The following list shows the template error messages which are currently used in 
the validator.error file. 
The list is separated in blocks with this structure:

error message 
continuation of error message
 - explanation
continuation of explanation 

The first line(s) in each block are the actual error message, as found in a 
single line of the validator.error file, while the next line(s) are the error 
explanation (which is not reported in the validator.error file). The first line 
of the explanation starts with a dash ("-"). A blank line is used as separator 
between 2 blocks of error message/explanation.

--------------------------------------------------------------------------------
Error list
--------------------------------------------------------------------------------

This release does not contain any file.
- The input release directory is either empty or it contains only files without 
reading permission.

<filename> : Error parsing metadata rules for category: <file-category> - Details 
are reported in the log file.
- The validator could not correctly parse the metadata rules  provided by ESO 
for the category <file-category>.

<science filename(s)> : invalid category <category> defined for file <filename>.
- <filename> is declared (in <science filename(s)>) to have the category <catg>, 
but <catg> is not present in the catg.list file downloaded from ESO.

<filename> : category is not set. Cannot validate file.
- The category for <filename> could not be parsed from the release structure.  

<filename> : Ignoring header. <header parsing error details>
- An error was found while trying to parse the release structure from the metadata 
of the FITS file <filename> (i.e. this error happened before applying the metadata 
validation rules). Therefore the content of the header of <filename> is not 
included in the release structure. The error could have happened while opening 
the header for reading, but it could also be an inconsistency or duplication in 
the parsed keywords, this is detailed  in the <header parsing error details>.  
 
<filename> : Metadata validation errors using rules of category <catg>. <error list>
- Applying the metadata verification rules for category <catg> on <filename>  
produced the errors reported in <error list>

<filename> : {CHECKSUM|DATASUM} keyword is not defined in header index = <index>.  
- The reported keyword was not found in the header with index=<index> of the fits 
file <fileName>. Note that the CHECKSUM and DATASUM keywords are not mandatory 
for generic fits compliance but they are mandatory for the delivered products.  

<fileName> : expected md5sum=<expected> is different from the computed md5sum=<computed>
- The computed value of md5sum of the ancillary file <fileName> is different 
from the value declared in the header of the corresponding science file. 

Fits File <fits file full PathName> is not readable.
- The fitsverify utility was not able to read the reported fits file.

Fits File <fits file full PathName> does not exist.
- The fitsverify utility did not find on disk the reported fits file.

<filename> : fits verification error. Details in the log file.
- The fitsverify utility reported an error after running on <filename>. 
The validator.log file contains the full output of fitsverify.

<filename> : duplicated on disk [ <filepath1> ... <filepathN>]
- The same file name <filename> was found N times in the release directory tree. 
The full paths of the N instances are reported.

<filename> : File in the release structure not found on disk
- <filename> is present in the release structure (for instance as component of a 
dataset) but it does not exist in the release directory tree.

Failed attempted execution of <name> : <system error message>
- <name> was given in input as fitsverify utility to use, or is the default 
configured utility, but trying to run it raised the error detailed in 
<system error message> (file not found, not executable, lack of permissions, etc.).

<filename> : <URL of the OCA file> (No such file or directory)
- The catg.list declares an OCA file containing the metadata validation rules 
applicable for the category of <filename>, but this file is not retrievable 
from the configured URL.

Category of file <filename> found in <filename header1> and <filename header2>
- Category of <filename>  is defined in two different fits headers of the release.
NOTE: if the category is the same in both header, this is NOT considered an 
error (example: an ancillary file belonging to 2 different datasets).  

Found duplication for <canonical file name> : <physical file full path name>
- The same physical file is referenced multiple times (for instance through 
links in the file system) with different names.

Duplicated definition of the same dataset found in <filename header1> and 
<filename header2> : <dataset components>
- The same group of files defines a dataset in two different fits headers of 
the release.

Found loop(s) in provenance definition for: [product1, .., productN]
- The reported products have a circular definition of their provenance. 

----------------------------------
Errors specific to UPDATE releases
----------------------------------

Missing CONTENT.ESO file. For a release with UPDATE modification type the file 
CONTENT.ESO must be present in the release base directory (<reldir>)
- The file CONTENT.ESO describing the remote structure of the release was not 
found in the release's local base directory. 

Cannot read file: <reldir>/CHANGES.USER
- The file CHANGES.USER exists but it is not readable.

This release does not contain any valid update.
- The release does not have local files nor valid changes to the release can be 
parsed from the CHANGES.USER file (note that the existence of this file is optional). 
An update to the release defined in CHANGES.USER is valid if it is composed by 
a valid action ( DELETE or REPLACE) followed by a filename which is declared part 
of the release in the file CONTENT.ESO.

Failed to parse the remote structure file <release directory>/CONTENT.ESO . 
Error: <parsing error details>
- The parsing of CONTENT.ESO file failed. Details of the failure are reported.
Note that due to this error any update defined in CHANGES.USER is invalid (because 
it cannot refer to filenames declared in CONTENT.ESO).    

Invalid line in <reldir>/CHANGES.USER - Line <line Number> : <read line>
-The line <line number> in CHANGES.USER is not in the expected format.
                        
Parsed an invalid action [<parsed value>] in <reldir>/CHANGES.USER  - Line 
<line Number> : <read line>
- The line <line number> in CHANGES.USER does not start with any of the expected  
actions (the action can either DELETE or REPLACE).

<action name> action specified for file not present in the original release 
structure: <filename>
- In CHANGES.USER is specified an action (DELETE or REPLACE) for <filename>, but 
filename is not part of the structure of the original release (parsed from the 
CONTENT.ESO file).

<filename> : was removed from the release but it is still part of a dataset definition.
- <filename> was part of the release and removed in the current update, but there 
is still at least one dataset containing it. 

<filename> : was removed from the release but it is still part of a provenance definition.
- <filename> was part of the release and removed in the current update, but there 
is still at least one provenance definition containing it

<filename> : is no longer contained in any dataset definition. 
- <filename> was included in a dataset which no longer exists after this update.  

<filename> : duplicated. It's a remote file also on disk at <pathname>
- <filename> is locally on disk (at location <pathname>) but also present in the 
remote content parsed from the CONTENT.ESO file and not declared in a DELETE or 
REPLACE instruction in CHANGES.USER.

<filename> : category defined both remotely (category=<remote-category>) and 
locally (category=<local-category>).
- Category of <filename> is defined in the remote content of the release but
also redefined locally and the two defined categories are different.  

<filename> : duplicated dataset. A remote file already defined this dataset: <dataset-components>
- The same group of files <dataset-components> are defined as dataset in a remote 
file and in <filename>

<filename> : REPLACE action specified but the file is not present on disk.
- REPLACE action is not valid because even if <filename> is part of the release 
before the update, it is not locally found on disk (therefore the correct action 
is DELETE). 

<filename> : DELETE action specified but the file is present on disk.
- DELETE action is not valid because even if <filename> is part of the release 
before the update, it is also found on disk (therefore the correct action 
is REPLACE).