deps log recovery (truncate) is performed even in dry run mode

[maximuska]

While running 'ninja -n -d explain' got:
ninja: warning: premature end of file; recovering

The deps file was truncated, w/o leaving any evidence of what the problem was.

[nico]

Is this a bug though? dry run mode means "don't run any build edges", which didn't happen.

(Also, was this with trunk ninja? Trunk should flush records after they're written.)

[maximuska]

Matter of definition, I guess. What the use-cases for the "dry run" are?
In the specific case it would be much better if ninja wouldn't touch the logs, as I could investigate these then.

As for your question, it has happened with ninja based on master with newish fflushes code. ninja always runs till the end uninterrupted in the tests, and I am out of sane ideas for what the problem is, but something is very wrong there. I've now added more logs and assertions to test for ret values of all fwrites/fflushes to debug this (the code still passes the tests;)

I am running this builds with 'ionice' in parallel to my regular activity (but in a completely separate build tree), but I am not sure if this is related.

[maximuska]

(the log corruption is likely explainable by #605)