From aceee796f175d5b4fc2741cd359038ef3bcf1cb3 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Tue, 19 May 2026 15:51:51 +0000
Subject: [PATCH 1/6] Initial plan


From 63f4f148ae1cd0eeebca6bcfcc932349340bd90d Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Tue, 19 May 2026 15:54:41 +0000
Subject: [PATCH 2/6] fix(copilot-cli): use semver sort for prerelease tag
 resolution

---
 src/copilot-cli/devcontainer-feature.json | 2 +-
 src/copilot-cli/install.sh                | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/copilot-cli/devcontainer-feature.json b/src/copilot-cli/devcontainer-feature.json
index bfd97286c..f4db33ced 100644
--- a/src/copilot-cli/devcontainer-feature.json
+++ b/src/copilot-cli/devcontainer-feature.json
@@ -1,6 +1,6 @@
 {
     "id": "copilot-cli",
-    "version": "1.1.2",
+    "version": "1.1.3",
     "name": "GitHub Copilot CLI",
     "documentationURL": "https://github.com/devcontainers/features/tree/main/src/copilot-cli",
     "description": "Installs the GitHub Copilot CLI.",
diff --git a/src/copilot-cli/install.sh b/src/copilot-cli/install.sh
index 47c2e3aca..0b91ee0aa 100755
--- a/src/copilot-cli/install.sh
+++ b/src/copilot-cli/install.sh
@@ -63,7 +63,7 @@ install_using_github() {
     if [ "${CLI_VERSION}" = "latest" ]; then
         download_from_github "https://github.com/github/copilot-cli/releases/latest/download/${cli_filename}"
     elif [ "${CLI_VERSION}" = "prerelease" ]; then
-        prerelease_version="$(git ls-remote --tags https://github.com/github/copilot-cli | tail -1 | awk -F/ '{print $NF}')"
+        prerelease_version="$(git ls-remote --tags https://github.com/github/copilot-cli | awk '{print $2}' | sed 's|refs/tags/||' | grep -E '^v[0-9]+\.[0-9]+\.[0-9]+(-[0-9]+)?' | sort -V | tail -n1)"
         download_from_github "https://github.com/github/copilot-cli/releases/download/${prerelease_version}/${cli_filename}"
     else
         # Install specific version

From e38d64bac98b9d34d919484edd052f2812949aa8 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Thu, 21 May 2026 11:24:09 +0000
Subject: [PATCH 3/6] refactor(copilot-cli): extract resolve_prerelease_version
 function and add test

Extract the prerelease tag resolution logic into a standalone
resolve_prerelease_version() function that can read from stdin for
testing. Add a scenario test that validates version sorting with mock
git ls-remote data to prevent regressions.
---
 src/copilot-cli/install.sh                    | 17 +++++-
 .../copilot-cli/resolve_prerelease_version.sh | 57 +++++++++++++++++++
 test/copilot-cli/scenarios.json               | 10 ++++
 3 files changed, 83 insertions(+), 1 deletion(-)
 create mode 100644 test/copilot-cli/resolve_prerelease_version.sh
 create mode 100644 test/copilot-cli/scenarios.json

diff --git a/src/copilot-cli/install.sh b/src/copilot-cli/install.sh
index 0b91ee0aa..519142f28 100755
--- a/src/copilot-cli/install.sh
+++ b/src/copilot-cli/install.sh
@@ -45,6 +45,21 @@ download_from_github() {
     rm -rf /tmp/copilotcli
 }
 
+# Resolves the latest prerelease version tag from git ls-remote output.
+# Filters to well-formed vX.Y.Z or vX.Y.Z-N tags and sorts by version.
+# Reads ls-remote formatted lines from stdin if no arguments are provided,
+# otherwise runs git ls-remote --tags against the given repository URL.
+resolve_prerelease_version() {
+    local repo_url="${1:-}"
+    if [ -n "${repo_url}" ]; then
+        git ls-remote --tags "${repo_url}"
+    else
+        cat
+    fi | awk '{print $2}' | sed 's|refs/tags/||' \
+      | grep -E '^v[0-9]+\.[0-9]+\.[0-9]+(-[0-9]+)?$' \
+      | sort -V | tail -n1
+}
+
 install_using_github() {
     check_packages wget tar ca-certificates git
     echo "Finished setting up dependencies"
@@ -63,7 +78,7 @@ install_using_github() {
     if [ "${CLI_VERSION}" = "latest" ]; then
         download_from_github "https://github.com/github/copilot-cli/releases/latest/download/${cli_filename}"
     elif [ "${CLI_VERSION}" = "prerelease" ]; then
-        prerelease_version="$(git ls-remote --tags https://github.com/github/copilot-cli | awk '{print $2}' | sed 's|refs/tags/||' | grep -E '^v[0-9]+\.[0-9]+\.[0-9]+(-[0-9]+)?' | sort -V | tail -n1)"
+        prerelease_version="$(resolve_prerelease_version "https://github.com/github/copilot-cli")"
         download_from_github "https://github.com/github/copilot-cli/releases/download/${prerelease_version}/${cli_filename}"
     else
         # Install specific version
diff --git a/test/copilot-cli/resolve_prerelease_version.sh b/test/copilot-cli/resolve_prerelease_version.sh
new file mode 100644
index 000000000..1ff182a2b
--- /dev/null
+++ b/test/copilot-cli/resolve_prerelease_version.sh
@@ -0,0 +1,57 @@
+#!/bin/bash
+
+set -e
+
+# Optional: Import test library
+source dev-container-features-test-lib
+
+# Source the install script's resolve_prerelease_version function
+# We extract it by sourcing, but we only need the function definition
+eval "$(sed -n '/^resolve_prerelease_version()/,/^}/p' /usr/local/share/copilot-cli-install.sh 2>/dev/null || true)"
+
+# If sourcing didn't work, define it inline (matches src/copilot-cli/install.sh)
+if ! type resolve_prerelease_version &>/dev/null; then
+    resolve_prerelease_version() {
+        local repo_url="${1:-}"
+        if [ -n "${repo_url}" ]; then
+            git ls-remote --tags "${repo_url}"
+        else
+            cat
+        fi | awk '{print $2}' | sed 's|refs/tags/||' \
+          | grep -E '^v[0-9]+\.[0-9]+\.[0-9]+(-[0-9]+)?$' \
+          | sort -V | tail -n1
+    }
+fi
+
+# Mock git ls-remote output (alphabetically v1.0.9 > v1.0.45)
+MOCK_LS_REMOTE="abc1234\trefs/tags/v1.0.1
+def5678\trefs/tags/v1.0.9
+ghi9012\trefs/tags/v1.0.10
+jkl3456\trefs/tags/v1.0.45
+mno7890\trefs/tags/v1.0.2"
+
+# Test: version sort picks v1.0.45, not v1.0.9
+result="$(echo "${MOCK_LS_REMOTE}" | resolve_prerelease_version)"
+check "picks highest version (v1.0.45)" bash -c "[ '${result}' = 'v1.0.45' ]"
+
+# Test: prerelease numeric suffixes sort correctly
+MOCK_PRERELEASE="abc1234\trefs/tags/v1.0.44
+def5678\trefs/tags/v1.0.45-1
+ghi9012\trefs/tags/v1.0.45-10
+jkl3456\trefs/tags/v1.0.45-2
+mno7890\trefs/tags/v1.0.45"
+
+result2="$(echo "${MOCK_PRERELEASE}" | resolve_prerelease_version)"
+check "picks highest prerelease (v1.0.45-10)" bash -c "[ '${result2}' = 'v1.0.45-10' ]"
+
+# Test: filters out non-version tags
+MOCK_STRAY="abc1234\trefs/tags/latest
+def5678\trefs/tags/v1.0.3
+ghi9012\trefs/tags/nightly
+jkl3456\trefs/tags/v1.0.20"
+
+result3="$(echo "${MOCK_STRAY}" | resolve_prerelease_version)"
+check "ignores non-version tags" bash -c "[ '${result3}' = 'v1.0.20' ]"
+
+# Report result
+reportResults
diff --git a/test/copilot-cli/scenarios.json b/test/copilot-cli/scenarios.json
new file mode 100644
index 000000000..87fcc541d
--- /dev/null
+++ b/test/copilot-cli/scenarios.json
@@ -0,0 +1,10 @@
+{
+  "resolve_prerelease_version": {
+    "image": "ubuntu:noble",
+    "features": {
+      "copilot-cli": {
+        "version": "latest"
+      }
+    }
+  }
+}

From fb8ecf611d47cfad9b1ca983170b099d530e5eea Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Thu, 21 May 2026 11:40:40 +0000
Subject: [PATCH 4/6] fix(copilot-cli): make repo_url mandatory in
 resolve_prerelease_version

Remove the stdin/cat fallback and use ${1:?} to error if no URL is
provided. Update the test to mock git via PATH instead of piping stdin.
---
 src/copilot-cli/install.sh                    | 13 +---
 .../copilot-cli/resolve_prerelease_version.sh | 73 +++++++++----------
 2 files changed, 39 insertions(+), 47 deletions(-)

diff --git a/src/copilot-cli/install.sh b/src/copilot-cli/install.sh
index 519142f28..d4c27ad1a 100755
--- a/src/copilot-cli/install.sh
+++ b/src/copilot-cli/install.sh
@@ -45,17 +45,12 @@ download_from_github() {
     rm -rf /tmp/copilotcli
 }
 
-# Resolves the latest prerelease version tag from git ls-remote output.
+# Resolves the latest prerelease version tag from a remote repository.
 # Filters to well-formed vX.Y.Z or vX.Y.Z-N tags and sorts by version.
-# Reads ls-remote formatted lines from stdin if no arguments are provided,
-# otherwise runs git ls-remote --tags against the given repository URL.
 resolve_prerelease_version() {
-    local repo_url="${1:-}"
-    if [ -n "${repo_url}" ]; then
-        git ls-remote --tags "${repo_url}"
-    else
-        cat
-    fi | awk '{print $2}' | sed 's|refs/tags/||' \
+    local repo_url="${1:?resolve_prerelease_version requires a repository URL}"
+    git ls-remote --tags "${repo_url}" \
+      | awk '{print $2}' | sed 's|refs/tags/||' \
       | grep -E '^v[0-9]+\.[0-9]+\.[0-9]+(-[0-9]+)?$' \
       | sort -V | tail -n1
 }
diff --git a/test/copilot-cli/resolve_prerelease_version.sh b/test/copilot-cli/resolve_prerelease_version.sh
index 1ff182a2b..8369788c8 100644
--- a/test/copilot-cli/resolve_prerelease_version.sh
+++ b/test/copilot-cli/resolve_prerelease_version.sh
@@ -5,53 +5,50 @@ set -e
 # Optional: Import test library
 source dev-container-features-test-lib
 
-# Source the install script's resolve_prerelease_version function
-# We extract it by sourcing, but we only need the function definition
-eval "$(sed -n '/^resolve_prerelease_version()/,/^}/p' /usr/local/share/copilot-cli-install.sh 2>/dev/null || true)"
-
-# If sourcing didn't work, define it inline (matches src/copilot-cli/install.sh)
-if ! type resolve_prerelease_version &>/dev/null; then
-    resolve_prerelease_version() {
-        local repo_url="${1:-}"
-        if [ -n "${repo_url}" ]; then
-            git ls-remote --tags "${repo_url}"
-        else
-            cat
-        fi | awk '{print $2}' | sed 's|refs/tags/||' \
-          | grep -E '^v[0-9]+\.[0-9]+\.[0-9]+(-[0-9]+)?$' \
-          | sort -V | tail -n1
-    }
-fi
-
-# Mock git ls-remote output (alphabetically v1.0.9 > v1.0.45)
-MOCK_LS_REMOTE="abc1234\trefs/tags/v1.0.1
-def5678\trefs/tags/v1.0.9
-ghi9012\trefs/tags/v1.0.10
-jkl3456\trefs/tags/v1.0.45
-mno7890\trefs/tags/v1.0.2"
+# Define the function under test (matches src/copilot-cli/install.sh)
+resolve_prerelease_version() {
+    local repo_url="${1:?resolve_prerelease_version requires a repository URL}"
+    git ls-remote --tags "${repo_url}" \
+      | awk '{print $2}' | sed 's|refs/tags/||' \
+      | grep -E '^v[0-9]+\.[0-9]+\.[0-9]+(-[0-9]+)?$' \
+      | sort -V | tail -n1
+}
+
+# Create a mock git script that returns controlled output
+MOCK_DIR="$(mktemp -d)"
+cat > "${MOCK_DIR}/git" << 'SCRIPT'
+#!/bin/bash
+# Return mock ls-remote output based on the repo URL argument
+repo="${*: -1}"
+case "${repo}" in
+  "mock://basic")
+    printf 'abc1234\trefs/tags/v1.0.1\ndef5678\trefs/tags/v1.0.9\nghi9012\trefs/tags/v1.0.10\njkl3456\trefs/tags/v1.0.45\nmno7890\trefs/tags/v1.0.2\n'
+    ;;
+  "mock://prerelease")
+    printf 'abc1234\trefs/tags/v1.0.44\ndef5678\trefs/tags/v1.0.45-1\nghi9012\trefs/tags/v1.0.45-10\njkl3456\trefs/tags/v1.0.45-2\nmno7890\trefs/tags/v1.0.45\n'
+    ;;
+  "mock://stray")
+    printf 'abc1234\trefs/tags/latest\ndef5678\trefs/tags/v1.0.3\nghi9012\trefs/tags/nightly\njkl3456\trefs/tags/v1.0.20\n'
+    ;;
+esac
+SCRIPT
+chmod +x "${MOCK_DIR}/git"
+export PATH="${MOCK_DIR}:${PATH}"
 
 # Test: version sort picks v1.0.45, not v1.0.9
-result="$(echo "${MOCK_LS_REMOTE}" | resolve_prerelease_version)"
+result="$(resolve_prerelease_version "mock://basic")"
 check "picks highest version (v1.0.45)" bash -c "[ '${result}' = 'v1.0.45' ]"
 
 # Test: prerelease numeric suffixes sort correctly
-MOCK_PRERELEASE="abc1234\trefs/tags/v1.0.44
-def5678\trefs/tags/v1.0.45-1
-ghi9012\trefs/tags/v1.0.45-10
-jkl3456\trefs/tags/v1.0.45-2
-mno7890\trefs/tags/v1.0.45"
-
-result2="$(echo "${MOCK_PRERELEASE}" | resolve_prerelease_version)"
+result2="$(resolve_prerelease_version "mock://prerelease")"
 check "picks highest prerelease (v1.0.45-10)" bash -c "[ '${result2}' = 'v1.0.45-10' ]"
 
 # Test: filters out non-version tags
-MOCK_STRAY="abc1234\trefs/tags/latest
-def5678\trefs/tags/v1.0.3
-ghi9012\trefs/tags/nightly
-jkl3456\trefs/tags/v1.0.20"
-
-result3="$(echo "${MOCK_STRAY}" | resolve_prerelease_version)"
+result3="$(resolve_prerelease_version "mock://stray")"
 check "ignores non-version tags" bash -c "[ '${result3}' = 'v1.0.20' ]"
 
+# Cleanup
+rm -rf "${MOCK_DIR}"
+
 # Report result
 reportResults

From 74de86ac3215fea2b3af5a9792bbab80dfbaa1ed Mon Sep 17 00:00:00 2001
From: Kaniska <kaniska244@github.com>
Date: Fri, 22 May 2026 09:15:14 +0000
Subject: [PATCH 5/6] Add tests as per review comments without git ls and
 separate test for prerelease tag

---
 src/copilot-cli/install.sh                    |  15 +--
 test/copilot-cli/install_prerelease.sh        |  19 ++++
 .../copilot-cli/resolve_prerelease_version.sh | 106 ++++++++++--------
 test/copilot-cli/scenarios.json               |   8 ++
 4 files changed, 93 insertions(+), 55 deletions(-)
 create mode 100644 test/copilot-cli/install_prerelease.sh

diff --git a/src/copilot-cli/install.sh b/src/copilot-cli/install.sh
index d4c27ad1a..f53150575 100755
--- a/src/copilot-cli/install.sh
+++ b/src/copilot-cli/install.sh
@@ -45,16 +45,6 @@ download_from_github() {
     rm -rf /tmp/copilotcli
 }
 
-# Resolves the latest prerelease version tag from a remote repository.
-# Filters to well-formed vX.Y.Z or vX.Y.Z-N tags and sorts by version.
-resolve_prerelease_version() {
-    local repo_url="${1:?resolve_prerelease_version requires a repository URL}"
-    git ls-remote --tags "${repo_url}" \
-      | awk '{print $2}' | sed 's|refs/tags/||' \
-      | grep -E '^v[0-9]+\.[0-9]+\.[0-9]+(-[0-9]+)?$' \
-      | sort -V | tail -n1
-}
-
 install_using_github() {
     check_packages wget tar ca-certificates git
     echo "Finished setting up dependencies"
@@ -73,7 +63,10 @@ install_using_github() {
     if [ "${CLI_VERSION}" = "latest" ]; then
         download_from_github "https://github.com/github/copilot-cli/releases/latest/download/${cli_filename}"
     elif [ "${CLI_VERSION}" = "prerelease" ]; then
-        prerelease_version="$(resolve_prerelease_version "https://github.com/github/copilot-cli")"
+        prerelease_version="$(git ls-remote --tags https://github.com/github/copilot-cli \
+            | awk '{print $2}' | sed 's|refs/tags/||' \
+            | grep -E '^v[0-9]+\.[0-9]+\.[0-9]+(-[0-9]+)?$' \
+            | sort -V | tail -n1)"
         download_from_github "https://github.com/github/copilot-cli/releases/download/${prerelease_version}/${cli_filename}"
     else
         # Install specific version
diff --git a/test/copilot-cli/install_prerelease.sh b/test/copilot-cli/install_prerelease.sh
new file mode 100644
index 000000000..6ef707418
--- /dev/null
+++ b/test/copilot-cli/install_prerelease.sh
@@ -0,0 +1,19 @@
+#!/usr/bin/env bash
+
+set -e
+
+# Optional: Import test library
+source dev-container-features-test-lib
+
+# End-to-end check that the "prerelease" channel actually resolves a tag and
+# installs the binary. Regression guard for the inline pipeline in
+# src/copilot-cli/install.sh.
+
+check "copilot binary is on PATH" which copilot
+check "copilot reports a version" bash -c "copilot -v"
+
+# Auto-update flag file must exist for prerelease channel.
+check "auto-update flag created for prerelease" test -f /etc/devcontainer-copilot-cli/auto-update
+
+# Report result
+reportResults
diff --git a/test/copilot-cli/resolve_prerelease_version.sh b/test/copilot-cli/resolve_prerelease_version.sh
index 8369788c8..fd92c92b4 100644
--- a/test/copilot-cli/resolve_prerelease_version.sh
+++ b/test/copilot-cli/resolve_prerelease_version.sh
@@ -5,50 +5,68 @@ set -e
 # Optional: Import test library
 source dev-container-features-test-lib
 
-# Define the function under test (matches src/copilot-cli/install.sh)
-resolve_prerelease_version() {
-    local repo_url="${1:?resolve_prerelease_version requires a repository URL}"
-    git ls-remote --tags "${repo_url}" \
-      | awk '{print $2}' | sed 's|refs/tags/||' \
-      | grep -E '^v[0-9]+\.[0-9]+\.[0-9]+(-[0-9]+)?$' \
-      | sort -V | tail -n1
-}
-
-# Create a mock git script that returns controlled output
-MOCK_DIR="$(mktemp -d)"
-cat > "${MOCK_DIR}/git" << 'SCRIPT'
-#!/bin/bash
-# Return mock ls-remote output based on the repo URL argument
-repo="${*: -1}"
-case "${repo}" in
-  "mock://basic")
-    printf 'abc1234\trefs/tags/v1.0.1\ndef5678\trefs/tags/v1.0.9\nghi9012\trefs/tags/v1.0.10\njkl3456\trefs/tags/v1.0.45\nmno7890\trefs/tags/v1.0.2\n'
-    ;;
-  "mock://prerelease")
-    printf 'abc1234\trefs/tags/v1.0.44\ndef5678\trefs/tags/v1.0.45-1\nghi9012\trefs/tags/v1.0.45-10\njkl3456\trefs/tags/v1.0.45-2\nmno7890\trefs/tags/v1.0.45\n'
-    ;;
-  "mock://stray")
-    printf 'abc1234\trefs/tags/latest\ndef5678\trefs/tags/v1.0.3\nghi9012\trefs/tags/nightly\njkl3456\trefs/tags/v1.0.20\n'
-    ;;
-esac
-SCRIPT
-chmod +x "${MOCK_DIR}/git"
-export PATH="${MOCK_DIR}:${PATH}"
-
-# Test: version sort picks v1.0.45, not v1.0.9
-result="$(resolve_prerelease_version "mock://basic")"
-check "picks highest version (v1.0.45)" bash -c "[ '${result}' = 'v1.0.45' ]"
-
-# Test: prerelease numeric suffixes sort correctly
-result2="$(resolve_prerelease_version "mock://prerelease")"
-check "picks highest prerelease (v1.0.45-10)" bash -c "[ '${result2}' = 'v1.0.45-10' ]"
-
-# Test: filters out non-version tags
-result3="$(resolve_prerelease_version "mock://stray")"
-check "ignores non-version tags" bash -c "[ '${result3}' = 'v1.0.20' ]"
-
-# Cleanup
-rm -rf "${MOCK_DIR}"
+# Tests the tag-resolution pipeline used by src/copilot-cli/install.sh for the
+# "prerelease" channel. The `git ls-remote` part is intentionally not exercised;
+# fixtures are piped directly into the same awk|sed|grep|sort|tail pipeline.
+
+# Regression: alphabetic sort would pick v1.0.9; version sort must pick v1.0.45 (issue #1646).
+basic=$'abc1234\trefs/tags/v1.0.1\ndef5678\trefs/tags/v1.0.9\nghi9012\trefs/tags/v1.0.10\njkl3456\trefs/tags/v1.0.45\nmno7890\trefs/tags/v1.0.2'
+check "picks highest semver (v1.0.45, not v1.0.9)" bash -c "
+    result=\$(printf '%s\n' \"$basic\" \
+        | awk '{print \$2}' | sed 's|refs/tags/||' \
+        | grep -E '^v[0-9]+\\.[0-9]+\\.[0-9]+(-[0-9]+)?\$' \
+        | sort -V | tail -n1)
+    [ \"\$result\" = 'v1.0.45' ]
+"
+
+# Numeric prerelease suffixes: -10 > -2 (not alphabetic).
+prerelease=$'abc1234\trefs/tags/v1.0.44\ndef5678\trefs/tags/v1.0.45-1\nghi9012\trefs/tags/v1.0.45-10\njkl3456\trefs/tags/v1.0.45-2\nmno7890\trefs/tags/v1.0.45'
+check "picks highest prerelease suffix (v1.0.45-10)" bash -c "
+    result=\$(printf '%s\n' \"$prerelease\" \
+        | awk '{print \$2}' | sed 's|refs/tags/||' \
+        | grep -E '^v[0-9]+\\.[0-9]+\\.[0-9]+(-[0-9]+)?\$' \
+        | sort -V | tail -n1)
+    [ \"\$result\" = 'v1.0.45-10' ]
+"
+
+# Stray refs (latest, nightly, etc.) must be filtered out.
+stray=$'abc1234\trefs/tags/latest\ndef5678\trefs/tags/v1.0.3\nghi9012\trefs/tags/nightly\njkl3456\trefs/tags/v1.0.20'
+check "ignores non-version tags" bash -c "
+    result=\$(printf '%s\n' \"$stray\" \
+        | awk '{print \$2}' | sed 's|refs/tags/||' \
+        | grep -E '^v[0-9]+\\.[0-9]+\\.[0-9]+(-[0-9]+)?\$' \
+        | sort -V | tail -n1)
+    [ \"\$result\" = 'v1.0.20' ]
+"
+
+# Anchored regex must reject tags with trailing junk (e.g. v1.0.5-rc1, v1.0.6foo).
+anchored=$'a\trefs/tags/v1.0.5\nb\trefs/tags/v1.0.5-rc1\nc\trefs/tags/v1.0.6foo'
+check "anchored regex rejects v1.0.5-rc1 and v1.0.6foo" bash -c "
+    result=\$(printf '%s\n' \"$anchored\" \
+        | awk '{print \$2}' | sed 's|refs/tags/||' \
+        | grep -E '^v[0-9]+\\.[0-9]+\\.[0-9]+(-[0-9]+)?\$' \
+        | sort -V | tail -n1)
+    [ \"\$result\" = 'v1.0.5' ]
+"
+
+# Empty input must produce empty output (no crash, no garbage).
+check "empty input -> empty output" bash -c "
+    result=\$(printf '' \
+        | awk '{print \$2}' | sed 's|refs/tags/||' \
+        | grep -E '^v[0-9]+\\.[0-9]+\\.[0-9]+(-[0-9]+)?\$' \
+        | sort -V | tail -n1)
+    [ -z \"\$result\" ]
+"
+
+# No matching tags -> empty output.
+nomatch=$'a\trefs/tags/main\nb\trefs/tags/HEAD'
+check "no version tags -> empty output" bash -c "
+    result=\$(printf '%s\n' \"$nomatch\" \
+        | awk '{print \$2}' | sed 's|refs/tags/||' \
+        | grep -E '^v[0-9]+\\.[0-9]+\\.[0-9]+(-[0-9]+)?\$' \
+        | sort -V | tail -n1)
+    [ -z \"\$result\" ]
+"
 
 # Report result
 reportResults
diff --git a/test/copilot-cli/scenarios.json b/test/copilot-cli/scenarios.json
index 87fcc541d..3d8336bec 100644
--- a/test/copilot-cli/scenarios.json
+++ b/test/copilot-cli/scenarios.json
@@ -6,5 +6,13 @@
         "version": "latest"
       }
     }
+  },
+  "install_prerelease": {
+    "image": "ubuntu:noble",
+    "features": {
+      "copilot-cli": {
+        "version": "prerelease"
+      }
+    }
   }
 }

From 6c0eac085eee448e23c5f5e1482ac7f8b6f4ff15 Mon Sep 17 00:00:00 2001
From: Kaniska <kaniska244@github.com>
Date: Fri, 22 May 2026 15:00:09 +0000
Subject: [PATCH 6/6] Further changes in the test and code cleanup

---
 src/copilot-cli/install.sh                    | 15 +++-
 .../copilot-cli/resolve_prerelease_version.sh | 74 +++++--------------
 2 files changed, 28 insertions(+), 61 deletions(-)

diff --git a/src/copilot-cli/install.sh b/src/copilot-cli/install.sh
index f53150575..ad4a19701 100755
--- a/src/copilot-cli/install.sh
+++ b/src/copilot-cli/install.sh
@@ -31,6 +31,14 @@ check_packages() {
     fi
 }
 
+resolve_prerelease_version() {
+    local repo_versions="${1:?resolve_prerelease_version requires the copilot-cli repo tags as input}"
+    printf '%s\n' "${repo_versions}" \
+      | awk '{print $2}' | sed 's|refs/tags/||' \
+      | grep -E '^v[0-9]+\.[0-9]+\.[0-9]+(-[0-9]+)?$' \
+      | sort -V | tail -n1
+}
+
 download_from_github() {
     local release_url=$1
     echo "Downloading GitHub Copilot CLI from ${release_url}..."
@@ -63,11 +71,10 @@ install_using_github() {
     if [ "${CLI_VERSION}" = "latest" ]; then
         download_from_github "https://github.com/github/copilot-cli/releases/latest/download/${cli_filename}"
     elif [ "${CLI_VERSION}" = "prerelease" ]; then
-        prerelease_version="$(git ls-remote --tags https://github.com/github/copilot-cli \
-            | awk '{print $2}' | sed 's|refs/tags/||' \
-            | grep -E '^v[0-9]+\.[0-9]+\.[0-9]+(-[0-9]+)?$' \
-            | sort -V | tail -n1)"
+
+        prerelease_version="$(resolve_prerelease_version "$(git ls-remote --tags https://github.com/github/copilot-cli)")"
         download_from_github "https://github.com/github/copilot-cli/releases/download/${prerelease_version}/${cli_filename}"
+        
     else
         # Install specific version
         # Add leading v to version if it doesn't start with v
diff --git a/test/copilot-cli/resolve_prerelease_version.sh b/test/copilot-cli/resolve_prerelease_version.sh
index fd92c92b4..aa4ff41fd 100644
--- a/test/copilot-cli/resolve_prerelease_version.sh
+++ b/test/copilot-cli/resolve_prerelease_version.sh
@@ -5,68 +5,28 @@ set -e
 # Optional: Import test library
 source dev-container-features-test-lib
 
-# Tests the tag-resolution pipeline used by src/copilot-cli/install.sh for the
-# "prerelease" channel. The `git ls-remote` part is intentionally not exercised;
-# fixtures are piped directly into the same awk|sed|grep|sort|tail pipeline.
-
-# Regression: alphabetic sort would pick v1.0.9; version sort must pick v1.0.45 (issue #1646).
-basic=$'abc1234\trefs/tags/v1.0.1\ndef5678\trefs/tags/v1.0.9\nghi9012\trefs/tags/v1.0.10\njkl3456\trefs/tags/v1.0.45\nmno7890\trefs/tags/v1.0.2'
-check "picks highest semver (v1.0.45, not v1.0.9)" bash -c "
-    result=\$(printf '%s\n' \"$basic\" \
-        | awk '{print \$2}' | sed 's|refs/tags/||' \
-        | grep -E '^v[0-9]+\\.[0-9]+\\.[0-9]+(-[0-9]+)?\$' \
-        | sort -V | tail -n1)
-    [ \"\$result\" = 'v1.0.45' ]
-"
+resolve_prerelease_version() {
+    local repo_versions="${1:?resolve_prerelease_version requires the copilot-cli repo tags as input}"
+    printf '%s\n' "${repo_versions}" \
+      | awk '{print $2}' | sed 's|refs/tags/||' \
+      | grep -E '^v[0-9]+\.[0-9]+\.[0-9]+(-[0-9]+)?$' \
+      | sort -V | tail -n1
+}
 
-# Numeric prerelease suffixes: -10 > -2 (not alphabetic).
-prerelease=$'abc1234\trefs/tags/v1.0.44\ndef5678\trefs/tags/v1.0.45-1\nghi9012\trefs/tags/v1.0.45-10\njkl3456\trefs/tags/v1.0.45-2\nmno7890\trefs/tags/v1.0.45'
-check "picks highest prerelease suffix (v1.0.45-10)" bash -c "
-    result=\$(printf '%s\n' \"$prerelease\" \
-        | awk '{print \$2}' | sed 's|refs/tags/||' \
-        | grep -E '^v[0-9]+\\.[0-9]+\\.[0-9]+(-[0-9]+)?\$' \
-        | sort -V | tail -n1)
-    [ \"\$result\" = 'v1.0.45-10' ]
-"
+# Tests the tag-resolution pipeline used by src/copilot-cli/install.sh for the
+# "prerelease" channel. 
 
-# Stray refs (latest, nightly, etc.) must be filtered out.
-stray=$'abc1234\trefs/tags/latest\ndef5678\trefs/tags/v1.0.3\nghi9012\trefs/tags/nightly\njkl3456\trefs/tags/v1.0.20'
-check "ignores non-version tags" bash -c "
-    result=\$(printf '%s\n' \"$stray\" \
-        | awk '{print \$2}' | sed 's|refs/tags/||' \
-        | grep -E '^v[0-9]+\\.[0-9]+\\.[0-9]+(-[0-9]+)?\$' \
-        | sort -V | tail -n1)
-    [ \"\$result\" = 'v1.0.20' ]
-"
+check "copilot binary is on PATH" which copilot
+check "copilot reports a version" bash -c "copilot -v"
 
-# Anchored regex must reject tags with trailing junk (e.g. v1.0.5-rc1, v1.0.6foo).
-anchored=$'a\trefs/tags/v1.0.5\nb\trefs/tags/v1.0.5-rc1\nc\trefs/tags/v1.0.6foo'
-check "anchored regex rejects v1.0.5-rc1 and v1.0.6foo" bash -c "
-    result=\$(printf '%s\n' \"$anchored\" \
-        | awk '{print \$2}' | sed 's|refs/tags/||' \
-        | grep -E '^v[0-9]+\\.[0-9]+\\.[0-9]+(-[0-9]+)?\$' \
-        | sort -V | tail -n1)
-    [ \"\$result\" = 'v1.0.5' ]
-"
+result1="$(resolve_prerelease_version $'abc1234\trefs/tags/v1.0.1\ndef5678\trefs/tags/v1.0.9\nghi9012\trefs/tags/v1.0.10\njkl3456\trefs/tags/v1.0.45\nmno7890\trefs/tags/v1.0.2\n')"
+check "picks highest version (v1.0.45)" bash -c "[ '${result1}' = 'v1.0.45' ]"
 
-# Empty input must produce empty output (no crash, no garbage).
-check "empty input -> empty output" bash -c "
-    result=\$(printf '' \
-        | awk '{print \$2}' | sed 's|refs/tags/||' \
-        | grep -E '^v[0-9]+\\.[0-9]+\\.[0-9]+(-[0-9]+)?\$' \
-        | sort -V | tail -n1)
-    [ -z \"\$result\" ]
-"
+result2="$(resolve_prerelease_version $'abc1234\trefs/tags/v1.0.44\ndef5678\trefs/tags/v1.0.45-1\nghi9012\trefs/tags/v1.0.45-10\njkl3456\trefs/tags/v1.0.45-2\nmno7890\trefs/tags/v1.0.45\n')"
+check "picks highest prerelease (v1.0.45-10)" bash -c "[ '${result2}' = 'v1.0.45-10' ]"
 
-# No matching tags -> empty output.
-nomatch=$'a\trefs/tags/main\nb\trefs/tags/HEAD'
-check "no version tags -> empty output" bash -c "
-    result=\$(printf '%s\n' \"$nomatch\" \
-        | awk '{print \$2}' | sed 's|refs/tags/||' \
-        | grep -E '^v[0-9]+\\.[0-9]+\\.[0-9]+(-[0-9]+)?\$' \
-        | sort -V | tail -n1)
-    [ -z \"\$result\" ]
-"
+result3="$(resolve_prerelease_version $'abc1234\trefs/tags/latest\ndef5678\trefs/tags/v1.0.3\nghi9012\trefs/tags/nightly\njkl3456\trefs/tags/v1.0.20\n')"
+check "picks highest version ignoring non-version tags (v1.0.20)" bash -c "[ '${result3}' = 'v1.0.20' ]"
 
 # Report result
 reportResults