WIP: [offline] Remove sqlx-data.json and sqlx prepare command

Query data is now stored in .sqlx/{query_hash}.json directly by the macro
invocations, rather than first writing to target/sqlx/{input_span_hash}.json
and then collecting those into sqlx-data.json separately.

sqlx-cli/src/cargo.rs

@@ -0,0 +1,47 @@
+use anyhow::Context;
+use serde::Deserialize;
+use std::env;
+use std::ffi::{OsStr, OsString};
+use std::path::PathBuf;
+use std::process::Command;
+use std::str;
+
+#[derive(Deserialize)]
+pub struct CargoMetadata {
+    pub target_directory: PathBuf,
+    pub workspace_root: PathBuf,
+}
+
+/// Path to the `cargo` executable
+pub fn cargo_path() -> anyhow::Result<OsString> {
+    env::var_os("CARGO").context("Failed to obtain value of `CARGO`")
+}
+
+pub fn manifest_dir(cargo: &OsStr) -> anyhow::Result<PathBuf> {
+    let stdout = Command::new(&cargo)
+        .args(&["locate-project", "--message-format=plain"])
+        .output()
+        .context("could not locate manifest dir")?
+        .stdout;
+
+    let mut manifest_path: PathBuf = str::from_utf8(&stdout)
+        .context("output of `cargo locate-project` was not valid UTF-8")?
+        // get rid of the trailing newline
+        .trim()
+        .into();
+
+    manifest_path.pop();
+
+    Ok(manifest_path)
+}
+
+pub fn metadata(cargo: &OsStr) -> anyhow::Result<CargoMetadata> {
+    let output = Command::new(&cargo)
+        .args(&["metadata", "--format-version=1"])
+        .output()
+        .context("Could not fetch metadata")?;
+
+    serde_json::from_slice(&output.stdout)
+        .context("Invalid `cargo metadata` output")
+        .map_err(Into::into)
+}

sqlx-cli/src/lib.rs

@@ -2,6 +2,12 @@ use anyhow::Result;
 
 use crate::opt::{Command, DatabaseCommand, MigrateCommand};
 
+use anyhow::{anyhow, Context};
+use dotenv::dotenv;
+use prepare::PrepareCtx;
+use std::env;
+
+mod cargo;
 mod database;
 // mod migration;
 // mod migrator;
@@ -51,18 +57,36 @@ pub async fn run(opt: Opt) -> Result<()> {
         },
 
         Command::Prepare {
-            check: false,
-            merged,
-            args,
+            check,
+            workspace,
             database_url,
-        } => prepare::run(&database_url, merged, args)?,
-
-        Command::Prepare {
-            check: true,
-            merged,
             args,
-            database_url,
-        } => prepare::check(&database_url, merged, args)?,
+        } => {
+            let cargo_path = cargo::cargo_path()?;
+            println!("cargo path: {:?}", cargo_path);
+
+            let manifest_dir = cargo::manifest_dir(&cargo_path)?;
+            let metadata = cargo::metadata(&cargo_path)
+                .context("`prepare` subcommand may only be invoked as `cargo sqlx prepare`")?;
+
+            let ctx = PrepareCtx {
+                workspace,
+                cargo: cargo_path,
+                cargo_args: args,
+                manifest_dir,
+                target_dir: metadata.target_directory,
+                workspace_root: metadata.workspace_root,
+                database_url,
+            };
+
+            println!("{:?}", ctx);
+
+            if check {
+                prepare::check(&ctx)?
+            } else {
+                prepare::run(&ctx)?
+            }
+        }
     };
 
     Ok(())

sqlx-cli/src/opt.rs

@@ -27,17 +27,20 @@ pub enum Command {
         #[clap(long)]
         check: bool,
 
-        /// Generate a single top-level `sqlx-data.json` file when using a cargo workspace.
+        /// Do a clean build of all crates in the workspace.
+        ///
+        /// This option is intended for workspaces where multiple crates use SQLx; if there is only
+        /// one, it is better to run `cargo sqlx prepare` without this option inside of that crate.
         #[clap(long)]
-        merged: bool,
+        workspace: bool,
 
         /// Arguments to be passed to `cargo rustc ...`.
         #[clap(last = true)]
         args: Vec<String>,
 
         /// Location of the DB, by default will be read from the DATABASE_URL env var
-        #[clap(long, short = 'D', env)]
-        database_url: String,
+        #[clap(long, short = 'D')]
+        database_url: Option<String>,
     },
 
     #[clap(alias = "mig")]