Cppcheck buffered file only (#3983)

* Add cppcheck handler match on misra msg

* Use --file-filter cppcheck option

Cppcheck recently added --file-filter so that cppcheck only checks the
filtered files, even when using --project option, which checks all files
in the project, by default. The --ccpcheck-build-dir option didn't help
enough (at all?).

* Added C test cases

Also fixed and assumed typo: foo.c, instead of foo.cpp

* Replace hard-coded full path filenames

Attempt to fix the windows platform test execution.

* Fix typo - foo.c, instead of foo.cpp

* Reset buffer var between tests

* Handle header files in cppcheck

Cppcheck isn't designed to check header files, stand-alone. Daniel
Marjamäki suggested using --suppress options to avoid FPs.

* Fix Vint complaint in cppcheck handler.

* Fix file path in cppcheck handler

Co-authored-by: Dan George <dgeorge@anduril.com>

3 files changed, 47 insertions, 3 deletions

diff --git a/autoload/ale/handlers/cppcheck.vim b/autoload/ale/handlers/cppcheck.vim
index bb8c8602..cf69df26 100644
--- a/autoload/ale/handlers/cppcheck.vim
+++ b/autoload/ale/handlers/cppcheck.vim
@@ -19,6 +19,18 @@ function! ale#handlers#cppcheck#GetBufferPathIncludeOptions(buffer) abort
 endfunction
 
 function! ale#handlers#cppcheck#GetCompileCommandsOptions(buffer) abort
+    " The compile_commands.json doesn't apply to headers and cppheck will
+    " bail out if it cannot find a file matching the filter, below. Skip out
+    " now, for headers. Also, suppress FPs; cppcheck is not meant to
+    " process lone header files.
+    let b:buffer_name = bufname(a:buffer)
+    let b:file_extension = fnamemodify(b:buffer_name, ':e')
+
+    if b:file_extension is# 'h' || b:file_extension is# 'hpp'
+        return ale#handlers#cppcheck#GetBufferPathIncludeOptions(a:buffer)
+        \   . ' --suppress=unusedStructMember'
+    endif
+
     " If the current buffer is modified, using compile_commands.json does no
     " good, so include the file's directory instead. It's not quite as good as
     " using --project, but is at least equivalent to running cppcheck on this
@@ -34,9 +46,13 @@ function! ale#handlers#cppcheck#GetCompileCommandsOptions(buffer) abort
     " If we find it, we'll `cd` to where the compile_commands.json file is,
     " then use the file to set up import paths, etc.
     let [l:dir, l:json_path] = ale#c#FindCompileCommands(a:buffer)
+    let b:root_index = len(l:dir) + 1
+    let b:buffer_file= bufname(a:buffer)
 
+    " By default, cppcheck processes every config in compile_commands.json.
+    " Use --file-filter to limit to just the buffer file.
     return !empty(l:json_path)
-    \   ? '--project=' . ale#Escape(l:json_path[len(l:dir) + 1: ])
+    \   ? '--project=' . ale#Escape(l:json_path[b:root_index: ]) . ' --file-filter=' . ale#Escape(b:buffer_file[b:root_index:])
     \   : ''
 endfunction
 
diff --git a/test/linter/test_c_cppcheck.vader b/test/linter/test_c_cppcheck.vader
index c84053f8..c0611143 100644
--- a/test/linter/test_c_cppcheck.vader
+++ b/test/linter/test_c_cppcheck.vader
@@ -22,20 +22,22 @@ Execute(cppcheck for C should detect compile_commands.json files):
   \   . ' -q --language=c'
   \   . ' --template=' . ale#Escape('{file}:{line}:{column}: {severity}:{inconclusive:inconclusive:} {message} [{id}]\\n{code}')
   \   . ' --project=' . ale#Escape('compile_commands.json')
+  \   . ' --file-filter=' . ale#Escape('foo.c')
   \   . ' --enable=style %t'
 
 Execute(cppcheck for C should detect compile_commands.json files in build directories):
-  call ale#test#SetFilename('../test-files/cppcheck/with_build_dir/foo.cpp')
+  call ale#test#SetFilename('../test-files/cppcheck/with_build_dir/foo.c')
 
   AssertLinterCwd ale#path#Simplify(g:dir . '/../test-files/cppcheck/with_build_dir')
   AssertLinter 'cppcheck', ale#Escape('cppcheck')
   \   . ' -q --language=c'
   \   . ' --template=' . ale#Escape('{file}:{line}:{column}: {severity}:{inconclusive:inconclusive:} {message} [{id}]\\n{code}')
   \   . ' --project=' . ale#Escape(ale#path#Simplify('build/compile_commands.json'))
+  \   . ' --file-filter=' . ale#Escape('foo.c')
   \   . ' --enable=style %t'
 
 Execute(cppcheck for C should include file dir if compile_commands.json file is not found):
-  call ale#test#SetFilename('../test-files/cppcheck/foo.cpp')
+  call ale#test#SetFilename('../test-files/cppcheck/foo.c')
 
   AssertLinter 'cppcheck',
   \   ale#Escape('cppcheck')
@@ -44,3 +46,15 @@ Execute(cppcheck for C should include file dir if compile_commands.json file is
   \   . ' --enable=style'
   \   . ' -I' . ale#Escape(ale#path#Simplify(g:dir . '/../test-files/cppcheck'))
   \   . ' %t'
+
+Execute(cppcheck for C header should include file dir and not use compile_commands.json):
+  call ale#test#SetFilename('../test-files/cppcheck/one/foo.h')
+
+  AssertLinter 'cppcheck',
+  \   ale#Escape('cppcheck')
+  \   . ' -q --language=c'
+  \   . ' --template=' . ale#Escape('{file}:{line}:{column}: {severity}:{inconclusive:inconclusive:} {message} [{id}]\\n{code}')
+  \   . '  -I' . ale#Escape(ale#path#Simplify(g:dir . '/../test-files/cppcheck/one'))
+  \   . ' --suppress=unusedStructMember'
+  \   . ' --enable=style'
+  \   . ' %t'
diff --git a/test/linter/test_cpp_cppcheck.vader b/test/linter/test_cpp_cppcheck.vader
index 62195803..2cde1da4 100644
--- a/test/linter/test_cpp_cppcheck.vader
+++ b/test/linter/test_cpp_cppcheck.vader
@@ -28,6 +28,7 @@ Execute(cppcheck for C++ should detect compile_commands.json files):
   \   . ' -q --language=c++'
   \   . ' --template=' . ale#Escape('{file}:{line}:{column}: {severity}:{inconclusive:inconclusive:} {message} [{id}]\\n{code}')
   \   . ' --project=' . ale#Escape('compile_commands.json')
+  \   . ' --file-filter=' . ale#Escape('foo.cpp')
   \   . ' --enable=style %t'
 
 Execute(cppcheck for C++ should detect compile_commands.json files in build directories):
@@ -38,6 +39,7 @@ Execute(cppcheck for C++ should detect compile_commands.json files in build dire
   \   . ' -q --language=c++'
   \   . ' --template=' . ale#Escape('{file}:{line}:{column}: {severity}:{inconclusive:inconclusive:} {message} [{id}]\\n{code}')
   \   . ' --project=' . ale#Escape(ale#path#Simplify('build/compile_commands.json'))
+  \   . ' --file-filter=' . ale#Escape('foo.cpp')
   \   . ' --enable=style %t'
 
 Execute(cppcheck for C++ should include file dir if compile_commands.json file is not found):
@@ -51,6 +53,18 @@ Execute(cppcheck for C++ should include file dir if compile_commands.json file i
   \   . ' -I' . ale#Escape(ale#path#Simplify(g:dir . '/../test-files/cppcheck'))
   \   . ' %t'
 
+Execute(cppcheck for C++ header should include file dir and not use compile_commands.json):
+  call ale#test#SetFilename('../test-files/cppcheck/one/foo.hpp')
+
+  AssertLinter 'cppcheck',
+  \   ale#Escape('cppcheck')
+  \   . ' -q --language=c++'
+  \   . ' --template=' . ale#Escape('{file}:{line}:{column}: {severity}:{inconclusive:inconclusive:} {message} [{id}]\\n{code}')
+  \   . '  -I' . ale#Escape(ale#path#Simplify(g:dir . '/../test-files/cppcheck/one'))
+  \   . ' --suppress=unusedStructMember'
+  \   . ' --enable=style'
+  \   . ' %t'
+
 Execute(cppcheck for C++ should ignore compile_commands.json file if buffer is modified):
   call ale#test#SetFilename('../test-files/cppcheck/one/foo.cpp')