test: show idents stamps are refreshed

Author: trefis

tests/dune.inc

@@ -1546,6 +1546,23 @@
          (diff? %{t} %{t}.corrected)))))))
 (alias (name runtest) (deps (alias typer-cache-load_path-test)))
 
+(alias
+ (name typer-cache-stamps-test)
+ (package merlin)
+ (deps (:t ./test-dirs/typer-cache/stamps/test.t)
+       (source_tree ./test-dirs/typer-cache/stamps)
+       %{bin:ocamlmerlin}
+       %{bin:ocamlmerlin-server}
+       %{bin:dot-merlin-reader})
+ (action
+   (chdir ./test-dirs/typer-cache/stamps
+     (setenv MERLIN %{exe:merlin-wrapper}
+     (setenv OCAMLC %{ocamlc}
+       (progn
+         (run %{bin:mdx} test --syntax=cram %{t})
+         (diff? %{t} %{t}.corrected)))))))
+(alias (name runtest) (deps (alias typer-cache-stamps-test)))
+
 (alias
  (name warnings-backtrack)
  (package merlin)

tests/test-dirs/typer-cache/stamps/test.t

@@ -0,0 +1,38 @@
+The server might already be running, we kill it to make sure we start from a
+clean slate:
+
+  $ $MERLIN server stop-server
+
+Then we can look at identifier stamps and whether they are being reset between
+buffers, and different runs for the same buffer:
+
+  $ echo "let f x = x" | \
+  > $MERLIN server dump -what browse -filename test.ml | \
+  > sed 's:\\n:\n:g' | grep Tpat_var
+    Tpat_var \"f/80\"
+    Tpat_var \"x/82\"
+
+  $ echo "let f x = let () = () in x" | \
+  > $MERLIN server dump -what browse -filename test.ml | \
+  > sed 's:\\n:\n:g' | grep Tpat_var
+    Tpat_var \"f/83\"
+    Tpat_var \"x/85\"
+
+  $ echo "let f x = x" | \
+  > $MERLIN server dump -what browse -filename other_test.ml | \
+  > sed 's:\\n:\n:g' | grep Tpat_var
+    Tpat_var \"f/80\"
+    Tpat_var \"x/82\"
+
+  $ echo "let f x = let () = () in x" | \
+  > $MERLIN server dump -what browse -filename test.ml | \
+  > sed 's:\\n:\n:g' | grep Tpat_var
+    Tpat_var \"f/80\"
+    Tpat_var \"x/82\"
+
+  $ echo "let f x = x" | \
+  > $MERLIN server dump -what browse -filename test.ml | \
+  > sed 's:\\n:\n:g' | grep Tpat_var
+    Tpat_var \"f/83\"
+    Tpat_var \"x/85\"
+