Re: bug#50469: [bison-3.8] bug or side effect to flex & automake

[Akim Demaille]

I propose the following patch to fix Automake's prototype of yyerror.

Cheers!

commit 38242845a146d6438e3f884100aa3e670142e393
Author: Akim Demaille <akim.demaille@gmail.com>
Date:   Sat Sep 11 09:39:00 2021 +0200

    tests: let yacc's yyerror take its argument as a const string
    
    Some of yacc error messages are const strings, it makes no sense for yyerror
    to take a `char*`, it should be a `const char*`.
    
    Fixes all the failures reported by Kiyoshi Kanazawa.
    <https://lists.gnu.org/r/bug-bison/2021-09/msg00005.html>
    See bug#50469.
    
    * t/cond35.sh, t/silent-many-languages.sh, t/silent-yacc-headers.sh,
    * t/silent-yacc.sh, t/subpkg-yacc.sh, t/suffix10.tap, t/yacc-basic.sh,
    * t/yacc-clean.sh, t/yacc-d-basic.sh, t/yacc-d-vpath.sh,
    * t/yacc-deleted-headers.sh, t/yacc-depend.sh, t/yacc-depend2.sh,
    * t/yacc-dist-nobuild-subdir.sh, t/yacc-dist-nobuild.sh, t/yacc-dry.sh,
    * t/yacc-line.sh, t/yacc-misc.sh, t/yacc-mix-c-cxx.sh, t/yacc-nodist.sh,
    * t/yacc-pr204.sh, t/yacc-subdir.sh, t/yacc-vpath.sh,
    * t/yflags-cmdline-override.sh, t/yflags-force-override.sh
    (yyerror): From `char*` to `const char*`.
    Enforce consistency: prefer `{}` to `{ return; }`.

diff --git a/t/cond35.sh b/t/cond35.sh
index 786bb3cf5..37a25eae3 100644
--- a/t/cond35.sh
+++ b/t/cond35.sh
@@ -73,7 +73,7 @@ END
 
 cat > tparse.y << 'END'
 %{
-void yyerror (char *s) {}
+void yyerror (const char *s) {}
 %}
 %token EOF
 %%
diff --git a/t/silent-many-languages.sh b/t/silent-many-languages.sh
index edb59e7c9..9361b2bf8 100644
--- a/t/silent-many-languages.sh
+++ b/t/silent-many-languages.sh
@@ -188,7 +188,7 @@ EOF
 cat > foo6.y <<'EOF'
 %{
 extern int yylex (void);
-void yyerror (char *s) {}
+void yyerror (const char *s) {}
 %}
 %token EOF
 %%
diff --git a/t/silent-yacc-headers.sh b/t/silent-yacc-headers.sh
index c10fc5cc4..0582973f5 100644
--- a/t/silent-yacc-headers.sh
+++ b/t/silent-yacc-headers.sh
@@ -39,7 +39,7 @@ EOF
 
 cat > parse.y <<'EOF'
 %{
-void yyerror (char *s) { return; }
+void yyerror (const char *s) {}
 int yylex (void) { return 0; }
 int main (void) { return 0; }
 %}
diff --git a/t/silent-yacc.sh b/t/silent-yacc.sh
index d11fc2ab2..3254d4014 100644
--- a/t/silent-yacc.sh
+++ b/t/silent-yacc.sh
@@ -50,7 +50,7 @@ EOF
 
 cat > foo.y <<'EOF'
 %{
-void yyerror (char *s) { return; }
+void yyerror (const char *s) {}
 int yylex (void) { return 0; }
 int main (void) { return 0; }
 %}
diff --git a/t/subpkg-yacc.sh b/t/subpkg-yacc.sh
index eac56cb1f..9e31c5151 100644
--- a/t/subpkg-yacc.sh
+++ b/t/subpkg-yacc.sh
@@ -88,7 +88,7 @@ EOF
 cat > lib/foo.y << 'END'
 %{
 int yylex (void) { return 0; }
-void yyerror (char *s) {}
+void yyerror (const char *s) {}
 %}
 %%
 foobar : 'f' 'o' 'o' 'b' 'a' 'r' {};
diff --git a/t/suffix10.tap b/t/suffix10.tap
index 2258120e7..d233c6c21 100644
--- a/t/suffix10.tap
+++ b/t/suffix10.tap
@@ -39,7 +39,7 @@ libfoo_la_SOURCES = foo.x_
        :; { echo '/* autogenerated */' \
          && echo '%{' \
          && echo 'int yylex () {return 0;}' \
-         && echo 'void yyerror (char *s) {}' \
+         && echo 'void yyerror (const char *s) {}' \
          && echo '%}' \
          && echo '%%' \
          && echo "foobar : 'f' 'o' 'o' 'b' 'a' 'r' {};" \
diff --git a/t/yacc-basic.sh b/t/yacc-basic.sh
index cfbaa1957..d50157099 100644
--- a/t/yacc-basic.sh
+++ b/t/yacc-basic.sh
@@ -42,7 +42,7 @@ cat > parse.y << 'END'
 #include <stdio.h>
 #include <stdlib.h>
 int yylex () { return getchar (); }
-void yyerror (char *s) {}
+void yyerror (const char *s) {}
 %}
 %%
 a : 'a' { exit(0); };
diff --git a/t/yacc-bison-skeleton.sh b/t/yacc-bison-skeleton.sh
index 60e85dd85..6069489da 100644
--- a/t/yacc-bison-skeleton.sh
+++ b/t/yacc-bison-skeleton.sh
@@ -44,7 +44,7 @@ void yyerror (const char *s);
 foobar : 'f' 'o' 'o' 'b' 'a' 'r' {};
 %%
 int yylex () { return 0; }
-void yyerror (const char *s) { return; }
+void yyerror (const char *s) {}
 END
 
 cat > foo.c << 'END'
diff --git a/t/yacc-clean-cxx.sh b/t/yacc-clean-cxx.sh
index fe2795894..811d46939 100644
--- a/t/yacc-clean-cxx.sh
+++ b/t/yacc-clean-cxx.sh
@@ -70,7 +70,7 @@ cat > sub1/parsefoo.yxx << 'END'
 #include <cstdio>
 // "std::" qualification required by Sun C++ 5.9.
 int yylex (void) { return std::getchar (); }
-void yyerror (const char *s) { return; }
+void yyerror (const char *s) {}
 %}
 %%
 x : 'x' { };
diff --git a/t/yacc-clean.sh b/t/yacc-clean.sh
index 9ea13a704..c248e5c89 100644
--- a/t/yacc-clean.sh
+++ b/t/yacc-clean.sh
@@ -66,7 +66,7 @@ END
 cat > sub1/parse.y << 'END'
 %{
 int yylex () { return (getchar ()); }
-void yyerror (char *s) {}
+void yyerror (const char *s) {}
 %}
 %%
 x : 'x' { };
diff --git a/t/yacc-cxx.sh b/t/yacc-cxx.sh
index 0e163eb44..b9dcd458b 100644
--- a/t/yacc-cxx.sh
+++ b/t/yacc-cxx.sh
@@ -48,7 +48,7 @@ cat > parse1.yy << 'END'
 #include <cstdlib>
 // "std::" qualification required by Sun C++ 5.9.
 int yylex (void) { return std::getchar (); }
-void yyerror (const char *s) { return; }
+void yyerror (const char *s) {}
 %}
 %%
 a : 'a' { exit(0); };
diff --git a/t/yacc-d-basic.sh b/t/yacc-d-basic.sh
index 66c11063e..b468d5532 100644
--- a/t/yacc-d-basic.sh
+++ b/t/yacc-d-basic.sh
@@ -48,7 +48,7 @@ cat > foo/parse.y << 'END'
 %{
 #include "parse.h"
 int yylex () { return 0; }
-void yyerror (char *s) {}
+void yyerror (const char *s) {}
 %}
 %%
 x : 'x' {};
diff --git a/t/yacc-d-vpath.sh b/t/yacc-d-vpath.sh
index e0fb951f2..86ae07b0c 100644
--- a/t/yacc-d-vpath.sh
+++ b/t/yacc-d-vpath.sh
@@ -41,7 +41,7 @@ END
 cat > parse.y << 'END'
 %{
 int yylex () { return 0; }
-void yyerror (char *s) {}
+void yyerror (const char *s) {}
 %}
 %token FOOBAR
 %%
@@ -74,7 +74,7 @@ $sleep
 cat > ../parse.y << 'END'
 %{
 int yylex () { return 0; }
-void yyerror (char *s) {}
+void yyerror (const char *s) {}
 %}
 %token FUBAR
 %%
@@ -94,7 +94,7 @@ $sleep
 cat > ../parse.y << 'END'
 %{
 int yylex () { return 0; }
-void yyerror (char *s) {}
+void yyerror (const char *s) {}
 %}
 %token MAUDE
 %%
diff --git a/t/yacc-deleted-headers.sh b/t/yacc-deleted-headers.sh
index 766caac5c..5b661d1e5 100644
--- a/t/yacc-deleted-headers.sh
+++ b/t/yacc-deleted-headers.sh
@@ -56,7 +56,7 @@ cat > parse1.y << 'END'
 %{
 #include "parse1.h"
 int yylex () { return 0; }
-void yyerror (char *s) { return; }
+void yyerror (const char *s) {}
 %}
 %token ZARDOZ
 %%
@@ -81,7 +81,7 @@ sed 's/"parse1\.h"/"parse3.h"/' main1.c > main3.c
 cat > parse4.y << 'END'
 %{
 int yylex () { return 0; }
-void yyerror (char *s) { return; }
+void yyerror (const char *s) {}
 %}
 %%
 x : 'x' {};
diff --git a/t/yacc-depend.sh b/t/yacc-depend.sh
index 27c704b3d..dc82a316a 100644
--- a/t/yacc-depend.sh
+++ b/t/yacc-depend.sh
@@ -36,7 +36,7 @@ END
 cat > foo.y << 'END'
 %{
 int yylex () { return 0; }
-void yyerror (char *s) { return; }
+void yyerror (const char *s) {}
 %}
 %token TOKEN
 %%
diff --git a/t/yacc-depend2.sh b/t/yacc-depend2.sh
index ce730f42b..c2b1b9be5 100644
--- a/t/yacc-depend2.sh
+++ b/t/yacc-depend2.sh
@@ -42,7 +42,7 @@ END
 cat > foo.y << 'END'
 %{
 int yylex () { return 0; }
-void yyerror (char *s) { return; }
+void yyerror (const char *s) {}
 %}
 %token TOKEN
 %%
diff --git a/t/yacc-dist-nobuild-subdir.sh b/t/yacc-dist-nobuild-subdir.sh
index c918c3996..8b15d2c2a 100644
--- a/t/yacc-dist-nobuild-subdir.sh
+++ b/t/yacc-dist-nobuild-subdir.sh
@@ -36,7 +36,7 @@ mkdir sub
 cat > sub/parse.y << 'END'
 %{
 int yylex () { return 0; }
-void yyerror (char *s) { return; }
+void yyerror (const char *s) {}
 %}
 %%
 x : 'x' {};
diff --git a/t/yacc-dist-nobuild.sh b/t/yacc-dist-nobuild.sh
index 5e1a2a70a..f4d3fbcb2 100644
--- a/t/yacc-dist-nobuild.sh
+++ b/t/yacc-dist-nobuild.sh
@@ -37,7 +37,7 @@ END
 cat > parse.y << 'END'
 %{
 int yylex () { return 0; }
-void yyerror (char *s) {}
+void yyerror (const char *s) {}
 %}
 %%
 foobar : 'f' 'o' 'o' 'b' 'a' 'r' {};
diff --git a/t/yacc-dry.sh b/t/yacc-dry.sh
index c9c1aa2e0..43e1422a6 100644
--- a/t/yacc-dry.sh
+++ b/t/yacc-dry.sh
@@ -38,7 +38,7 @@ END
 cat > parse.y << 'END'
 %{
 int yylex () { return 0; }
-void yyerror (char *s) {}
+void yyerror (const char *s) {}
 %}
 %%
 foobar : 'f' 'o' 'o' 'b' 'a' 'r' {};
diff --git a/t/yacc-line.sh b/t/yacc-line.sh
index 10e8a8cd4..ef48d83c5 100644
--- a/t/yacc-line.sh
+++ b/t/yacc-line.sh
@@ -57,7 +57,7 @@ END
 cat > zardoz.y << 'END'
 %{
 int yylex () { return 0; }
-void yyerror (char *s) { return; }
+void yyerror (const char *s) {}
 %}
 %%
 x : 'x' {};
diff --git a/t/yacc-misc.sh b/t/yacc-misc.sh
index 2371a099f..9dc8f9dfd 100644
--- a/t/yacc-misc.sh
+++ b/t/yacc-misc.sh
@@ -35,7 +35,7 @@ END
 cat > parse.y << 'END'
 %{
 int yylex () { return 0; }
-void yyerror (char *s) {}
+void yyerror (const char *s) {}
 %}
 %%
 foobar : 'f' 'o' 'o' 'b' 'a' 'r' {};
@@ -45,7 +45,7 @@ END
 cat > bar.y << 'END'
 %{
 int yylex () { return 0; }
-void yyerror (char *s) {}
+void yyerror (const char *s) {}
 %}
 %%
 fubar : 'f' 'o' 'o' 'b' 'a' 'r' {};
diff --git a/t/yacc-mix-c-cxx.sh b/t/yacc-mix-c-cxx.sh
index ad9bf9523..45dffa0d2 100644
--- a/t/yacc-mix-c-cxx.sh
+++ b/t/yacc-mix-c-cxx.sh
@@ -53,7 +53,7 @@ END
 cat > p.y <<'END'
 %{
 int yylex (void) { int new = 0; return new; }
-void yyerror (char *s) { return; }
+void yyerror (const char *s) {}
 %}
 %token ZARDOZ
 %%
@@ -85,7 +85,7 @@ cat > parse.yy <<'END'
 #include <cstdlib>
 #include "parse.hh"
 int yylex (void) { return 0; }
-void yyerror (const char *s) { return; }
+void yyerror (const char *s) {}
 %}
 %token FOOBAR
 %%
@@ -97,7 +97,7 @@ cat > parse2.y++ <<'END'
 %{
 #include <cstdlib>
 int yylex (void) { return 0; }
-void yyerror (const char *s) { return; }
+void yyerror (const char *s) {}
 %}
 %%
 x : 'x' {};
diff --git a/t/yacc-nodist.sh b/t/yacc-nodist.sh
index 075e07743..3b523e888 100644
--- a/t/yacc-nodist.sh
+++ b/t/yacc-nodist.sh
@@ -59,7 +59,7 @@ parse.y:
        :; { : \
          && echo "%{" \
          && echo "int yylex () { return 0; }" \
-         && echo "void yyerror (char *s) {}" \
+         && echo "void yyerror (const char *s) {}" \
          && echo "%}" \
          && echo "%%" \
          && echo "maude : 'm' 'a' 'u' 'd' 'e' {}"; \
diff --git a/t/yacc-pr204.sh b/t/yacc-pr204.sh
index 9606f7b3d..e07f5e5c9 100644
--- a/t/yacc-pr204.sh
+++ b/t/yacc-pr204.sh
@@ -51,7 +51,7 @@ EOF
 cat > parse.y << 'END'
 %{
 int yylex () {return 0;}
-void yyerror (char *s) {}
+void yyerror (const char *s) {}
 %}
 %%
 maude : 'm' 'a' 'u' 'd' 'e' {};
diff --git a/t/yacc-subdir.sh b/t/yacc-subdir.sh
index 5f3862187..879b433c6 100644
--- a/t/yacc-subdir.sh
+++ b/t/yacc-subdir.sh
@@ -49,7 +49,7 @@ mkdir foo
 cat > foo/parse.y << 'END'
 %{
 int yylex () { return 0; }
-void yyerror (char *s) {}
+void yyerror (const char *s) {}
 %}
 %%
 foobar : 'f' 'o' 'o' 'b' 'a' 'r' {};
diff --git a/t/yacc-vpath.sh b/t/yacc-vpath.sh
index f9bb719da..5481d9646 100644
--- a/t/yacc-vpath.sh
+++ b/t/yacc-vpath.sh
@@ -40,7 +40,7 @@ END
 cat > parse.y << 'END'
 %{
 int yylex () { return 0; }
-void yyerror (char *s) {}
+void yyerror (const char *s) {}
 %}
 %%
 foobar : 'f' 'o' 'o' 'b' 'a' 'r' {};
@@ -67,7 +67,7 @@ $sleep
 cat > ../parse.y << 'END'
 %{
 int yylex () { return 0; }
-void yyerror (char *s) {}
+void yyerror (const char *s) {}
 %}
 %%
 fubar : 'f' 'o' 'o' 'b' 'a' 'r' {};
@@ -85,7 +85,7 @@ $sleep
 cat > ../parse.y << 'END'
 %{
 int yylex () { return 0; }
-void yyerror (char *s) {}
+void yyerror (const char *s) {}
 %}
 %%
 maude : 'm' 'a' 'u' 'd' 'e' {};
diff --git a/t/yflags-cmdline-override.sh b/t/yflags-cmdline-override.sh
index eaee47849..63d31fbfa 100644
--- a/t/yflags-cmdline-override.sh
+++ b/t/yflags-cmdline-override.sh
@@ -43,7 +43,7 @@ END
 cat > foo.y << 'END'
 %{
 int yylex () { return 0; }
-void yyerror (char *s) { return; }
+void yyerror (const char *s) {}
 int main () { return 0; }
 %}
 %%
diff --git a/t/yflags-force-override.sh b/t/yflags-force-override.sh
index 2d5cb55e1..1346c1259 100644
--- a/t/yflags-force-override.sh
+++ b/t/yflags-force-override.sh
@@ -37,7 +37,7 @@ END
 cat > foo.y << 'END'
 %{
 int yylex () { return 0; }
-void yyerror (char *s) { return; }
+void yyerror (const char *s) {}
 int main () { return 0; }
 %}
 %%