From e709637b3a87048d3dfaf51525d7a42e5bb8e135 Mon Sep 17 00:00:00 2001
From: Julian Andres Klode <julian.klode@canonical.com>
Date: Sat, 28 Dec 2024 22:57:59 +0100
Subject: Re-include std:: symbols in the symbols file as optional again

This will restore most of the symbols from before and ensure
reverse dependencies not depending on new symbols can migrate.

It also ensures we see any missing symbols.
---
 abicheck/symbol-merge.py | 65 ++++++++++++++++++++++++++++--------------------
 1 file changed, 38 insertions(+), 27 deletions(-)

(limited to 'abicheck')

diff --git a/abicheck/symbol-merge.py b/abicheck/symbol-merge.py
index 1fa540c94..1b4048e08 100644
--- a/abicheck/symbol-merge.py
+++ b/abicheck/symbol-merge.py
@@ -17,7 +17,7 @@ import apt_inst
 
 import apt.progress.text
 
-IGNORE = (
+STDLIB = (
     "^typeinfo for std::"
     "|^vtable for std::"
     "|^typeinfo name for std::"
@@ -31,7 +31,7 @@ IGNORE = (
     "|^__gnu_cxx::"
     "|^[a-z]* __gnu_cxx::"
 )
-IGNORE_RE = re.compile(IGNORE)
+STDLIB_RE = re.compile(STDLIB)
 
 
 def get_archs(dist: str) -> set[str]:
@@ -109,13 +109,15 @@ def read_main_symbols() -> dict[str, str]:
     with open(glob.glob("debian/libapt-pkg*.symbols")[0]) as sf:
         for line in sf:
             if not line.startswith(" "):
-                prelude.append(line.strip())
+                if not symbols:
+                    prelude.append(line.strip())
                 continue
             if line.startswith(" "):
                 symbol, version = line.strip().rsplit(None, 1)
                 if '"' in symbol:
                     print(symbol.strip().split('"'))
-                    symbol = '(c++)"{}"'.format(symbol.strip().split('"')[1])
+                    prefix="(c++|optional=std)" if "optional=std" in symbol else "(c++)"
+                    symbol = '{}"{}"'.format(prefix, symbol.strip().split('"')[1])
                 symbols[symbol] = version
                 # Register the symbol so we keep the ordering later.
                 print("SYMBOL", symbol)
@@ -136,10 +138,11 @@ def read_symbol_file(debname: str) -> None:
         symbol, version = decoded_line.strip().rsplit(None, 1)
         symbol = symbol.strip()
         # Our version is higher than the registered one, so lower it again
-        if IGNORE_RE.search(symbol):
-            continue
         if line != decoded_line:
-            symbol = '(c++)"{}"'.format(symbol)
+            if STDLIB_RE.search(symbol):
+                symbol = '(c++|optional=std)"{}"'.format(symbol)
+            else:
+                symbol = '(c++)"{}"'.format(symbol)
         if (
             symbol not in smallest_symbol_version
             or apt_pkg.version_compare(version, smallest_symbol_version[symbol]) < 0
@@ -160,28 +163,36 @@ def print_merged() -> None:
     for line in prelude:
         print(line)
 
-    print(f' (c++|regex)"{IGNORE}" 999:0misbuilt')
-
-    for symbol, line_archs in symbol_archs.items():
-        if archs == line_archs:
-            print("", symbol, smallest_symbol_version[symbol])
+    for optional in False, True:
+        if optional:
+            print("# Optional C++ standard library symbols")
+            print("# These are inlined libstdc++ symbols and not supposed to be part of our ABI")
+            print("# but we cannot stop stuff from linking against it, sigh.")
 
-    for symbol, line_archs in symbol_archs.items():
-        if archs != line_archs and line_archs:
-            print_archs = " ".join(sorted(line_archs))
-            if len(line_archs) > len(archs - line_archs):
-                print_archs = " ".join("!" + a for a in sorted(archs - line_archs))
+        for symbol, line_archs in symbol_archs.items():
+            if optional != ("optional=std" in symbol):
+                continue
+            if archs == line_archs:
+                print("", symbol, smallest_symbol_version[symbol])
 
-            if "(c++)" in symbol:
-                print(
-                    "",
-                    symbol.replace("(c++)", f"(arch={print_archs}|c++)"),
-                    smallest_symbol_version[symbol],
-                )
-            else:
-                print(
-                    f" (arch={print_archs}){symbol} {smallest_symbol_version[symbol]}"
-                )
+        for symbol, line_archs in symbol_archs.items():
+            if optional != ("optional=std" in symbol):
+                continue
+            if archs != line_archs and line_archs:
+                print_archs = " ".join(sorted(line_archs))
+                if len(line_archs) > len(archs - line_archs):
+                    print_archs = " ".join("!" + a for a in sorted(archs - line_archs))
+
+                if "(c++" in symbol:
+                    print(
+                        "",
+                        symbol.replace("(c++", f"(arch={print_archs}|c++"),
+                        smallest_symbol_version[symbol],
+                    )
+                else:
+                    print(
+                        f" (arch={print_archs}){symbol} {smallest_symbol_version[symbol]}"
+                    )
 
 
 if __name__ == "__main__":
-- 
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