Re: [PATCH v2] Capture warnings when writing to the index cache

[Tom Tromey <tromey@adacore.com>]

>>>>> "Simon" == Simon Marchi <simark@simark.ca> writes:

Simon> My interpretation of this is that we bind a function marked with
Simon> `ATTRIBUTE_PRINTF (2,0)` (deferred_warnings::operator()) to a function
Simon> view that doesn't convey the attribute.  So I guess the compiler is
Simon> telling us that whenever the function view is invoked, there won't be a
Simon> format string check, and that's dangerous.

Simon> I didn't find a good fix that :(.

Please try the appended.

thanks,
Tom

commit 8be8061ea5d0ec37289070f16717d3d0aa0c93af
Author: Tom Tromey <tromey@adacore.com>
Date:   Wed Mar 27 07:21:56 2024 -0600

    patch

diff --git a/gdb/utils.h b/gdb/utils.h
index d7db1d84e2f..875a2583179 100644
--- a/gdb/utils.h
+++ b/gdb/utils.h
@@ -444,10 +444,18 @@ struct deferred_warnings
      hook; see scoped_restore_warning_hook.  Note that no locking is
      done, so users have to be careful to only install this into a
      single thread at a time.  */
-  void operator() (const char *format, va_list args) ATTRIBUTE_PRINTF (2, 0)
+  void operator() (const char *format, va_list args)
   {
     string_file msg (m_can_style);
+    /* Clang warns if we add ATTRIBUTE_PRINTF to this method (because
+       the function-view wrapper doesn't also have the attribute), but
+       then warns again if we remove it, because this vprintf call
+       does not use a literal format string.  So, suppress the
+       warnings here.  */
+    DIAGNOSTIC_PUSH
+    DIAGNOSTIC_IGNORE_FORMAT_NONLITERAL
     msg.vprintf (format, args);
+    DIAGNOSTIC_POP
     m_warnings.emplace_back (std::move (msg));
   }