fix: recognize DEV-version files that need serialization upgrade

src/Serialization/Upgrades/main.jl

@@ -195,13 +195,15 @@ function upgrade_recursive(upgrade::Function, s::UpgradeState, dict::AbstractDic
   elseif type_name == "Tuple"
     upgraded_entries = Dict{Symbol, Any}[]
     upgraded_entry = nothing
+
+    # catch empty tuples here before zip
+    !haskey(dict, :data) && return dict
     for (type, entry) in zip(dict[:_type][:params], dict[:data])
       upgraded_entry = upgrade(s, Dict{Symbol, Any}(:_type => type, :data => entry))
       push!(upgraded_entries, upgraded_entry)
     end
     dict[:_type][:params] = [u_e[:_type] for u_e in upgraded_entries]
     dict[:data] = [u_e[:data] for u_e in upgraded_entries]
-
   elseif type_name == "NamedTuple"
     upgraded_entries = Dict{Symbol, Any}[]
     upgraded_entry = nothing
@@ -314,6 +316,32 @@ include("1.8.0+1.jl")
 const upgrade_scripts = collect(upgrade_scripts_set)
 sort!(upgrade_scripts; by=version)
 
+# For DEV versions like "1.8.0-DEV-1-hash", the n_upgrades count tells us how many
+# upgrade scripts for that base version existed when the file was saved — meaning those
+# scripts were already applied. Map to the version of the n-th script so upgrade()
+# correctly skips already-applied scripts.
+#
+# Julia parses "1.8.0-DEV-1-hash" with prerelease = ("DEV-1-hash",) as a single
+# identifier, so we split on "-" to extract n_upgrades.
+function effective_upgrade_version(format_version::VersionNumber)
+  pre = format_version.prerelease
+  isempty(pre) && return format_version
+
+  # pre[1] has format "DEV-<n_upgrades>-<hash>" or "DEV-<hash>" (n_upgrades=0)
+  pre_str = string(only(pre))
+  startswith(pre_str, "DEV-") || return format_version
+
+  parts = split(pre_str, "-")
+  length(parts) < 3 && return format_version  # no n_upgrades encoded
+
+  n_upgrades = tryparse(Int, string(parts[2]))
+  (isnothing(n_upgrades) || iszero(n_upgrades)) && return format_version
+
+  base = Base.thispatch(format_version)
+  base_num = findfirst(s -> version(s) == base, upgrade_scripts)
+  return version(upgrade_scripts[base_num+n_upgrades-1])
+end
+
 ################################################################################
 # Loading with upgrade checks on dict
 const backref_sym = Symbol("#backref")
@@ -327,9 +355,10 @@ has been achieved.
 """
 function upgrade(format_version::VersionNumber, dict::AbstractDict{Symbol, Any})
   upgraded_dict = dict
+  eff_version = effective_upgrade_version(format_version)
   for upgrade_script in upgrade_scripts
     script_version = version(upgrade_script)
-    if format_version < script_version
+    if eff_version < script_version
       # TODO: use a macro from Hecke that will allow user to suppress
       # such a message
       @debug("upgrading serialized data....",

src/Serialization/main.jl

@@ -893,7 +893,12 @@ function load(io::IO; params::Any = nothing, type::Any = nothing,
   file_version = load_node(s) do obj
     serialization_version_info(obj)
   end
-  if file_version < VERSION_NUMBER
+  # A file needs upgrading iff some upgrade script targets a version newer than the
+  # file's effective version. Gate on the newest upgrade script rather than on
+  # VERSION_NUMBER: for DEV builds the file's version string carries a commit hash
+  # (e.g. "1.8.0-DEV-<hash>"), and comparing that against VERSION_NUMBER orders the two
+  # by hash characters rather than by upgrade state, which can wrongly skip upgrades.
+  if effective_upgrade_version(file_version) < version(last(upgrade_scripts))
     # we need a mutable dictionary
     jsondict = copy(s.obj)
     jsondict = upgrade(file_version, jsondict)

test/Serialization/upgrades/setup_tests.jl

@@ -9,7 +9,7 @@ if !isdefined(Main, :serialization_upgrade_test_path) ||
   !isfile(joinpath(Main.serialization_upgrade_test_path, "LICENSE.md"))
 
 
-  serialization_upgrade_test_path = let commit_hash = "e3473ad614217bc19fad7f809de2d863984be157"
+  serialization_upgrade_test_path = let commit_hash = "46416710289058b38fd69fecb0809905e7b667bb"
     tarball = Downloads.download("https://github.com/oscar-system/serialization-upgrade-tests/archive/$(commit_hash).tar.gz")
 
     destpath = open(CodecZlib.GzipDecompressorStream, tarball) do io