diff --git a/contrib/automation/hgautomation/linux.py b/contrib/automation/hgautomation/linux.py
--- a/contrib/automation/hgautomation/linux.py
+++ b/contrib/automation/hgautomation/linux.py
@@ -75,7 +75,7 @@
 sudo -H -u hg -g hg /home/hg/.cargo/bin/rustup install 1.31.1 1.46.0
 sudo -H -u hg -g hg /home/hg/.cargo/bin/rustup component add clippy
 
-sudo -H -u hg -g hg /home/hg/.cargo/bin/cargo install --version 0.7.0 pyoxidizer
+sudo -H -u hg -g hg /home/hg/.cargo/bin/cargo install --git https://github.com/indygreg/PyOxidizer.git --rev 4697fb25918dfad6dc73288daeea501063963a08 pyoxidizer
 '''
 
 
diff --git a/contrib/install-windows-dependencies.ps1 b/contrib/install-windows-dependencies.ps1
--- a/contrib/install-windows-dependencies.ps1
+++ b/contrib/install-windows-dependencies.ps1
@@ -130,7 +130,7 @@
     Invoke-Process "${prefix}\cargo\bin\rustup.exe" "component add clippy"
 
     # Install PyOxidizer for packaging.
-    Invoke-Process "${prefix}\cargo\bin\cargo.exe" "install --version 0.7.0 pyoxidizer"
+    Invoke-Process "${prefix}\cargo\bin\cargo.exe" "install --git https://github.com/indygreg/PyOxidizer.git --rev 4697fb25918dfad6dc73288daeea501063963a08 pyoxidizer"
 }
 
 function Install-Dependencies($prefix) {
diff --git a/contrib/packaging/hgpackaging/pyoxidizer.py b/contrib/packaging/hgpackaging/pyoxidizer.py
--- a/contrib/packaging/hgpackaging/pyoxidizer.py
+++ b/contrib/packaging/hgpackaging/pyoxidizer.py
@@ -42,10 +42,10 @@
 ]
 
 STAGING_RULES_APP = [
-    ('mercurial/helptext/**/*.txt', 'helptext/'),
-    ('mercurial/defaultrc/*.rc', 'defaultrc/'),
-    ('mercurial/locale/**/*', 'locale/'),
-    ('mercurial/templates/**/*', 'templates/'),
+    ('lib/mercurial/helptext/**/*.txt', 'helptext/'),
+    ('lib/mercurial/defaultrc/*.rc', 'defaultrc/'),
+    ('lib/mercurial/locale/**/*', 'locale/'),
+    ('lib/mercurial/templates/**/*', 'templates/'),
 ]
 
 STAGING_EXCLUDES_WINDOWS = [
@@ -109,11 +109,9 @@
     # Now assemble all the files from PyOxidizer into the staging directory.
     shutil.copytree(build_dir, out_dir)
 
-    # Move some of those files around.
+    # Move some of those files around. We can get rid of this once Mercurial
+    # is taught to use the importlib APIs for reading resources.
     process_install_rules(STAGING_RULES_APP, build_dir, out_dir)
-    # Nuke the mercurial/* directory, as we copied resources
-    # to an appropriate location just above.
-    shutil.rmtree(out_dir / "mercurial")
 
     # We also need to run setup.py build_doc to produce html files,
     # as they aren't built as part of ``pip install``.
diff --git a/rust/hgcli/Cargo.lock b/rust/hgcli/Cargo.lock
--- a/rust/hgcli/Cargo.lock
+++ b/rust/hgcli/Cargo.lock
@@ -2,7 +2,7 @@
 # It is not intended for manual editing.
 [[package]]
 name = "aho-corasick"
-version = "0.7.10"
+version = "0.7.13"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "memchr 2.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -10,12 +10,25 @@
 
 [[package]]
 name = "anyhow"
-version = "1.0.28"
+version = "1.0.32"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "autocfg"
-version = "1.0.0"
+version = "1.0.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "base64"
+version = "0.10.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "byteorder 1.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "base64"
+version = "0.12.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
@@ -25,7 +38,7 @@
 
 [[package]]
 name = "cc"
-version = "1.0.50"
+version = "1.0.60"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
@@ -34,28 +47,55 @@
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
+name = "charset"
+version = "0.1.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "base64 0.10.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "encoding_rs 0.8.24 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
 name = "cpython"
-version = "0.4.1"
-source = "git+https://github.com/dgrunwald/rust-cpython?rev=387e87d9deb6b678508888239f9f87dc36973d3f#387e87d9deb6b678508888239f9f87dc36973d3f"
+version = "0.5.0"
+source = "git+https://github.com/dgrunwald/rust-cpython.git?rev=4283acd94f4e794fe03679efc7a6c18bc50938a8#4283acd94f4e794fe03679efc7a6c18bc50938a8"
 dependencies = [
- "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
- "num-traits 0.2.11 (registry+https://github.com/rust-lang/crates.io-index)",
- "paste 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)",
- "python3-sys 0.4.1 (git+https://github.com/dgrunwald/rust-cpython?rev=387e87d9deb6b678508888239f9f87dc36973d3f)",
+ "libc 0.2.78 (registry+https://github.com/rust-lang/crates.io-index)",
+ "num-traits 0.2.12 (registry+https://github.com/rust-lang/crates.io-index)",
+ "paste 0.1.18 (registry+https://github.com/rust-lang/crates.io-index)",
+ "python3-sys 0.5.0 (git+https://github.com/dgrunwald/rust-cpython.git?rev=4283acd94f4e794fe03679efc7a6c18bc50938a8)",
+]
+
+[[package]]
+name = "either"
+version = "1.6.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "encoding_rs"
+version = "0.8.24"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "cfg-if 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "fs_extra"
-version = "1.1.0"
+version = "1.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "fuchsia-cprng"
+version = "0.1.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "getrandom"
-version = "0.1.14"
+version = "0.1.15"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "cfg-if 0.1.10 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.78 (registry+https://github.com/rust-lang/crates.io-index)",
  "wasi 0.9.0+wasi-snapshot-preview1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
@@ -64,7 +104,15 @@
 version = "0.1.0"
 dependencies = [
  "jemallocator-global 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "pyembed 0.7.0-pre (git+https://github.com/indygreg/PyOxidizer.git?rev=c772a1379c3026314eda1c8ea244b86c0658951d)",
+ "pyembed 0.8.0-pre (git+https://github.com/indygreg/PyOxidizer.git?rev=4697fb25918dfad6dc73288daeea501063963a08)",
+]
+
+[[package]]
+name = "itertools"
+version = "0.9.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "either 1.6.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -72,9 +120,9 @@
 version = "0.3.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "cc 1.0.50 (registry+https://github.com/rust-lang/crates.io-index)",
- "fs_extra 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cc 1.0.60 (registry+https://github.com/rust-lang/crates.io-index)",
+ "fs_extra 1.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.78 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -83,7 +131,7 @@
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "jemalloc-sys 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.78 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -102,110 +150,147 @@
 
 [[package]]
 name = "libc"
-version = "0.2.68"
+version = "0.2.78"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
+name = "mailparse"
+version = "0.13.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "base64 0.12.3 (registry+https://github.com/rust-lang/crates.io-index)",
+ "charset 0.1.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "quoted_printable 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
 name = "memchr"
 version = "2.3.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
+name = "memmap"
+version = "0.7.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "libc 0.2.78 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
 name = "memory-module-sys"
 version = "0.3.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "cc 1.0.50 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
- "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cc 1.0.60 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.78 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "num-traits"
-version = "0.2.11"
+version = "0.2.12"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "autocfg 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "autocfg 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "paste"
-version = "0.1.9"
+version = "0.1.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "paste-impl 0.1.9 (registry+https://github.com/rust-lang/crates.io-index)",
- "proc-macro-hack 0.5.15 (registry+https://github.com/rust-lang/crates.io-index)",
+ "paste-impl 0.1.18 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro-hack 0.5.18 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "paste-impl"
-version = "0.1.9"
+version = "0.1.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "proc-macro-hack 0.5.15 (registry+https://github.com/rust-lang/crates.io-index)",
- "proc-macro2 1.0.10 (registry+https://github.com/rust-lang/crates.io-index)",
- "quote 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "syn 1.0.17 (registry+https://github.com/rust-lang/crates.io-index)",
+ "proc-macro-hack 0.5.18 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "ppv-lite86"
-version = "0.2.6"
+version = "0.2.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "proc-macro-hack"
-version = "0.5.15"
+version = "0.5.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
-name = "proc-macro2"
-version = "1.0.10"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-dependencies = [
- "unicode-xid 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
-]
-
-[[package]]
 name = "pyembed"
-version = "0.7.0-pre"
-source = "git+https://github.com/indygreg/PyOxidizer.git?rev=c772a1379c3026314eda1c8ea244b86c0658951d#c772a1379c3026314eda1c8ea244b86c0658951d"
+version = "0.8.0-pre"
+source = "git+https://github.com/indygreg/PyOxidizer.git?rev=4697fb25918dfad6dc73288daeea501063963a08#4697fb25918dfad6dc73288daeea501063963a08"
 dependencies = [
- "cpython 0.4.1 (git+https://github.com/dgrunwald/rust-cpython?rev=387e87d9deb6b678508888239f9f87dc36973d3f)",
+ "anyhow 1.0.32 (registry+https://github.com/rust-lang/crates.io-index)",
+ "cpython 0.5.0 (git+https://github.com/dgrunwald/rust-cpython.git?rev=4283acd94f4e794fe03679efc7a6c18bc50938a8)",
  "jemalloc-sys 0.3.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.78 (registry+https://github.com/rust-lang/crates.io-index)",
+ "memmap 0.7.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "memory-module-sys 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
- "python-packed-resources 0.1.0-pre (git+https://github.com/indygreg/PyOxidizer.git?rev=c772a1379c3026314eda1c8ea244b86c0658951d)",
- "python3-sys 0.4.1 (git+https://github.com/dgrunwald/rust-cpython?rev=387e87d9deb6b678508888239f9f87dc36973d3f)",
+ "python-packaging 0.1.0-pre (git+https://github.com/indygreg/PyOxidizer.git?rev=4697fb25918dfad6dc73288daeea501063963a08)",
+ "python-packed-resources 0.2.0-pre (git+https://github.com/indygreg/PyOxidizer.git?rev=4697fb25918dfad6dc73288daeea501063963a08)",
+ "python3-sys 0.5.0 (git+https://github.com/dgrunwald/rust-cpython.git?rev=4283acd94f4e794fe03679efc7a6c18bc50938a8)",
  "uuid 0.8.1 (registry+https://github.com/rust-lang/crates.io-index)",
- "winapi 0.3.8 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "python-packaging"
+version = "0.1.0-pre"
+source = "git+https://github.com/indygreg/PyOxidizer.git?rev=4697fb25918dfad6dc73288daeea501063963a08#4697fb25918dfad6dc73288daeea501063963a08"
+dependencies = [
+ "anyhow 1.0.32 (registry+https://github.com/rust-lang/crates.io-index)",
+ "byteorder 1.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
+ "encoding_rs 0.8.24 (registry+https://github.com/rust-lang/crates.io-index)",
+ "itertools 0.9.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "lazy_static 1.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "mailparse 0.13.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "python-packed-resources 0.2.0-pre (git+https://github.com/indygreg/PyOxidizer.git?rev=4697fb25918dfad6dc73288daeea501063963a08)",
+ "regex 1.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "tempdir 0.3.7 (registry+https://github.com/rust-lang/crates.io-index)",
+ "walkdir 2.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "python-packed-resources"
-version = "0.1.0-pre"
-source = "git+https://github.com/indygreg/PyOxidizer.git?rev=c772a1379c3026314eda1c8ea244b86c0658951d#c772a1379c3026314eda1c8ea244b86c0658951d"
+version = "0.2.0-pre"
+source = "git+https://github.com/indygreg/PyOxidizer.git?rev=4697fb25918dfad6dc73288daeea501063963a08#4697fb25918dfad6dc73288daeea501063963a08"
 dependencies = [
- "anyhow 1.0.28 (registry+https://github.com/rust-lang/crates.io-index)",
+ "anyhow 1.0.32 (registry+https://github.com/rust-lang/crates.io-index)",
  "byteorder 1.3.4 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "python3-sys"
-version = "0.4.1"
-source = "git+https://github.com/dgrunwald/rust-cpython?rev=387e87d9deb6b678508888239f9f87dc36973d3f#387e87d9deb6b678508888239f9f87dc36973d3f"
+version = "0.5.0"
+source = "git+https://github.com/dgrunwald/rust-cpython.git?rev=4283acd94f4e794fe03679efc7a6c18bc50938a8#4283acd94f4e794fe03679efc7a6c18bc50938a8"
 dependencies = [
- "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
- "regex 1.3.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.78 (registry+https://github.com/rust-lang/crates.io-index)",
+ "regex 1.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
-name = "quote"
-version = "1.0.3"
+name = "quoted_printable"
+version = "0.4.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "rand"
+version = "0.4.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "proc-macro2 1.0.10 (registry+https://github.com/rust-lang/crates.io-index)",
+ "fuchsia-cprng 0.1.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.78 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rand_core 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rdrand 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -213,8 +298,8 @@
 version = "0.7.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "getrandom 0.1.14 (registry+https://github.com/rust-lang/crates.io-index)",
- "libc 0.2.68 (registry+https://github.com/rust-lang/crates.io-index)",
+ "getrandom 0.1.15 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.78 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand_chacha 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand_core 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand_hc 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -225,16 +310,29 @@
 version = "0.2.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "ppv-lite86 0.2.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "ppv-lite86 0.2.9 (registry+https://github.com/rust-lang/crates.io-index)",
  "rand_core 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "rand_core"
+version = "0.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "rand_core 0.4.2 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "rand_core"
+version = "0.4.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
+[[package]]
+name = "rand_core"
 version = "0.5.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "getrandom 0.1.14 (registry+https://github.com/rust-lang/crates.io-index)",
+ "getrandom 0.1.15 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -246,29 +344,52 @@
 ]
 
 [[package]]
-name = "regex"
-version = "1.3.6"
+name = "rdrand"
+version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "aho-corasick 0.7.10 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rand_core 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "regex"
+version = "1.3.9"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "aho-corasick 0.7.13 (registry+https://github.com/rust-lang/crates.io-index)",
  "memchr 2.3.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "regex-syntax 0.6.17 (registry+https://github.com/rust-lang/crates.io-index)",
+ "regex-syntax 0.6.18 (registry+https://github.com/rust-lang/crates.io-index)",
  "thread_local 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
 name = "regex-syntax"
-version = "0.6.17"
+version = "0.6.18"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
-name = "syn"
-version = "1.0.17"
+name = "remove_dir_all"
+version = "0.5.3"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
- "proc-macro2 1.0.10 (registry+https://github.com/rust-lang/crates.io-index)",
- "quote 1.0.3 (registry+https://github.com/rust-lang/crates.io-index)",
- "unicode-xid 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "same-file"
+version = "1.0.6"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "winapi-util 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "tempdir"
+version = "0.3.7"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "rand 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "remove_dir_all 0.5.3 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -280,11 +401,6 @@
 ]
 
 [[package]]
-name = "unicode-xid"
-version = "0.2.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-
-[[package]]
 name = "uuid"
 version = "0.8.1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
@@ -293,13 +409,23 @@
 ]
 
 [[package]]
+name = "walkdir"
+version = "2.3.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "same-file 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
+ "winapi-util 0.1.5 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
 name = "wasi"
 version = "0.9.0+wasi-snapshot-preview1"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
 name = "winapi"
-version = "0.3.8"
+version = "0.3.9"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 dependencies = [
  "winapi-i686-pc-windows-gnu 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -312,48 +438,72 @@
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
 [[package]]
+name = "winapi-util"
+version = "0.1.5"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "winapi 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
 name = "winapi-x86_64-pc-windows-gnu"
 version = "0.4.0"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
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diff --git a/rust/hgcli/Cargo.toml b/rust/hgcli/Cargo.toml
--- a/rust/hgcli/Cargo.toml
+++ b/rust/hgcli/Cargo.toml
@@ -13,7 +13,11 @@
 
 [dependencies]
 jemallocator-global = { version = "0.3", optional = true }
-pyembed = { git = "https://github.com/indygreg/PyOxidizer.git", rev = "c772a1379c3026314eda1c8ea244b86c0658951d", default-features=false }
+
+[dependencies.pyembed]
+git = "https://github.com/indygreg/PyOxidizer.git"
+rev = "4697fb25918dfad6dc73288daeea501063963a08"
+default-features = false
 
 [features]
 default = ["build-mode-pyoxidizer-exe"]
diff --git a/rust/hgcli/pyoxidizer.bzl b/rust/hgcli/pyoxidizer.bzl
--- a/rust/hgcli/pyoxidizer.bzl
+++ b/rust/hgcli/pyoxidizer.bzl
@@ -1,5 +1,7 @@
 ROOT = CWD + "/../.."
 
+IS_WINDOWS = "windows" in BUILD_TARGET_TRIPLE
+
 # Code to run in Python interpreter.
 RUN_CODE = "import hgdemandimport; hgdemandimport.enable(); from mercurial import dispatch; dispatch.run()"
 
@@ -11,8 +13,35 @@
 def make_distribution_windows():
     return default_python_distribution(flavor = "standalone_dynamic")
 
+def resource_callback(policy, resource):
+    # We use a custom resource routing policy to influence where things are loaded
+    # from.
+    #
+    # For Python modules and resources, we load from memory if they are in
+    # the standard library and from the filesystem if not. This is because
+    # parts of Mercurial and some 3rd party packages aren't yet compatible
+    # with memory loading.
+    #
+    # For Python extension modules, we load from the filesystem because
+    # this yields greatest compatibility.
+    if type(resource) in ("PythonModuleSource", "PythonPackageResource", "PythonPackageDistributionResource"):
+        if resource.is_stdlib:
+            resource.add_location = "in-memory"
+        else:
+            resource.add_location = "filesystem-relative:lib"
+
+    elif type(resource) == "PythonExtensionModule":
+        resource.add_location = "filesystem-relative:lib"
+
 def make_exe(dist):
     """Builds a Rust-wrapped Mercurial binary."""
+    packaging_policy = dist.make_python_packaging_policy()
+    # Extension may depend on any Python functionality. Include all
+    # extensions.
+    packaging_policy.extension_module_filter = "all"
+    packaging_policy.resources_policy = "prefer-in-memory-fallback-filesystem-relative:lib"
+    packaging_policy.register_resource_callback(resource_callback)
+
     config = PythonInterpreterConfig(
         raw_allocator = "system",
         run_eval = RUN_CODE,
@@ -25,37 +54,17 @@
 
     exe = dist.to_python_executable(
         name = "hg",
-        resources_policy = "prefer-in-memory-fallback-filesystem-relative:lib",
+        packaging_policy = packaging_policy,
         config = config,
-        # Extension may depend on any Python functionality. Include all
-        # extensions.
-        extension_module_filter = "all",
     )
 
     # Add Mercurial to resources.
-    for resource in dist.pip_install(["--verbose", ROOT]):
-        # This is a bit wonky and worth explaining.
-        #
-        # Various parts of Mercurial don't yet support loading package
-        # resources via the ResourceReader interface. Or, not having
-        # file-based resources would be too inconvenient for users.
-        #
-        # So, for package resources, we package them both in the
-        # filesystem as well as in memory. If both are defined,
-        # PyOxidizer will prefer the in-memory location. So even
-        # if the filesystem file isn't packaged in the location
-        # specified here, we should never encounter an errors as the
-        # resource will always be available in memory.
-        if type(resource) == "PythonPackageResource":
-            exe.add_filesystem_relative_python_resource(".", resource)
-            exe.add_in_memory_python_resource(resource)
-        else:
-            exe.add_python_resource(resource)
+    exe.add_python_resources(exe.pip_install(["--verbose", ROOT]))
 
     # On Windows, we install extra packages for convenience.
-    if "windows" in BUILD_TARGET_TRIPLE:
+    if IS_WINDOWS:
         exe.add_python_resources(
-            dist.pip_install(["-r", ROOT + "/contrib/packaging/requirements_win32.txt"]),
+            exe.pip_install(["-r", ROOT + "/contrib/packaging/requirements_win32.txt"]),
         )
 
     return exe
@@ -95,4 +104,5 @@
 # Everything below this is typically managed by PyOxidizer and doesn't need
 # to be updated by people.
 
-PYOXIDIZER_VERSION = "0.7.0"
+PYOXIDIZER_VERSION = "0.8.0-pre"
+PYOXIDIZER_COMMIT = "4697fb25918dfad6dc73288daeea501063963a08"