#562 Join split JSON lines together for new Rust output

autoload/ale/handlers/rust.vim

@@ -20,17 +20,37 @@ function! s:FindErrorInExpansion(span, file_name) abort
     return []
 endfunction
 
+" The JSON output for Rust can be split over many lines.
+" Those lines should be joined together again.
+function! s:JoinJSONLines(lines) abort
+    let l:corrected_lines = []
+    let l:object_continues = 0
+
+    for l:line in a:lines
+        if l:object_continues
+            let l:corrected_lines[-1] .= l:line
+
+            if l:line =~# '}$'
+                let l:object_continues = 0
+            endif
+        elseif l:line =~# '^{'
+            call add(l:corrected_lines, l:line)
+
+            if l:line !~# '}$'
+                let l:object_continues = 1
+            endif
+        endif
+    endfor
+
+    return l:corrected_lines
+endfunction
+
 " A handler function which accepts a file name, to make unit testing easier.
 function! ale#handlers#rust#HandleRustErrorsForFile(buffer, full_filename, lines) abort
     let l:filename = fnamemodify(a:full_filename, ':t')
     let l:output = []
 
-    for l:errorline in a:lines
+    for l:errorline in s:JoinJSONLines(a:lines)
-        " ignore everything that is not Json
-        if l:errorline !~# '^{'
-            continue
-        endif
-
         let l:error = json_decode(l:errorline)
 
         if has_key(l:error, 'message') && type(l:error.message) == type({})

test/handler/test_rust_handler.vader

@@ -46,3 +46,21 @@ Execute(The Rust handler should handle cargo output):
   \   '{"message":{"children":[],"code":null,"level":"error","message":"no method named `wat` found for type `std::string::String` in the current scope","rendered":null,"spans":[{"byte_end":11497,"byte_start":11494,"column_end":10,"column_start":7,"expansion":null,"file_name":"src/playpen.rs","is_primary":true,"label":null,"line_end":13,"line_start":13,"suggested_replacement":null,"text":[{"highlight_end":10,"highlight_start":7,"text":"    s.wat()"}]}]},"package_id":"update 0.0.1 (path+file:///home/w0rp/Downloads/rust-by-example)","reason":"compiler-message","target":{"kind":["bin"],"name":"update","src_path":"/home/w0rp/Downloads/rust-by-example/src/main.rs"}}',
   \   '{"message":{"children":[],"code":null,"level":"error","message":"aborting due to previous error","rendered":null,"spans":[]},"package_id":"update 0.0.1 (path+file:///home/w0rp/Downloads/rust-by-example)","reason":"compiler-message","target":{"kind":["bin"],"name":"update","src_path":"/home/w0rp/Downloads/rust-by-example/src/main.rs"}}',
   \ ])
+
+Execute(The Rust handler should handle JSON split over many lines):
+  AssertEqual
+  \ [
+  \   {
+  \     'lnum': 15,
+  \     'type': 'E',
+  \     'col': 11505,
+  \     'text': 'expected one of `.`, `;`, `?`, `}`, or an operator, found `for`',
+  \   },
+  \ ],
+  \ ale#handlers#rust#HandleRustErrorsForFile(347, 'src/playpen.rs', [
+  \   '',
+  \   'ignore this',
+  \   '{"message":{"children":[],"code":null,"level":"error","message":"expected one of `.`, `;`, `?`, `}`, or an operator, found `for`","rendered":null,"spans":[{"byte_end":11508,"byte_start":11505,"column_end":8,"column_start":5,"expansion":null',
+  \   ',"file_name":"src/playpen.rs","is_primary":true,"label":null,"line_end":15,"line_start":15,"suggested_replacement":null,',
+  \   '"text":[{"highlight_end":8,"highlight_start":5,"text":"    for chr in source.trim().chars() {"}]}]},"package_id":"update 0.0.1 (path+file:///home/w0rp/Downloads/rust-by-example)","reason":"compiler-message","target":{"kind":["bin"],"name":"update","src_path":"/home/w0rp/Downloads/rust-by-example/src/main.rs"}}',
+  \ ])