From 8299032074705defe06b87bd1e4e7a25188a5500 Mon Sep 17 00:00:00 2001
From: Lan Luo <lanl@nvidia.com>
Date: Fri, 22 May 2026 11:18:00 -0700
Subject: [PATCH 1/6] shorten windows dir

---
 .github/scripts/shorten-conda-env-windows.sh | 65 ++++++++++++++++++++
 .github/workflows/build-tensorrt-windows.yml |  3 +
 .github/workflows/build_windows.yml          |  4 ++
 .github/workflows/windows-test.yml           |  4 ++
 4 files changed, 76 insertions(+)
 create mode 100644 .github/scripts/shorten-conda-env-windows.sh

diff --git a/.github/scripts/shorten-conda-env-windows.sh b/.github/scripts/shorten-conda-env-windows.sh
new file mode 100644
index 0000000000..f8bb607663
--- /dev/null
+++ b/.github/scripts/shorten-conda-env-windows.sh
@@ -0,0 +1,65 @@
+#!/usr/bin/env bash
+
+set -euo pipefail
+
+if [[ -z "${CONDA_ENV:-}" ]]; then
+  echo "::error::CONDA_ENV is not set"
+  exit 1
+fi
+
+if [[ -z "${GITHUB_ENV:-}" ]]; then
+  echo "::error::GITHUB_ENV is not set"
+  exit 1
+fi
+
+if ! command -v cygpath >/dev/null 2>&1; then
+  echo "::error::cygpath is required to shorten Windows paths"
+  exit 1
+fi
+
+conda_env="${CONDA_ENV%/}"
+conda_env_name="$(basename "${conda_env}")"
+conda_env_parent="$(dirname "${conda_env}")"
+conda_env_parent_win="$(cygpath -w "${conda_env_parent}")"
+
+if [[ -n "${SHORT_CONDA_DRIVE:-}" ]]; then
+  short_drive="${SHORT_CONDA_DRIVE%:}:"
+else
+  short_drive=""
+  for drive in T S R Q P O N M L K J I H G F E D; do
+    if [[ ! -e "/${drive,,}" ]]; then
+      short_drive="${drive}:"
+      break
+    fi
+  done
+fi
+
+if [[ -z "${short_drive}" ]]; then
+  echo "::error::Could not find an unused drive letter for the Conda env path"
+  exit 1
+fi
+
+if [[ ! "${short_drive}" =~ ^[A-Za-z]:$ ]]; then
+  echo "::error::SHORT_CONDA_DRIVE must be a Windows drive letter like T:"
+  exit 1
+fi
+
+cmd //c "subst ${short_drive} /D >NUL 2>NUL || exit /B 0"
+cmd //c "subst ${short_drive} \"${conda_env_parent_win}\""
+
+short_conda_env="${short_drive}/${conda_env_name}"
+
+{
+  echo "CONDA_ENV=${short_conda_env}"
+  echo "CONDA_RUN=conda run --no-capture-output -p ${short_conda_env}"
+} >> "${GITHUB_ENV}"
+
+if [[ -n "${BUILD_ENV_FILE:-}" && -f "${BUILD_ENV_FILE}" ]]; then
+  {
+    echo "CONDA_ENV=${short_conda_env}"
+    echo "CONDA_RUN=conda run --no-capture-output -p ${short_conda_env}"
+  } >> "${BUILD_ENV_FILE}"
+fi
+
+echo "Mapped ${conda_env_parent_win} to ${short_drive}"
+echo "Using ${short_conda_env} as the Conda environment prefix"
diff --git a/.github/workflows/build-tensorrt-windows.yml b/.github/workflows/build-tensorrt-windows.yml
index b9be0b0530..3c69427a22 100644
--- a/.github/workflows/build-tensorrt-windows.yml
+++ b/.github/workflows/build-tensorrt-windows.yml
@@ -131,6 +131,9 @@ jobs:
           python-version: ${{ env.PYTHON_VERSION }}
           cuda-version: ${{ env.CU_VERSION }}
           arch: ${{ env.ARCH }}
+      - name: Shorten Conda environment path
+        run: |
+          bash "${REPOSITORY}/.github/scripts/shorten-conda-env-windows.sh"
       - name: Install XPU support package
         if: ${{ matrix.gpu_arch_type == 'xpu' }}
         run: |
diff --git a/.github/workflows/build_windows.yml b/.github/workflows/build_windows.yml
index ba5b6ac1a9..5187f6e2a6 100644
--- a/.github/workflows/build_windows.yml
+++ b/.github/workflows/build_windows.yml
@@ -167,6 +167,10 @@ jobs:
           python-version: ${{ env.PYTHON_VERSION }}
           cuda-version: ${{ env.CU_VERSION }}
           arch: ${{ inputs.architecture }}
+      - name: Shorten Conda environment path
+        if: inputs.architecture == 'x64'
+        run: |
+          bash "${REPOSITORY}/.github/scripts/shorten-conda-env-windows.sh"
       - name: Install XPU support package
         if: ${{ matrix.gpu_arch_type == 'xpu' }}
         env:
diff --git a/.github/workflows/windows-test.yml b/.github/workflows/windows-test.yml
index ad17387e7c..0d919ca3c3 100644
--- a/.github/workflows/windows-test.yml
+++ b/.github/workflows/windows-test.yml
@@ -102,6 +102,10 @@ jobs:
           python-version: ${{ env.PYTHON_VERSION }}
           cuda-version: ${{ env.CU_VERSION }}
           arch: ${{ env.ARCH }}
+      - name: Shorten Conda environment path
+        if: inputs.architecture == 'x64'
+        run: |
+          bash "${REPOSITORY}/.github/scripts/shorten-conda-env-windows.sh"
       - name: Run Pre-Script with Caching
         if: ${{ inputs.pre-script != '' }}
         uses: ./test-infra/.github/actions/run-script-with-cache

From d3cfa1030b175a66bdd5ec7590c350e5e944d57c Mon Sep 17 00:00:00 2001
From: Lan Luo <lanl@nvidia.com>
Date: Fri, 22 May 2026 11:50:34 -0700
Subject: [PATCH 2/6] test

---
 .github/scripts/shorten-conda-env-windows.sh | 47 +++++++++++++++-----
 1 file changed, 37 insertions(+), 10 deletions(-)

diff --git a/.github/scripts/shorten-conda-env-windows.sh b/.github/scripts/shorten-conda-env-windows.sh
index f8bb607663..9bc4e2b0ab 100644
--- a/.github/scripts/shorten-conda-env-windows.sh
+++ b/.github/scripts/shorten-conda-env-windows.sh
@@ -17,10 +17,31 @@ if ! command -v cygpath >/dev/null 2>&1; then
   exit 1
 fi
 
+to_windows_path() {
+  local path="${1//\\//}"
+
+  if [[ "${path}" =~ ^[A-Za-z]:/ ]]; then
+    printf "%s\n" "${path//\//\\}"
+  else
+    cygpath -w "${path}"
+  fi
+}
+
+to_bash_path() {
+  local path="${1//\\//}"
+
+  if [[ "${path}" =~ ^([A-Za-z]):(/.*)?$ ]]; then
+    printf "/%s%s\n" "${BASH_REMATCH[1],,}" "${BASH_REMATCH[2]}"
+  else
+    printf "%s\n" "${path}"
+  fi
+}
+
 conda_env="${CONDA_ENV%/}"
-conda_env_name="$(basename "${conda_env}")"
-conda_env_parent="$(dirname "${conda_env}")"
-conda_env_parent_win="$(cygpath -w "${conda_env_parent}")"
+conda_env_bash="$(to_bash_path "${conda_env}")"
+conda_env_name="$(basename "${conda_env_bash}")"
+conda_env_parent="$(dirname "${conda_env_bash}")"
+conda_env_parent_win="$(to_windows_path "${conda_env_parent}")"
 
 if [[ -n "${SHORT_CONDA_DRIVE:-}" ]]; then
   short_drive="${SHORT_CONDA_DRIVE%:}:"
@@ -44,21 +65,27 @@ if [[ ! "${short_drive}" =~ ^[A-Za-z]:$ ]]; then
   exit 1
 fi
 
-cmd //c "subst ${short_drive} /D >NUL 2>NUL || exit /B 0"
-cmd //c "subst ${short_drive} \"${conda_env_parent_win}\""
+MSYS2_ARG_CONV_EXCL='*' cmd.exe /D /S /C "subst ${short_drive} /D >NUL 2>NUL || exit /B 0"
+MSYS2_ARG_CONV_EXCL='*' cmd.exe /D /S /C "subst ${short_drive} \"${conda_env_parent_win}\""
 
 short_conda_env="${short_drive}/${conda_env_name}"
+short_conda_run="conda run --no-capture-output -p ${short_conda_env}"
 
 {
   echo "CONDA_ENV=${short_conda_env}"
-  echo "CONDA_RUN=conda run --no-capture-output -p ${short_conda_env}"
+  echo "CONDA_RUN=${short_conda_run}"
 } >> "${GITHUB_ENV}"
 
-if [[ -n "${BUILD_ENV_FILE:-}" && -f "${BUILD_ENV_FILE}" ]]; then
+build_env_file="${BUILD_ENV_FILE:-}"
+if [[ -n "${build_env_file}" ]]; then
+  build_env_file="$(to_bash_path "${build_env_file}")"
+fi
+
+if [[ -n "${build_env_file}" && -f "${build_env_file}" ]]; then
   {
-    echo "CONDA_ENV=${short_conda_env}"
-    echo "CONDA_RUN=conda run --no-capture-output -p ${short_conda_env}"
-  } >> "${BUILD_ENV_FILE}"
+    printf "export CONDA_ENV=%q\n" "${short_conda_env}"
+    printf "export CONDA_RUN=%q\n" "${short_conda_run}"
+  } >> "${build_env_file}"
 fi
 
 echo "Mapped ${conda_env_parent_win} to ${short_drive}"

From b5457e4dd7d9e096ad52c44c4a8666f1d02daa02 Mon Sep 17 00:00:00 2001
From: Lan Luo <lanl@nvidia.com>
Date: Fri, 22 May 2026 12:15:20 -0700
Subject: [PATCH 3/6] test

---
 .github/scripts/shorten-conda-env-windows.sh | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/.github/scripts/shorten-conda-env-windows.sh b/.github/scripts/shorten-conda-env-windows.sh
index 9bc4e2b0ab..dfea605c5e 100644
--- a/.github/scripts/shorten-conda-env-windows.sh
+++ b/.github/scripts/shorten-conda-env-windows.sh
@@ -65,8 +65,19 @@ if [[ ! "${short_drive}" =~ ^[A-Za-z]:$ ]]; then
   exit 1
 fi
 
-MSYS2_ARG_CONV_EXCL='*' cmd.exe /D /S /C "subst ${short_drive} /D >NUL 2>NUL || exit /B 0"
-MSYS2_ARG_CONV_EXCL='*' cmd.exe /D /S /C "subst ${short_drive} \"${conda_env_parent_win}\""
+SHORT_CONDA_DRIVE="${short_drive}" CONDA_ENV_PARENT_WIN="${conda_env_parent_win}" powershell.exe -NoProfile -ExecutionPolicy Bypass -Command '
+$ErrorActionPreference = "Stop"
+$drive = $env:SHORT_CONDA_DRIVE
+$target = $env:CONDA_ENV_PARENT_WIN
+if (-not (Test-Path -LiteralPath $target -PathType Container)) {
+  throw "Conda env parent path not found: $target"
+}
+& subst.exe $drive /D 2>$null
+& subst.exe $drive $target
+if ($LASTEXITCODE -ne 0) {
+  throw "subst failed to map $drive to $target"
+}
+'
 
 short_conda_env="${short_drive}/${conda_env_name}"
 short_conda_run="conda run --no-capture-output -p ${short_conda_env}"

From e9193505ae66cf09be74f69eac930b688ee9405d Mon Sep 17 00:00:00 2001
From: Lan Luo <lanl@nvidia.com>
Date: Fri, 22 May 2026 12:22:20 -0700
Subject: [PATCH 4/6] test

---
 .github/scripts/shorten-conda-env-windows.sh | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/.github/scripts/shorten-conda-env-windows.sh b/.github/scripts/shorten-conda-env-windows.sh
index dfea605c5e..440461d9cc 100644
--- a/.github/scripts/shorten-conda-env-windows.sh
+++ b/.github/scripts/shorten-conda-env-windows.sh
@@ -65,10 +65,12 @@ if [[ ! "${short_drive}" =~ ^[A-Za-z]:$ ]]; then
   exit 1
 fi
 
-SHORT_CONDA_DRIVE="${short_drive}" CONDA_ENV_PARENT_WIN="${conda_env_parent_win}" powershell.exe -NoProfile -ExecutionPolicy Bypass -Command '
+MSYS2_ARG_CONV_EXCL="*" MSYS2_ENV_CONV_EXCL="CONDA_ENV_PARENT_WIN" SHORT_CONDA_DRIVE="${short_drive}" CONDA_ENV_PARENT_WIN="${conda_env_parent_win}" powershell.exe -NoProfile -ExecutionPolicy Bypass -Command '
 $ErrorActionPreference = "Stop"
 $drive = $env:SHORT_CONDA_DRIVE
 $target = $env:CONDA_ENV_PARENT_WIN
+$target = $target -replace "^[\\/]+(?=[A-Za-z]:[\\/])", ""
+Write-Host "Mapping Conda env parent path: $target"
 if (-not (Test-Path -LiteralPath $target -PathType Container)) {
   throw "Conda env parent path not found: $target"
 }

From ae8339ee3942c462ee82dfbd3b3bf6a51ed09756 Mon Sep 17 00:00:00 2001
From: Lan Luo <lanl@nvidia.com>
Date: Fri, 22 May 2026 15:03:15 -0700
Subject: [PATCH 5/6] test

---
 packaging/pre_build_script_windows.sh | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/packaging/pre_build_script_windows.sh b/packaging/pre_build_script_windows.sh
index 0b52e24064..9698ba07ce 100644
--- a/packaging/pre_build_script_windows.sh
+++ b/packaging/pre_build_script_windows.sh
@@ -1,6 +1,6 @@
 set -x
 
-pip install -U numpy packaging pyyaml setuptools wheel fmt
+python -m pip install -U numpy packaging pyyaml setuptools wheel fmt
 
 choco install bazelisk -y
 
@@ -20,12 +20,13 @@ fi
 TORCH=$(grep "^torch>" py/requirements.txt)
 INDEX_URL=https://download.pytorch.org/whl/${CHANNEL}/${CU_VERSION}
 
-# Install all the dependencies required for Torch-TensorRT
-pip uninstall -y torch torchvision
-pip install --force-reinstall --pre ${TORCH} --index-url ${INDEX_URL}
+# The workflow installs torch before this script runs. Avoid uninstalling and
+# force-reinstalling it here: with the shortened Windows conda prefix, pip can
+# rediscover a half-removed torch dist-info through the original C:\ path.
+python -m pip install --pre "${TORCH}" --index-url "${INDEX_URL}" || exit 1
 
 export CUDA_HOME="$(echo ${CUDA_PATH} | sed -e 's#\\#\/#g')"
-export TORCH_INSTALL_PATH="$(python -c "import torch, os; print(os.path.dirname(torch.__file__))" | sed -e 's#\\#\/#g')"
+export TORCH_INSTALL_PATH="$(python -c "import torch, os; print(os.path.dirname(torch.__file__).replace('\\\\', '/'))")" || exit 1
 
 # tried with conda install -c conda-forge fmt -y, but build still failed in windows with the following error:
 # C:\actions-runner\_work\_temp\conda_environment_18042354682\lib\site-packages\torch\include\torch/csrc/utils/python_arg_parser.h(42): fatal error C1083: Cannot open include file: 'fmt/format.h': No such file or directory

From d7dc38fa74262e95cd0a19f2f5e54b007cafa965 Mon Sep 17 00:00:00 2001
From: Lan Luo <lanl@nvidia.com>
Date: Mon, 25 May 2026 12:26:35 -0700
Subject: [PATCH 6/6] resolve comments

---
 .github/scripts/shorten-conda-env-windows.sh | 25 +++++++++++---------
 1 file changed, 14 insertions(+), 11 deletions(-)

diff --git a/.github/scripts/shorten-conda-env-windows.sh b/.github/scripts/shorten-conda-env-windows.sh
index 440461d9cc..0ff1d2d2d5 100644
--- a/.github/scripts/shorten-conda-env-windows.sh
+++ b/.github/scripts/shorten-conda-env-windows.sh
@@ -37,6 +37,19 @@ to_bash_path() {
   fi
 }
 
+find_unused_drive() {
+  local drive
+
+  for drive in T S R Q P O N M L K J I H G F E D; do
+    if [[ ! -e "/${drive,,}" ]]; then
+      printf "%s:\n" "${drive}"
+      return 0
+    fi
+  done
+
+  return 1
+}
+
 conda_env="${CONDA_ENV%/}"
 conda_env_bash="$(to_bash_path "${conda_env}")"
 conda_env_name="$(basename "${conda_env_bash}")"
@@ -45,17 +58,7 @@ conda_env_parent_win="$(to_windows_path "${conda_env_parent}")"
 
 if [[ -n "${SHORT_CONDA_DRIVE:-}" ]]; then
   short_drive="${SHORT_CONDA_DRIVE%:}:"
-else
-  short_drive=""
-  for drive in T S R Q P O N M L K J I H G F E D; do
-    if [[ ! -e "/${drive,,}" ]]; then
-      short_drive="${drive}:"
-      break
-    fi
-  done
-fi
-
-if [[ -z "${short_drive}" ]]; then
+elif ! short_drive="$(find_unused_drive)"; then
   echo "::error::Could not find an unused drive letter for the Conda env path"
   exit 1
 fi