Close #2556 - Support filename mapping

ALE now supports mapping files between different systems for running
linters and fixers with Docker, in virtual machines, in servers, etc.

README.md

@@ -79,6 +79,7 @@ other content at [w0rp.com](https://w0rp.com).
     17. [How can I configure my C or C++ project?](#faq-c-configuration)
     18. [How can I configure ALE differently for different buffers?](#faq-buffer-configuration)
     19. [How can I configure the height of the list in which ALE displays errors?](#faq-list-window-height)
+    20. [How can I run linters or fixers via Docker or a VM?](#faq-vm)
 
 <a name="supported-languages"></a>
 
@@ -877,3 +878,14 @@ To set a default height for the error list, use the `g:ale_list_window_size` var
 " Show 5 lines of errors (default: 10)
 let g:ale_list_window_size = 5
 ```
+
+<a name="faq-vm"></a>
+
+### 5.xx. How can I run linters or fixers via Docker or a VM?
+
+ALE supports running linters or fixers via Docker, virtual machines, or in
+combination with any remote machine with a different file system, so long as the
+tools are well-integrated with ALE, and ALE is properly configured to run the
+correct commands and map filename paths between different file systems. See
+`:help ale-lint-other-machines` for the full documentation on how to configure
+ALE to support this.

autoload/ale.vim

@@ -266,3 +266,23 @@ function! ale#GetLocItemMessage(item, format_string) abort
 
     return l:msg
 endfunction
+
+" Given a buffer and a linter or fixer name, return an Array of two-item
+" Arrays describing how to map filenames to and from the local to foreign file
+" systems.
+function! ale#GetFilenameMappings(buffer, name) abort
+    let l:linter_mappings = ale#Var(a:buffer, 'filename_mappings')
+
+    if type(l:linter_mappings) is v:t_list
+        return l:linter_mappings
+    endif
+
+    let l:name = a:name
+
+    if !has_key(l:linter_mappings, l:name)
+        " Use * as a default setting for all tools.
+        let l:name = '*'
+    endif
+
+    return get(l:linter_mappings, l:name, [])
+endfunction

autoload/ale/command.vim

@@ -133,11 +133,30 @@ function! ale#command#EscapeCommandPart(command_part) abort
     return substitute(a:command_part, '%', '%%', 'g')
 endfunction
 
+" Format a filename, converting it with filename mappings, if non-empty,
+" and escaping it for putting into a command string.
+function! s:FormatFilename(filename, mappings) abort
+    let l:filename = a:filename
+
+    if !empty(a:mappings)
+        let l:filename = ale#filename_mapping#Map(l:filename, a:mappings)
+    endif
+
+    return ale#Escape(l:filename)
+endfunction
+
 " Given a command string, replace every...
 " %s -> with the current filename
 " %t -> with the name of an unused file in a temporary directory
 " %% -> with a literal %
-function! ale#command#FormatCommand(buffer, executable, command, pipe_file_if_needed, input) abort
+function! ale#command#FormatCommand(
+\   buffer,
+\   executable,
+\   command,
+\   pipe_file_if_needed,
+\   input,
+\   filename_mappings,
+\) abort
     let l:temporary_file = ''
     let l:command = a:command
 
@@ -154,14 +173,14 @@ function! ale#command#FormatCommand(buffer, executable, command, pipe_file_if_ne
     " file.
     if l:command =~# '%s'
         let l:filename = fnamemodify(bufname(a:buffer), ':p')
-        let l:command = substitute(l:command, '%s', '\=ale#Escape(l:filename)', 'g')
+        let l:command = substitute(l:command, '%s', '\=s:FormatFilename(l:filename, a:filename_mappings)', 'g')
     endif
 
     if a:input isnot v:false && l:command =~# '%t'
         " Create a temporary filename, <temp_dir>/<original_basename>
         " The file itself will not be created by this function.
         let l:temporary_file = s:TemporaryFilename(a:buffer)
-        let l:command = substitute(l:command, '%t', '\=ale#Escape(l:temporary_file)', 'g')
+        let l:command = substitute(l:command, '%t', '\=s:FormatFilename(l:temporary_file, a:filename_mappings)', 'g')
     endif
 
     " Finish formatting so %% becomes %.
@@ -265,6 +284,7 @@ function! ale#command#Run(buffer, command, Callback, ...) abort
     \   a:command,
     \   get(l:options, 'read_buffer', 0),
     \   get(l:options, 'input', v:null),
+    \   get(l:options, 'filename_mappings', []),
     \)
     let l:command = ale#job#PrepareCommand(a:buffer, l:command)
     let l:job_options = {

autoload/ale/engine.vim

@@ -256,6 +256,13 @@ function! s:RemapItemTypes(type_map, loclist) abort
 endfunction
 
 function! ale#engine#FixLocList(buffer, linter_name, from_other_source, loclist) abort
+    let l:mappings = ale#GetFilenameMappings(a:buffer, a:linter_name)
+
+    if !empty(l:mappings)
+        " We need to apply reverse filename mapping here.
+        let l:mappings = ale#filename_mapping#Invert(l:mappings)
+    endif
+
     let l:bufnr_map = {}
     let l:new_loclist = []
 
@@ -296,13 +303,19 @@ function! ale#engine#FixLocList(buffer, linter_name, from_other_source, loclist)
             let l:item.code = l:old_item.code
         endif
 
-        if has_key(l:old_item, 'filename')
+        let l:old_name = get(l:old_item, 'filename', '')
-        \&& !ale#path#IsTempName(l:old_item.filename)
+
+        " Map parsed from output to local filesystem files.
+        if !empty(l:old_name) && !empty(l:mappings)
+            let l:old_name = ale#filename_mapping#Map(l:old_name, l:mappings)
+        endif
+
+        if !empty(l:old_name) && !ale#path#IsTempName(l:old_name)
             " Use the filename given.
             " Temporary files are assumed to be for this buffer,
             " and the filename is not included then, because it looks bad
             " in the loclist window.
-            let l:filename = l:old_item.filename
+            let l:filename = l:old_name
             let l:item.filename = l:filename
 
             if has_key(l:old_item, 'bufnr')
@@ -415,6 +428,7 @@ function! s:RunJob(command, options) abort
     \   'executable': l:executable,
     \   'read_buffer': l:read_buffer,
     \   'log_output': 1,
+    \   'filename_mappings': ale#GetFilenameMappings(l:buffer, l:linter.name),
     \})
 
     " Only proceed if the job is being run.

autoload/ale/filename_mapping.vim

@@ -0,0 +1,22 @@
+" Author: w0rp <devw0rp@gmail.com>
+" Description: Logic for handling mappings between files
+
+" Invert filesystem mappings so they can be mapped in reverse.
+function! ale#filename_mapping#Invert(filename_mappings) abort
+    return map(copy(a:filename_mappings), '[v:val[1], v:val[0]]')
+endfunction
+
+" Given a filename and some filename_mappings, map a filename.
+function! ale#filename_mapping#Map(filename, filename_mappings) abort
+    let l:simplified_filename = ale#path#Simplify(a:filename)
+
+    for [l:mapping_from, l:mapping_to] in a:filename_mappings
+        let l:mapping_from = ale#path#Simplify(l:mapping_from)
+
+        if l:simplified_filename[:len(l:mapping_from) - 1] is# l:mapping_from
+            return l:mapping_to . l:simplified_filename[len(l:mapping_from):]
+        endif
+    endfor
+
+    return a:filename
+endfunction

autoload/ale/fix.vim

@@ -1,4 +1,8 @@
+" Author: w0rp <devw0rp@gmail.com>
+" Description: Functions for fixing code with programs, or other means.
+
 call ale#Set('fix_on_save_ignore', {})
+call ale#Set('filename_mappings', {})
 
 " Apply fixes queued up for buffers which may be hidden.
 " Vim doesn't let you modify hidden buffers.
@@ -110,7 +114,6 @@ function! s:HandleExit(job_info, buffer, job_output, data) abort
     call s:RunFixer({
     \   'buffer': a:buffer,
     \   'input': l:input,
-    \   'output': l:output,
     \   'callback_list': a:job_info.callback_list,
     \   'callback_index': a:job_info.callback_index + 1,
     \})
@@ -125,6 +128,7 @@ function! s:RunJob(result, options) abort
 
     let l:buffer = a:options.buffer
     let l:input = a:options.input
+    let l:fixer_name = a:options.fixer_name
 
     if a:result is 0 || type(a:result) is v:t_list
         if type(a:result) is v:t_list
@@ -150,7 +154,6 @@ function! s:RunJob(result, options) abort
         \   'input': l:input,
         \   'callback_index': a:options.callback_index,
         \   'callback_list': a:options.callback_list,
-        \   'output': [],
         \})
 
         return
@@ -177,6 +180,7 @@ function! s:RunJob(result, options) abort
     \   'read_buffer': l:read_buffer,
     \   'input': l:input,
     \   'log_output': 0,
+    \   'filename_mappings': ale#GetFilenameMappings(l:buffer, l:fixer_name),
     \})
 
     if empty(l:run_result)
@@ -200,32 +204,22 @@ function! s:RunFixer(options) abort
         return
     endif
 
-    let l:ChainCallback = get(a:options, 'chain_callback', v:null)
+    let [l:fixer_name, l:Function] = a:options.callback_list[l:index]
-
-    let l:Function = l:ChainCallback isnot v:null
-    \   ? ale#util#GetFunction(l:ChainCallback)
-    \   : a:options.callback_list[l:index]
 
     " Record new jobs started as fixer jobs.
     call setbufvar(l:buffer, 'ale_job_type', 'fixer')
 
-    if l:ChainCallback isnot v:null
+    " Regular fixer commands accept (buffer, [input])
-        " Chained commands accept (buffer, output, [input])
+    let l:result = ale#util#FunctionArgCount(l:Function) == 1
-        let l:result = ale#util#FunctionArgCount(l:Function) == 2
+    \   ? call(l:Function, [l:buffer])
-        \   ? call(l:Function, [l:buffer, a:options.output])
+    \   : call(l:Function, [l:buffer, copy(l:input)])
-        \   : call(l:Function, [l:buffer, a:options.output, copy(l:input)])
-    else
-        " Regular fixer commands accept (buffer, [input])
-        let l:result = ale#util#FunctionArgCount(l:Function) == 1
-        \   ? call(l:Function, [l:buffer])
-        \   : call(l:Function, [l:buffer, copy(l:input)])
-    endif
 
     call s:RunJob(l:result, {
     \   'buffer': l:buffer,
     \   'input': l:input,
     \   'callback_list': a:options.callback_list,
     \   'callback_index': l:index,
+    \   'fixer_name': l:fixer_name,
     \})
 endfunction
 
@@ -293,16 +287,24 @@ function! s:GetCallbacks(buffer, fixing_flag, fixers) abort
     " Variables with capital characters are needed, or Vim will complain about
     " funcref variables.
     for l:Item in l:callback_list
+        " Try to capture the names of registered fixer names, so we can use
+        " them for filename mapping or other purposes later.
+        let l:fixer_name = v:null
+
         if type(l:Item) is v:t_string
             let l:Func = ale#fix#registry#GetFunc(l:Item)
 
             if !empty(l:Func)
+                let l:fixer_name = l:Item
                 let l:Item = l:Func
             endif
         endif
 
         try
-            call add(l:corrected_list, ale#util#GetFunction(l:Item))
+            call add(l:corrected_list, [
+            \   l:fixer_name,
+            \   ale#util#GetFunction(l:Item)
+            \])
         catch /E475/
             " Rethrow exceptions for failing to get a function so we can print
             " a friendly message about it.

autoload/ale/fix/registry.vim

@@ -160,11 +160,11 @@ let s:default_registry = {
 \       'suggested_filetypes': ['php'],
 \       'description': 'Fix PHP files with php-cs-fixer.',
 \   },
-\    'astyle': {
+\   'astyle': {
 \       'function': 'ale#fixers#astyle#Fix',
 \       'suggested_filetypes': ['c', 'cpp'],
 \       'description': 'Fix C/C++ with astyle.',
-\    },
+\   },
 \   'clangtidy': {
 \       'function': 'ale#fixers#clangtidy#Fix',
 \       'suggested_filetypes': ['c', 'cpp', 'objc'],

autoload/ale/lsp_linter.vim

@@ -265,7 +265,14 @@ function! s:StartLSP(options, address, executable, command) abort
             call ale#lsp#MarkConnectionAsTsserver(l:conn_id)
         endif
 
-        let l:command = ale#command#FormatCommand(l:buffer, a:executable, a:command, 0, v:false)[1]
+        let l:command = ale#command#FormatCommand(
+        \   l:buffer,
+        \   a:executable,
+        \   a:command,
+        \   0,
+        \   v:false,
+        \   [],
+        \)[1]
         let l:command = ale#job#PrepareCommand(l:buffer, l:command)
         let l:ready = ale#lsp#StartProgram(l:conn_id, a:executable, l:command)
     endif

autoload/ale/path.vim

@@ -95,7 +95,7 @@ function! ale#path#IsAbsolute(filename) abort
     return a:filename[:0] is# '/' || a:filename[1:2] is# ':\'
 endfunction
 
-let s:temp_dir = ale#path#Simplify(fnamemodify(ale#util#Tempname(), ':h'))
+let s:temp_dir = ale#path#Simplify(fnamemodify(ale#util#Tempname(), ':h:h'))
 
 " Given a filename, return 1 if the file represents some temporary file
 " created by Vim.

doc/ale.txt

@@ -9,8 +9,9 @@ CONTENTS                                                         *ale-contents*
   1. Introduction.........................|ale-introduction|
   2. Supported Languages & Tools..........|ale-support|
   3. Linting..............................|ale-lint|
-    3.1 Adding Language Servers...........|ale-lint-language-servers|
+    3.1 Linting On Other Machines.........|ale-lint-other-machines|
-    3.2 Other Sources.....................|ale-lint-other-sources|
+    3.2 Adding Language Servers...........|ale-lint-language-servers|
+    3.3 Other Sources.....................|ale-lint-other-sources|
   4. Fixing Problems......................|ale-fix|
   5. Language Server Protocol Support.....|ale-lsp|
     5.1 Completion........................|ale-completion|
@@ -148,7 +149,61 @@ ALE offers several options for controlling which linters are run.
 
 
 -------------------------------------------------------------------------------
-3.1 Adding Language Servers                         *ale-lint-language-servers*
+3.1 Linting On Other Machines                         *ale-lint-other-machines*
+
+ALE offers support for running linters or fixers on files you are editing
+locally on other machines, so long as the other machine has access the file
+you are editing. This could be a linter or fixer run inside of a Docker image,
+running in a virtual machine, running on a remote server, etc.
+
+In order to run tools on other machines, you will need to configure your tools
+to run via scripts that execute commands on those machines, such as by setting
+the ALE `_executable` options for those tools to a path for a script to run,
+or by using |g:ale_command_wrapper| to specify a script to wrap all commands
+that are run by ALE, before they are executed. For tools that ALE runs where
+ALE looks for locally installed executables first, you may need to set the
+`_use_global` options for those tools to `1`, or you can set
+|g:ale_use_global_executables| to `1` before ALE is loaded to only use global
+executables for all tools.
+
+In order for ALE to properly lint or fix files which are running on another
+file system, you must provide ALE with |List|s of strings for mapping paths to
+and from your local file system and the remote file system, such as the file
+system of your Docker container. See |g:ale_filename_mappings| for all of the
+different ways these filename mappings can be configured.
+
+For example, you might configure `pylint` to run via Docker by creating a
+script like so. >
+
+  #!/usr/bin/env bash
+
+  exec docker run --rm -v "$(pwd):/data" cytopia/pylint "$@"
+<
+With the above script in mind, you might configure ALE to lint your Python
+project with `pylint` by providing the path to the script to execute, and
+mappings which describe how to between the two file systems in your
+`python.vim` |ftplugin| file, like so: >
+
+  if expand('%:p') =~# '^/home/w0rp/git/test-pylint/'
+    let b:ale_linters = ['pylint']
+    let b:ale_python_pylint_use_global = 1
+    " This is the path to the script above.
+    let b:ale_python_pylint_executable = '/home/w0rp/git/test-pylint/pylint.sh'
+    " /data matches the path in Docker.
+    let b:ale_filename_mappings = {
+    \ 'pylint': [
+    \   ['/home/w0rp/git/test-pylint', '/data'],
+    \ ],
+    \}
+  endif
+<
+
+You might consider using a Vim plugin for loading Vim configuration files
+specific to each project, if you have a lot of projects to manage.
+
+
+-------------------------------------------------------------------------------
+3.2 Adding Language Servers                         *ale-lint-language-servers*
 
 ALE comes with many default configurations for language servers, so they can
 be detected and run automatically. ALE can connect to other language servers
@@ -189,7 +244,7 @@ address to connect to instead. >
 
 
 -------------------------------------------------------------------------------
-3.2 Other Sources                                      *ale-lint-other-sources*
+3.3 Other Sources                                      *ale-lint-other-sources*
 
 Problems for a buffer can be taken from other sources and rendered by ALE.
 This allows ALE to be used in combination with other plugins which also want
@@ -356,6 +411,10 @@ by default.
 Fixers can be disabled on save with |g:ale_fix_on_save_ignore|. They will
 still be run when you manually run |ALEFix|.
 
+Fixers can be run on another machines, just like linters, such as fixers run
+from a Docker container, running in a virtual machine, running a remote
+server, etc. See |ale-lint-other-machines|.
+
 
 ===============================================================================
 5. Language Server Protocol Support                                   *ale-lsp*
@@ -1286,6 +1345,90 @@ g:ale_linter_aliases                                     *g:ale_linter_aliases*
 <
   No linters will be loaded when the buffer's filetype is empty.
 
+
+g:ale_filename_mappings                               *g:ale_filename_mappings*
+                                                      *b:ale_filename_mappings*
+
+  Type: |Dictionary| or |List|
+  Default: `{}`
+
+  Either a |Dictionary| mapping a linter or fixer name, as displayed in
+  |:ALEInfo|, to a |List| of two-item |List|s for filename mappings, or just a
+  |List| of two-item |List|s. When given some paths to files, the value of
+  this setting will be used to convert filenames on a local file system to
+  filenames on some remote file system, such as paths in a Docker image,
+  virtual machine, or network drive.
+
+  For example: >
+
+  let g:ale_filename_mappings = {
+  \   'pylint': [
+  \       ['/home/john/proj', '/data'],
+  \   ],
+  \}
+<
+  With the above configuration, a filename such as `/home/john/proj/foo.py`
+  will be provided to the linter/fixer as `/data/foo.py`, and paths parsed
+  from linter results such as `/data/foo.py` will be converted back to
+  `/home/john/proj/foo.py`.
+
+  You can use `*` as to apply a |List| of filename mappings to all other
+  linters or fixers not otherwise matched. >
+
+  " Use one List of paths for pylint.
+  " Use another List of paths for everything else.
+  let g:ale_filename_mappings = {
+  \   'pylint': [
+  \       ['/home/john/proj', '/data'],
+  \   ],
+  \   '*': [
+  \       ['/home/john/proj', '/other-data'],
+  \   ],
+  \}
+<
+  If you just want every single linter or fixer to use the same filename
+  mapping, you can just use a |List|. >
+
+  " Same as above, but for ALL linters and fixers.
+  let g:ale_filename_mappings = [
+  \   ['/home/john/proj', '/data'],
+  \]
+<
+  You can provide many such filename paths for multiple projects. Paths are
+  matched by checking if the start of a file path matches the given strings,
+  in a case-sensitive manner. Earlier entries in the |List| will be tried
+  before later entries when mapping to a given file system.
+
+  Buffer-local options can be set to the same values to override the global
+  options, such as in |ftplugin| files.
+
+  NOTE: Only fixers registered with a short name can support filename mapping
+  by their fixer names. See |ale-fix|. Filename mappings set for all tools by
+  using only a |List| for the setting will also be applied to fixers not in
+  the registry.
+
+  NOTE: In order for this filename mapping to work correctly, linters and
+  fixers must exclusively determine paths to files to lint or fix via ALE
+  command formatting as per |ale-command-format-strings|, and paths parsed
+  from linter files must be provided in `filename` keys if a linter returns
+  results for more than one file at a time, as per |ale-loclist-format|. If
+  you discover a linter or fixer which does not behave properly, please report
+  it as an issue.
+
+  If you are running a linter or fixer through Docker or another remote file
+  system, you may have to mount your temporary directory, which you can
+  discover with the following command: >
+
+  :echo fnamemodify(tempname(), ':h:h')
+<
+  You should provide a mapping from this temporary directory to whatever you
+  mount this directory to in Docker, or whatever remote file system you are
+  working with.
+
+  You can inspect the filename mappings ALE will use with the
+  |ale#GetFilenameMappings()| function.
+
+
 g:ale_linters                                                   *g:ale_linters*
                                                                 *b:ale_linters*
   Type: |Dictionary|
@@ -3073,6 +3216,15 @@ ale#Env(variable_name, value)                                       *ale#Env()*
     'set VAR="some value" && command' # On Windows
 
 
+ale#GetFilenameMappings(buffer, name)               *ale#GetFilenameMappings()*
+
+  Given a `buffer` and the `name` of either a linter for fixer, return a
+  |List| of two-item |List|s that describe mapping to and from the local and
+  foreign file systems for running a particular linter or fixer.
+
+  See |g:ale_filename_mappings| for details on filename mapping.
+
+
 ale#Has(feature)                                                    *ale#Has()*
 
   Return `1` if ALE supports a given feature, like |has()| for Vim features.
@@ -3187,23 +3339,36 @@ ale#command#Run(buffer, command, callback, [options])       *ale#command#Run()*
 <
   The following `options` can be provided.
 
-    `output_stream` - Either `'stdout'`, `'stderr'`, `'both'`, or `'none`' for
+    `output_stream`     - Either `'stdout'`, `'stderr'`, `'both'`, or
-                    selecting which output streams to read lines from.
+                        `'none`' for selecting which output streams to read
+                        lines from.
 
-                    The default is `'stdout'`
+                        The default is `'stdout'`
 
-    `executable`    - An executable for formatting into `%e` in the command.
+    `executable`        - An executable for formatting into `%e` in the
-                    If this option is not provided, formatting commands with
+                        command. If this option is not provided, formatting
-                    `%e` will not work.
+                        commands with `%e` will not work.
 
-    `read_buffer`   - If set to `1`, the buffer will be piped into the
+    `read_buffer`       - If set to `1`, the buffer will be piped into the
-                    command.
+                        command.
 
-                    The default is `0`.
+                        The default is `0`.
+
+    `input`             - When creating temporary files with `%t` or piping
+                        text into a command `input` can be set to a |List| of
+                        text to use instead of the buffer's text.
+
+    `filename_mappings` - A |List| of two-item |List|s describing filename
+                        mappings to apply for formatted filenames in the
+                        command string, as per |g:ale_filename_mappings|.
+
+                        If the call to this function is being used for a
+                        linter or fixer, the mappings should be provided with
+                        this option, and can be retrieved easily with
+                        |ale#GetFilenameMappings()|.
+
+                        The default is `[]`.
 
-    `input`         - When creating temporary files with `%t` or piping text
-                    into a command `input` can be set to a |List| of text to
-                    use instead of the buffer's text.
 
 
 ale#command#EscapeCommandPart(command_part)   *ale#command#EscapeCommandPart()*

plugin/ale.vim

@@ -97,6 +97,10 @@ let g:ale_fix_on_save = get(g:, 'ale_fix_on_save', 0)
 " should be used instead.
 let g:ale_enabled = get(g:, 'ale_enabled', 1)
 
+" A Dictionary mapping linter or fixer names to Arrays of two-item Arrays
+" mapping filename paths from one system to another.
+let g:ale_filename_mappings = get(g:, 'ale_filename_mappings', {})
+
 " These flags dictates if ale uses the quickfix or the loclist (loclist is the
 " default, quickfix overrides loclist).
 let g:ale_set_loclist = get(g:, 'ale_set_loclist', 1)

test/fix/test_ale_fix.vader

@@ -6,6 +6,7 @@ Before:
   Save g:ale_lint_on_save
   Save g:ale_echo_cursor
   Save g:ale_command_wrapper
+  Save g:ale_filename_mappings
 
   silent! cd /testplugin/test/fix
 
@@ -19,6 +20,7 @@ Before:
   let g:ale_fixers = {
   \ 'testft': [],
   \}
+  let g:ale_filename_mappings = {}
 
   let g:pre_success = 0
   let g:post_success = 0
@@ -72,6 +74,10 @@ Before:
     return {'command': 'cat %t <(echo d)'}
   endfunction
 
+  function EchoFilename(buffer, lines) abort
+    return {'command': 'echo %s'}
+  endfunction
+
   function RemoveLastLine(buffer, lines) abort
     return ['a', 'b']
   endfunction
@@ -155,6 +161,7 @@ After:
   delfunction CatLineDeferred
   delfunction ReplaceWithTempFile
   delfunction CatWithTempFile
+  delfunction EchoFilename
   delfunction RemoveLastLine
   delfunction RemoveLastLineOneArg
   delfunction TestCallback
@@ -209,6 +216,23 @@ Expect(The first function should be used):
   ^b
   ^c
 
+Execute(Should apply filename mpapings):
+  " The command echos %s, and we'll map the current path so we can check
+  " that ALEFix applies filename mappings, end-to-end.
+  let g:ale_filename_mappings = {
+  \ 'echo_filename': [
+  \   [expand('%:p:h'), '/some/fake/path'],
+  \ ],
+  \}
+
+  call ale#fix#registry#Add('echo_filename', 'EchoFilename', [], 'echo filename')
+  let g:ale_fixers.testft = ['echo_filename']
+  ALEFix
+  call ale#test#FlushJobs()
+
+Expect(The mapped filename should be printed):
+  /some/fake/path/test.txt
+
 Execute(ALEFix should apply simple functions in a chain):
   let g:ale_fixers.testft = ['AddCarets', 'Capitalize']
   ALEFix

test/test_filename_mapping.vader

@@ -0,0 +1,62 @@
+Before:
+  Save g:ale_filename_mappings
+  Save b:ale_filename_mappings
+
+  let g:ale_filename_mappings = {}
+  unlet! b:ale_filename_mappings
+
+After:
+  Restore
+
+Execute(ale#GetFilenameMappings should return the correct mappings for given linters/fixers):
+  let g:ale_filename_mappings = {'a': [['foo', 'bar']], 'b': [['baz', 'foo']]}
+
+  AssertEqual [['foo', 'bar']], ale#GetFilenameMappings(bufnr(''), 'a')
+  AssertEqual [['baz', 'foo']], ale#GetFilenameMappings(bufnr(''), 'b')
+  AssertEqual [], ale#GetFilenameMappings(bufnr(''), 'c')
+
+  let b:ale_filename_mappings = {'b': [['abc', 'xyz']]}
+
+  AssertEqual [], ale#GetFilenameMappings(bufnr(''), 'a')
+  AssertEqual [['abc', 'xyz']], ale#GetFilenameMappings(bufnr(''), 'b')
+  AssertEqual [], ale#GetFilenameMappings(bufnr(''), 'c')
+
+Execute(ale#GetFilenameMappings should return Lists set for use with all tools):
+  let g:ale_filename_mappings = [['foo', 'bar']]
+
+  AssertEqual [['foo', 'bar']], ale#GetFilenameMappings(bufnr(''), 'a')
+  AssertEqual [['foo', 'bar']], ale#GetFilenameMappings(bufnr(''), '')
+  AssertEqual [['foo', 'bar']], ale#GetFilenameMappings(bufnr(''), v:null)
+
+  let b:ale_filename_mappings = [['abc', 'xyz']]
+
+  AssertEqual [['abc', 'xyz']], ale#GetFilenameMappings(bufnr(''), 'a')
+  AssertEqual [['abc', 'xyz']], ale#GetFilenameMappings(bufnr(''), '')
+  AssertEqual [['abc', 'xyz']], ale#GetFilenameMappings(bufnr(''), v:null)
+
+Execute(ale#GetFilenameMappings should let you use * as a fallback):
+  let g:ale_filename_mappings = {'a': [['foo', 'bar']], '*': [['abc', 'xyz']]}
+
+  AssertEqual [['foo', 'bar']], ale#GetFilenameMappings(bufnr(''), 'a')
+  AssertEqual [['abc', 'xyz']], ale#GetFilenameMappings(bufnr(''), 'b')
+  AssertEqual [['abc', 'xyz']], ale#GetFilenameMappings(bufnr(''), '')
+  AssertEqual [['abc', 'xyz']], ale#GetFilenameMappings(bufnr(''), v:null)
+
+Execute(ale#filename_mapping#Invert should invert filename mappings):
+  AssertEqual
+  \ [['b', 'a'], ['y', 'x']],
+  \ ale#filename_mapping#Invert([['a', 'b'], ['x', 'y']])
+  \
+Execute(ale#filename_mapping#Map return the filename as-is if there are no mappings):
+  AssertEqual
+  \ '/foo//bar',
+  \ ale#filename_mapping#Map('/foo//bar', [['/bar', '/data/']])
+
+Execute(ale#filename_mapping#Map should map filenames):
+  AssertEqual
+  \ '/data/bar',
+  \ ale#filename_mapping#Map('/foo//bar', [
+  \   ['/data', '/baz'],
+  \   ['/foo', '/data'],
+  \   ['/foo', '/xyz'],
+  \ ])

test/test_format_command.vader

@@ -25,12 +25,12 @@ After:
 Execute(FormatCommand should do nothing to basic command strings):
   AssertEqual
   \ ['', 'awesome-linter do something', 0],
-  \ ale#command#FormatCommand(bufnr('%'), '', 'awesome-linter do something', 0, v:null)
+  \ ale#command#FormatCommand(bufnr('%'), '', 'awesome-linter do something', 0, v:null, [])
 
 Execute(FormatCommand should handle %%, and ignore other percents):
   AssertEqual
   \ ['', '% %%d %%f %x %', 0],
-  \ ale#command#FormatCommand(bufnr('%'), '', '%% %%%d %%%f %x %', 0, v:null)
+  \ ale#command#FormatCommand(bufnr('%'), '', '%% %%%d %%%f %x %', 0, v:null, [])
 
 Execute(FormatCommand should convert %s to the current filename):
   AssertEqual
@@ -39,10 +39,10 @@ Execute(FormatCommand should convert %s to the current filename):
   \   'foo ' . ale#Escape(expand('%:p')) . ' bar ' . ale#Escape(expand('%:p')),
   \   0,
   \ ],
-  \ ale#command#FormatCommand(bufnr('%'), '', 'foo %s bar %s', 0, v:null)
+  \ ale#command#FormatCommand(bufnr('%'), '', 'foo %s bar %s', 0, v:null, [])
 
 Execute(FormatCommand should convert %t to a new temporary filename):
-  let g:result = ale#command#FormatCommand(bufnr('%'), '', 'foo %t bar %t', 0, v:null)
+  let g:result = ale#command#FormatCommand(bufnr('%'), '', 'foo %t bar %t', 0, v:null, [])
 
   call CheckTempFile(g:result[0])
 
@@ -56,21 +56,21 @@ Execute(FormatCommand should convert %t to a new temporary filename):
   AssertEqual g:match[1], g:match[2]
 
 Execute(FormatCommand should not convert %t to a new temporary filename when the input is given as v:false):
-  let g:result = ale#command#FormatCommand(bufnr('%'), '', 'foo %t bar %t', 0, v:false)
+  let g:result = ale#command#FormatCommand(bufnr('%'), '', 'foo %t bar %t', 0, v:false, [])
 
   AssertEqual ['', 'foo %t bar %t', 0], g:result
 
 Execute(FormatCommand should signal that files are created when temporary files are needed):
   AssertEqual
   \ 1,
-  \ ale#command#FormatCommand(bufnr('%'), '', 'foo %t', 0, v:null)[2]
+  \ ale#command#FormatCommand(bufnr('%'), '', 'foo %t', 0, v:null, [])[2]
 
   AssertEqual
   \ 0,
-  \ ale#command#FormatCommand(bufnr('%'), '', 'foo %s', 0, v:null)[2]
+  \ ale#command#FormatCommand(bufnr('%'), '', 'foo %s', 0, v:null, [])[2]
 
 Execute(FormatCommand should let you combine %s and %t):
-  let g:result = ale#command#FormatCommand(bufnr('%'), '', 'foo %t bar %s', 0, v:null)
+  let g:result = ale#command#FormatCommand(bufnr('%'), '', 'foo %t bar %s', 0, v:null, [])
 
   call CheckTempFile(g:result[0])
 
@@ -87,30 +87,30 @@ Execute(FormatCommand should replace %e with the escaped executable):
   if has('win32')
     AssertEqual
     \ ['', 'foo foo', 0],
-    \ ale#command#FormatCommand(bufnr('%'), 'foo', '%e %e', 0, v:null)
+    \ ale#command#FormatCommand(bufnr('%'), 'foo', '%e %e', 0, v:null, [])
     AssertEqual
     \ ['', '"foo bar"', 0],
-    \ ale#command#FormatCommand(bufnr('%'), 'foo bar', '%e', 0, v:null)
+    \ ale#command#FormatCommand(bufnr('%'), 'foo bar', '%e', 0, v:null, [])
     AssertEqual
     \ ['', '%e %e', 0],
-    \ ale#command#FormatCommand(bufnr('%'), '', '%e %e', 0, v:null)
+    \ ale#command#FormatCommand(bufnr('%'), '', '%e %e', 0, v:null, [])
   else
     AssertEqual
     \ ['', '''foo'' ''foo''', 0],
-    \ ale#command#FormatCommand(bufnr('%'), 'foo', '%e %e', 0, v:null)
+    \ ale#command#FormatCommand(bufnr('%'), 'foo', '%e %e', 0, v:null, [])
     AssertEqual
     \ ['', '''foo bar''', 0],
-    \ ale#command#FormatCommand(bufnr('%'), 'foo bar', '%e', 0, v:null)
+    \ ale#command#FormatCommand(bufnr('%'), 'foo bar', '%e', 0, v:null, [])
     AssertEqual
     \ ['', '%e %e', 0],
-    \ ale#command#FormatCommand(bufnr('%'), '', '%e %e', 0, v:null)
+    \ ale#command#FormatCommand(bufnr('%'), '', '%e %e', 0, v:null, [])
   endif
 
 Execute(EscapeCommandPart should escape all percent signs):
   AssertEqual '%%s %%t %%%% %%s %%t %%%%', ale#engine#EscapeCommandPart('%s %t %% %s %t %%')
 
 Execute(EscapeCommandPart should pipe in temporary files appropriately):
-  let g:result = ale#command#FormatCommand(bufnr('%'), '', 'foo bar', 1, v:null)
+  let g:result = ale#command#FormatCommand(bufnr('%'), '', 'foo bar', 1, v:null, [])
 
   call CheckTempFile(g:result[0])
 
@@ -118,10 +118,24 @@ Execute(EscapeCommandPart should pipe in temporary files appropriately):
   Assert !empty(g:match), 'No match found! Result was: ' . g:result[1]
   AssertEqual ale#Escape(g:result[0]), g:match[1]
 
-  let g:result = ale#command#FormatCommand(bufnr('%'), '', 'foo bar %t', 1, v:null)
+  let g:result = ale#command#FormatCommand(bufnr('%'), '', 'foo bar %t', 1, v:null, [])
 
   call CheckTempFile(g:result[0])
 
   let g:match = matchlist(g:result[1], '\v^foo bar (.*)$')
   Assert !empty(g:match), 'No match found! Result was: ' . g:result[1]
   AssertEqual ale#Escape(g:result[0]), g:match[1]
+
+Execute(FormatCommand should apply filename mappings the current file):
+  let g:result = ale#command#FormatCommand(bufnr('%'), '', '%s', 1, v:null, [
+  \ [expand('%:p:h'), '/foo/bar'],
+  \])
+
+  Assert g:result[1] =~# '/foo/bar'
+
+Execute(FormatCommand should apply filename mappings to temporary files):
+  let g:result = ale#command#FormatCommand(bufnr('%'), '', '%t', 1, v:null, [
+  \ [fnamemodify(tempname(), ':h:h'), '/foo/bar']
+  \])
+
+  Assert g:result[1] =~# '/foo/bar'

test/test_loclist_corrections.vader

@@ -1,7 +1,50 @@
+Before:
+  Save g:ale_filename_mappings
+
+  let g:ale_filename_mappings = {}
+
 After:
   unlet! b:temp_name
   unlet! b:other_bufnr
 
+  Restore
+
+
+Execute(FixLocList should map filenames):
+  " Paths converted back into temporary filenames shouldn't be included.
+  let g:ale_filename_mappings = {
+  \ 'linter2': [['/xxx', '/data']],
+  \ 'linter1': [
+  \   ['/bar', '/data/special'],
+  \   ['/foo', '/data'],
+  \   [
+  \     ale#path#Simplify(fnamemodify(ale#util#Tempname(), ':h:h')),
+  \     '/x-tmp',
+  \   ],
+  \ ],
+  \}
+
+  AssertEqual
+  \ [
+  \   '/foo/file.txt',
+  \   v:null,
+  \   '/bar/file.txt',
+  \ ],
+  \ map(
+  \   ale#engine#FixLocList(
+  \     bufnr('%'),
+  \     'linter1',
+  \     0,
+  \     [
+  \       {'text': 'x', 'lnum': 1, 'filename': '/data/file.txt'},
+  \       {'text': 'x', 'lnum': 1, 'filename': '/x-tmp/file.txt'},
+  \       {'text': 'x', 'lnum': 1, 'filename': '/data/special/file.txt'},
+  \     ],
+  \   ),
+  \   'get(v:val, ''filename'', v:null)',
+  \ )
+
+
 Given foo (Some file with lines to count):
   foo12345678
   bar12345678
@@ -37,7 +80,7 @@ Execute(FixLocList should set all the default values correctly):
   \     'nr': -1,
   \     'linter_name': 'foobar',
   \   },
-  \],
+  \ ],
   \ ale#engine#FixLocList(
   \   bufnr('%'),
   \   'foobar',
@@ -58,7 +101,7 @@ Execute(FixLocList should use the values we supply):
   \     'nr': 42,
   \     'linter_name': 'foobar',
   \   },
-  \],
+  \ ],
   \ ale#engine#FixLocList(
   \   bufnr('%'),
   \   'foobar',
@@ -87,7 +130,7 @@ Execute(FixLocList should set items with lines beyond the end to the last line):
   \     'nr': -1,
   \     'linter_name': 'foobar',
   \   },
-  \],
+  \ ],
   \ ale#engine#FixLocList(
   \   bufnr('%'),
   \   'foobar',
@@ -108,7 +151,7 @@ Execute(FixLocList should move line 0 to line 1):
   \     'nr': -1,
   \     'linter_name': 'foobar',
   \   },
-  \],
+  \ ],
   \ ale#engine#FixLocList(
   \   bufnr('%'),
   \   'foobar',
@@ -130,7 +173,7 @@ Execute(FixLocList should convert line and column numbers correctly):
   \     'nr': -1,
   \     'linter_name': 'foobar',
   \   },
-  \],
+  \ ],
   \ ale#engine#FixLocList(
   \   bufnr('%'),
   \   'foobar',
@@ -164,7 +207,7 @@ Execute(FixLocList should pass on end_col values):
   \     'nr': -1,
   \     'linter_name': 'foobar',
   \   },
-  \],
+  \ ],
   \ ale#engine#FixLocList(
   \   bufnr('%'),
   \   'foobar',
@@ -202,7 +245,7 @@ Execute(FixLocList should pass on end_lnum values):
   \     'nr': -1,
   \     'linter_name': 'foobar',
   \   },
-  \],
+  \ ],
   \ ale#engine#FixLocList(
   \   bufnr('%'),
   \   'foobar',
@@ -227,7 +270,7 @@ Execute(FixLocList should allow subtypes to be set):
   \     'nr': -1,
   \     'linter_name': 'foobar',
   \   },
-  \],
+  \ ],
   \ ale#engine#FixLocList(
   \   bufnr('%'),
   \   'foobar',
@@ -289,7 +332,7 @@ Execute(FixLocList should accept filenames):
   \     'nr': -1,
   \     'linter_name': 'foobar',
   \   },
-  \],
+  \ ],
   \ ale#engine#FixLocList(
   \   bufnr('%'),
   \   'foobar',
@@ -327,7 +370,7 @@ Execute(FixLocList should interpret temporary filenames as being the current buf
   \     'nr': -1,
   \     'linter_name': 'foobar',
   \   },
-  \],
+  \ ],
   \ ale#engine#FixLocList(
   \   bufnr(''),
   \   'foobar',
@@ -352,7 +395,7 @@ Execute(The error code should be passed on):
   \     'linter_name': 'foobar',
   \     'code': 'some-code'
   \   },
-  \],
+  \ ],
   \ ale#engine#FixLocList(
   \   bufnr('%'),
   \   'foobar',
@@ -385,7 +428,7 @@ Execute(FixLocList should mark problems as coming from other sources if requeste
   \     'linter_name': 'foobar',
   \     'from_other_source': 1,
   \   },
-  \],
+  \ ],
   \ ale#engine#FixLocList(
   \   bufnr('%'),
   \   'foobar',
@@ -407,7 +450,7 @@ Execute(character positions should be converted to byte positions):
   \   {'lnum': 1, 'bufnr': bufnr(''), 'col': 7, 'end_col': 13, 'end_lnum': 1, 'linter_name': 'foobar', 'nr': -1, 'type': 'E', 'vcol': 0, 'text': 'a'},
   \   {'lnum': 1, 'bufnr': bufnr(''), 'col': 7, 'end_col': 17, 'end_lnum': 2, 'linter_name': 'foobar', 'nr': -1, 'type': 'E', 'vcol': 0, 'text': 'a'},
   \   {'lnum': 2, 'bufnr': bufnr(''), 'col': 17, 'linter_name': 'foobar', 'nr': -1, 'type': 'E', 'vcol': 0, 'text': 'a'},
-  \],
+  \ ],
   \ ale#engine#FixLocList(
   \   bufnr('%'),
   \   'foobar',