cmd/go,testing,doc: better information about debugging test cache failures #35301
I'm trying to figure out why Go is not caching a test I wrote. First, after about 10-15 minutes of searching (including through old issues here) I could not find the flag to enable the debug output that shows you how Go builds its cache. Finally, I found it
I am trying to read through the output of
Next I tried sorting each output file and printing it. This yields a pretty manageable diff.
I repeated the same exercise with a test that printed out
However I am confused by this one as well because the content hash of the opened file is identical, so I'm not sure why Go is refusing to use the test cache.
Am I correct that these "stat" lines are the reason Go is not caching the result of this test? If so, what is the problem that is leading Go to not cache the results?
Can we build a tool to automate the process of debugging test hashes? E.g. run a test twice, capture the output, sort it, print the lines that differ.
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Ah, okay, that's frustrating but fair enough.
Maybe this is worth posting a second ticket about. I have a test that generates configuration files in the
Would it work to walk the file tree and set the mtime of every file after writing it, to a constant value? Alternatively it would be nice to have a hook to say "you can ignore changes to this file when computing the build cache" but maybe that is a Pandora's box we don't want to open.
(Please let me know if commenting here is the wrong move, i will create an issue then)
Currently trying to debug why our Go unit tests are not completely cached when retrying a CI pipeline. Stumbled over this issue because i find cache-misses hard to debug as well.
Discoverability of the current debug features could be easily improved by extending some texts. There are some problems related to the documentation:
That is my user experience so far with debugging test cache misses.
So the next thing what i am wondering is i guess why Go files are cached on their content but these used input files are not? I am wondering the same thing as #35301 (comment) i guess.