patch 9.1.0935: SpotBugs compiler can be improved

Problem:  SpotBugs compiler can be improved
Solution: runtime(compiler): Improve defaults and error handling for
          SpotBugs; update test_compiler.vim (Aliaksei Budavei)

runtime(compiler): Improve defaults and error handling for SpotBugs

* Keep "spotbugs#DefaultPreCompilerTestAction()" defined but
  do not assign its Funcref to the "PreCompilerTestAction"
  key of "g:spotbugs_properties": there are no default and
  there can only be introduced arbitrary "*sourceDirPath"
  entries; therefore, this assignment is confusing at best,
  given that the function's implementation delegates to
  whatever "PreCompilerAction" is.

* Allow for the possibility of relative source pathnames
  passed as arguments to Vim for the Javac default actions,
  and the necessity to have them properly reconciled when
  the current working directory is changed.

* Do not expect users to remember or know that new source
  files ‘must be’ ":argadd"'d to be then known to the Javac
  default actions; so collect the names of Java-file buffers
  and Java-file Vim arguments; and let users providing the
  "@sources" file-lists in the "g:javac_makeprg_params"
  variable update these file-lists themselves.

* Strive to not leave behind a fire-once Syntax ":autocmd"
  for a Java buffer whenever an arbitrary pre-compile action
  errors out.

* Only attempt to run a post-compiler action in the absence
  of failures for a pre-compiler action.  Note that warnings
  and failures are treated alike (?!) by the Javac compiler,
  so when previews are tried out with "--enable-preview",
  remember about passing "-Xlint:-preview" too to also let
  SpotBugs have a go.

* Properly group conditional operators when testing for key
  entries in a user-defined variable.

* Also test whether "javaExternal" is defined when choosing
  an implementation for source-file parsing.

* Two commands are provided to toggle actions for buffer-local
  autocommands:
  - SpotBugsRemoveBufferAutocmd;
  - SpotBugsDefineBufferAutocmd.

For example, try this from "~/.vim/after/ftplugin/java.vim":
------------------------------------------------------------
if exists(':SpotBugsDefineBufferAutocmd') == 2
	SpotBugsDefineBufferAutocmd BufWritePost SigUSR1
endif
------------------------------------------------------------

And ":doautocmd java_spotbugs User" can be manually used at will.

closes: #16140

Signed-off-by: Aliaksei Budavei <0x000c70@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/compiler/spotbugs.vim b/runtime/compiler/spotbugs.vim
index 72a5084..10d164b 100644
--- a/runtime/compiler/spotbugs.vim
+++ b/runtime/compiler/spotbugs.vim
@@ -1,7 +1,7 @@
 " Vim compiler file
 " Compiler:     Spotbugs (Java static checker; needs javac compiled classes)
 " Maintainer:   @konfekt and @zzzyxwvut
-" Last Change:  2024 Nov 27
+" Last Change:  2024 Dec 14
 
 if exists('g:current_compiler') || bufname() !~# '\.java\=$' || wordcount().chars < 9
   finish
@@ -24,8 +24,9 @@
 let s:package_names = '\C\<package\s*\(\K\%(\k*\.\=\)\+;\)'
 let s:package = ''
 
-if has('syntax') && exists('g:syntax_on') && exists('b:current_syntax') &&
-    \ b:current_syntax == 'java' && hlexists('javaClassDecl')
+if has('syntax') && exists('g:syntax_on') &&
+    \ exists('b:current_syntax') && b:current_syntax == 'java' &&
+    \ hlexists('javaClassDecl') && hlexists('javaExternal')
 
   function! s:GetDeclaredTypeNames() abort
     if bufname() =~# '\<\%(module\|package\)-info\.java\=$'
@@ -105,53 +106,113 @@
   endfunction
 endif
 
-if exists('g:spotbugs_properties') &&
-    \ (has_key(g:spotbugs_properties, 'sourceDirPath') &&
-    \ has_key(g:spotbugs_properties, 'classDirPath')) ||
-    \ (has_key(g:spotbugs_properties, 'testSourceDirPath') &&
-    \ has_key(g:spotbugs_properties, 'testClassDirPath'))
+if exists('b:spotbugs_properties')
+  " Let "ftplugin/java.vim" merge global entries, if any, in buffer-local
+  " entries
 
-function! s:FindClassFiles(src_type_name) abort
-  let class_files = []
-  " Match pairwise the components of source and class pathnames
-  for [src_dir, bin_dir] in filter([
-            \ [get(g:spotbugs_properties, 'sourceDirPath', ''),
-                \ get(g:spotbugs_properties, 'classDirPath', '')],
-            \ [get(g:spotbugs_properties, 'testSourceDirPath', ''),
-                \ get(g:spotbugs_properties, 'testClassDirPath', '')]],
-        \ '!(empty(v:val[0]) || empty(v:val[1]))')
-    " Since only the rightmost "src" is sought, while there can be any number of
-    " such filenames, no "fnamemodify(a:src_type_name, ':p:s?src?bin?')" is used
-    let tail_idx = strridx(a:src_type_name, src_dir)
-    " No such directory or no such inner type (i.e. without "$")
-    if tail_idx < 0 | continue | endif
-    " Substitute "bin_dir" for the rightmost "src_dir"
-    let candidate_type_name = strpart(a:src_type_name, 0, tail_idx)..
-        \ bin_dir..
-        \ strpart(a:src_type_name, (tail_idx + strlen(src_dir)))
-    for candidate in insert(s:GlobClassFiles(candidate_type_name),
-            \ candidate_type_name..'.class')
-      if filereadable(candidate) | call add(class_files, shellescape(candidate)) | endif
-    endfor
-    if !empty(class_files) | break | endif
-  endfor
-  return class_files
-endfunction
+  function! s:GetProperty(name, default) abort
+    return get(b:spotbugs_properties, a:name, a:default)
+  endfunction
+
+elseif exists('g:spotbugs_properties')
+
+  function! s:GetProperty(name, default) abort
+    return get(g:spotbugs_properties, a:name, a:default)
+  endfunction
 
 else
-function! s:FindClassFiles(src_type_name) abort
-  let class_files = []
-  for candidate in insert(s:GlobClassFiles(a:src_type_name),
+  function! s:GetProperty(dummy, default) abort
+    return a:default
+  endfunction
+endif
+
+if (exists('g:spotbugs_properties') || exists('b:spotbugs_properties')) &&
+    \ ((!empty(s:GetProperty('sourceDirPath', [])) &&
+        \ !empty(s:GetProperty('classDirPath', []))) ||
+    \ (!empty(s:GetProperty('testSourceDirPath', [])) &&
+        \ !empty(s:GetProperty('testClassDirPath', []))))
+
+  function! s:CommonIdxsAndDirs() abort
+    let src_dir_path = s:GetProperty('sourceDirPath', [])
+    let bin_dir_path = s:GetProperty('classDirPath', [])
+    let test_src_dir_path = s:GetProperty('testSourceDirPath', [])
+    let test_bin_dir_path = s:GetProperty('testClassDirPath', [])
+    let dir_cnt = min([len(src_dir_path), len(bin_dir_path)])
+    let test_dir_cnt = min([len(test_src_dir_path), len(test_bin_dir_path)])
+    " Do not break up path pairs with filtering!
+    return [[range(dir_cnt),
+            \ src_dir_path[0 : dir_cnt - 1],
+            \ bin_dir_path[0 : dir_cnt - 1]],
+        \ [range(test_dir_cnt),
+            \ test_src_dir_path[0 : test_dir_cnt - 1],
+            \ test_bin_dir_path[0 : test_dir_cnt - 1]]]
+  endfunction
+
+  let s:common_idxs_and_dirs = s:CommonIdxsAndDirs()
+  delfunction s:CommonIdxsAndDirs
+
+  function! s:FindClassFiles(src_type_name) abort
+    let class_files = []
+    " Match pairwise the components of source and class pathnames
+    for [idxs, src_dirs, bin_dirs] in s:common_idxs_and_dirs
+      " Do not use "fnamemodify(a:src_type_name, ':p:s?src?bin?')" because
+      " only the rightmost "src" is looked for
+      for idx in idxs
+        let tail_idx = strridx(a:src_type_name, src_dirs[idx])
+        " No such directory or no such inner type (i.e. without "$")
+        if tail_idx < 0 | continue | endif
+        " Substitute "bin_dirs[idx]" for the rightmost "src_dirs[idx]"
+        let candidate_type_name = strpart(a:src_type_name, 0, tail_idx)..
+            \ bin_dirs[idx]..
+            \ strpart(a:src_type_name, (tail_idx + strlen(src_dirs[idx])))
+        for candidate in insert(s:GlobClassFiles(candidate_type_name),
+              \ candidate_type_name..'.class')
+          if filereadable(candidate) | call add(class_files, shellescape(candidate)) | endif
+        endfor
+        if !empty(class_files) | break | endif
+      endfor
+      if !empty(class_files) | break | endif
+    endfor
+    return class_files
+  endfunction
+
+else
+  function! s:FindClassFiles(src_type_name) abort
+    let class_files = []
+    for candidate in insert(s:GlobClassFiles(a:src_type_name),
           \ a:src_type_name..'.class')
-    if filereadable(candidate) | call add(class_files, shellescape(candidate)) | endif
-  endfor
-  return class_files
-endfunction
+      if filereadable(candidate) | call add(class_files, shellescape(candidate)) | endif
+    endfor
+    return class_files
+  endfunction
+endif
+
+if exists('g:spotbugs_alternative_path') &&
+    \ !empty(get(g:spotbugs_alternative_path, 'fromPath', '')) &&
+    \ !empty(get(g:spotbugs_alternative_path, 'toPath', ''))
+
+  " See https://github.com/spotbugs/spotbugs/issues/909
+  function! s:ResolveAbsolutePathname() abort
+    let pathname = expand('%:p')
+    let head_idx = stridx(pathname, g:spotbugs_alternative_path.toPath)
+    " No such file: a mismatched path request for a project
+    if head_idx < 0 | return pathname | endif
+    " Settle for failure with file readability tests _in s:FindClassFiles()_
+    return strpart(pathname, 0, head_idx)..
+        \ g:spotbugs_alternative_path.fromPath..
+        \ strpart(pathname, (head_idx + strlen(g:spotbugs_alternative_path.toPath)))
+  endfunction
+
+else
+  function! s:ResolveAbsolutePathname() abort
+    return expand('%:p')
+  endfunction
 endif
 
 function! s:CollectClassFiles() abort
+  " Possibly obtain a symlinked path for an unsupported directory name
+  let pathname = s:ResolveAbsolutePathname()
   " Get a platform-independent pathname prefix, cf. "expand('%:p:h')..'/'"
-  let pathname = expand('%:p')
   let tail_idx = strridx(pathname, expand('%:t'))
   let src_pathname = strpart(pathname, 0, tail_idx)
   let all_class_files = []
@@ -166,11 +227,12 @@
 " Expose class files for removal etc.
 let b:spotbugs_class_files = s:CollectClassFiles()
 let s:package_dir_heads = repeat(':h', (1 + strlen(substitute(s:package, '[^.;]', '', 'g'))))
+let s:package_root_dir = fnamemodify(s:ResolveAbsolutePathname(), s:package_dir_heads..':S')
 let g:current_compiler = 'spotbugs'
 " CompilerSet makeprg=spotbugs
 let &l:makeprg = 'spotbugs'..(has('win32') ? '.bat' : '')..' '..
     \ get(b:, 'spotbugs_makeprg_params', get(g:, 'spotbugs_makeprg_params', '-workHard -experimental'))..
-    \ ' -textui -emacs -auxclasspath %:p'..s:package_dir_heads..':S -sourcepath %:p'..s:package_dir_heads..':S '..
+    \ ' -textui -emacs -auxclasspath '..s:package_root_dir..' -sourcepath '..s:package_root_dir..' '..
     \ join(b:spotbugs_class_files, ' ')
 " Emacs expects doubled line numbers
 setlocal errorformat=%f:%l:%*[0-9]\ %m,%f:-%*[0-9]:-%*[0-9]\ %m
@@ -180,10 +242,13 @@
 " exe 'CompilerSet errorformat='..escape(&l:errorformat, ' \|"')
 
 delfunction s:CollectClassFiles
+delfunction s:ResolveAbsolutePathname
 delfunction s:FindClassFiles
+delfunction s:GetProperty
 delfunction s:GlobClassFiles
 delfunction s:GetDeclaredTypeNames
 let &cpo = s:cpo_save
-unlet s:package_dir_heads s:package s:package_names s:type_names s:keywords s:cpo_save
+unlet! s:package_root_dir s:package_dir_heads s:common_idxs_and_dirs s:package
+unlet! s:package_names s:type_names s:keywords s:cpo_save
 
 " vim: set foldmethod=syntax shiftwidth=2 expandtab: