package hash: gracefully handle @when with non-string args (#14153)

* when constructing package hash, default to including a method in the content hash if we can't determine whether it would be included by examining the AST
* add a test for updated content-hash calculations
* refactor content hash tests to eliminate repeated lines

4 files changed, 95 insertions, 27 deletions

diff --git a/lib/spack/spack/test/packages.py b/lib/spack/spack/test/packages.py
index 186b0d0007..bd4ba95053 100644
--- a/lib/spack/spack/test/packages.py
+++ b/lib/spack/spack/test/packages.py
@@ -16,6 +16,11 @@ from spack.version import VersionChecksumError
 import spack.directives
 
 
+def _generate_content_strip_name(spec):
+    content = package_content(spec)
+    return content.replace(spec.package.__class__.__name__, '')
+
+
 @pytest.mark.usefixtures('config', 'mock_packages')
 class TestPackage(object):
     def test_load_package(self):
@@ -53,38 +58,43 @@ class TestPackage(object):
         assert '_3db' == mod_to_class('3db')
 
     def test_content_hash_all_same_but_patch_contents(self):
-        spec1 = Spec("hash-test1@1.1")
-        spec2 = Spec("hash-test2@1.1")
-        spec1.concretize()
-        spec2.concretize()
-        content1 = package_content(spec1)
-        content1 = content1.replace(spec1.package.__class__.__name__, '')
-        content2 = package_content(spec2)
-        content2 = content2.replace(spec2.package.__class__.__name__, '')
+        spec1 = Spec("hash-test1@1.1").concretized()
+        spec2 = Spec("hash-test2@1.1").concretized()
+        content1 = _generate_content_strip_name(spec1)
+        content2 = _generate_content_strip_name(spec2)
         assert spec1.package.content_hash(content=content1) != \
             spec2.package.content_hash(content=content2)
 
     def test_content_hash_different_variants(self):
-        spec1 = Spec("hash-test1@1.2 +variantx")
-        spec2 = Spec("hash-test2@1.2 ~variantx")
-        spec1.concretize()
-        spec2.concretize()
-        content1 = package_content(spec1)
-        content1 = content1.replace(spec1.package.__class__.__name__, '')
-        content2 = package_content(spec2)
-        content2 = content2.replace(spec2.package.__class__.__name__, '')
+        spec1 = Spec("hash-test1@1.2 +variantx").concretized()
+        spec2 = Spec("hash-test2@1.2 ~variantx").concretized()
+        content1 = _generate_content_strip_name(spec1)
+        content2 = _generate_content_strip_name(spec2)
         assert spec1.package.content_hash(content=content1) == \
             spec2.package.content_hash(content=content2)
 
+    def test_content_hash_cannot_get_details_from_ast(self):
+        """Packages hash-test1 and hash-test3 would be considered the same
+           except that hash-test3 conditionally executes a phase based on
+           a "when" directive that Spack cannot evaluate by examining the
+           AST. This test ensures that Spack can compute a content hash
+           for hash-test3. If Spack cannot determine when a phase applies,
+           it adds it by default, so the test also ensures that the hashes
+           differ where Spack includes a phase on account of AST-examination
+           failure.
+        """
+        spec3 = Spec("hash-test1@1.7").concretized()
+        spec4 = Spec("hash-test3@1.7").concretized()
+        content3 = _generate_content_strip_name(spec3)
+        content4 = _generate_content_strip_name(spec4)
+        assert(spec3.package.content_hash(content=content3) !=
+               spec4.package.content_hash(content=content4))
+
     def test_all_same_but_archive_hash(self):
-        spec1 = Spec("hash-test1@1.3")
-        spec2 = Spec("hash-test2@1.3")
-        spec1.concretize()
-        spec2.concretize()
-        content1 = package_content(spec1)
-        content1 = content1.replace(spec1.package.__class__.__name__, '')
-        content2 = package_content(spec2)
-        content2 = content2.replace(spec2.package.__class__.__name__, '')
+        spec1 = Spec("hash-test1@1.3").concretized()
+        spec2 = Spec("hash-test2@1.3").concretized()
+        content1 = _generate_content_strip_name(spec1)
+        content2 = _generate_content_strip_name(spec2)
         assert spec1.package.content_hash(content=content1) != \
             spec2.package.content_hash(content=content2)
 
diff --git a/lib/spack/spack/util/package_hash.py b/lib/spack/spack/util/package_hash.py
index 2a3ee80fd5..18b126486c 100644
--- a/lib/spack/spack/util/package_hash.py
+++ b/lib/spack/spack/util/package_hash.py
@@ -69,8 +69,17 @@ class TagMultiMethods(ast.NodeVisitor):
         if node.decorator_list:
             dec = node.decorator_list[0]
             if isinstance(dec, ast.Call) and dec.func.id == 'when':
-                cond = dec.args[0].s
-                nodes.append((node, self.spec.satisfies(cond, strict=True)))
+                try:
+                    cond = dec.args[0].s
+                    nodes.append(
+                        (node, self.spec.satisfies(cond, strict=True)))
+                except AttributeError:
+                    # In this case the condition for the 'when' decorator is
+                    # not a string literal (for example it may be a Python
+                    # variable name). Therefore the function is added
+                    # unconditionally since we don't know whether the
+                    # constraint applies or not.
+                    nodes.append((node, None))
         else:
             nodes.append((node, None))
 
diff --git a/var/spack/repos/builtin.mock/packages/hash-test1/package.py b/var/spack/repos/builtin.mock/packages/hash-test1/package.py
index 879e08147e..ffcaa89eb9 100644
--- a/var/spack/repos/builtin.mock/packages/hash-test1/package.py
+++ b/var/spack/repos/builtin.mock/packages/hash-test1/package.py
@@ -19,6 +19,9 @@ class HashTest1(Package):
     version('1.2', 'b' * 32)
     version('1.3', 'c' * 32)
     version('1.4', 'd' * 32)
+    version('1.5', 'd' * 32)
+    version('1.6', 'e' * 32)
+    version('1.7', 'f' * 32)
 
     patch('patch1.patch', when="@1.1")
     patch('patch2.patch', when="@1.4")
@@ -34,6 +37,10 @@ class HashTest1(Package):
         print("install 1")
         os.listdir(os.getcwd())
 
-    @when('@1.5')
+    @when('@1.5:')
     def install(self, spec, prefix):
         os.listdir(os.getcwd())
+
+    @when('@1.5,1.6')
+    def extra_phase(self, spec, prefix):
+        pass
diff --git a/var/spack/repos/builtin.mock/packages/hash-test3/package.py b/var/spack/repos/builtin.mock/packages/hash-test3/package.py
new file mode 100644
index 0000000000..345309a5eb
--- /dev/null
+++ b/var/spack/repos/builtin.mock/packages/hash-test3/package.py
@@ -0,0 +1,42 @@
+# Copyright 2013-2019 Lawrence Livermore National Security, LLC and other
+# Spack Project Developers. See the top-level COPYRIGHT file for details.
+#
+# SPDX-License-Identifier: (Apache-2.0 OR MIT)
+
+from spack import *
+
+import os
+
+
+class HashTest3(Package):
+    """Used to test package hashing
+    """
+
+    homepage = "http://www.hashtest3.org"
+    url = "http://www.hashtest1.org/downloads/hashtest3-1.1.tar.bz2"
+
+    version('1.2', 'b' * 32)
+    version('1.3', 'c' * 32)
+    version('1.5', 'd' * 32)
+    version('1.6', 'e' * 32)
+    version('1.7', 'f' * 32)
+
+    variant('variantx', default=False, description='Test variant X')
+    variant('varianty', default=False, description='Test variant Y')
+
+    def setup_dependent_environment(self, spack_env, run_env, dependent_spec):
+        pass
+
+    @when('@:1.4')
+    def install(self, spec, prefix):
+        print("install 1")
+        os.listdir(os.getcwd())
+
+    @when('@1.5:')
+    def install(self, spec, prefix):
+        os.listdir(os.getcwd())
+
+    for _version_constraint in ['@1.5', '@1.6']:
+        @when(_version_constraint)
+        def extra_phase(self, spec, prefix):
+            pass