Issue #23865: close() methods in multiple modules now are idempotent and more

robust at shutdown. If needs to release multiple resources, they are released
even if errors are occured.

1 files changed, 25 insertions, 21 deletions

diff --git a/Lib/fileinput.py b/Lib/fileinput.py
index 87758ad..af810d1 100644
--- a/Lib/fileinput.py
+++ b/Lib/fileinput.py
@@ -238,8 +238,10 @@ class FileInput:
         self.close()
 
     def close(self):
-        self.nextfile()
-        self._files = ()
+        try:
+            self.nextfile()
+        finally:
+            self._files = ()
 
     def __enter__(self):
         return self
@@ -275,29 +277,31 @@ class FileInput:
 
     def nextfile(self):
         savestdout = self._savestdout
-        self._savestdout = 0
+        self._savestdout = None
         if savestdout:
             sys.stdout = savestdout
 
         output = self._output
-        self._output = 0
-        if output:
-            output.close()
-
-        file = self._file
-        self._file = 0
-        if file and not self._isstdin:
-            file.close()
-
-        backupfilename = self._backupfilename
-        self._backupfilename = 0
-        if backupfilename and not self._backup:
-            try: os.unlink(backupfilename)
-            except OSError: pass
-
-        self._isstdin = False
-        self._buffer = []
-        self._bufindex = 0
+        self._output = None
+        try:
+            if output:
+                output.close()
+        finally:
+            file = self._file
+            self._file = None
+            try:
+                if file and not self._isstdin:
+                    file.close()
+            finally:
+                backupfilename = self._backupfilename
+                self._backupfilename = None
+                if backupfilename and not self._backup:
+                    try: os.unlink(backupfilename)
+                    except OSError: pass
+
+                self._isstdin = False
+                self._buffer = []
+                self._bufindex = 0
 
     def readline(self):
         try: