Cardinal crashes on "require Test"

[tadzik]

Turns out a lex_lookup may return something that triggers a NULL PMC Access when trying to check its value. Here's a piece of code I added to actions.pm

src/gen_diff --git a/src/parser/actions.pm b/src/parser/actions.pm
index cd49492..f706b95 100644
--- a/src/parser/actions.pm
+++ b/src/parser/actions.pm
@@ -905,6 +905,9 @@ sub is_a_sub($name) {
         }
     }
     my $lex := lex_lookup($name);
+    print("is_a_sub('"); print($name); print("'), here we crash\n");
+    if $lex { print("lex ok\n"); }
+    print("never happens\n");
     if $lex && ~lookup_class($lex) eq 'Sub' { return 1; }
     return 0;
 }

Running ./installable_cardinal t/02-functions.t results in:

is_a_sub('Test'), here we crash
Null PMC access in get_bool()
current instr.: 'cardinal;cardinal;Grammar;Actions;is_a_sub' pc 64437 (src/gen_grammar.pir:288)
called from Sub 'cardinal;cardinal;Grammar;Actions;variable' pc 68543 (src/gen_grammar.pir:1720)
called from Sub 'cardinal;cardinal;Grammar;variable' pc 34593 (src/classes/File.pir:8150)
called from Sub 'cardinal;cardinal;Grammar;basic_primary' pc 36938 (src/classes/FileStat.pir:9021)
called from Sub 'cardinal;cardinal;Grammar;primary' pc 37455 (src/classes/Dir.pir:9206)
called from Sub 'cardinal;PGE;OPTable;parse' pc 1940 (compilers/pge/PGE/OPTable.pir:566)
called from Sub 'cardinal;cardinal;Grammar;args' pc 35975 (src/classes/FileStat.pir:8665)
called from Sub 'cardinal;cardinal;Grammar;call_args' pc 29791 (src/classes/Kernel.pir:6346)
called from Sub 'cardinal;cardinal;Grammar;post_primary_expr' pc 37995 (src/classes/Dir.pir:9406)
called from Sub 'cardinal;cardinal;Grammar;primary' pc 37567 (src/classes/Dir.pir:9246)
called from Sub 'cardinal;PGE;OPTable;parse' pc 1940 (compilers/pge/PGE/OPTable.pir:566)
called from Sub 'cardinal;cardinal;Grammar;expr' pc 20368 (src/classes/Array.pir:2777)
called from Sub 'cardinal;cardinal;Grammar;basic_stmt' pc 17591 (src/classes/Array.pir:1717)
called from Sub 'cardinal;cardinal;Grammar;stmt' pc 18974 (src/classes/Array.pir:2227)
called from Sub 'cardinal;cardinal;Grammar;stmts' pc 14166 (src/classes/Array.pir:448)
called from Sub 'cardinal;cardinal;Grammar;comp_stmt' pc 13647 (src/classes/Array.pir:249)
called from Sub 'cardinal;cardinal;Grammar;TOP' pc 13302 (src/classes/Array.pir:115)
called from Sub 'cardinal;PCT;HLLCompiler;parse' pc 826 (compilers/pct/src/PCT/HLLCompiler.pir:463)
called from Sub 'cardinal;PCT;HLLCompiler;compile' pc 464 (compilers/pct/src/PCT/HLLCompiler.pir:331)
called from Sub 'cardinal;PCT;HLLCompiler;eval' pc 1081 (compilers/pct/src/PCT/HLLCompiler.pir:582)
called from Sub 'cardinal;PCT;HLLCompiler;evalfiles' pc 1501 (compilers/pct/src/PCT/HLLCompiler.pir:764)
called from Sub 'cardinal;PCT;HLLCompiler;command_line' pc 1712 (compilers/pct/src/PCT/HLLCompiler.pir:873)
called from Sub 'cardinal;cardinal;Compiler;main' pc 78706 (src/gen_grammar.pir:5354)

[bluescreen10]

the following patch works for me

diff --git a/src/parser/actions.pm b/src/parser/actions.pm
index cd49492..8102303 100644
--- a/src/parser/actions.pm
+++ b/src/parser/actions.pm
@@ -905,7 +905,7 @@ sub is_a_sub($name) {
         }
     }
     my $lex := lex_lookup($name);
-    if $lex && ~lookup_class($lex) eq 'Sub' { return 1; }
+    if defined($lex) && ~lookup_class($lex) eq 'Sub' { return 1; }
     return 0;
 }

[tadzik]

Thanks bluescreen, it fixes the issue. Cardinal is now usable.

[gerd]

I applied the patch from "bluescreen10". Thanks for the help!