Respect max-substitution-jobs again

edolstra · mergify[bot] · commit 0c25bea7cca2 · 2024-09-03T11:36:39.000Z
This broke in #11005. Any number of PathSubstitutionGoals would be woken up by a single build slot becoming available. If there are a lot of substitution goals active, this could lead to us running out of file descriptors (especially on macOS where the default limit is 256). (cherry picked from commit a33cb8a)
diff --git a/src/libstore/build/substitution-goal.cc b/src/libstore/build/substitution-goal.cc
@@ -183,7 +183,7 @@ Goal::Co PathSubstitutionGoal::tryToRun(StorePath subPath, nix::ref<Store> sub,
     /* Make sure that we are allowed to start a substitution.  Note that even
        if maxSubstitutionJobs == 0, we still allow a substituter to run. This
        prevents infinite waiting. */
-    if (worker.getNrSubstitutions() >= std::max(1U, (unsigned int) settings.maxSubstitutionJobs)) {
+    while (worker.getNrSubstitutions() >= std::max(1U, (unsigned int) settings.maxSubstitutionJobs)) {
         worker.waitForBuildSlot(shared_from_this());
         co_await Suspend{};
     }

Original file line number	Diff line number	Diff line change
`@@ -183,7 +183,7 @@ Goal::Co PathSubstitutionGoal::tryToRun(StorePath subPath, nix::ref<Store> sub,`
`183`	`183`	`/* Make sure that we are allowed to start a substitution. Note that even`
`184`	`184`	`if maxSubstitutionJobs == 0, we still allow a substituter to run. This`
`185`	`185`	`prevents infinite waiting. */`
`186`		`- if (worker.getNrSubstitutions() >= std::max(1U, (unsigned int) settings.maxSubstitutionJobs)) {`
	`186`	`+ while (worker.getNrSubstitutions() >= std::max(1U, (unsigned int) settings.maxSubstitutionJobs)) {`
`187`	`187`	`worker.waitForBuildSlot(shared_from_this());`
`188`	`188`	`co_await Suspend{};`
`189`	`189`	`}`