Fix chktex highlighting wrong column when using tabs instead of spaces (#4661)

* Fix chktex highlighting wrong column when using tabs instead of spaces

Fixes #723

chktex implemented feature request [1] for allowing setting options from
the command line. Thanks to that we can tell it to treat tab character
as of one space width, i.e. one char. That means, after we translate the
output back to Vim columns, we get correct numbers.

[1]: https://savannah.nongnu.org/bugs/?56486

* Add test_tex_chktex.vader

* Use functions to set g: variables in ale_linters/tex/chktex.vim

* Update ale_linters#tex#chktex#GetCommand() to use '%e'

2 files changed, 40 insertions, 15 deletions

diff --git a/ale_linters/tex/chktex.vim b/ale_linters/tex/chktex.vim
index 160baf0d..7708b1ea 100644
--- a/ale_linters/tex/chktex.vim
+++ b/ale_linters/tex/chktex.vim
@@ -1,29 +1,27 @@
 " Author: Andrew Balmos - <andrew@balmos.org>
 " Description: chktex for LaTeX files
 
-let g:ale_tex_chktex_executable =
-\   get(g:, 'ale_tex_chktex_executable', 'chktex')
-
-let g:ale_tex_chktex_options =
-\   get(g:, 'ale_tex_chktex_options', '-I')
+call ale#Set('tex_chktex_executable', 'chktex')
+call ale#Set('tex_chktex_options', '-I')
 
 function! ale_linters#tex#chktex#GetCommand(buffer) abort
-    " Check for optional .chktexrc
-    let l:chktex_config = ale#path#FindNearestFile(
-    \   a:buffer,
-    \   '.chktexrc')
+    let l:options = ''
 
-    let l:command = ale#Var(a:buffer, 'tex_chktex_executable')
     " Avoid bug when used without -p (last warning has gibberish for a filename)
-    let l:command .= ' -v0 -p stdin -q'
+    let l:options .= ' -v0 -p stdin -q'
+    " Avoid bug of reporting wrong column when using tabs (issue #723)
+    let l:options .= ' -s TabSize=1'
+
+    " Check for optional .chktexrc
+    let l:chktex_config = ale#path#FindNearestFile(a:buffer, '.chktexrc')
 
     if !empty(l:chktex_config)
-        let l:command .= ' -l ' . ale#Escape(l:chktex_config)
+        let l:options .= ' -l ' . ale#Escape(l:chktex_config)
     endif
 
-    let l:command .= ' ' . ale#Var(a:buffer, 'tex_chktex_options')
+    let l:options .= ' ' . ale#Var(a:buffer, 'tex_chktex_options')
 
-    return l:command
+    return '%e' . l:options
 endfunction
 
 function! ale_linters#tex#chktex#Handle(buffer, lines) abort
@@ -48,7 +46,7 @@ endfunction
 
 call ale#linter#Define('tex', {
 \   'name': 'chktex',
-\   'executable': 'chktex',
+\   'executable': {b -> ale#Var(b, 'tex_chktex_executable')},
 \   'command': function('ale_linters#tex#chktex#GetCommand'),
 \   'callback': 'ale_linters#tex#chktex#Handle'
 \})
diff --git a/test/linter/test_tex_chktex.vader b/test/linter/test_tex_chktex.vader
new file mode 100644
index 00000000..7052c367
--- /dev/null
+++ b/test/linter/test_tex_chktex.vader
@@ -0,0 +1,27 @@
+Before:
+  call ale#assert#SetUpLinterTest('tex', 'chktex')
+
+After:
+  call ale#assert#TearDownLinterTest()
+
+Execute(The default command should be correct):
+  AssertLinter 'chktex',
+  \ ale#Escape('chktex')
+  \   . ' -v0 -p stdin -q -s TabSize=1'
+  \   . ' -I'
+
+Execute(The executable should be configurable):
+  let g:ale_tex_chktex_executable = 'bin/foo'
+
+  AssertLinter 'bin/foo',
+  \ ale#Escape('bin/foo')
+  \   . ' -v0 -p stdin -q -s TabSize=1'
+  \   . ' -I'
+
+Execute(The options should be configurable):
+  let b:ale_tex_chktex_options = '--something'
+
+  AssertLinter 'chktex',
+  \ ale#Escape('chktex')
+  \   . ' -v0 -p stdin -q -s TabSize=1'
+  \   . ' --something'