feat: Improve error message (#22)

build_script/BUILD.bazel

@@ -6,11 +6,16 @@ package(
 )
 
 sh_binary(
-    name = "conditionally_execute",
-    srcs = ["conditionally_execute.bash"],
+    name = "check_each_message",
+    srcs = ["check_each_message.bash"],
 )
 
 sh_binary(
     name = "check_emptiness",
     srcs = ["check_emptiness.bash"],
 )
+
+sh_binary(
+    name = "try_build",
+    srcs = ["try_build.bash"],
+)

build_script/check_each_message.bash

@@ -0,0 +1,53 @@
+#!/usr/bin/env bash
+
+set -euo pipefail
+
+usage() {
+    cat <<EOS >&2
+Check each message file.
+
+Exits with an error if the pattern is not found in the message file.
+
+Usage: $0 MATCHER PATTERN MESSAGE_FILE [MARKER_FILE ...]
+
+MATCHER
+    Executable to check if the pattern string is inside the message file
+
+PATTERN
+    Pattern string
+
+MESSAGE_FILE
+    Text file containing a message
+
+MARKER_FILE ...
+    Empty text files are created at the specified paths before exiting the script
+EOS
+}
+
+if [ "$#" -lt 3 ]; then
+  echo "ERROR: Incorrect number of arguments" >&2
+  usage
+  exit 1
+fi
+
+matcher=$1
+pattern=$2
+message_file=$3
+shift 3
+
+files_to_touch=("$@")
+
+# Make sure the required files are touched before exiting
+if [[ "${#files_to_touch[@]}" -gt 0 ]]; then
+    trap 'touch "${files_to_touch[@]}"' EXIT
+fi
+
+if ! "${matcher}" "${pattern}" "${message_file}" ; then
+    echo "Pattern '${pattern}' is not found in the message file '${message_file}' with the matcher '${matcher}'." >&2
+    echo "" >&2
+    echo "---------- Message: BEGIN ----------" >&2
+    cat "${message_file}" >&2
+    echo "---------- Message:  END  ----------" >&2
+    echo "" >&2
+    exit 1
+fi

build_script/check_emptiness.bash

@@ -16,7 +16,7 @@ OPTIONS
     -m MESSAGE
         Error message when no files are empty
     -n NEW_FILE_PATH
-        If specified, create a new empty file
+        If specified, create a new empty file before exiting the script
 EOS
 }
 

build_script/conditionally_execute.bash → build_script/try_build.bash

@@ -4,17 +4,17 @@ set -euo pipefail
 
 usage() {
     cat <<EOS >&2
-Wrapper to conditionally execute the command.
+Try building the code.
 
 With the option '-f', this script can receive arbitrary number of files.
 If any of them is an empty file, this script exits successfully
-without executing the command.
+without executing the build command.
+
+Even if the build command fails, this script won't exit with an error.
 
 Usage: $0 [OPTIONS] COMMAND
 
 OPTIONS
-    -i
-        Ignore error when executing the command.
     -f FILE_TO_CHECK
         Successfully exit if the file is empty
     -h
@@ -23,12 +23,11 @@ OPTIONS
         A file path to write stderr message
     -o STDOUT_FILE
         A file path to write stdout message
-    -m MESSAGE
-        Message when the command fails
     -n NEW_FILE_PATH
-        If specified, create a new empty file before executing the command
+        If specified, create a new empty file with 'touch' before exiting the script.
 
 COMMAND
+    Build command.
     Executed if there's no empty file given with '-f'.
 EOS
 }
@@ -53,10 +52,10 @@ exit_if_empty_file() {
 
 files_to_check=()
 files_to_touch=()
-ignore_error="false"
-error_message="ERROR: execution failed"
+stdout_file="/dev/null"
+stderr_file="/dev/null"
 
-while getopts "e:f:him:n:o:" opt; do
+while getopts "e:f:hn:o:" opt; do
     case "${opt}" in
         e)
             stderr_file="${OPTARG}"
@@ -68,12 +67,6 @@ while getopts "e:f:him:n:o:" opt; do
             usage
             exit 0
         ;;
-        i)
-            ignore_error="true"
-        ;;
-        m)
-            error_message="${OPTARG}"
-        ;;
         n)
             files_to_touch+=("${OPTARG}")
         ;;
@@ -95,11 +88,4 @@ if [[ "${#files_to_check[@]}" -gt 0 ]]; then
     done
 fi
 
-if [[ "${ignore_error}" == "true" ]]; then
-    "$@" >"${stdout_file:-"/dev/null"}" 2>"${stderr_file:-"/dev/null"}" || true
-else
-    if ! "$@" >"${stdout_file:-"/dev/null"}" 2>"${stderr_file:-"/dev/null"}" ; then
-        echo "${error_message}"
-        exit 1
-    fi
-fi
+"$@" >"${stdout_file}" 2>"${stderr_file}" || true

lang/cc/build_error.bzl

@@ -138,9 +138,8 @@ def _try_compile(ctx):
     # Input files for executing the action
     inputs = [ctx.file.src]
 
-    # Arguments for `conditionally_execute`
+    # Arguments for `try_build.bash`
     args = ctx.actions.args()
-    args.add("-i")
     args.add("-e", compile_stderr)
     args.add("-o", compile_stdout)
     args.add("-n", compile_output)
@@ -169,7 +168,7 @@ def _try_compile(ctx):
     ctx.actions.run(
         outputs = [compile_output, compile_stdout, compile_stderr],
         inputs = inputs,
-        executable = _get_executable_file(ctx.attr._conditionally_execute),
+        executable = _get_executable_file(ctx.attr._try_build),
         arguments = [args],
         tools = cc_toolchain.all_files,
     )
@@ -228,9 +227,8 @@ def _try_link(ctx, compile_output):
 
     inputs = [compile_output] + ctx.attr.additional_linker_inputs
 
-    # Arguments for `conditionally_execute`
+    # Arguments for `try_build.bash`
     args = ctx.actions.args()
-    args.add("-i")
     args.add("-e", link_stderr)
     args.add("-o", link_stdout)
     args.add("-n", link_output)
@@ -262,7 +260,7 @@ def _try_link(ctx, compile_output):
     ctx.actions.run(
         outputs = [link_output, link_stdout, link_stderr],
         inputs = inputs,
-        executable = _get_executable_file(ctx.attr._conditionally_execute),
+        executable = _get_executable_file(ctx.attr._try_build),
         arguments = [args],
         tools = cc_toolchain.all_files,
     )
@@ -383,8 +381,8 @@ _try_build = rule(
         "_check_emptiness": attr.label(
             default = Label("//build_script:check_emptiness"),
         ),
-        "_conditionally_execute": attr.label(
-            default = Label("//build_script:conditionally_execute"),
+        "_try_build": attr.label(
+            default = Label("//build_script:try_build"),
         ),
     },
     fragments = ["cpp"],
@@ -436,20 +434,12 @@ def _check_each_message(ctx, message_file, matcher, pattern):
         ctx.actions.run(
             outputs = [marker_file],
             inputs = [message_file],
-            executable = _get_executable_file(ctx.attr._conditionally_execute),
+            executable = _get_executable_file(ctx.attr._check_each_message),
             arguments = [
-                "-m",
-                "Pattern '{pattern}' is not found in '{message_file}' with the matcher '{matcher}'".format(
-                    pattern = pattern,
-                    message_file = message_file.path,
-                    matcher = matcher.path,
-                ),
-                "-n",
-                marker_file.path,
-                # From here, the matcher command starts
                 matcher.path,
                 pattern,
                 message_file.path,
+                marker_file.path,
             ],
             tools = [matcher],
         )
@@ -551,8 +541,8 @@ _check_messages = rule(
             doc = "Pattern string for stdout while linking",
             mandatory = False,
         ),
-        "_conditionally_execute": attr.label(
-            default = Label("//build_script:conditionally_execute"),
+        "_check_each_message": attr.label(
+            default = Label("//build_script:check_each_message"),
         ),
     },
     provides = [CcBuildErrorInfo, DefaultInfo],