From faf6ea2675f8793412f78ef9ac3c35d8b6b3d2b3 Mon Sep 17 00:00:00 2001
From: Sebastian Pfitzner <pfitzseb@gmail.com>
Date: Fri, 3 Jul 2026 12:48:02 +0000
Subject: [PATCH] fix: evict memoized derived values when files are removed
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Removing a file only deleted its inputs; every derived value keyed by the
URI (parse trees, diagnostics, testitems, ...) stayed in the Salsa storage
for the lifetime of the workspace — measured at ~1.5 MB retained per
removed file. Use the new Salsa.evict_derived! to drop all entries keyed by
removed URIs in remove_file!, remove_all_children! (batched per call), and
clear_indirect_file!.

The promotion path in add_file! (indirect file becoming a regular file)
deliberately does not evict: the URI stays live and its derived values
revalidate through normal Salsa invalidation.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
---
 src/public.jl         | 16 +++++++++++++
 test/test_eviction.jl | 55 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 71 insertions(+)
 create mode 100644 test/test_eviction.jl

diff --git a/src/public.jl b/src/public.jl
index 13f09634..2fa39089 100644
--- a/src/public.jl
+++ b/src/public.jl
@@ -263,9 +263,20 @@ function remove_file!(jw::JuliaWorkspace, uri::URI)
 
     process_from_dynamic(jw)
     _remove_file!(jw, uri)
+    _evict_derived_for_uris!(jw, (uri,))
     _reconcile!(jw)
 end
 
+# Evict all memoized derived values keyed by any of the given (removed) URIs.
+# Without this they would stay in the Salsa storage for the lifetime of the
+# workspace, since nothing queries a removed URI again.
+function _evict_derived_for_uris!(jw::JuliaWorkspace, uris)
+    uri_set = Set{URI}(uris)
+    Salsa.evict_derived!(jw.runtime) do key
+        any(arg -> arg isa URI && arg in uri_set, key.args)
+    end
+end
+
 # Input-only removal. Does not drain results or reconcile.
 function _remove_file!(jw::JuliaWorkspace, uri::URI)
     files = input_files(jw.runtime)
@@ -293,14 +304,18 @@ function remove_all_children!(jw::JuliaWorkspace, uri::URI)
 
     uri_as_string = string(uri)
 
+    removed = URI[]
     for file in files
         file_as_string = string(file)
 
         if startswith(file_as_string, uri_as_string)
             _remove_file!(jw, file)
+            push!(removed, file)
         end
     end
 
+    isempty(removed) || _evict_derived_for_uris!(jw, removed)
+
     _reconcile!(jw)
 end
 
@@ -346,6 +361,7 @@ function clear_indirect_file!(jw::JuliaWorkspace, uri::URI)
     process_from_dynamic(jw)
 
     _clear_indirect_tracking!(jw, uri)
+    _evict_derived_for_uris!(jw, (uri,))
 
     _reconcile!(jw)
 end
diff --git a/test/test_eviction.jl b/test/test_eviction.jl
new file mode 100644
index 00000000..796133d8
--- /dev/null
+++ b/test/test_eviction.jl
@@ -0,0 +1,55 @@
+@testitem "remove_file! evicts derived values for the removed URI" begin
+    using JuliaWorkspaces.URIs2: URI
+    using JuliaWorkspaces: Salsa
+
+    n_entries_for(jw, uri) =
+        Salsa.evict_derived!(key -> any(arg -> isequal(arg, uri), key.args), jw.runtime)
+
+    uri1 = URI("file:///evicttest/src/a.jl")
+    uri2 = URI("file:///evicttest/src/b.jl")
+
+    jw = JuliaWorkspace()
+    add_file!(jw, TextFile(uri1, SourceText("f(x) = x + 1", "julia")))
+    add_file!(jw, TextFile(uri2, SourceText("g(x) = x - 1", "julia")))
+
+    # Populate the derived caches.
+    get_diagnostic(jw, uri1)
+    get_diagnostic(jw, uri2)
+
+    remove_file!(jw, uri1)
+
+    # No derived entry may still be keyed by the removed URI. (The probe uses
+    # evict_derived! itself: it returns the number of matching entries.)
+    @test n_entries_for(jw, uri1) == 0
+
+    # The surviving file is untouched and still queryable.
+    @test get_diagnostic(jw, uri2) isa Vector
+    @test has_file(jw, uri2)
+end
+
+@testitem "remove_all_children! evicts derived values for all removed URIs" begin
+    using JuliaWorkspaces.URIs2: URI
+    using JuliaWorkspaces: Salsa
+
+    n_entries_for(jw, uri) =
+        Salsa.evict_derived!(key -> any(arg -> isequal(arg, uri), key.args), jw.runtime)
+
+    uris = [URI("file:///evictfolder/src/f$i.jl") for i in 1:5]
+    outside = URI("file:///other/src/g.jl")
+
+    jw = JuliaWorkspace()
+    for uri in uris
+        add_file!(jw, TextFile(uri, SourceText("h(x) = x", "julia")))
+    end
+    add_file!(jw, TextFile(outside, SourceText("h(x) = x", "julia")))
+
+    get_diagnostics(jw)
+
+    remove_all_children!(jw, URI("file:///evictfolder"))
+
+    for uri in uris
+        @test n_entries_for(jw, uri) == 0
+    end
+    @test has_file(jw, outside)
+    @test get_diagnostic(jw, outside) isa Vector
+end