Verify tool suggestion

[rgeary1]

I'm generating ninja files which I find occasionally misses a dependency. The only symptom is the build will break with high -j numbers. I propose a "verify" tool to catch these reliably :

The tool builds each ready-to-build edge. If an edge is successfully built, it renames the output files (eg. add a .x suffix), does NOT add the edge's depenedents to the ready-to-built list & then builds the next ready-to-build edge. Once all the ready edges are exhausted, it removes the .x suffix from one of the output files, and adds that build edge's dependents to the ready-to-build list & repeats the task.

Thus if any edge has missing implicit dependencies, the verify tool will fail.

[sorbits]

On Sep 27, 2012, at 12:32 PM, rgeary1 wrote:

[…] I propose a "verify" tool to catch these reliably […]

I’d definitely use such tool.

An alternative implementation would be to use multiple build directories and add hardlinks for the explicit dependencies, this should allow parallel execution while verifying the DAG.

[maximuska]

On Thu, Sep 27, 2012 at 12:32 PM, rgeary1 [email protected] wrote:

to-build edge. Once all the ready edges are exhausted, it removes the .x
suffix from one of the output files, and adds that build edge's dependents
to the ready-to-build list & repeats the task.

Shouldn't you iterate over all permutations here? Do you think it is
practical then?

[rgeary1]

Actually there is another level of permutations I hadn't considered, eg. if A, B & C are on the ready list, but a dependent of B secretly depends on a dependent of A. My algorithm would only find missing dependencies between A, B & C.

Instead, could you use strace to find the file dependencies and match those files to the known build edge outputs? Not as thorough, but faster to run.