ci: extract disabling git crlf handling into a script

Author: pietroalbini

src/ci/azure-pipelines/steps/install-windows-build-deps.yml

@@ -1,7 +1,4 @@
 steps:
-- bash: git config --replace-all --global core.autocrlf false
-  displayName: "Disable git automatic line ending conversion (on C:/)"
-
 # Download and install MSYS2, needed primarily for the test suite (run-make) but
 # also used by the MinGW toolchain for assembling things.
 #

src/ci/azure-pipelines/steps/run.yml

@@ -87,6 +87,10 @@ steps:
   displayName: Ensure the build happens on C:\ instead of D:\
   condition: and(succeeded(), not(variables.SKIP_JOB))
 
+- bash: src/ci/scripts/disable-git-crlf-conversion.sh
+  displayName: "Disable git automatic line ending conversion (on C:/)"
+  condition: and(succeeded(), not(variables.SKIP_JOB))
+
 - template: install-windows-build-deps.yml
 
 # Looks like docker containers have IPv6 disabled by default, so let's turn it
@@ -104,8 +108,9 @@ steps:
 # re-enables autocrlf. We've not tracked down the exact cause -- and there may
 # be multiple -- but this should ensure submodules are checked out with the
 # appropriate line endings.
-- bash: git config --replace-all --global core.autocrlf false
-  displayName: "Disable git automatic line ending conversion"
+- bash: src/ci/scripts/disable-git-crlf-conversion.sh
+  displayName: Disable git automatic line ending conversion
+  condition: and(succeeded(), not(variables.SKIP_JOB))
 
 # Check out all our submodules, but more quickly than using git by using one of
 # our custom scripts

src/ci/scripts/disable-git-crlf-conversion.sh

@@ -0,0 +1,13 @@
+#!/bin/bash
+# Disable automatic line ending conversion, which is enabled by default on
+# Azure's Windows image. Having the conversion enabled caused regressions both
+# in our test suite (it broke miri tests) and in the ecosystem, since we
+# started shipping install scripts with CRLF endings instead of the old LF.
+#
+# Note that we do this a couple times during the build as the PATH and current
+# user/directory change, e.g. when mingw is enabled.
+
+set -euo pipefail
+IFS=$'\n\t'
+
+git config --replace-all --global core.autocrlf false