Fix #15010: ErrorLogger: do not open and read from files unless necessary

[ludviggunne]

Not exactly sure how to test the number of times the file is read.
I was thinking of adding a test under test/scripts using strace, but I'm not sure how robust it would be.

[ludviggunne]

Before this change:

$ strace --trace=openat --trace-path=zerodiv.c --follow-forks ./cppcheck --suppress=zerodiv zerodiv.c
Checking zerodiv.c ...
openat(AT_FDCWD, "zerodiv.c", O_RDONLY) = 3
openat(AT_FDCWD, "zerodiv.c", O_RDONLY) = 3
openat(AT_FDCWD, "zerodiv.c", O_RDONLY) = 3
openat(AT_FDCWD, "zerodiv.c", O_RDONLY) = 3
openat(AT_FDCWD, "zerodiv.c", O_RDONLY) = 3
+++ exited with 0 +++

After this change:

$ strace --trace=openat --trace-path=zerodiv.c --follow-forks ./cppcheck --suppress=zerodiv zerodiv.c
zerodiv.c"
Checking zerodiv.c ...
openat(AT_FDCWD, "zerodiv.c", O_RDONLY) = 3
+++ exited with 0 +++

[danmar]

I was thinking of adding a test under test/scripts using strace, but I'm not sure how robust it would be.

Imho, such a test in test/cli that uses strace would be great. I guess it can be added in the other_test.py. It could test with --suppress , --xml and --template=cppcheck1 .. each of those options should mean the file is only opened once.

so I guess it will only run in linux but that is OK.