Clean up CI bash scripts, add docs/STYLE_GUIDE.md

docs/STYLE_GUIDE.md

@@ -0,0 +1,29 @@
+# Style Guide
+
+The majority of our style recommendations are automatically enforced via our
+automated linters. This document has guidelines that are less easy to lint for.
+
+## Shell scripts
+
+Shell scripts are OK for small tasks or wrappers, but prefer to use Python for
+anything with a hint of complexity or in general.
+
+Shell scripts should be written against bash, starting with this shebang:
+```
+#!/usr/bin/env bash
+```
+
+Note that the version of bash available on OS X by default is quite old, so be
+careful when using new features.
+
+Scripts should enable a few options at the top for robustness:
+```
+set -o errexit
+set -o nounset
+set -o pipefail
+```
+
+Quote all variables, using the full form: `"${SOME_VARIABLE}"`.
+
+Use `"$(some-command)"` instead of backticks for command substitution. Note
+that these should be quoted as well.

etc/ci/check_no_unwrap.sh

@@ -1,11 +1,12 @@
-#!/bin/bash
+#!/usr/bin/env bash
 #
 # Make sure listed files do not contain "unwrap"
+
 set -o errexit
 set -o nounset
 set -o pipefail
 
-cd $(git rev-parse --show-toplevel) # cd into repo root so make sure paths works in any case
+cd "$(git rev-parse --show-toplevel)" # cd into repo root so make sure paths works in any case
 
 # files that should not contain "unwrap"
 FILES=("components/compositing/compositor.rs"

etc/ci/lockfile_changed.sh

@@ -1,4 +1,9 @@
-#!/bin/bash
-diff=$(git diff -- */*/Cargo.lock)
+#!/usr/bin/env bash
+
+set -o errexit
+set -o nounset
+set -o pipefail
+
+diff="$(git diff -- */*/Cargo.lock)"
 echo "$diff"
 [[ ! $diff ]]

etc/ci/manifest_changed.sh

@@ -1,4 +1,5 @@
-#!/bin/bash
+#!/usr/bin/env bash
+
 set -o errexit
 set -o nounset
 set -o pipefail
@@ -11,6 +12,6 @@ set -o pipefail
 # Adding "--binary=" to skip looking for a compiled servo binary.
 ./mach test-wpt --manifest-update --binary= SKIP_TESTS > /dev/null
 
-diff=$(git diff -- tests/*/MANIFEST.json)
+diff="$(git diff -- tests/*/MANIFEST.json)"
 echo "$diff"
 [[ ! $diff ]]

etc/ci/retry.sh

@@ -1,17 +1,19 @@
-#!/bin/bash
+#!/usr/bin/env bash
 
 # Retries a given command until it passes
 # Run as `retry.sh N command args...`
 # where `N` is the maximum  number of tries, and `command args...` is the
 # command to run, with arguments
 
-n=$1
+set -o errexit
+set -o nounset
+set -o pipefail
+
+n="$1"
 shift; # this removes the first argument from $@
-for i in `seq $n`; do
+for i in $(seq $n); do
         echo "====== RUN NUMBER: $i ======";
-        if $@ # run command, check if exit code is zero
-        then
-                exit 0 # command passed, all is well
-        fi
+        # Run command and exit success if return code is 0, else ignore it
+        "$@" && exit 0 || true
 done
 exit 1

etc/ci/upload_docs.sh

@@ -1,10 +1,12 @@
-#!/bin/bash
+#!/usr/bin/env bash
 #
 # Helper script to upload docs to doc.servo.org.
 # Requires ghp-import (from pip)
 # GitHub API token must be passed in environment var TOKEN
 
-set -e
+set -o errexit
+set -o nounset
+set -o pipefail
 
 cd "$(dirname $0)/../.."
 
@@ -15,4 +17,4 @@ cp etc/doc.servo.org/* target/doc/
 python components/style/properties/build.py servo html
 
 ghp-import -n target/doc
-git push -qf https://${TOKEN}@github.com/servo/doc.servo.org.git gh-pages
+git push -qf "https://${TOKEN}@github.com/servo/doc.servo.org.git" gh-pages