GHA/windows: replace GfW with MSYS2 runtime downgrade

We recently switched to a known good version of Git for Windows to avoid
the MSYS2/Cygwin runtime performance regression.

MSYS2 is closer to the source of the MSYS2/Cygwin projects. Its known
good version is newer. Installing the downgrade is faster and safer. It
also allows to restore the scripts to their original iteration, making
the workaround easier to drop once the perf issue is fixed upstream.

Therefore, switch back to using MSYS2, and install the runtime downgrade
before running curl tests.

Also disable `pacman`'s `CheckSpace` for best performance.

Jeremy identified to the root cause of the perf regression in this
Cygwin commit (from 2024-09-17):
https://cygwin.com/git/?p=newlib-cygwin.git;a=commit;h=c7fe29f5cb85242ae2607945762f7e0b9af02513

Co-authored-by: Jeremy Drake
Patch: https://github.com/jeremyd2019/curl/commit/95a404e19ae03ba8d35089e66d9690e3a4f11b7c
Ref: https://github.com/curl/curl/pull/16217#issuecomment-2673158597
Ref: https://github.com/curl/curl/pull/16217#issuecomment-2673461330

Follow-up to 116950a25066257f86461f9d1dfa5f787f55e73c #16265
Follow-up to 1bf774df57e873d08f0c6e525e6ec3a0f6e62bce #16217
Follow-up to 5f9411f953f35ca84645b5a6824fb9fef20887ed #15380

Closes #16424

diff --git a/.github/workflows/windows.yml b/.github/workflows/windows.yml
index 9b4abe7c3adb52babe1bc0daf6103f8dd9d4aa09..8176b3b9841cf4a2a7a419b2c2c2dcd2f0b5c700 100644 (file)
--- a/.github/workflows/windows.yml
+++ b/.github/workflows/windows.yml
@@ -369,7 +369,7 @@ jobs:
     timeout-minutes: 20
     defaults:
       run:
-        shell: ${{ matrix.tflags != 'skipall' && matrix.tflags != 'skiprun' && 'C:\_gfw\usr\bin\bash.exe {0}' || 'C:\msys64\usr\bin\bash.exe {0}' }}
+        shell: C:\msys64\usr\bin\bash.exe {0}
     strategy:
       matrix:
         include:
@@ -396,21 +396,6 @@ jobs:
             tflags: 'skiprun'
       fail-fast: false
     steps:
-      - name: 'install Git for Windows'
-        if: ${{ matrix.tflags != 'skipall' && matrix.tflags != 'skiprun' }}
-        shell: bash
-        timeout-minutes: 5
-        run: |
-          mkdir /c/_gfw
-          cd /c/_gfw || exit 1
-          # The last known good Perl version (as of v2.47.1.windows.2) without pipe/signal MSYS2
-          # runtime (?) regressions that cause runtests.pl to run at 2.5x reduced speed, is this:
-          #   https://github.com/git-for-windows/git/releases/tag/v2.46.2.windows.1
-          curl --disable --fail --silent --show-error --connect-timeout 15 --max-time 120 --retry 3 \
-            --location https://github.com/git-for-windows/git/releases/download/v2.46.2.windows.1/PortableGit-2.46.2-64-bit.7z.exe --output bin.7z
-          7z x -bd -y bin.7z
-          rm -f bin.7z
-
       - name: 'cache compiler (gcc ${{ matrix.env }})'
         uses: actions/cache@1bd1e32a3bdc45362d1e726936510720a7c30a57 # v4
         id: cache-compiler
@@ -441,7 +426,6 @@ jobs:
         timeout-minutes: 5
         run: |
           PATH="$(cygpath "${USERPROFILE}")/my-cache/${{ matrix.dir }}/bin:/c/msys64/usr/bin:$PATH"
-          [ -d /c/_gfw ] && PATH="/c/_gfw/usr/bin:$PATH"
           [ '${{ matrix.type }}' = 'Debug' ] && options+=' -DCMAKE_RUNTIME_OUTPUT_DIRECTORY_DEBUG='
           [ '${{ matrix.type }}' = 'Release' ] && options+=' -DCMAKE_RUNTIME_OUTPUT_DIRECTORY_RELEASE='
           cmake -B bld -G 'MSYS Makefiles' ${options} \
@@ -465,7 +449,6 @@ jobs:
         timeout-minutes: 5
         run: |
           PATH="$(cygpath "${USERPROFILE}")/my-cache/${{ matrix.dir }}/bin:/c/msys64/usr/bin:$PATH"
-          [ -d /c/_gfw ] && PATH="/c/_gfw/usr/bin:$PATH"
           cmake --build bld --config '${{ matrix.type }}' --parallel 5
 
       - name: 'curl version'
@@ -480,7 +463,6 @@ jobs:
         timeout-minutes: 10
         run: |
           PATH="$(cygpath "${USERPROFILE}")/my-cache/${{ matrix.dir }}/bin:/c/msys64/usr/bin:$PATH"
-          [ -d /c/_gfw ] && PATH="/c/_gfw/usr/bin:$PATH"
           cmake --build bld --config '${{ matrix.type }}' --parallel 5 --target testdeps
 
       - name: 'install test prereqs'
@@ -491,6 +473,15 @@ jobs:
           curl --disable --fail --silent --show-error --connect-timeout 15 --max-time 60 --retry 3 https://live.sysinternals.com/handle64.exe --output /bin/handle64.exe
           python3 -m pip --disable-pip-version-check --no-input --no-cache-dir install --progress-bar off --prefer-binary impacket
 
+      - name: 'downgrade msys2-runtime'
+        if: ${{ matrix.tflags != 'skipall' && matrix.tflags != 'skiprun' }}
+        timeout-minutes: 2
+        # Downgrade to a known good MSYS2 runtime version to avoid the performance regression
+        # causing runtests.pl to run at 2-3x reduced speed.
+        run: |
+          /usr/bin/sed -i 's/^CheckSpace/#CheckSpace/' /etc/pacman.conf
+          exec /usr/bin/pacman --noconfirm --noprogressbar --upgrade https://mirror.msys2.org/msys/x86_64/msys2-runtime-3.5.4-8-x86_64.pkg.tar.zst
+
       - name: 'run tests'
         if: ${{ matrix.tflags != 'skipall' && matrix.tflags != 'skiprun' }}
         timeout-minutes: 10
@@ -501,14 +492,12 @@ jobs:
             TFLAGS+=" -ac $(cygpath "${SYSTEMROOT}/System32/curl.exe")"
           fi
           PATH="$PWD/bld/lib:$PATH:/c/Program Files (x86)/stunnel/bin"
-          [ -d /c/_gfw ] && PATH="/c/_gfw/usr/bin:$PATH"
           cmake --build bld --config '${{ matrix.type }}' --target test-ci
 
       - name: 'build examples'
         timeout-minutes: 5
         run: |
           PATH="$(cygpath "${USERPROFILE}")/my-cache/${{ matrix.dir }}/bin:/c/msys64/usr/bin:$PATH"
-          [ -d /c/_gfw ] && PATH="/c/_gfw/usr/bin:$PATH"
           cmake --build bld --config '${{ matrix.type }}' --parallel 5 --target curl-examples
 
   linux-cross-mingw-w64:
@@ -701,7 +690,7 @@ jobs:
     timeout-minutes: 55
     defaults:
       run:
-        shell: ${{ matrix.tflags != 'skipall' && matrix.tflags != 'skiprun' && 'C:\_gfw\usr\bin\bash.exe {0}' || 'C:\msys64\usr\bin\bash.exe {0}' }}
+        shell: C:\msys64\usr\bin\bash.exe {0}
     env:
       VCPKG_BINARY_SOURCES: 'clear;x-gha,readwrite'
       VCPKG_DISABLE_METRICS: '1'
@@ -793,21 +782,6 @@ jobs:
 
       fail-fast: false
     steps:
-      - name: 'install Git for Windows'
-        if: ${{ matrix.tflags != 'skipall' && matrix.tflags != 'skiprun' }}
-        shell: bash
-        timeout-minutes: 5
-        run: |
-          mkdir /c/_gfw
-          cd /c/_gfw || exit 1
-          # The last known good Perl version (as of v2.47.1.windows.2) without pipe/signal MSYS2
-          # runtime (?) regressions that cause runtests.pl to run at 2.5x reduced speed, is this:
-          #   https://github.com/git-for-windows/git/releases/tag/v2.46.2.windows.1
-          curl --disable --fail --silent --show-error --connect-timeout 15 --max-time 120 --retry 3 \
-            --location https://github.com/git-for-windows/git/releases/download/v2.46.2.windows.1/PortableGit-2.46.2-64-bit.7z.exe --output bin.7z
-          7z x -bd -y bin.7z
-          rm -f bin.7z
-
       - name: 'vcpkg cache setup'
         uses: actions/github-script@60a0d83039c74a4aee543508d2ffcb1c3799cdea # v7
         with:
@@ -832,7 +806,7 @@ jobs:
       - name: 'configure'
         timeout-minutes: 5
         run: |
-          [ -d /c/_gfw ] && PATH="/c/_gfw/usr/bin:$PATH"
+          PATH="/c/msys64/usr/bin:$PATH"
           for _chkprefill in '' ${{ matrix.chkprefill }}; do
             options=''
             if [ '${{ matrix.plat }}' = 'uwp' ]; then
@@ -878,7 +852,7 @@ jobs:
       - name: 'build'
         timeout-minutes: 5
         run: |
-          [ -d /c/_gfw ] && PATH="/c/_gfw/usr/bin:$PATH"
+          PATH="/c/msys64/usr/bin:$PATH"
           cmake --build bld --config '${{ matrix.type }}' --parallel 5
 
       - name: 'curl version'
@@ -894,7 +868,7 @@ jobs:
         if: ${{ matrix.tflags != 'skipall' }}
         timeout-minutes: 10
         run: |
-          [ -d /c/_gfw ] && PATH="/c/_gfw/usr/bin:$PATH"
+          PATH="/c/msys64/usr/bin:$PATH"
           cmake --build bld --config '${{ matrix.type }}' --parallel 5 --target testdeps
 
       - name: 'install test prereqs'
@@ -909,6 +883,15 @@ jobs:
           curl --disable --fail --silent --show-error --connect-timeout 15 --max-time 60 --retry 3 https://live.sysinternals.com/handle64.exe --output /bin/handle64.exe
           python3 -m pip --disable-pip-version-check --no-input --no-cache-dir install --progress-bar off --prefer-binary impacket
 
+      - name: 'downgrade msys2-runtime'
+        if: ${{ matrix.tflags != 'skipall' && matrix.tflags != 'skiprun' }}
+        timeout-minutes: 2
+        # Downgrade to a known good MSYS2 runtime version to avoid the performance regression
+        # causing runtests.pl to run at 2-3x reduced speed.
+        run: |
+          /usr/bin/sed -i 's/^CheckSpace/#CheckSpace/' /etc/pacman.conf
+          exec /usr/bin/pacman --noconfirm --noprogressbar --upgrade https://mirror.msys2.org/msys/x86_64/msys2-runtime-3.5.4-8-x86_64.pkg.tar.zst
+
       - name: 'run tests'
         if: ${{ matrix.tflags != 'skipall' && matrix.tflags != 'skiprun' }}
         timeout-minutes: 10
@@ -920,11 +903,11 @@ jobs:
             TFLAGS+=' ~614'  # 'SFTP pre-quote chmod' SFTP, pre-quote, directory
           fi
           PATH="$PWD/bld/lib:$PATH:/c/Program Files (x86)/stunnel/bin:/c/Program Files/OpenSSH-Win64"
-          [ -d /c/_gfw ] && PATH="/c/_gfw/usr/bin:$PATH"
+          PATH="/c/msys64/usr/bin:$PATH"
           cmake --build bld --config '${{ matrix.type }}' --target test-ci
 
       - name: 'build examples'
         timeout-minutes: 5
         run: |
-          [ -d /c/_gfw ] && PATH="/c/_gfw/usr/bin:$PATH"
+          PATH="/c/msys64/usr/bin:$PATH"
           cmake --build bld --config '${{ matrix.type }}' --parallel 5 --target curl-examples