Fix prefer_system_check failing in aliBuild but not aliDoctor (#880) (#996)

Checks that depended on a variable that had `_VERSION` were silently
failing in `aliBuild build` but not in `aliBuild doctor`, causing
unnecesary rebuilds

Regression from #327

Author: singiamtel

alibuild_helpers/build.py

@@ -6,7 +6,7 @@
 from alibuild_helpers.log import debug, info, banner, warning
 from alibuild_helpers.log import dieOnError
 from alibuild_helpers.cmd import execute, DockerRunner, BASH, install_wrapper_script, getstatusoutput
-from alibuild_helpers.utilities import prunePaths, symlink, call_ignoring_oserrors, topological_sort, detectArch
+from alibuild_helpers.utilities import pruneWorkdirFromPaths, pruneVersionEnvVars, symlink, call_ignoring_oserrors, topological_sort, detectArch
 from alibuild_helpers.utilities import resolve_store_path
 from alibuild_helpers.utilities import parseDefaults, readDefaults
 from alibuild_helpers.utilities import getPackageList, asList
@@ -460,7 +460,7 @@ def doBuild(args, parser):
   specs = {}
   buildOrder = []
   workDir = abspath(args.workDir)
-  prunePaths(workDir)
+  pruneWorkdirFromPaths(workDir)
 
   dieOnError(not exists(args.configDir),
              'Cannot find alidist recipes under directory "%s".\n'
@@ -534,6 +534,8 @@ def performPreferCheckWithTempDir(pkg, cmd):
                      taps                    = taps,
                      log                     = debug)
 
+  pruneVersionEnvVars()
+
   dieOnError(validDefaults and args.defaults not in validDefaults,
              "Specified default `%s' is not compatible with the packages you want to build.\n"
              "Valid defaults:\n\n- %s" % (args.defaults, "\n- ".join(sorted(validDefaults or []))))

alibuild_helpers/utilities.py

@@ -169,16 +169,26 @@ def resolve_tag(spec):
 def normalise_multiple_options(option, sep=","):
   return [x for x in ",".join(option).split(sep) if x]
 
-def prunePaths(workDir):
+def pruneWorkdirFromPaths(workDir):
+  """Remove workDir entries from PATH, LD_LIBRARY_PATH, and DYLD_LIBRARY_PATH."""
   for x in ["PATH", "LD_LIBRARY_PATH", "DYLD_LIBRARY_PATH"]:
     if x not in os.environ:
       continue
     workDirEscaped = re.escape("%s" % workDir) + "[^:]*:?"
     os.environ[x] = re.sub(workDirEscaped, "", os.environ[x])
+
+
+def pruneVersionEnvVars():
+  """Remove all *_VERSION environment variables except ALIBUILD_VERSION."""
   for x in list(os.environ.keys()):
     if x.endswith("_VERSION") and x != "ALIBUILD_VERSION":
       os.environ.pop(x)
 
+
+def prunePaths(workDir):
+  pruneWorkdirFromPaths(workDir)
+  pruneVersionEnvVars()
+
 def validateSpec(spec):
   if not spec:
     raise SpecError("Empty recipe.")

tests/test_packagelist.py

@@ -78,6 +78,16 @@
       exit 0
     ---
     """),
+    # Recipe for issue #880: prefer_system_check relies on _VERSION env var
+    "CONFIG_DIR/version-check.sh": dedent("""\
+    package: version-check
+    version: v1
+    prefer_system: '.*'
+    prefer_system_check: |
+      [ "$GENFIT_VERSION" = "v1.0.0" ] && exit 0
+      exit 1
+    ---
+    """),
 }
 
 class MockReader:
@@ -229,6 +239,26 @@ def fake_exists(n):
             self.assertTrue(specs["defaults-release"]["force_rebuild"])
 
 
+@mock.patch("alibuild_helpers.utilities.getRecipeReader", new=MockReader)
+class Issue880TestCase(unittest.TestCase):
+    """Test for issue #880: pruneWorkdirFromPaths preserves _VERSION env vars."""
+
+    def test_version_check_uses_env_var(self) -> None:
+        """prefer_system_check can use _VERSION env vars after pruneWorkdirFromPaths."""
+        from alibuild_helpers.utilities import pruneWorkdirFromPaths
+
+        def fake_exists(n):
+            return n in RECIPES.keys()
+
+        os.environ["GENFIT_VERSION"] = "v1.0.0"
+        try:
+            with patch.object(os.path, "exists", fake_exists):
+                pruneWorkdirFromPaths("/fake/workdir")
+                self.assertIn("GENFIT_VERSION", os.environ)
+                _, systemPkgs, ownPkgs, _, _ = getPackageListWithDefaults(["version-check"])
+                self.assertIn("version-check", systemPkgs)
+        finally:
+            os.environ.pop("GENFIT_VERSION", None)
 
 
 if __name__ == '__main__':