Fix perl build when using Build.PL

This fixes #12852 where perl builds that use Build.PL will fail when the
shebang of the Build script produced from the configure step is too
long.

1 files changed, 12 insertions, 0 deletions

diff --git a/lib/spack/spack/build_systems/perl.py b/lib/spack/spack/build_systems/perl.py
index bdd1e7fda3..28f1fc5608 100644
--- a/lib/spack/spack/build_systems/perl.py
+++ b/lib/spack/spack/build_systems/perl.py
@@ -10,6 +10,7 @@ import os
 from spack.directives import depends_on, extends
 from spack.package import PackageBase, run_after
 from spack.util.executable import Executable
+from llnl.util.filesystem import filter_file
 
 
 class PerlPackage(PackageBase):
@@ -80,6 +81,17 @@ class PerlPackage(PackageBase):
 
         inspect.getmodule(self).perl(*options)
 
+    # It is possible that the shebang in the Build script that is created from
+    # Build.PL may be too long causing the build to fail. Patching the shebang
+    # does not happen until after install so set '/usr/bin/env perl' here in
+    # the Build script.
+    @run_after('configure')
+    def fix_shebang(self):
+        if self.build_method == 'Build.PL':
+            pattern = '#!{0}'.format(self.spec['perl'].command.path)
+            repl = '#!/usr/bin/env perl'
+            filter_file(pattern, repl, 'Build', backup=False)
+
     def build(self, spec, prefix):
         """Builds a Perl package."""
         self.build_executable()