.vim
+
+  function! ale#engine#IsExecutable(buffer, executable) abort
+    return has_key(g:executable_map, a:executable)
+  endfunction
 
   function! ale#c#GetCFlags(buffer, output) abort
     return g:get_cflags_return_value
   endfunction
 
-  let g:ale_c_parse_makefile = 0
-
-  call ale#assert#SetUpLinterTest('c', 'gcc')
+  call ale#assert#SetUpLinterTest('c', 'cc')
 
   let b:command_tail = ' -S -x c'
   \   . ' -o ' . (has('win32') ? 'nul': '/dev/null')
@@ -19,16 +28,23 @@ Before:
 
 After:
   unlet! g:get_cflags_return_value
+  unlet! g:executable_map
   unlet! b:command_tail
 
   runtime autoload/ale/c.vim
+  runtime autoload/ale/engine.vim
 
   call ale#assert#TearDownLinterTest()
 
+Execute(clang should be used instead of gcc, if available):
+  let g:executable_map = {'clang': 1}
+
+  AssertLinter 'clang', [ale#Escape('clang') . b:command_tail]
+
 Execute(The executable should be configurable):
   AssertLinter 'gcc', [ale#Escape('gcc') . b:command_tail]
 
-  let b:ale_c_gcc_executable = 'foobar'
+  let b:ale_c_cc_executable = 'foobar'
 
   AssertLinter 'foobar', [ale#Escape('foobar') . b:command_tail]
 
diff --git a/test/command_callback/test_c_clang_command_callbacks.vader b/test/command_callback/test_c_clang_command_callbacks.vader
deleted file mode 100644
index 01be18e0..00000000
--- a/test/command_callback/test_c_clang_command_callbacks.vader
+++ /dev/null
@@ -1,37 +0,0 @@
-Before:
-  Save g:ale_c_parse_makefile
-  let g:ale_c_parse_makefile = 0
-
-  let g:get_cflags_return_value = ''
-
-  runtime autoload/ale/c.vim
-
-  function! ale#c#GetCFlags(buffer, output) abort
-    return g:get_cflags_return_value
-  endfunction
-
-  call ale#assert#SetUpLinterTest('c', 'clang')
-  let b:command_tail = ' -S -x c -fsyntax-only -iquote'
-  \   . ' ' . ale#Escape(getcwd())
-  \   . ' -std=c11 -Wall -'
-
-After:
-  unlet! g:get_cflags_return_value
-  unlet! b:command_tail
-
-  runtime autoload/ale/c.vim
-
-  call ale#assert#TearDownLinterTest()
-
-Execute(The executable should be configurable):
-  AssertLinter 'clang', [ale#Escape('clang') . b:command_tail]
-
-  let b:ale_c_clang_executable = 'foobar'
-
-  AssertLinter 'foobar', [ale#Escape('foobar') . b:command_tail]
-
-Execute(The -std flag should be replaced by parsed C flags):
-  let b:command_tail = substitute(b:command_tail, 'c11', 'c99 ', '')
-  let g:get_cflags_return_value = '-std=c99'
-
-  AssertLinter 'clang', ale#Escape('clang') . b:command_tail
diff --git a/test/command_callback/test_c_import_paths.vader b/test/command_callback/test_c_import_paths.vader
index e6102998..8384a659 100644
--- a/test/command_callback/test_c_import_paths.vader
+++ b/test/command_callback/test_c_import_paths.vader
@@ -7,6 +7,7 @@ Before:
   Save g:__ale_c_project_filenames
 
   let g:original_project_filenames = g:__ale_c_project_filenames
+  let g:executable_map = {}
 
   " Remove the .git/HEAD dir for C import paths for these tests.
   " The tests run inside of a git repo.
@@ -18,17 +19,26 @@ Before:
   let g:ale_c_parse_compile_commands = 0
   let g:ale_c_parse_makefile = 0
 
+  runtime autoload/ale/engine.vim
+
+  function! ale#engine#IsExecutable(buffer, executable) abort
+    return has_key(g:executable_map, a:executable)
+  endfunction
+
 After:
   Restore
 
   unlet! g:original_project_filenames
+  unlet! g:executable_map
+
+  runtime autoload/ale/engine.vim
 
   call ale#assert#TearDownLinterTest()
 
-Execute(The C GCC handler should include 'include' directories for projects with a Makefile):
-  call ale#assert#SetUpLinterTest('c', 'gcc')
+Execute(The C cc linter should include 'include' directories for projects with a Makefile):
+  call ale#assert#SetUpLinterTest('c', 'cc')
   call ale#test#SetFilename('../test_c_projects/makefile_project/subdir/file.c')
-  let g:ale_c_gcc_options = ''
+  let g:ale_c_cc_options = ''
 
   AssertLinter 'gcc',
   \ ale#Escape('gcc')
@@ -37,10 +47,10 @@ Execute(The C GCC handler should include 'include' directories for projects with
   \   . ' -I' . ale#Escape(ale#path#Simplify(g:dir .  '/../test_c_projects/makefile_project/include'))
   \   . ' -'
 
-Execute(The C GCC handler should include 'include' directories for projects with a configure file):
-  call ale#assert#SetUpLinterTest('c', 'gcc')
+Execute(The C cc linter should include 'include' directories for projects with a configure file):
+  call ale#assert#SetUpLinterTest('c', 'cc')
   call ale#test#SetFilename('../test_c_projects/configure_project/subdir/file.c')
-  let g:ale_c_gcc_options = ''
+  let g:ale_c_cc_options = ''
 
   AssertLinter 'gcc',
   \ ale#Escape('gcc')
@@ -49,10 +59,10 @@ Execute(The C GCC handler should include 'include' directories for projects with
   \   . ' -I' . ale#Escape(ale#path#Simplify(g:dir .  '/../test_c_projects/configure_project/include'))
   \   . ' -'
 
-Execute(The C GCC handler should include root directories for projects with .h files in them):
-  call ale#assert#SetUpLinterTest('c', 'gcc')
+Execute(The C cc linter should include root directories for projects with .h files in them):
+  call ale#assert#SetUpLinterTest('c', 'cc')
   call ale#test#SetFilename('../test_c_projects/h_file_project/subdir/file.c')
-  let g:ale_c_gcc_options = ''
+  let g:ale_c_cc_options = ''
 
   AssertLinter 'gcc',
   \ ale#Escape('gcc')
@@ -61,10 +71,10 @@ Execute(The C GCC handler should include root directories for projects with .h f
   \   . ' -I' . ale#Escape(ale#path#Simplify(g:dir .  '/../test_c_projects/h_file_project'))
   \   . ' -'
 
-Execute(The C GCC handler should include root directories for projects with .hpp files in them):
-  call ale#assert#SetUpLinterTest('c', 'gcc')
+Execute(The C cc linter should include root directories for projects with .hpp files in them):
+  call ale#assert#SetUpLinterTest('c', 'cc')
   call ale#test#SetFilename('../test_c_projects/hpp_file_project/subdir/file.c')
-  let g:ale_c_gcc_options = ''
+  let g:ale_c_cc_options = ''
 
   AssertLinter 'gcc',
   \ ale#Escape('gcc')
@@ -73,54 +83,6 @@ Execute(The C GCC handler should include root directories for projects with .hpp
   \   . ' -I' . ale#Escape(ale#path#Simplify(g:dir .  '/../test_c_projects/hpp_file_project'))
   \   . ' -'
 
-Execute(The C Clang handler should include 'include' directories for projects with a Makefile):
-  call ale#assert#SetUpLinterTest('c', 'clang')
-  call ale#test#SetFilename('../test_c_projects/makefile_project/subdir/file.c')
-  let g:ale_c_clang_options = ''
-
-  AssertLinter 'clang',
-  \   ale#Escape('clang')
-  \   . ' -S -x c -fsyntax-only'
-  \   . ' -iquote ' . ale#Escape(ale#path#Simplify(g:dir .  '/../test_c_projects/makefile_project/subdir'))
-  \   . ' -I' . ale#Escape(ale#path#Simplify(g:dir .  '/../test_c_projects/makefile_project/include'))
-  \   . ' -'
-
-Execute(The C Clang handler should include 'include' directories for projects with a configure file):
-  call ale#assert#SetUpLinterTest('c', 'clang')
-  call ale#test#SetFilename('../test_c_projects/h_file_project/subdir/file.c')
-  let g:ale_c_clang_options = ''
-
-  AssertLinter 'clang',
-  \   ale#Escape('clang')
-  \   . ' -S -x c -fsyntax-only'
-  \   . ' -iquote ' . ale#Escape(ale#path#Simplify(g:dir .  '/../test_c_projects/h_file_project/subdir'))
-  \   . ' -I' . ale#Escape(ale#path#Simplify(g:dir .  '/../test_c_projects/h_file_project'))
-  \   . ' -'
-
-Execute(The C Clang handler should include root directories for projects with .h files in them):
-  call ale#assert#SetUpLinterTest('c', 'clang')
-  call ale#test#SetFilename('../test_c_projects/h_file_project/subdir/file.c')
-  let g:ale_c_clang_options = ''
-
-  AssertLinter 'clang',
-  \   ale#Escape('clang')
-  \   . ' -S -x c -fsyntax-only'
-  \   . ' -iquote ' . ale#Escape(ale#path#Simplify(g:dir .  '/../test_c_projects/h_file_project/subdir'))
-  \   . ' -I' . ale#Escape(ale#path#Simplify(g:dir .  '/../test_c_projects/h_file_project'))
-  \   . ' -'
-
-Execute(The C Clang handler should include root directories for projects with .hpp files in them):
-  call ale#assert#SetUpLinterTest('c', 'clang')
-  call ale#test#SetFilename('../test_c_projects/hpp_file_project/subdir/file.c')
-  let g:ale_c_clang_options = ''
-
-  AssertLinter 'clang',
-  \   ale#Escape('clang')
-  \   . ' -S -x c -fsyntax-only'
-  \   . ' -iquote ' . ale#Escape(ale#path#Simplify(g:dir .  '/../test_c_projects/hpp_file_project/subdir'))
-  \   . ' -I' . ale#Escape(ale#path#Simplify(g:dir .  '/../test_c_projects/hpp_file_project'))
-  \   . ' -'
-
 Execute(The C ClangTidy handler should include 'include' directories for projects with a Makefile):
   call ale#assert#SetUpLinterTest('c', 'clangtidy')
   call ale#test#SetFilename('../test_c_projects/makefile_project/subdir/file.cpp')
@@ -131,10 +93,10 @@ Execute(The C ClangTidy handler should include 'include' directories for project
   \ . ' %s '
   \ . '-- -I' . ale#Escape(ale#path#Simplify(g:dir . '/../test_c_projects/makefile_project/include'))
 
-Execute(The C++ GCC handler should include 'include' directories for projects with a Makefile):
-  call ale#assert#SetUpLinterTest('cpp', 'gcc')
+Execute(The C++ cc linter should include 'include' directories for projects with a Makefile):
+  call ale#assert#SetUpLinterTest('cpp', 'cc')
   call ale#test#SetFilename('../test_c_projects/makefile_project/subdir/file.cpp')
-  let g:ale_cpp_gcc_options = ''
+  let g:ale_cpp_cc_options = ''
 
   AssertLinter 'gcc',
   \   ale#Escape('gcc')
@@ -143,10 +105,10 @@ Execute(The C++ GCC handler should include 'include' directories for projects wi
   \   . ' -I' . ale#Escape(ale#path#Simplify(g:dir .  '/../test_c_projects/makefile_project/include'))
   \   . ' -'
 
-Execute(The C++ GCC handler should include 'include' directories for projects with a configure file):
-  call ale#assert#SetUpLinterTest('cpp', 'gcc')
+Execute(The C++ cc linter should include 'include' directories for projects with a configure file):
+  call ale#assert#SetUpLinterTest('cpp', 'cc')
   call ale#test#SetFilename('../test_c_projects/configure_project/subdir/file.cpp')
-  let g:ale_cpp_gcc_options = ''
+  let g:ale_cpp_cc_options = ''
 
   AssertLinter 'gcc',
   \   ale#Escape('gcc')
@@ -155,10 +117,10 @@ Execute(The C++ GCC handler should include 'include' directories for projects wi
   \   . ' -I' . ale#Escape(ale#path#Simplify(g:dir .  '/../test_c_projects/configure_project/include'))
   \   . ' -'
 
-Execute(The C++ GCC handler should include root directories for projects with .h files in them):
-  call ale#assert#SetUpLinterTest('cpp', 'gcc')
+Execute(The C++ cc linter should include root directories for projects with .h files in them):
+  call ale#assert#SetUpLinterTest('cpp', 'cc')
   call ale#test#SetFilename('../test_c_projects/h_file_project/subdir/file.cpp')
-  let g:ale_cpp_gcc_options = ''
+  let g:ale_cpp_cc_options = ''
 
   AssertLinter 'gcc',
   \   ale#Escape('gcc')
@@ -167,10 +129,10 @@ Execute(The C++ GCC handler should include root directories for projects with .h
   \   . ' -I' . ale#Escape(ale#path#Simplify(g:dir .  '/../test_c_projects/h_file_project'))
   \   . ' -'
 
-Execute(The C++ GCC handler should include root directories for projects with .hpp files in them):
-  call ale#assert#SetUpLinterTest('cpp', 'gcc')
+Execute(The C++ cc linter should include root directories for projects with .hpp files in them):
+  call ale#assert#SetUpLinterTest('cpp', 'cc')
   call ale#test#SetFilename('../test_c_projects/hpp_file_project/subdir/file.cpp')
-  let g:ale_cpp_gcc_options = ''
+  let g:ale_cpp_cc_options = ''
 
   AssertLinter 'gcc',
   \   ale#Escape('gcc')
@@ -179,54 +141,6 @@ Execute(The C++ GCC handler should include root directories for projects with .h
   \   . ' -I' . ale#Escape(ale#path#Simplify(g:dir .  '/../test_c_projects/hpp_file_project'))
   \   . ' -'
 
-Execute(The C++ Clang handler should include 'include' directories for projects with a Makefile):
-  call ale#assert#SetUpLinterTest('cpp', 'clang')
-  call ale#test#SetFilename('../test_c_projects/makefile_project/subdir/file.cpp')
-  let g:ale_cpp_clang_options = ''
-
-  AssertLinter 'clang++',
-  \   ale#Escape('clang++')
-  \   . ' -S -x c++ -fsyntax-only'
-  \   . ' -iquote ' . ale#Escape(ale#path#Simplify(g:dir .  '/../test_c_projects/makefile_project/subdir'))
-  \   . ' -I' . ale#Escape(ale#path#Simplify(g:dir .  '/../test_c_projects/makefile_project/include'))
-  \   . ' -'
-
-Execute(The C++ Clang handler should include 'include' directories for projects with a configure file):
-  call ale#assert#SetUpLinterTest('cpp', 'clang')
-  call ale#test#SetFilename('../test_c_projects/configure_project/subdir/file.cpp')
-  let g:ale_cpp_clang_options = ''
-
-  AssertLinter 'clang++',
-  \   ale#Escape('clang++')
-  \   . ' -S -x c++ -fsyntax-only'
-  \   . ' -iquote ' . ale#Escape(ale#path#Simplify(g:dir .  '/../test_c_projects/configure_project/subdir'))
-  \   . ' -I' . ale#Escape(ale#path#Simplify(g:dir .  '/../test_c_projects/configure_project/include'))
-  \   . ' -'
-
-Execute(The C++ Clang handler should include root directories for projects with .h files in them):
-  call ale#assert#SetUpLinterTest('cpp', 'clang')
-  call ale#test#SetFilename('../test_c_projects/h_file_project/subdir/file.cpp')
-  let g:ale_cpp_clang_options = ''
-
-  AssertLinter 'clang++',
-  \   ale#Escape('clang++')
-  \   . ' -S -x c++ -fsyntax-only'
-  \   . ' -iquote ' . ale#Escape(ale#path#Simplify(g:dir .  '/../test_c_projects/h_file_project/subdir'))
-  \   . ' -I' . ale#Escape(ale#path#Simplify(g:dir .  '/../test_c_projects/h_file_project'))
-  \   . ' -'
-
-Execute(The C++ Clang handler should include root directories for projects with .hpp files in them):
-  call ale#assert#SetUpLinterTest('cpp', 'clang')
-  call ale#test#SetFilename('../test_c_projects/hpp_file_project/subdir/file.cpp')
-  let g:ale_cpp_clang_options = ''
-
-  AssertLinter 'clang++',
-  \   ale#Escape('clang++')
-  \   . ' -S -x c++ -fsyntax-only'
-  \   . ' -iquote ' . ale#Escape(ale#path#Simplify(g:dir .  '/../test_c_projects/hpp_file_project/subdir'))
-  \   . ' -I' . ale#Escape(ale#path#Simplify(g:dir .  '/../test_c_projects/hpp_file_project'))
-  \   . ' -'
-
 Execute(The C++ ClangTidy handler should include json folders for projects with suitable build directory in them):
   call ale#assert#SetUpLinterTest('cpp', 'clangtidy')
   call ale#test#SetFilename('../test_c_projects/json_project/subdir/file.cpp')
diff --git a/test/command_callback/test_cpp_clang_command_callbacks.vader b/test/command_callback/test_cpp_clang_command_callbacks.vader
deleted file mode 100644
index 7d5fe989..00000000
--- a/test/command_callback/test_cpp_clang_command_callbacks.vader
+++ /dev/null
@@ -1,37 +0,0 @@
-Before:
-  Save g:ale_c_parse_makefile
-  let g:ale_c_parse_makefile = 0
-
-  let g:get_cflags_return_value = ''
-
-  runtime autoload/ale/c.vim
-
-  function! ale#c#GetCFlags(buffer, output) abort
-    return g:get_cflags_return_value
-  endfunction
-
-  call ale#assert#SetUpLinterTest('cpp', 'clang')
-  let b:command_tail = ' -S -x c++ -fsyntax-only -iquote'
-  \   . ' ' . ale#Escape(getcwd())
-  \   . ' -std=c++14 -Wall -'
-
-After:
-  unlet! g:get_cflags_return_value
-  unlet! b:command_tail
-
-  runtime autoload/ale/c.vim
-
-  call ale#assert#TearDownLinterTest()
-
-Execute(The executable should be configurable):
-  AssertLinter 'clang++', ale#Escape('clang++') . b:command_tail
-
-  let b:ale_cpp_clang_executable = 'foobar'
-
-  AssertLinter 'foobar', ale#Escape('foobar') . b:command_tail
-
-Execute(The -std flag should be replaced by parsed C flags):
-  let b:command_tail = substitute(b:command_tail, 'c++14', 'c++11 ', '')
-  let g:get_cflags_return_value = '-std=c++11'
-
-  AssertLinter 'clang++', ale#Escape('clang++') . b:command_tail
diff --git a/test/command_callback/test_cpp_gcc_command_callbacks.vader b/test/command_callback/test_cpp_gcc_command_callbacks.vader
index 9a64e6a4..930cc68a 100644
--- a/test/command_callback/test_cpp_gcc_command_callbacks.vader
+++ b/test/command_callback/test_cpp_gcc_command_callbacks.vader
@@ -1,16 +1,26 @@
 Before:
   Save g:ale_c_parse_makefile
+  Save g:ale_history_enabled
+
   let g:ale_c_parse_makefile = 0
+  let g:ale_history_enabled = 0
 
   let g:get_cflags_return_value = ''
+  let g:executable_map = {}
 
   runtime autoload/ale/c.vim
+  runtime autoload/ale/engine.vim
+
+  function! ale#engine#IsExecutable(buffer, executable) abort
+    return has_key(g:executable_map, a:executable)
+  endfunction
 
   function! ale#c#GetCFlags(buffer, output) abort
     return g:get_cflags_return_value
   endfunction
 
-  call ale#assert#SetUpLinterTest('cpp', 'gcc')
+  call ale#assert#SetUpLinterTest('cpp', 'cc')
+
   let b:command_tail = ' -S -x c++'
   \   . ' -o ' . (has('win32') ? 'nul': '/dev/null')
   \   . ' -iquote ' . ale#Escape(getcwd())
@@ -18,18 +28,25 @@ Before:
 
 After:
   unlet! g:get_cflags_return_value
+  unlet! g:executable_map
   unlet! b:command_tail
 
   runtime autoload/ale/c.vim
+  runtime autoload/ale/engine.vim
 
   call ale#assert#TearDownLinterTest()
 
+Execute(clang++ should be used instead of gcc, if available):
+  let g:executable_map = {'clang++': 1}
+
+  AssertLinter 'clang++', [ale#Escape('clang++') . b:command_tail]
+
 Execute(The executable should be configurable):
-  AssertLinter 'gcc', ale#Escape('gcc') . b:command_tail
+  AssertLinter 'gcc', [ale#Escape('gcc') . b:command_tail]
 
-  let b:ale_cpp_gcc_executable = 'foobar'
+  let b:ale_cpp_cc_executable = 'foobar'
 
-  AssertLinter 'foobar', ale#Escape('foobar') . b:command_tail
+  AssertLinter 'foobar', [ale#Escape('foobar') . b:command_tail]
 
 Execute(The -std flag should be replaced by parsed C flags):
   let b:command_tail = substitute(b:command_tail, 'c++14', 'c++11 ', '')