validate_example.bash

#!/usr/bin/env bash
#
# Validate example directory

set -euo pipefail

SCRIPT_DIR=$(cd -- "$( dirname -- "${BASH_SOURCE[0]}" )" &> /dev/null && pwd)
source "${SCRIPT_DIR}/common.bash"

cd "${REPO_ROOT_DIR}/examples"


# Collect incompatibility flags to raise early warnings for potential migration blockers.

# URL of the YAML file containing a mapping of Bazel incompatibility flags to affected Bazel versions.
INCOMPATIBILITY_FLAGS_URL="https://raw.githubusercontent.com/bazelbuild/bazel-central-registry/main/incompatible_flags.yml"

# Extract the Bazel version in use.
BAZEL_VERSION="$(bazel --version | cut -d' ' -f2)"

# Download the YAML content
INCOMPATIBILITY_FLAGS_YAML=$(curl "${INCOMPATIBILITY_FLAGS_URL}" 2>/dev/null)

# Normalize the YAML into a flat list containing flags and versions.
INCOMPATIBILITY_FLAGS_FLATTENED=$(echo "${INCOMPATIBILITY_FLAGS_YAML}" \
    | perl -ne '
        next if /^\s*#/;                        # Skip full-line comments
        s/#.*$//;                               # Remove trailing comments
        s/^\s*-\s+//;                           # Remove leading dash and spaces from list items (i.e. Bazel versions)
        s/^\s*"\s*([^"]+)\s*"\s*:*$/$1/;        # Extract key (i.e. incompatibility flag) from quoted key
        print if /\S/;                          # Skip empty lines
    '
)

# Initialize array to collect incompatibility flags supported for the current Bazel version.
incompatibility_flags=()

# Track the current flag while iterating over the flattened lines.
current_flag=""

# Read the lines one by one.
# If the line is a flag (starts with "--"), update `current_flag`.
# If the line matches the Bazel version, add the current_flag to the results.
while IFS= read -r line; do
    if [[ "${line}" == --* ]]; then
        current_flag="${line}"
    elif [[ "${line}" == "${BAZEL_VERSION}" ]]; then
        incompatibility_flags+=("${current_flag}")
    fi
done <<< "${INCOMPATIBILITY_FLAGS_FLATTENED}"

if [[ "${#incompatibility_flags[@]}" -eq 0 ]]; then
    bazel test //...
else
    echo "INFO: Incompatibility flags enabled:" "${incompatibility_flags[@]}"
    bazel test "${incompatibility_flags[@]}" //...
fi