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@gaborbernat gaborbernat commented Nov 13, 2025

Fix assertion failure in cxxScopePushTop when parsing member function pointer template specializations. The debug assertion requiring tokens to
be simple identifiers was too strict for complex template constructs like "TestUtil<MEMTYPE CLASS::*>::isNull".

Replace the strict assertion with adaptive logic that converts non-identifier tokens to identifier type when they have valid text content, following the
established pattern used elsewhere in the parser for similar cases.

Fixes #4344

Fix assertion failure in cxxScopePushTop when parsing member function
pointer template specializations. The debug assertion requiring tokens to
be simple identifiers was too strict for complex template constructs like
"TestUtil<MEMTYPE CLASS::*>::isNull".

Replace the strict assertion with adaptive logic that converts non-identifier
tokens to identifier type when they have valid text content, following the
established pattern used elsewhere in the parser for similar cases.

Fixes universal-ctags#4344
The CI was failing due to missing trailing newline in expected output.
Add proper line ending to match ctags output format.
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codecov bot commented Nov 13, 2025

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 85.87%. Comparing base (d48558f) to head (c95b08e).
⚠️ Report is 11 commits behind head on master.

Additional details and impacted files
@@           Coverage Diff           @@
##           master    #4348   +/-   ##
=======================================
  Coverage   85.87%   85.87%           
=======================================
  Files         252      252           
  Lines       62597    62598    +1     
=======================================
+ Hits        53755    53756    +1     
  Misses       8842     8842           

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isNull input.cpp /^ static bool isNull(const T&) { return false; }$/;" f struct:TestUtil typeref:typename:bool file:
TestUtil input.cpp /^struct TestUtil<T*> {$/;" s file:
isNull input.cpp /^ static bool isNull(T* f) { return 0 == f; }$/;" f struct:TestUtil typeref:typename:bool file:
isNull input.cpp /^TestUtil<MEMTYPE CLASS::*>::isNull(MEMTYPE CLASS::* f)$/;" f class:TestUtil::* typeref:typename:bool
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class:TestUtil::*

Do you think we need the last *?

I also tried to fix the original issue.

diff --git a/parsers/cxx/cxx_parser_function.c b/parsers/cxx/cxx_parser_function.c
index d8126019f..5e15e51e1 100644
--- a/parsers/cxx/cxx_parser_function.c
+++ b/parsers/cxx/cxx_parser_function.c
@@ -1591,10 +1591,21 @@ int cxxParserEmitFunctionTags(
            {
                CXXToken * pScopeId = pInfo->pScopeStart;
 
-               pInfo->pScopeStart = cxxTokenChainNextTokenOfType(
+               while (1)
+               {
+                   pInfo->pScopeStart = cxxTokenChainNextTokenOfType(
                        pInfo->pScopeStart,
-                       CXXTokenTypeMultipleColons
-                   );
+                       CXXTokenTypeMultipleColons|CXXTokenTypeSmallerThanSign);
+                   /* ??? */
+                   CXX_DEBUG_ASSERT(pInfo->pScopeStart,"We should have found a next token here");
+                   if (cxxTokenTypeIs(pInfo->pScopeStart, CXXTokenTypeMultipleColons))
+                       break;
+                   if (cxxTokenTypeIs(pInfo->pScopeStart, CXXTokenTypeSmallerThanSign)) {
+                       pInfo->pScopeStart = cxxTokenChainSkipToEndOfTemplateAngleBracket(pInfo->pScopeStart);
+                       /* if (pInfo->pScopeStart == NULL) what I should do? */
+                       CXX_DEBUG_ASSERT(pInfo->pScopeStart,"We should have found a next token here <>");
+                   }
+               }
 
                CXX_DEBUG_ASSERT(pInfo->pScopeStart,"We should have found a next token here");
 

With this change, the parser can skip <...> in the scope.
My version passed most of your new test cases. The exception is:

[yamato@dev64]~/var/ctags-github% misc/review                  
1) <a>ccept
2) <s>kip (or <n>)
3) <S>hell
4) <d>iff
5) show args.<c>tags
6) show <i>nput
7) <e>xpected tags
8) <q>uit
[1/1 [ Units/parser-cxx.r/template-member-function-pointer-scope.d ]]? =
--- ./Units/parser-cxx.r/template-member-function-pointer-scope.d/expected.tags	2025-11-14 03:32:44.593286373 +0900
+++ /home/yamato/var/ctags-github/Units/parser-cxx.r/template-member-function-pointer-scope.d/FILTERED.tmp	2025-11-14 03:33:58.558081369 +0900
@@ -5 +5 @@
-isNull	input.cpp	/^TestUtil<MEMTYPE CLASS::*>::isNull(MEMTYPE CLASS::* f)$/;"	f	class:TestUtil::*	typeref:typename:bool
+isNull	input.cpp	/^TestUtil<MEMTYPE CLASS::*>::isNull(MEMTYPE CLASS::* f)$/;"	f	class:TestUtil	typeref:typename:bool
---

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Do you think we need the last *?

I think there's value on having it, but alas I'm +0.1 on it, so don't feel strongly about it.

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Do you think class:TestUtil<MEMTYPE CLASS::*>:: is better than class:TestUtil::*?

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I'd say yes.

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I'd say yes.

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I have looked into other test cases.
In expected.tags files in the test cases, Tokens in <...> are just dropped.
Till someone having a strong opinion appears, I will choose class:TestUtil.
I will make a pull request based on your work.

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You can always update this PR rather than create a brand new one 🤔

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You can always update this PR rather than create a brand new one 🤔

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You can always update this PR rather than create a brand new one 🤔

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Can you also take a look at the other bugs I discovered and have PRs in via #4347 and #4349, thanks!

@masatake masatake added this to the 6.3 milestone Nov 17, 2025
masatake added a commit to masatake/ctags that referenced this pull request Nov 23, 2025
Fixes universal-ctags#4344
Derived from universal-ctags#4348.

Fix assertion failure in cxxScopePushTop when parsing member function
pointer template specializations. The debug assertion requiring tokens to
be simple identifiers was too strict for complex template constructs like
"TestUtil<MEMTYPE CLASS::*>::isNull".

The original code searched :: and pushed the following token to the
scope stack. In "TestUtil<MEMTYPE CLASS::*>::isNull", "*" was pushed
as the next token. However, "*" is no an identifier.

The new code skips template arguments. So "*" is never pushed.

Co-Authored-By: Bernát Gábor <bgabor8@bloomberg.net>
Signed-off-by: Masatake YAMATO <yamato@redhat.com>
masatake added a commit to masatake/ctags that referenced this pull request Nov 23, 2025
Fixes universal-ctags#4344
Derived from universal-ctags#4348.

Fix assertion failure in cxxScopePushTop when parsing member function
pointer template specializations. The debug assertion requiring tokens to
be simple identifiers was too strict for complex template constructs like
"TestUtil<MEMTYPE CLASS::*>::isNull".

The original code searched :: and pushed the following token to the
scope stack. In "TestUtil<MEMTYPE CLASS::*>::isNull", "*" was pushed
as the next token. However, "*" is no an identifier.

The new code skips template arguments. So "*" is never pushed.

Co-Authored-By: Bernát Gábor <bgabor8@bloomberg.net>
Signed-off-by: Masatake YAMATO <yamato@redhat.com>
masatake added a commit to masatake/ctags that referenced this pull request Nov 23, 2025
Fixes universal-ctags#4344
Derived from universal-ctags#4348.

Fix assertion failure in cxxScopePushTop when parsing member function
pointer template specializations. The debug assertion requiring tokens to
be simple identifiers was too strict for complex template constructs like
"TestUtil<MEMTYPE CLASS::*>::isNull".

The original code searched :: and pushed the following token to the
scope stack. In "TestUtil<MEMTYPE CLASS::*>::isNull", "*" was pushed
as the next token. However, "*" is no an identifier.

The new code skips template arguments. So "*" is never pushed.

Co-Authored-By: Bernát Gábor <bgabor8@bloomberg.net>
Signed-off-by: Masatake YAMATO <yamato@redhat.com>
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In #4354, I added code skipping <...> when extracting scopes.
I added a test case based on your one.
I kept the assert statement as is.

Thank you.

@masatake masatake closed this Nov 26, 2025
@gaborbernat
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Thank you for fixing this.

That being said I feel it's a bit odd how you decide to implement it on your own without any attribution, the way you end up going about this means that my contribution wasn't recognized and codified within the project source history, this is unusual in my open source contributions.

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C++ Scope Management Assertion Failure

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