Raise errors when src_info subprocess fails. (#638)

* Raise errors when `src_info` subprocess fails.

* Log errors in constructor if not compiling.

* Explicitly set `check=False` for source info subprocess.

* Only catch `ValueError` when calling `src_info`.

Author: tillahoffmann

cmdstanpy/model.py

@@ -169,9 +169,14 @@ def __init__(
             if not cmdstan_version_before(
                 2, 27
             ):  # unknown end of version range
-                model_info = self.src_info()
-                if 'parameters' in model_info:
-                    self._fixed_param |= len(model_info['parameters']) == 0
+                try:
+                    model_info = self.src_info()
+                    if 'parameters' in model_info:
+                        self._fixed_param |= len(model_info['parameters']) == 0
+                except ValueError as e:
+                    if compile:
+                        raise
+                    get_logger().debug(e)
 
         if exe_file is not None:
             self._exe_file = os.path.realpath(os.path.expanduser(exe_file))
@@ -269,32 +274,22 @@ def src_info(self) -> Dict[str, Any]:
         If stanc is older than 2.27 or if the stan
         file cannot be found, returns an empty dictionary.
         """
-        result: Dict[str, Any] = {}
-        if self.stan_file is None:
-            return result
-        try:
-            cmd = (
-                [os.path.join(cmdstan_path(), 'bin', 'stanc' + EXTENSION)]
-                # handle include-paths, allow-undefined etc
-                + self._compiler_options.compose_stanc()
-                + [
-                    '--info',
-                    str(self.stan_file),
-                ]
-            )
-            proc = subprocess.run(
-                cmd, capture_output=True, text=True, check=True
+        if self.stan_file is None or cmdstan_version_before(2, 27):
+            return {}
+        cmd = (
+            [os.path.join(cmdstan_path(), 'bin', 'stanc' + EXTENSION)]
+            # handle include-paths, allow-undefined etc
+            + self._compiler_options.compose_stanc()
+            + ['--info', str(self.stan_file)]
+        )
+        proc = subprocess.run(cmd, capture_output=True, text=True, check=False)
+        if proc.returncode:
+            raise ValueError(
+                f"Failed to get source info for Stan model "
+                f"'{self._stan_file}'. Console:\n{proc.stderr}"
             )
-            result = json.loads(proc.stdout)
-            return result
-        except (
-            ValueError,
-            RuntimeError,
-            OSError,
-            subprocess.CalledProcessError,
-        ) as e:
-            get_logger().debug(e)
-            return result
+        result: Dict[str, Any] = json.loads(proc.stdout)
+        return result
 
     def format(
         self,

test/test_model.py

@@ -207,6 +207,33 @@ def test_model_info(self):
         self.assertIn('theta', model_info_include['parameters'])
         self.assertIn('included_files', model_info_include)
 
+    def test_compile_with_bad_includes(self):
+        # Ensure compilation fails if we break an included file.
+        stan_file = os.path.join(DATAFILES_PATH, "add_one_model.stan")
+        exe_file = os.path.splitext(stan_file)[0] + EXTENSION
+        if os.path.isfile(exe_file):
+            os.unlink(exe_file)
+        with tempfile.TemporaryDirectory() as include_path:
+            include_source = os.path.join(
+                DATAFILES_PATH, "include-path", "add_one_function.stan"
+            )
+            include_target = os.path.join(include_path, "add_one_function.stan")
+            shutil.copy(include_source, include_target)
+            model = CmdStanModel(
+                stan_file=stan_file,
+                compile=False,
+                stanc_options={"include-paths": [include_path]},
+            )
+            with LogCapture(level=logging.INFO) as log:
+                model.compile()
+            log.check_present(
+                ('cmdstanpy', 'INFO', StringComparison('compiling stan file'))
+            )
+            with open(include_target, "w") as fd:
+                fd.write("gobbledygook")
+            with pytest.raises(ValueError, match="Failed to get source info"):
+                model.compile()
+
     def test_compile_with_includes(self):
         getmtime = os.path.getmtime
         configs = [
@@ -215,6 +242,9 @@ def test_compile_with_includes(self):
         ]
         for stan_file, include_paths in configs:
             stan_file = os.path.join(DATAFILES_PATH, stan_file)
+            exe_file = os.path.splitext(stan_file)[0] + EXTENSION
+            if os.path.isfile(exe_file):
+                os.unlink(exe_file)
             include_paths = [
                 os.path.join(DATAFILES_PATH, path) for path in include_paths
             ]
@@ -348,6 +378,10 @@ def test_model_syntax_error(self):
         with self.assertRaisesRegex(ValueError, r'.*Syntax error.*'):
             CmdStanModel(stan_file=stan)
 
+    def test_model_syntax_error_without_compile(self):
+        stan = os.path.join(DATAFILES_PATH, 'bad_syntax.stan')
+        CmdStanModel(stan_file=stan, compile=False)
+
     def test_repr(self):
         model = CmdStanModel(stan_file=BERN_STAN)
         model_repr = repr(model)