Merge pull request #3595 from mrmundt/issue-3579

Resolve GAMS/Windows logfile name issue

Author: mrmundt

pyomo/solvers/plugins/solvers/GAMS.py

@@ -18,6 +18,7 @@
 from pyomo.opt import ProblemFormat, SolverFactory
 
 import pyomo.common
+from pyomo.common.dependencies import pathlib
 from pyomo.common.collections import Bunch
 from pyomo.common.tee import TeeStream
 
@@ -300,7 +301,7 @@ def solve(self, *args, **kwds):
                 filename=output_file,
                 format=ProblemFormat.gams,
                 _called_by_solver=True,
-                **io_options
+                **io_options,
             )
             symbolMap = getattr(model, "._symbol_maps")[smap_id]
         else:
@@ -739,6 +740,32 @@ def _parse_special_values(value):
             return sys.float_info.epsilon
         return value
 
+    def _rewrite_path_win8p3(self, path):
+        """
+        Return the 8.3 short path on Windows; unchanged elsewhere.
+
+        This change is in response to Pyomo/pyomo#3579 which reported
+        that GAMS (direct) fails on Windows if there is a space in
+        the path. This utility converts paths to their 8.3 short-path version
+        (which never have spaces).
+        """
+        if not sys.platform.startswith("win"):
+            return str(path)
+
+        import ctypes, ctypes.wintypes as wt
+
+        GetShortPathNameW = ctypes.windll.kernel32.GetShortPathNameW
+        GetShortPathNameW.argtypes = [wt.LPCWSTR, wt.LPWSTR, wt.DWORD]
+
+        # the file must exist, or Windows will not create a short name
+        pathlib.Path(path).parent.mkdir(parents=True, exist_ok=True)
+        pathlib.Path(path).touch(exist_ok=True)
+
+        buf = ctypes.create_unicode_buffer(260)
+        if GetShortPathNameW(str(path), buf, 260):
+            return buf.value
+        return str(path)
+
     def solve(self, *args, **kwds):
         """
         Solve a model via the GAMS executable.
@@ -845,7 +872,7 @@ def solve(self, *args, **kwds):
                 filename=output_filename,
                 format=ProblemFormat.gams,
                 _called_by_solver=True,
-                **io_options
+                **io_options,
             )
             symbolMap = getattr(model, "._symbol_maps")[smap_id]
         else:
@@ -881,7 +908,7 @@ def solve(self, *args, **kwds):
         elif tee and logfile:
             command.append("lo=4")
         if logfile:
-            command.append("lf=" + str(logfile))
+            command.append(f"lf={self._rewrite_path_win8p3(logfile)}")
 
         try:
             ostreams = [StringIO()]

pyomo/solvers/tests/checks/test_GAMS.py

@@ -355,7 +355,7 @@ def tearDown(self):
         """Clean up temporary directory after tests are over."""
         shutil.rmtree(self.tmpdir)
 
-    def _check_logfile(self, exists=True):
+    def _check_logfile(self, exists=True, logfile=None):
         """Check for logfiles existence and contents.
 
         exists=True:
@@ -364,12 +364,14 @@ def _check_logfile(self, exists=True):
             Optionally check that the logfiles contents is equal to this value.
 
         """
+        if not logfile:
+            logfile = self.logfile
         if not exists:
-            self.assertFalse(os.path.exists(self.logfile))
+            self.assertFalse(os.path.exists(logfile))
             return
 
-        self.assertTrue(os.path.exists(self.logfile))
-        with open(self.logfile) as f:
+        self.assertTrue(os.path.exists(logfile))
+        with open(logfile) as f:
             logfile_contents = f.read()
         self.assertIn(self.characteristic_output_string, logfile_contents)
 
@@ -416,6 +418,15 @@ def test_logfile(self):
         self._check_stdout(output.getvalue(), exists=False)
         self._check_logfile(exists=True)
 
+    def test_logfile_with_spaces(self):
+        # In response to Issue 3579
+        logfile_with_spaces = os.path.join(self.tmpdir, "My File.log")
+        with SolverFactory("gams", solver_io="gms") as opt:
+            with capture_output() as output:
+                opt.solve(self.m, logfile=logfile_with_spaces)
+        self._check_stdout(output.getvalue(), exists=False)
+        self._check_logfile(exists=True, logfile=logfile_with_spaces)
+
     def test_logfile_relative(self):
         cwd = os.getcwd()
         with TempfileManager:
@@ -470,6 +481,15 @@ def test_logfile(self):
         self._check_stdout(output.getvalue(), exists=False)
         self._check_logfile(exists=True)
 
+    def test_logfile_with_spaces(self):
+        # In response to Issue 3579
+        logfile_with_spaces = os.path.join(self.tmpdir, "My File.log")
+        with SolverFactory("gams", solver_io="gms") as opt:
+            with capture_output() as output:
+                opt.solve(self.m, logfile=logfile_with_spaces)
+        self._check_stdout(output.getvalue(), exists=False)
+        self._check_logfile(exists=True, logfile=logfile_with_spaces)
+
     def test_logfile_relative(self):
         cwd = os.getcwd()
         with TempfileManager: