mdscts occasionally refuses to delete the last crate listed in the crate.db file

[mwinkel-dev]

Affiliation
MIT PSFC

Version(s) Affected
The MDSplus Version(s) affected, if any.
Client & Server: alpha-7-158-0

Platform(s)
Ubuntu-24, but presumably affects other platforms too

Installation Method(s)
Developer build.

Describe the bug
The mdscts utility is used to add CAMAC crates to the crate.db file and CAMAC modules to the cts.db file. In some circumstances, the CTS DelCrate command refuses to delete the last crate listed in the crate.db file. Presumably, the same problem exists regarding the last module in the cts.db file.

To Reproduce
Steps to reproduce the behavior:

1. Install alpha-7-158-0 on Ubuntu 24.
2. Create a "/tmp/cts" directory that will contain the two *.db files.
3. Use a text editor to create cts.db file that contains two bytes, a space and a newline.
4. Use a text editor to create this crate.db file (it can also be created using CTS AddCrate commands)

GKA401:...:.:.:.
GKA402:...:.:.:.
GKA403:...:.:.:.
GKA404:...:.:.:.
GKA405:...:.:.:.
GKA406:...:.:.:.
GKA407:...:.:.:.
GKA408:...:.:.:.
GKA409:...:.:.:.
GKA410:...:.:.:.
GKA411:...:.:.:.
GKA412:...:.:.:.
GKA413:...:.:.:.

5. Run mdscts and execute the following commands:

CTS> delcrate gka413
CTS> delcrate gka412
CTS> delcrate gka405
CTS> delcrate gka411
CTS> delcrate gka410
Error: entry 'GKA410' not found
mdsdcl: --> failed on line 'delcrate gka410'

Expected behavior
Displaying the crate.db file shows that GKA410 does indeed exist in the file. Therefore, mdscts should find the crate and delete it. No errors should be thrown.

Screenshots
n/a

Additional context
n/a

[mwinkel-dev]

Experiments with the debugger reveal that there are few related causes.

• When a crate is deleted, the list of crates of course shrinks but the last record in the previous list is not erased correctly.
• Which causes another routine to incorrectly count the number of active records in the crate.db file.
• Which in turn can cause the binary search to skip beyond the list of active records and search for the crate in the erased inactive records.
• Also, there is a problem caused by some indices being zero-based and others being one-based.