Fix #626 - Automatically use cargo check and cargo check --all-targets for cargo versions that are new enough

ale_linters/rust/cargo.vim

@@ -1,7 +1,10 @@
 " Author: Daniel Schemala <istjanichtzufassen@gmail.com>
 " Description: rustc invoked by cargo for rust files
 
-let g:ale_rust_cargo_use_check = get(g:, 'ale_rust_cargo_use_check', 0)
+call ale#Set('rust_cargo_use_check', 1)
+call ale#Set('rust_cargo_check_all_targets', 1)
+
+let s:version_cache = {}
 
 function! ale_linters#rust#cargo#GetCargoExecutable(bufnr) abort
     if ale#path#FindNearestFile(a:bufnr, 'Cargo.toml') isnot# ''
@@ -13,18 +16,70 @@ function! ale_linters#rust#cargo#GetCargoExecutable(bufnr) abort
     endif
 endfunction
 
-function! ale_linters#rust#cargo#GetCommand(buffer) abort
-    let l:command = ale#Var(a:buffer, 'rust_cargo_use_check')
+function! ale_linters#rust#cargo#VersionCheck(buffer) abort
+    if has_key(s:version_cache, 'cargo')
+        return ''
+    endif
+
+    return 'cargo --version'
+endfunction
+
+function! s:GetVersion(executable, output) abort
+    let l:version = get(s:version_cache, a:executable, [])
+
+    for l:match in ale#util#GetMatches(a:output, '\v\d+\.\d+\.\d+')
+        let l:version = ale#semver#Parse(l:match[0])
+        let s:version_cache[a:executable] = l:version
+    endfor
+
+    return l:version
+endfunction
+
+function! s:CanUseCargoCheck(buffer, version) abort
+    " Allow `cargo check` to be disabled.
+    if !ale#Var(a:buffer, 'rust_cargo_use_check')
+        return 0
+    endif
+
+    return !empty(a:version)
+    \   && ale#semver#GreaterOrEqual(a:version, [0, 17, 0])
+endfunction
+
+function! s:CanUseAllTargets(buffer, version) abort
+    if !ale#Var(a:buffer, 'rust_cargo_use_check')
+        return 0
+    endif
+
+    if !ale#Var(a:buffer, 'rust_cargo_check_all_targets')
+        return 0
+    endif
+
+    return !empty(a:version)
+    \   && ale#semver#GreaterOrEqual(a:version, [0, 22, 0])
+endfunction
+
+function! ale_linters#rust#cargo#GetCommand(buffer, version_output) abort
+    let l:version = s:GetVersion('cargo', a:version_output)
+    let l:command = s:CanUseCargoCheck(a:buffer, l:version)
     \   ? 'check'
     \   : 'build'
+    let l:all_targets = s:CanUseAllTargets(a:buffer, l:version)
+    \   ? ' --all-targets'
+    \   : ''
 
-    return 'cargo ' . l:command . ' --frozen --message-format=json -q'
+    return 'cargo '
+    \   . l:command
+    \   . l:all_targets
+    \   . ' --frozen --message-format=json -q'
 endfunction
 
 call ale#linter#Define('rust', {
 \   'name': 'cargo',
 \   'executable_callback': 'ale_linters#rust#cargo#GetCargoExecutable',
-\   'command_callback': 'ale_linters#rust#cargo#GetCommand',
+\   'command_chain': [
+\       {'callback': 'ale_linters#rust#cargo#VersionCheck'},
+\       {'callback': 'ale_linters#rust#cargo#GetCommand'},
+\   ],
 \   'callback': 'ale#handlers#rust#HandleRustErrors',
 \   'output_stream': 'both',
 \   'lint_file': 1,