Add shellcheck as a linter.

Fixes #10162.

Tweaked by tabbott to cover documentation as well.

Signed-off-by: Anders Kaseorg <andersk@mit.edu>

docs/testing/linters.md

@@ -210,10 +210,19 @@ its CSS; see our
 [configuration](https://github.com/zulip/zulip/blob/master/.stylelintrc)
 for the rules we currently enforce.
 
+#### Shell scripts
+
+Zulip uses [shellcheck](https://github.com/koalaman/shellcheck) to
+lint our shell scripts.  We recommend the
+[shellcheck gallery of bad code][shellcheck-bad-code] as a resource on
+how to not write bad shell.
+
+[shellcheck-bad-code]: https://github.com/koalaman/shellcheck/blob/master/README.md#user-content-gallery-of-bad-code
+
 #### Markdown, shell scripts, JSON fixtures
 
-We mostly validate miscellaneous source files like `.sh`, `.json`, and `.md` files for
-whitespace issues.
+We mostly validate miscellaneous source files like `.json`, and `.md`
+files for whitespace issues.
 
 ## Philosophy
 

scripts/lib/install-shellcheck

@@ -0,0 +1,14 @@
+#!/bin/bash
+set -eu
+
+version=0.5.0
+
+if ! out="$(shellcheck --version 2>/dev/null)" || [[ "$out" != *"
+version: $version
+"* ]]; then
+    tmpdir="$(mktemp -d)"
+    trap 'rm -r "$tmpdir"' EXIT
+    cd "$tmpdir"
+    wget -nv "https://storage.googleapis.com/shellcheck/shellcheck-v$version.linux.x86_64.tar.xz"
+    tar -xJf "shellcheck-v$version.linux.x86_64.tar.xz" --no-same-owner --strip-components=1 -C /usr/local/bin "shellcheck-v$version/shellcheck"
+fi

tools/lib/provision.py

@@ -260,6 +260,9 @@ def main(options):
         print(WARNING + "`yarn install` failed; retrying..." + ENDC)
         setup_node_modules()
 
+    # Install shellcheck.
+    run(["sudo", "scripts/lib/install-shellcheck"])
+
     # Import tools/setup_venv.py instead of running it so that we get an
     # activated virtualenv for the rest of the provisioning process.
     from tools.setup import setup_venvs

tools/lint

@@ -97,6 +97,7 @@ def run():
     linter_config.external_linter('templates', ['tools/check-templates'], ['handlebars', 'html'])
     linter_config.external_linter('urls', ['tools/check-urls'], ['py'])
     linter_config.external_linter('swagger', ['node', 'tools/check-swagger'], ['yaml'])
+    linter_config.external_linter('shellcheck', ['shellcheck', '-x'], ['sh'])
 
     # Disabled check for imperative mood until it is stabilized
     if not args.no_gitlint:

tools/linter_lib/exclude.py

@@ -8,6 +8,8 @@ EXCLUDED_FILES = [
     "puppet/apt/manifests/release.pp",
     "puppet/apt/manifests/unattended_upgrades.pp",
     "puppet/stdlib/tests/file_line.pp",
+    "puppet/zulip/files/nagios_plugins/zulip_nagios_server/check_website_response.sh",
+    "scripts/lib/third",
     "static/third",
     # Transifex syncs translation.json files without trailing
     # newlines; there's nothing other than trailing newlines we'd be

version.py

@@ -8,4 +8,4 @@ ZULIP_VERSION = "1.9.0-rc2+git"
 # Typically, adding a dependency only requires a minor version bump, and
 # removing a dependency requires a major version bump.
 
-PROVISION_VERSION = '26.9'
+PROVISION_VERSION = '26.10'