From 98ad34f0df6be93db98046d4b34d35f6476d5179 Mon Sep 17 00:00:00 2001
From: Giovanni Bussi <giovanni.bussi@gmail.com>
Date: Fri, 1 Dec 2023 17:18:34 +0100
Subject: [PATCH] pass filesystem_error to python, including paths

---
 python/cplumed.pxd |  6 ++++++
 python/plumed.pyx  | 13 +++++++++++++
 2 files changed, 19 insertions(+)

diff --git a/python/cplumed.pxd b/python/cplumed.pxd
index fd90c97a2b..440b03981a 100644
--- a/python/cplumed.pxd
+++ b/python/cplumed.pxd
@@ -35,10 +35,16 @@ cdef extern from "Plumed.h":
     ctypedef struct plumed_nothrow_handler:
         void* ptr
         void (*handler)(void*,int,const char*,const void*)
+    ctypedef struct plumed_error_filesystem_path:
+        size_t numbytes
+        void* ptr
     ctypedef struct plumed_error:
         int code
         const char* what
         void* nested
+        int error_code
+        plumed_error_filesystem_path path1
+        plumed_error_filesystem_path path2
         # ignore other members
     void plumed_cmd_safe_nothrow(plumed p,const char*key,plumed_safeptr safe,plumed_nothrow_handler nothrow)
     void plumed_error_set(void*ptr,int code,const char*what,const void* opt)
diff --git a/python/plumed.pyx b/python/plumed.pyx
index cfb43c986d..318734c063 100644
--- a/python/plumed.pyx
+++ b/python/plumed.pyx
@@ -130,6 +130,17 @@ cdef class Plumed:
           raise_from = None
         msg = error.what
         what = msg.decode("utf-8")
+
+        # this is likely not working on Windows, where encoding would be different:
+        if error.path1.ptr:
+            path1=(<char*>error.path1.ptr).decode("utf-8")
+        else:
+            path1=None
+        if error.path2.ptr:
+            path2=(<char*>error.path2.ptr).decode("utf-8")
+        else:
+            path2=None
+
         # this map is from cython doc
         if error.code>=20300 and error.code<20400: # PLMD::Plumed::ExceptionTypeError
            raise TypeError(what) from raise_from
@@ -143,6 +154,8 @@ cdef class Plumed:
            raise ValueError(what) from raise_from
         elif error.code>=10105 and error.code<10110: # std::invalid_argument
            raise ValueError(what) from raise_from
+        elif error.code==10229: # filesystem::filesystem_error
+           raise OSError(error.error_code,what,path1,None,path2) from raise_from
         elif error.code>=10230 and error.code<10240: # std::ios_base::failure
            # Unfortunately, in standard C++ we have no way of distinguishing EOF
            # from other errors here; be careful with the exception mask