Implement recompilation checking for pre-build rules#11731
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sheaf wants to merge 2 commits intohaskell:masterfrom
Open
Implement recompilation checking for pre-build rules#11731sheaf wants to merge 2 commits intohaskell:masterfrom
sheaf wants to merge 2 commits intohaskell:masterfrom
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sheaf
changed the title
This commit adds 'Structured' instances for the 'RuleCommands' and 'RuleData' datatypes. This allows us to serialise and deserialise them, which allows us to compute which rules have changed across builds. This is necessary for recompilation checking for pre-build rules.
This commit adds recompilation logic for SetupHooks pre-build rules.
This implements the behaviour described in the SetupHooks API. That is,
a rule is considered stale if:
[N] The rule is new, or
[S1] A dependency of the rule is stale. That is, either we have
re-run another rule that this rule depends on, or one of the
file inputs to the rule is newer than the oldest output of the
rule (or the rule output doesn't exist at all), or
[S2] The rule itself has changed, e.g. the parameters stored in
RuleData have changed.
Fixes haskell#11730
geekosaur
reviewed
Apr 10, 2026
| -- Load the rule cache from the previous build. | ||
| -- Used to detect when rule definitions have changed. | ||
| oldRules <- do | ||
| cacheExists <- doesFileExist rulesCacheFile |
Collaborator
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Does this have a TOCTOU issue?
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| mtimeIfExists :: FilePath -> IO (Maybe UTCTime) | ||
| mtimeIfExists fp = do | ||
| ex <- doesFileExist fp |
Collaborator
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Granting that it's brief, but this looks like a TOCTOU as well.
| have changed. | ||
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| In particular, Cabal will now write per-component caches of pre-build rules | ||
| in order to compute which rules have changed across run, with file name |
Collaborator
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Suggested change
| in order to compute which rules have changed across run, with file name | |
| in order to compute which rules have changed between runs, with file name |
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Template Α: This PR modifies behaviour or interface
This PR adds recompilation logic for SetupHooks pre-build rules, implementing the behaviour described in the SetupHooks API. That is, a rule is considered stale if:
RuleDatahave changed.Tested in
cabal-testsuite/PackageTests/SetupHooks/SetupHooksRecompRules/setup.test.hs.