diff --git a/configerator/structs/scm/hg/hgclientconf/hgclient.thrift b/configerator/structs/scm/hg/hgclientconf/hgclient.thrift
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+++ b/configerator/structs/scm/hg/hgclientconf/hgclient.thrift
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+// @generated SignedSource<<01965ea0e1ef6bd5e49df926eac98611>>
+// DO NOT EDIT THIS FILE MANUALLY!
+// This file is a mechanical copy of the version in the configerator repo. To
+// modify it, edit the copy in the configerator repo instead and copy it over by
+// running the following in your fbcode directory:
+//
+// configerator-thrift-updater scm/hg/hgclientconf/hgclient.thrift
+
+namespace py3 configerator
+
+struct TimeShard {
+    1: string start,
+    2: string end,
+}
+
+// Represents a boolean condition that evaluates to true or false.
+// Condition composition can be done via the not, and, and or values.
+// The possible condition values largely conform with the values available in
+// Mercurial configparser crate. Case does not matter.
+// - https://www.internalfb.com/intern/diffusion/FBS/browse/master/fbcode/eden/scm/lib/configparser/src/dynamicconfig.rs
+// - https://www.internalfb.com/intern/diffusion/FBS/browse/master/fbcode/eden/scm/lib/configparser/src/fb/mod.rs
+union Condition {
+    // True if the inner condition is False
+    1: Condition not_condition (rust.box, cpp.ref_type = "unique"),
+    // True if all the inner conditions are True
+    2: list<Condition> and_condition,
+    // True if any of the inner conditions is True
+    3: list<Condition> or_condition,
+    // True if the current repo is one of the listed repos.
+    // Ex: ["fbsource", "www"]
+    4: list<string> repos,
+    // True if the current platform is one of the listed platforms.
+    // Ex: ["osx", "windows", "centos", "fedora", "ubuntu"]
+    5: list<string> platforms,
+    // True if the current domain is one of the listed domains
+    // Ex: ["corp", "prod"]
+    6: list<string> domains,
+    // True if the current host is in one of the listed smc tiers
+    // Ex: ["sys.devservers"]
+    7: list<string> tiers,
+    // True if the current host is one of the listed hosts
+    // Ex: ["devvm1069.prn3.facebook.com"]
+    8: list<string> hosts,
+    // True if the current host is in the given release phase
+    // Ex: "dev", "alpha", "beta", or "stable"
+    9: string group,
+    // True if the current host is in the given shard
+    // Ex: "1", "5", "45", "90", or "100"
+    10: i32 shard,
+    // True if the current user is in the given user shard. User shard is based
+    // off their Mercurial ui.username value.
+    // Ex: "1", "5", "45", "90", or "100"
+    11: i32 user_shard,
+    // True if the current time is within the given time shard. It contains a
+    // start and end date, and more clients return True for this as it gets
+    // closer to the end date. Standard Mercurial date strings are allowed.
+    // Ex: ("June 9, 2020", "June 21, 2020")
+    12: TimeShard time_shard,
+    // True if the current host has one of the listed host prefixes
+    // Ex: ["devvm"]
+    13: list<string> host_prefixes,
+}
+
+struct Hotfix {
+    1: string config,
+    2: Condition condition,
+}
+
+// The various configs that should be applied on Mercurial clients. There are
+// likely to be three types of configs in the long run: hotfixes, features, and
+// raw lua. The order of prededence between them will be such that the most
+// flexible configuration can overwrite the least flexible. So the order they
+// are applied in will be:
+// 1. features
+// 2. hotfixes
+// 3. lua
+struct ClientConfig {
+    // Hotfixes are ordered and configs are applied in order.
+    1: list<Hotfix> hotfixes,
+
+    // Features will be supported later.
+    // A feature is single condition that enables or disables a particular
+    // feature in Mercurial. The actual configs for that feature are in the
+    // client itself, and the feature flag only controls enabling or disabling
+    // the feature, and will likely be controlled via automation.
+    // Roughly equivalent to a Gatekeeper.
+    // Ex: 2: map<string, Condition> features,
+
+    // The features/hotfixes fields facilitate well structured configs and
+    // easy changes via automation. In the future we may want to supplement or
+    // replace it with more powerful raw lua configuration abilities.
+    // Ex: 3: string lua_config,
+}