Add code-generation facilities for adding new rustdoc versions. (#36)

crates/generator/Cargo.toml

@@ -0,0 +1,11 @@
+[workspace]
+
+[package]
+name = "generator"
+publish = false
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+fs-err = "2.11.0"
+handlebars = "5.1.2"

crates/generator/src/main.rs

@@ -0,0 +1,41 @@
+use std::{collections::BTreeMap, env, path::Path};
+
+use handlebars::Handlebars;
+
+fn main() {
+    let versions: Vec<i64> = env::args()
+        .skip(1) // skip the binary's own name, only keep explicit args
+        .map(|value| {
+            value
+                .parse()
+                .unwrap_or_else(|e| panic!("invalid version \"{value}\": {e}"))
+        })
+        .collect();
+    let mut handlebars = Handlebars::new();
+    let mut args = BTreeMap::new();
+    args.insert("version_numbers", versions.as_slice());
+
+    let template_and_output = [
+        ("../../template/parser.template.rs", "../../src/parser.rs"),
+        ("../../template/query.template.rs", "../../src/query.rs"),
+        (
+            "../../template/versioned.template.rs",
+            "../../src/versioned.rs",
+        ),
+    ];
+    for (template_file, target) in template_and_output {
+        let output = materialize(&mut handlebars, Path::new(template_file), &args);
+        fs_err::write(Path::new(target), output).expect("failed to write file");
+    }
+}
+
+fn materialize(
+    handlebars: &mut Handlebars,
+    template_file: &Path,
+    args: &BTreeMap<&str, &[i64]>,
+) -> String {
+    let template = fs_err::read_to_string(template_file).expect("failed to read file");
+    handlebars
+        .render_template(&template, args)
+        .expect("failed to render template")
+}

scripts/add_next_rustdoc_version.sh

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+#!/usr/bin/env bash
+
+# Script requirements:
+# - python
+# - yq
+
+# Fail on first error, on undefined variables, and on failures in pipelines.
+set -euo pipefail
+
+# Go to the repo root directory.
+cd "$(git rev-parse --show-toplevel)"
+
+CURRENT_VERSIONS="$(yq '.features.default' Cargo.toml -o json | \
+    python -m json.tool --compact | \
+    sed 's/,/, /g' | \
+    sed 's/\[//g' | \
+    sed 's/]//g')"
+NEXT_VERSION_NUMBER="$(yq '.features.default.[-1] | sub("v(\d+)", "${1}") | to_number | (. + 1)' Cargo.toml -o json -r)"
+
+ALL_VERSIONS="$(yq '.features.default[] | sub("v(\d+)", "${1}")' Cargo.toml -o json -r) ${NEXT_VERSION_NUMBER}"
+
+# Generate the new Rust source for the specified versions.
+pushd crates/generator
+cargo run -- $ALL_VERSIONS
+popd
+
+# Reformat the generated Rust source code.
+cargo fmt
+
+# Update the Cargo.toml file to add the new dependency and feature number.
+
+# '1h;2,$H;$!d;g' means "look two lines at a time":
+# https://unix.stackexchange.com/questions/26284/how-can-i-use-sed-to-replace-a-multi-line-string
+sed -e '1h;2,$H;$!d;g' \
+    -e "s/\n\[features\]/trustfall-rustdoc-adapter-v${NEXT_VERSION_NUMBER} = { package = \"trustfall-rustdoc-adapter\", version = \">=${NEXT_VERSION_NUMBER}.0.0,<${NEXT_VERSION_NUMBER}.1.0\", optional = true }\n\n[features]/" \
+    -i Cargo.toml
+
+DEFAULT_MATCHER="default = \[${CURRENT_VERSIONS}\]"
+sed -e "s/$DEFAULT_MATCHER/default = [${CURRENT_VERSIONS}, \"v${NEXT_VERSION_NUMBER}\"]/" \
+    -i Cargo.toml
+
+echo "v${NEXT_VERSION_NUMBER} = [\"dep:trustfall-rustdoc-adapter-v${NEXT_VERSION_NUMBER}\"]" >>Cargo.toml
+
+# Ensure cargo regenerates the lockfile.
+cargo check