skip lines that start with 'module-version' when determining whether a module exists in ModulesTool.exist

easybuild/tools/modules.py

@@ -547,6 +547,7 @@ def mod_exists_via_show(mod_name):
 
             :param mod_name: module name
             """
+            self.log.info("Checking whether %s exists based on output of 'module show'", mod_name)
             stderr = self.show(mod_name)
             res = False
             # Parse the output:
@@ -555,13 +556,38 @@ def mod_exists_via_show(mod_name):
             # - Check first non-whitespace line for something that looks like an absolute path terminated by a colon
             mod_exists_regex = r'\s*/.+:\s*'
             for line in stderr.split('\n'):
+
+                self.log.debug("Checking line '%s' to determine whether %s exists...", line, mod_name)
+
+                # skip whitespace lines
                 if OUTPUT_MATCHES['whitespace'].search(line):
+                    self.log.debug("Treating line '%s' as whitespace, so skipping it", line)
                     continue
+
+                # if any errors occured, conclude that module doesn't exist
                 if OUTPUT_MATCHES['error'].search(line):
+                    self.log.debug("Line '%s' looks like an error, so concluding that %s doesn't exist",
+                                   line, mod_name)
                     break
-                if re.match(mod_exists_regex, line):
-                    res = True
+
+                # skip warning lines, which may be produced by modules tool but should not be used
+                # to determine whether a module file exists
+                if line.startswith('WARNING: '):
+                    self.log.debug("Skipping warning line '%s'", line)
+                    continue
+
+                # skip lines that start with 'module-' (like 'module-version'),
+                # see https://github.com/easybuilders/easybuild-framework/issues/3376
+                if line.startswith('module-'):
+                    self.log.debug("Skipping line '%s' since it starts with 'module-'", line)
+                    continue
+
+                # if line matches pattern that indicates an existing module file, the module file exists
+                res = bool(re.match(mod_exists_regex, line))
+                self.log.debug("Result for existence check of %s based on 'module show' output line '%s': %s",
+                               mod_name, line, res)
                 break
+
             return res
 
         if skip_avail:
@@ -577,10 +603,15 @@ def mod_exists_via_show(mod_name):
 
         mods_exist = []
         for (mod_name, visible) in mod_names:
+            self.log.info("Checking whether %s exists...", mod_name)
             if visible:
                 mod_exists = mod_name in avail_mod_names
                 # module name may be partial, so also check via 'module show' as fallback
-                if not mod_exists and maybe_partial:
+                if mod_exists:
+                    self.log.info("Module %s exists (found in list of available modules)", mod_name)
+                elif not mod_exists and maybe_partial:
+                    self.log.info("Module %s not found in list of available modules, checking via 'module show'...",
+                                  mod_name)
                     mod_exists = mod_exists_via_show(mod_name)
             else:
                 # hidden modules are not visible in 'avail', need to use 'show' instead

test/framework/modules.py

@@ -310,6 +310,34 @@ def test_exist(self):
         if self.modtool.__class__ != EnvironmentModulesC:
             self.assertEqual(self.modtool.exist(['Java/Alias', 'Java/NonExist']), [True, False])
 
+        # set 'module avail' cache entries to empty lists,
+        # to enforce fallback to 'module show'
+        import easybuild.tools.modules
+        for key in easybuild.tools.modules.MODULE_AVAIL_CACHE:
+            easybuild.tools.modules.MODULE_AVAIL_CACHE[key] = []
+
+        # clear 'module show' cache, to keep control below
+        easybuild.tools.modules.MODULE_SHOW_CACHE.clear()
+        self.assertEqual(self.modtool.exist(['Java/1.8', 'Java/1.8.0_181']), [True, True])
+
+        # mimic more verbose stderr output produced by old Tmod version,
+        # including a warning produced when multiple .modulerc files are being picked up
+        # see https://github.com/easybuilders/easybuild-framework/issues/3376
+        ml_show_java18_stderr = '\n'.join([
+            "module-version    Java/1.8.0_181 1.8",
+            "WARNING: Duplicate version symbol '1.8' found",
+            "module-version  Java/1.8.0_181 1.8",
+            "-------------------------------------------------------------------",
+            "/modulefiles/lang/Java/1.8.0_181:",
+            "-------------------------------------------------------------------",
+        ])
+
+        # overwrite 'module show' cache entries with output that includes extra lines
+        for key in easybuild.tools.modules.MODULE_SHOW_CACHE:
+            easybuild.tools.modules.MODULE_SHOW_CACHE[key] = ml_show_java18_stderr
+
+        self.assertEqual(self.modtool.exist(['Java/1.8', 'Java/1.8.0_181']), [True, True])
+
         reset_module_caches()
 
         # what if we're in an HMNS setting...