[FIX] report: always close pdf files after merge

If an exception during the merges (such as a file descriptor overrun), we
would otherwise depend on the next garbage collection to close the
files. But the next GC may never come.

For example if we ran out of OS file descriptors during merge, all future
requests will crash for the same reason, and the process will never recover
because the GC will never run.

Much easier to explicitly close the files all the time.

addons/report/models/report.py

@@ -560,19 +560,23 @@ class Report(osv.Model):
         """
         writer = PdfFileWriter()
         streams = []  # We have to close the streams *after* PdfFilWriter's call to write()
-        for document in documents:
-            pdfreport = file(document, 'rb')
-            streams.append(pdfreport)
-            reader = PdfFileReader(pdfreport)
-            for page in range(0, reader.getNumPages()):
-                writer.addPage(reader.getPage(page))
+        try:
+            for document in documents:
+                pdfreport = file(document, 'rb')
+                streams.append(pdfreport)
+                reader = PdfFileReader(pdfreport)
+                for page in range(0, reader.getNumPages()):
+                    writer.addPage(reader.getPage(page))
 
-        merged_file_fd, merged_file_path = tempfile.mkstemp(suffix='.html', prefix='report.merged.tmp.')
-        with closing(os.fdopen(merged_file_fd, 'w')) as merged_file:
-            writer.write(merged_file)
-
-        for stream in streams:
-            stream.close()
+            merged_file_fd, merged_file_path = tempfile.mkstemp(suffix='.pdf', prefix='report.merged.tmp.')
+            with closing(os.fdopen(merged_file_fd, 'w')) as merged_file:
+                writer.write(merged_file)
+        finally:
+            for stream in streams:
+                try:
+                    stream.close()
+                except Exception:
+                    pass
 
         return merged_file_path