unikernel/duniverse/dune_/test/blackbox-tests/test-cases/watching/target-promotion.t

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+Test target promotion in file-watching mode.
+
+  $ . ./helpers.sh
+
+  $ echo '(lang dune 3.0)' > dune-project
+  $ cat > dune <<EOF
+  > (rule
+  >  (mode promote)
+  >  (deps original)
+  >  (target promoted)
+  >  (action (copy %{deps} %{target})))
+  > (rule
+  >  (deps promoted)
+  >  (target result)
+  >  (action (system "cat promoted promoted > result")))
+  > EOF
+  $ echo hi > original
+
+  $ start_dune
+
+  $ build result
+  Success
+  $ cat promoted
+  hi
+  $ cat _build/default/result
+  hi
+  hi
+
+Now change the [original] and rebuild.
+
+  $ echo bye > original
+  $ build result
+  Success
+  $ cat promoted
+  bye
+  $ cat _build/default/result
+  bye
+  bye
+
+Now try deleting the promoted file.
+
+  $ rm promoted
+  $ build result
+  Success
+  $ cat promoted
+  bye
+  $ cat _build/default/result
+  bye
+  bye
+
+Now try replacing its content.
+
+  $ echo hi > promoted
+  $ build result
+  Success
+  $ cat promoted
+  bye
+  $ cat _build/default/result
+  bye
+  bye
+
+Now switch the mode to standard. Dune reports an error about multiple rules for
+[_build/default/promoted], as expected (see the error at the end of the test).
+
+  $ cat > dune <<EOF
+  > (rule
+  >  (mode standard)
+  >  (deps original)
+  >  (target promoted)
+  >  (action (copy %{deps} %{target})))
+  > (rule
+  >  (deps promoted)
+  >  (target result)
+  >  (action (system "cat promoted promoted > result")))
+  > EOF
+
+  $ build result
+  Failure
+
+We use the hint and it starts to work.
+
+  $ rm -f promoted
+  $ build result
+  Success
+  $ cat promoted
+  cat: promoted: No such file or directory
+  [1]
+  $ cat _build/default/promoted
+  bye
+  $ cat _build/default/result
+  bye
+  bye
+
+Now use [fallback] to override the rule that generates [promoted].
+
+  $ cat > dune <<EOF
+  > (rule
+  >  (mode fallback)
+  >  (deps original)
+  >  (target promoted)
+  >  (action (copy %{deps} %{target})))
+  > (rule
+  >  (deps promoted)
+  >  (target result)
+  >  (action (system "cat promoted promoted > result")))
+  > EOF
+
+At first, we don't have the source, so the rule is used.
+
+  $ build result
+  Success
+  $ cat promoted
+  cat: promoted: No such file or directory
+  [1]
+  $ cat _build/default/promoted
+  bye
+  $ cat _build/default/result
+  bye
+  bye
+
+Now we create the source file and it overrides the rule.
+
+  $ echo hi > promoted
+  $ build result
+  Success
+  $ cat promoted
+  hi
+  $ cat _build/default/promoted
+  hi
+  $ cat _build/default/result
+  hi
+  hi
+
+We're done.
+
+  $ stop_dune
+  Success, waiting for filesystem changes...
+  Success, waiting for filesystem changes...
+  Success, waiting for filesystem changes...
+  Success, waiting for filesystem changes...
+  Error: Multiple rules generated for _build/default/promoted:
+  - dune:1
+  - file present in source tree
+  Hint: rm -f promoted
+  Had 1 error, waiting for filesystem changes...
+  Success, waiting for filesystem changes...
+  Success, waiting for filesystem changes...
+  Success, waiting for filesystem changes...
+
+Now test file-system events generated during target promotion.
+
+  $ cat > dune <<EOF
+  > (rule
+  >  (mode promote)
+  >  (deps original)
+  >  (target promoted)
+  >  (action (copy %{deps} %{target})))
+  > (rule
+  >  (deps promoted)
+  >  (target result)
+  >  (action (system "cat promoted promoted > result")))
+  > EOF
+
+  $ cat promoted
+  hi
+  $ start_dune --debug-cache=fs
+  $ build result
+  Success
+  $ cat promoted
+  bye
+
+  $ stop_dune > .#debug-output
+
+Show that Dune ignores the initial "dune-workspace" events (injected by Dune).
+
+  $ cat .#debug-output | grep dune-workspace
+  Updating dir_contents cache for "dune-workspace": Skipped
+  Updating file_digest cache for "dune-workspace": Skipped
+  Updating path_stat cache for "dune-workspace": Updated { changed = false }
+
+Show that Dune ignores "promoted" events. Events for ".#promoted.dune-temp" are
+filtered out by Dune's file watcher and don't show up here. The [path_digest]
+event for [promoted] is more interesting: the file's content did change from "hi"
+to "bye" but Dune subscribed to it *after* making the promotion, precisely to
+avoid unnecessarily restarting after receiving the event that it caused itself.
+
+  $ cat .#debug-output | grep promoted
+  Updating dir_contents cache for "promoted": Skipped
+  Updating file_digest cache for "promoted": Updated { changed = false }
+  Updating path_stat cache for "promoted": Skipped
+
+Show that Dune ignores events for the . directory: [dir_contents] didn't change
+because [promoted] existed before running the build. Also, the subset of fields
+of [path_stat] that matter to Dune didn't change either (the [mtime] field did
+change but [fs_memo] does not provide a way to subscribe to it).
+
+  $ cat .#debug-output | grep '"."'
+  Updating dir_contents cache for ".": Updated { changed = false }
+  Updating file_digest cache for ".": Skipped
+  Updating path_stat cache for ".": Updated { changed = false }