🚀 go-pugleaf

I write the software for the company I work for using Delphi addressing a 
MySQL database.  My project therefore has a DataModule in a file named 
DataUnit.pas.  This is a large project and the DataUnit.pas file is large. 
It represents many hours of work!

It's been a while since I've needed to do anything to the DataModule but the 
other day I needed to look at something, when I discovered to my horror that 
the unit appears to be corrupt.

When a project is compiled, small blue dots are placed in the left margin, 
to indicate lines on which a a breakpoint may be set.  In the case of my 
DataModule, there are no blue dots until, in the middle of a procedure, the 
blue dots appear from line 4145 to the last line, line 5637.  When present, 
the blue dots appear to make sense (for example, there is no blue dot next 
to a line starting with the word "procedure", but there is one on that 
procedures "begin" statement.  However, if I set a breakpoint on a line in 
this region, it is not honoured; its as though no breakpoint is set. 
Suspecting that the blue dots might be offset, I set a breakpoint on the 
first blue dot (line 4145) and then set a breakpoint in another unit of the 
code at a point where the first routine in the data module is called.  Sure 
enough, when I singlestep (F7) onto the line calling the first routine in 
the data module, control jumps to the data module, to line 4145, the line in 
the middle of a procedure.  When next I press F7, an access-violation error 
message is generated.  Makes sense - I can't expect to start in the middle 
of a procedure!

When I run without breakpoints, the code does its job correctly, so the code 
is (I hope!) fine, the problem is in the breakpoint mechanism.

I've asked my question in a forum with limited relevance and the consensus 
was that I was somehow linking to an out-of-date DataUnit.dcu file, hence 
the inappropriate positions for the blue dots.  (I recently bought and 
installed EurekaLog - to track a memory leak - and wanted to eliminate the 
possibility that this was the cause of the problem.  No-one in the EurekaLog 
forum thought EurekaLog was the culprit.)  In short, please don't suggest 
that I delete all dcu's for my project, then build it (rather than compile 
it).  I've tested this suggestion and a number of similar ones, all based on 
the assumption that my DataUnit.dcu file is not the one I think it is. As 
another example of suggestions tested, I removed the DatUnit.pas file from 
my project then added to the project, making sure I was selecting the 
correct DataUnit.pas file.  All the units I've made for this project are in 
a single folder, the folder containing the dpr file.

Does anybody know what's wrong here, and how to fix the problem?  The idea 
that I will not be able to singlestep into my data module when needed 
horrifies me!

Many thanks in advance for your assistance.
John Randall.