[3.13] gh-137450: macOS installer shell path management improvements (GH-137451) (#137452)

Separate the installer `Shell profile updater` postinstall script from the `Update Shell Profile.command` to enable more robust error handling.
(cherry picked from commit 781eb1a688e0575a38c79575493f3ff83208a33e)

Co-authored-by: Ned Deily <nad@python.org>

1 files changed, 72 insertions, 84 deletions

diff --git a/Mac/BuildScript/scripts/postflight.patch-profile b/Mac/BuildScript/scripts/postflight.patch-profile
index 9caf622..ce8720f 100755
--- a/Mac/BuildScript/scripts/postflight.patch-profile
+++ b/Mac/BuildScript/scripts/postflight.patch-profile
@@ -1,116 +1,104 @@
 #!/bin/sh
 
-echo "This script will update your shell profile when the 'bin' directory"
-echo "of python is not early enough of the PATH of your shell."
-echo "These changes will be effective only in shell windows that you open"
-echo "after running this script."
-
 PYVER=@PYVER@
 PYTHON_ROOT="/Library/Frameworks/Python.framework/Versions/@PYVER@"
 
-if [ `id -ur` = 0 ]; then
-	# Run from the installer, do some trickery to fetch the information
-	# we need.
-	theShell="`finger $USER | grep Shell: | head  -1 | awk '{ print $NF }'`"
 
-else
-	theShell="${SHELL}"
-fi
+# Run from the installer, do some trickery to fetch the information
+# we need.
+theShell="`finger $USER | grep Shell: | head  -1 | awk '{ print $NF }'`"
 
 # Make sure the directory ${PYTHON_ROOT}/bin is on the users PATH.
 BSH="`basename "${theShell}"`"
 case "${BSH}" in
 bash|ksh|sh|*csh|zsh|fish)
-	if [ `id -ur` = 0 ]; then
-		P=`su - ${USER} -c 'echo A-X-4-X@@$PATH@@X-4-X-A' | grep 'A-X-4-X@@.*@@X-4-X-A' | sed -e 's/^A-X-4-X@@//g' -e 's/@@X-4-X-A$//g'`
-	else
-		P="`(exec -l ${theShell} -c 'echo $PATH')`"
-	fi
-	;;
+    true
+    ;;
 *)
-	echo "Sorry, I don't know how to patch $BSH shells"
-	exit 0
-	;;
+    exit 0
+    ;;
 esac
 
-# Now ensure that our bin directory is on $P and before /usr/bin at that
-for elem in `echo $P | tr ':' ' '`
-do
-	if [ "${elem}" = "${PYTHON_ROOT}/bin" ]; then
-		echo "All right, you're a python lover already"
-		exit 0
-	elif [ "${elem}" = "/usr/bin" ]; then
-		break
-	fi
-done
-
-echo "${PYTHON_ROOT}/bin is not on your PATH or at least not early enough"
 case "${BSH}" in
 *csh)
-	if [ -f "${HOME}/.tcshrc" ]; then
-		RC="${HOME}/.tcshrc"
-	else
-		RC="${HOME}/.cshrc"
-	fi
-	# Create backup copy before patching
-	if [ -f "${RC}" ]; then
-		cp -fp "${RC}" "${RC}.pysave"
-	fi
-	echo "" >> "${RC}"
-	echo "# Setting PATH for Python ${PYVER}" >> "${RC}"
-	echo "# The original version is saved in .cshrc.pysave" >> "${RC}"
-	echo "set path=(${PYTHON_ROOT}/bin "'$path'")" >> "${RC}"
-	if [ `id -ur` = 0 ]; then
-		chown "${USER}" "${RC}"
-	fi
-	exit 0
-	;;
+    if [ -f "${HOME}/.tcshrc" ]; then
+        RC="${HOME}/.tcshrc"
+    else
+        RC="${HOME}/.cshrc"
+    fi
+
+    # Drop privileges while writing files.
+    su -m ${USER} <<EOFC
+    # Create backup copy before patching
+    if [ -f "${RC}" ]; then
+        cp -fp "${RC}" "${RC}.pysave"
+    fi
+    echo "" >> "${RC}"
+    echo "# Setting PATH for Python ${PYVER}" >> "${RC}"
+    echo "# The original version is saved in .cshrc.pysave" >> "${RC}"
+    echo "set path=(${PYTHON_ROOT}/bin "'\$path'")" >> "${RC}"
+EOFC
+
+    if [ `id -ur` = 0 ]; then
+        chown -h "${USER}" "${RC}"
+    fi
+    exit 0
+    ;;
 bash)
-	if [ -e "${HOME}/.bash_profile" ]; then
-		PR="${HOME}/.bash_profile"
-	elif [ -e "${HOME}/.bash_login" ]; then
-		PR="${HOME}/.bash_login"
-	elif [ -e "${HOME}/.profile" ]; then
-		PR="${HOME}/.profile"
-	else
-		PR="${HOME}/.bash_profile"
-	fi
-	;;
+    if [ -e "${HOME}/.bash_profile" ]; then
+        PR="${HOME}/.bash_profile"
+    elif [ -e "${HOME}/.bash_login" ]; then
+        PR="${HOME}/.bash_login"
+    elif [ -e "${HOME}/.profile" ]; then
+        PR="${HOME}/.profile"
+    else
+        PR="${HOME}/.bash_profile"
+    fi
+    ;;
 fish)
-	CONFIG_DIR="${HOME}/.config/fish/conf.d/"
-	RC="${CONFIG_DIR}/python-${PYVER}.fish"
-	mkdir -p "$CONFIG_DIR"
-	if [ -f "${RC}" ]; then
-		cp -fp "${RC}" "${RC}.pysave"
-	fi
-	echo "# Setting PATH for Python ${PYVER}" > "${RC}"
-	if [ -f "${RC}.pysave" ]; then
-		echo "# The original version is saved in ${RC}.pysave" >> "${RC}"
-	fi
-	echo "fish_add_path -g \"${PYTHON_ROOT}/bin\"" >> "${RC}"
-	if [ `id -ur` = 0 ]; then
-		chown "${USER}" "${RC}"
-	fi
-	exit 0
-	;;
+    CONFIG_DIR="${HOME}/.config/fish/conf.d/"
+    RC="${CONFIG_DIR}/python-${PYVER}.fish"
+
+    # Drop privileges while writing files.
+    su -m ${USER} <<EOFF
+    mkdir -p "$CONFIG_DIR"
+    if [ -f "${RC}" ]; then
+        cp -fp "${RC}" "${RC}.pysave"
+    fi
+    echo "# Setting PATH for Python ${PYVER}" > "${RC}"
+    if [ -f "${RC}.pysave" ]; then
+        echo "# The original version is saved in ${RC}.pysave" >> "${RC}"
+    fi
+    echo "fish_add_path -g \"${PYTHON_ROOT}/bin\"" >> "${RC}"
+EOFF
+
+    if [ `id -ur` = 0 ]; then
+        chown -h "${USER}" "${RC}"
+    fi
+    exit 0
+    ;;
 zsh)
-        PR="${HOME}/.zprofile"
-        ;;
+    PR="${HOME}/.zprofile"
+    ;;
 *sh)
-	PR="${HOME}/.profile"
-	;;
+    PR="${HOME}/.profile"
+    ;;
 esac
 
+# Drop privileges while writing files.
+su -m ${USER} <<EOFS
 # Create backup copy before patching
 if [ -f "${PR}" ]; then
-	cp -fp "${PR}" "${PR}.pysave"
+    cp -fp "${PR}" "${PR}.pysave"
 fi
 echo "" >> "${PR}"
 echo "# Setting PATH for Python ${PYVER}" >> "${PR}"
 echo "# The original version is saved in `basename ${PR}`.pysave" >> "${PR}"
-echo 'PATH="'"${PYTHON_ROOT}/bin"':${PATH}"' >> "${PR}"
+echo 'PATH="'"${PYTHON_ROOT}/bin"':\${PATH}"' >> "${PR}"
 echo 'export PATH' >> "${PR}"
+EOFS
+
 if [ `id -ur` = 0 ]; then
-	chown "${USER}" "${PR}"
+    chown -h "${USER}" "${PR}"
 fi
 exit 0