[clang] Propely handle tests for open DRs in make_cxx_dr_status

[Endill]

Summary

A follow-up to D136133. It was mentioned in #58382 that there is a need to test for DRs that have not been officially resolved yet. This patch aims to replace original "hackery" with proper handling for such cases. Highlights:

• Availability can be suffixed (further) with "open", "drafting", or "review", e.g. // dr2565: 16 open, // drXXXX: 16 c++17 drafting
• Checks are implemented to ensure that this suffix corresponds to actual issue status
• Non-resolved DRs are counted (stdout of make_cxx_dr_status)
• No changes made to cxx_dr_status.html
• 'c++20' availability suffix added
• Remove 'concurrency' status since it's no longer on the list of statuses in CWG Active Issues

[erichkeane]

I like the change, thank you! I don't see anything to be concerned about, but my python is awful, so I'd like at least a 2nd set of eyes to take a look.

[aaron.ballman]

LGTM though my Python skills are lacking, so additional eyeballs on that would be appreciated.

clang/www/make_cxx_dr_status

187–189

Thank you for this! It resolves the biggest concern I had with our markings getting out of sync with the issues list.

[Endill]

Can I kindly ask you to commit this?
I guess I can ask for commit access after this patch, and not bother you any further.

[cor3ntin]

I don't see anything wrong with the python either. There are probably clever ways to deal with the successions of if statements but i don't think it would be worth it.

[erichkeane]

Thanks @cor3ntin , I'll commit this then.

[h-vetinari]

I'd also use newlines more liberally since the two-space indentation is pretty dense already.

clang/www/make_cxx_dr_status

190–191

These two lines are the same with the end of the else-branch, i.e. they could both be lifted out of the if-clause and unified at the end.

198–199

clang/test/CXX/drs/dr25xx.cpp

 // RUN: %clang_cc1 -std=c++20 -triple x86_64-unknown-unknown %s -verify
 
-namespace dr2565 { // dr2565: 16
+namespace dr2565 { // dr2565: 16 open
   template<typename T>
     concept C = requires (typename T::type x) {
       x + 1;
     };
   static_assert(!C<int>);
 
   // Variant of this as reported in GH57487.
   template<bool B> struct bool_constant

clang/test/CXX/drs/dr26xx.cpp

 // RUN: %clang_cc1 -std=c++20 -triple x86_64-unknown-unknown %s -verify
 
 namespace dr2621 { // dr2621: yes
 enum class E { a };
 namespace One {
 using E_t = E;
 using enum E_t; // typedef ok
 auto v = a;
 }
 namespace Two {
 using dr2621::E;
 int E; // we see this
 using enum E; // expected-error {{unknown type name E}}
 }
 }
 
-namespace dr2628 { // dr2628: yes
+namespace dr2628 { // dr2628: yes open
 
 template <bool A = false, bool B = false>
 struct foo {
   constexpr foo() requires (!A && !B) = delete; // #DR2628_CTOR
   constexpr foo() requires (A || B) = delete;
 };
 
 void f() {

clang/www/make_cxx_dr_status

<tr>
     <th>Issue title</th>
     <th>Available in Clang?</th>
   </tr>''')
 
 latest_release = 15
 
 def availability(issue):
   status = status_map.get(issue, 'unknown')
+  
+  unresolved_status = ''
+  if status.endswith(' open'):
+    status = status[:-5]
+    unresolved_status = 'open'
+  elif status.endswith(' drafting'):
+    status = status[:-9]
+    unresolved_status = 'drafting'
+  elif status.endswith(' review'):
+    status = status[:-7]
+    unresolved_status = 'review'
+
   avail_suffix = ''
   if status.endswith(' c++11'):
     status = status[:-6]
     avail_suffix = ' (C++11 onwards)'
   elif status.endswith(' c++14'):
     status = status[:-6]
     avail_suffix = ' (C++14 onwards)'
   elif status.endswith(' c++17'):
     status = status[:-6]
     avail_suffix = ' (C++17 onwards)'
+  elif status.endswith(' c++20'):
+    status = status[:-6]
+    avail_suffix = ' (C++20 onwards)'
   if status == 'unknown':
     avail = 'Unknown'
     avail_style = ' class="none"'
   elif re.match('^[0-9]+\.?[0-9]*', status):
     avail = 'Clang %s' % status
     if float(status) > latest_release:
       avail_style = ' class="unreleased"'
     else:
def availability(issue):
   elif status.startswith('sup '):
     dup = status.split(' ', 1)[1]
     if dup.startswith('P'):
       avail = 'Superseded by <a href="https://wg21.link/%s">%s</a>' % (dup, dup)
       avail_style = ' class="na"'
     else:
       avail = 'Superseded by <a href="#%s">%s</a>' % (dup, dup)
       try:
-        _, avail_style = availability(int(dup))
+        _, avail_style, _ = availability(int(dup))
       except:
         print("issue %s marked as sup %s" % (issue, dup), file=sys.stderr)
         avail_style = ' class="none"'
   elif status.startswith('dup '):
     dup = int(status.split(' ', 1)[1])
     avail = 'Duplicate of <a href="#%s">%s</a>' % (dup, dup)
-    _, avail_style = availability(dup)
+    _, avail_style, _ = availability(dup)
   else:
     assert False, 'unknown status %s for issue %s' % (status, dr.issue)
-  return (avail + avail_suffix, avail_style)
+  return (avail + avail_suffix, avail_style, unresolved_status)
 
 count = {}
 for dr in drs:
   if dr.status in ('concepts',):
     # This refers to the old ("C++0x") concepts feature, which was not part
     # of any C++ International Standard or Technical Specification.
     continue
-  if dr.issue in (2565, 2628):
+  elif dr.status == 'extension':
     row_style = ' class="open"'
-    avail, avail_style = availability(dr.issue)
-  elif dr.status in ('open', 'concurrency', 'drafting', 'review', 'extension'):
-    # We may have to deal with these some day, but not yet.
-    row_style = ' class="open"'
-    if dr.status == 'extension':
-      avail = 'Extension'
-    else:
+    avail_style = ''
+  elif dr.status in ('open', 'drafting', 'review'):
+    row_style = ' class="open"'
+    avail, avail_style, unresolved_status = availability(dr.issue)
+    if avail == 'Unknown':
       avail = 'Not resolved'
       avail_style = ''
-    assert dr.issue not in status_map, "have status for not-ready dr %s" % dr.issue
+    else:
+      assert unresolved_status == dr.status, \
+             "Issue %s is marked '%s', which differs from CWG index status '%s'" \
+             % (dr.issue, unresolved_status, dr.status)
+    if not avail.startswith('Sup') and not avail.startswith('Dup'):
+      count[avail] = count.get(avail, 0) + 1
   else:
     row_style = ''
-    avail, avail_style = availability(dr.issue)
+    avail, avail_style, unresolved_status = availability(dr.issue)
+    assert not unresolved_status, \
+           "Issue %s is marked '%s', even though it is resolved in CWG index" \
+           % (dr.issue, unresolved_status)
     if not avail.startswith('Sup') and not avail.startswith('Dup'):
       count[avail] = count.get(avail, 0) + 1
 
   out_file.write('''
   <tr%s id="%s">
     <td><a href="https://wg21.link/cwg%s">%s</a></td>
     <td>%s</td>
     <td>%s</td>
     <td%s align="center">%s</td>
   </tr>''' % (row_style, dr.issue, dr.issue, dr.issue, dr.status, dr.title, avail_style, avail))