From 0f883482880bc00619f2cc756ad70735bda3a4aa Mon Sep 17 00:00:00 2001
From: Brad Warren <bmw@eff.org>
Date: Mon, 8 Jan 2018 14:52:50 -0800
Subject: [PATCH] Fix #5387

---
 letsencrypt-auto-source/letsencrypt-auto      | 20 +++++++++++++------
 .../letsencrypt-auto.template                 | 20 +++++++++++++------
 2 files changed, 28 insertions(+), 12 deletions(-)

diff --git a/letsencrypt-auto-source/letsencrypt-auto b/letsencrypt-auto-source/letsencrypt-auto
index f1361d8ea..5f46e3a31 100755
--- a/letsencrypt-auto-source/letsencrypt-auto
+++ b/letsencrypt-auto-source/letsencrypt-auto
@@ -246,10 +246,14 @@ DeprecationBootstrap() {
   fi
 }
 
+MIN_PYTHON_VERSION="2.6"
+MIN_PYVER=$(echo "$MIN_PYTHON_VERSION" | sed 's/\.//')
 # Sets LE_PYTHON to Python version string and PYVER to the first two
 # digits of the python version
 DeterminePythonVersion() {
   # Arguments: "NOCRASH" if we shouldn't crash if we don't find a good python
+  #
+  # If no Python is found, PYVER is set to 0.
   if [ -n "$USE_PYTHON_3" ]; then
     for LE_PYTHON in "$LE_PYTHON" python3; do
       # Break (while keeping the LE_PYTHON value) if found.
@@ -273,10 +277,12 @@ DeterminePythonVersion() {
   export LE_PYTHON
 
   PYVER=`"$LE_PYTHON" -V 2>&1 | cut -d" " -f 2 | cut -d. -f1,2 | sed 's/\.//'`
-  if [ "$PYVER" -lt 26 ]; then
-    error "You have an ancient version of Python entombed in your operating system..."
-    error "This isn't going to work; you'll need at least version 2.6."
-    exit 1
+  if [ "$PYVER" -lt "$MIN_PYVER" ]; then
+    if [ "$1" != "NOCRASH" ]; then
+      error "You have an ancient version of Python entombed in your operating system..."
+      error "This isn't going to work; you'll need at least version $MIN_PYTHON_VERSION."
+      exit 1
+    fi
   fi
 }
 
@@ -1575,8 +1581,10 @@ if __name__ == '__main__':
 
 UNLIKELY_EOF
     # ---------------------------------------------------------------------------
-    DeterminePythonVersion
-    if ! REMOTE_VERSION=`"$LE_PYTHON" "$TEMP_DIR/fetch.py" --latest-version` ; then
+    DeterminePythonVersion "NOCRASH"
+    if [ "$PYVER" -lt "$MIN_PYVER" ]; then
+      error "WARNING: couldn't find Python $MIN_PYTHON_VERSION+ to check for updates."
+    elif ! REMOTE_VERSION=`"$LE_PYTHON" "$TEMP_DIR/fetch.py" --latest-version` ; then
       error "WARNING: unable to check for updates."
     elif [ "$LE_AUTO_VERSION" != "$REMOTE_VERSION" ]; then
       say "Upgrading certbot-auto $LE_AUTO_VERSION to $REMOTE_VERSION..."
diff --git a/letsencrypt-auto-source/letsencrypt-auto.template b/letsencrypt-auto-source/letsencrypt-auto.template
index f4c1b202f..7c3cbac08 100755
--- a/letsencrypt-auto-source/letsencrypt-auto.template
+++ b/letsencrypt-auto-source/letsencrypt-auto.template
@@ -246,10 +246,14 @@ DeprecationBootstrap() {
   fi
 }
 
+MIN_PYTHON_VERSION="2.6"
+MIN_PYVER=$(echo "$MIN_PYTHON_VERSION" | sed 's/\.//')
 # Sets LE_PYTHON to Python version string and PYVER to the first two
 # digits of the python version
 DeterminePythonVersion() {
   # Arguments: "NOCRASH" if we shouldn't crash if we don't find a good python
+  #
+  # If no Python is found, PYVER is set to 0.
   if [ -n "$USE_PYTHON_3" ]; then
     for LE_PYTHON in "$LE_PYTHON" python3; do
       # Break (while keeping the LE_PYTHON value) if found.
@@ -273,10 +277,12 @@ DeterminePythonVersion() {
   export LE_PYTHON
 
   PYVER=`"$LE_PYTHON" -V 2>&1 | cut -d" " -f 2 | cut -d. -f1,2 | sed 's/\.//'`
-  if [ "$PYVER" -lt 26 ]; then
-    error "You have an ancient version of Python entombed in your operating system..."
-    error "This isn't going to work; you'll need at least version 2.6."
-    exit 1
+  if [ "$PYVER" -lt "$MIN_PYVER" ]; then
+    if [ "$1" != "NOCRASH" ]; then
+      error "You have an ancient version of Python entombed in your operating system..."
+      error "This isn't going to work; you'll need at least version $MIN_PYTHON_VERSION."
+      exit 1
+    fi
   fi
 }
 
@@ -586,8 +592,10 @@ else
 {{ fetch.py }}
 UNLIKELY_EOF
     # ---------------------------------------------------------------------------
-    DeterminePythonVersion
-    if ! REMOTE_VERSION=`"$LE_PYTHON" "$TEMP_DIR/fetch.py" --latest-version` ; then
+    DeterminePythonVersion "NOCRASH"
+    if [ "$PYVER" -lt "$MIN_PYVER" ]; then
+      error "WARNING: couldn't find Python $MIN_PYTHON_VERSION+ to check for updates."
+    elif ! REMOTE_VERSION=`"$LE_PYTHON" "$TEMP_DIR/fetch.py" --latest-version` ; then
       error "WARNING: unable to check for updates."
     elif [ "$LE_AUTO_VERSION" != "$REMOTE_VERSION" ]; then
       say "Upgrading certbot-auto $LE_AUTO_VERSION to $REMOTE_VERSION..."