From db529a2e91d6731e8b5e052e1b7b7092be268918 Mon Sep 17 00:00:00 2001
From: Bas Zalmstra <zalmstra.bas@gmail.com>
Date: Mon, 22 Jul 2024 15:38:43 +0200
Subject: [PATCH] feat: use implicit variants.yaml

---
 src/consts.rs |  3 +++
 src/lib.rs    | 75 ++++++++++++++++++++++++++++++---------------------
 2 files changed, 48 insertions(+), 30 deletions(-)
 create mode 100644 src/consts.rs

diff --git a/src/consts.rs b/src/consts.rs
new file mode 100644
index 00000000..370a6b6a
--- /dev/null
+++ b/src/consts.rs
@@ -0,0 +1,3 @@
+/// A `recipe.yaml` file might be accompanied by a `variants.toml` file from
+/// which we can read variant configuration for that specific recipe..
+pub const VARIANTS_CONFIG_FILE: &str = "variants.toml";
diff --git a/src/lib.rs b/src/lib.rs
index f2263f4a..b2e58c57 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -22,6 +22,7 @@ pub mod used_variables;
 pub mod utils;
 pub mod variant_config;
 
+mod consts;
 mod env_vars;
 pub mod hash;
 mod linux;
@@ -33,41 +34,35 @@ mod unix;
 pub mod upload;
 mod windows;
 
-use build::skip_existing;
+use std::{
+    collections::{BTreeMap, HashMap},
+    env::current_dir,
+    path::{Path, PathBuf},
+    sync::{Arc, Mutex},
+};
 
+use build::{run_build, skip_existing};
+use console_utils::LoggingOutputHandler;
 use dunce::canonicalize;
 use fs_err as fs;
-use metadata::Output;
+use hash::HashInfo;
+use metadata::{
+    BuildConfiguration, BuildSummary, Directories, Output, PackageIdentifier, PackagingSettings,
+};
 use miette::{IntoDiagnostic, WrapErr};
+use opt::*;
+use package_test::TestConfiguration;
 use petgraph::{algo::toposort, graph::DiGraph, visit::DfsPostOrder};
 use rattler_conda_types::{package::ArchiveType, Channel, ChannelConfig, Platform};
 use rattler_solve::{ChannelPriority, SolveStrategy};
-use recipe::parser::Dependency;
-use std::{
-    collections::{BTreeMap, HashMap},
-    env::current_dir,
-    path::{Path, PathBuf},
-    sync::{Arc, Mutex},
+use recipe::{
+    parser::{find_outputs_from_src, Dependency, Recipe},
+    ParsingError,
 };
+use selectors::SelectorConfig;
+use system_tools::SystemTools;
 use tool_configuration::Configuration;
-
-use {
-    build::run_build,
-    console_utils::LoggingOutputHandler,
-    hash::HashInfo,
-    metadata::{
-        BuildConfiguration, BuildSummary, Directories, PackageIdentifier, PackagingSettings,
-    },
-    opt::*,
-    package_test::TestConfiguration,
-    recipe::{
-        parser::{find_outputs_from_src, Recipe},
-        ParsingError,
-    },
-    selectors::SelectorConfig,
-    system_tools::SystemTools,
-    variant_config::{ParseErrors, VariantConfig},
-};
+use variant_config::{ParseErrors, VariantConfig};
 
 /// Returns the recipe path.
 pub fn get_recipe_path(path: &Path) -> miette::Result<PathBuf> {
@@ -177,13 +172,31 @@ pub async fn get_build_output(
     };
 
     let span = tracing::info_span!("Finding outputs from recipe");
-
     let enter = span.enter();
+
     // First find all outputs from the recipe
     let outputs = find_outputs_from_src(&recipe_text)?;
 
+    // Check if there is a `variants.yaml` file next to the recipe that we should
+    // potentially use.
+    let mut variant_configs;
+    let variant_configs = if let Some(variant_path) = recipe_path
+        .parent()
+        .map(|parent| parent.join(consts::VARIANTS_CONFIG_FILE))
+    {
+        if variant_path.is_file() {
+            variant_configs = args.variant_config.clone();
+            variant_configs.push(variant_path);
+            &variant_configs
+        } else {
+            &args.variant_config
+        }
+    } else {
+        &args.variant_config
+    };
+
     let variant_config =
-        VariantConfig::from_files(&args.variant_config, &selector_config).into_diagnostic()?;
+        VariantConfig::from_files(variant_configs, &selector_config).into_diagnostic()?;
 
     let outputs_and_variants =
         variant_config.find_variants(&outputs, &recipe_text, &selector_config)?;
@@ -416,7 +429,8 @@ pub async fn rebuild_from_args(
 ) -> miette::Result<()> {
     tracing::info!("Rebuilding {}", args.package_file.to_string_lossy());
     // we extract the recipe folder from the package file (info/recipe/*)
-    // and then run the rendered recipe with the same arguments as the original build
+    // and then run the rendered recipe with the same arguments as the original
+    // build
     let temp_folder = tempfile::tempdir().into_diagnostic()?;
 
     rebuild::extract_recipe(&args.package_file, temp_folder.path()).into_diagnostic()?;
@@ -586,7 +600,8 @@ pub fn sort_build_outputs_topologically(
             miette::miette!("The package '{}' was not found in the outputs", up_to)
         })?;
 
-        // Perform a DFS post-order traversal from the "up-to" node to find all dependencies
+        // Perform a DFS post-order traversal from the "up-to" node to find all
+        // dependencies
         let mut dfs = DfsPostOrder::new(&graph, up_to_index);
         let mut sorted_indices = Vec::new();
         while let Some(nx) = dfs.next(&graph) {