cargo pgrx test --runas envar passing

Cargo.toml

@@ -65,6 +65,7 @@ owo-colors =  { version = "3.5", features = [ "supports-colors" ] } # for output
 proc-macro2 = { version = "1.0.78", features = [ "span-locations" ] }
 quote = "1.0.33"
 regex = "1.1" # used for build/test
+shlex = "1.3" # shell lexing, also used by many of our deps
 syn = { version = "2", features = [ "extra-traits", "full", "parsing" ] }
 toml = "0.8" # our config files
 thiserror = "1"

pgrx-pg-sys/Cargo.toml

@@ -55,10 +55,10 @@ pgrx-pg-config.workspace = true
 
 eyre.workspace = true
 proc-macro2.workspace = true
+shlex.workspace = true
 syn.workspace = true
 walkdir.workspace = true
 
 bindgen = { version = "0.69", default-features = false, features = ["runtime"] }
 clang-sys = { version = "1", features = ["clang_6_0", "runtime"] }
 quote = "1.0.33"
-shlex = "1.3" # shell lexing, also used by many of our deps

pgrx-tests/Cargo.toml

@@ -56,6 +56,7 @@ eyre.workspace = true
 libc.workspace = true
 owo-colors.workspace = true
 regex.workspace = true
+shlex.workspace = true
 thiserror.workspace = true
 
 paste = "1"

pgrx-tests/src/framework.rs

@@ -546,7 +546,30 @@ fn start_pg(loglines: LogLines) -> eyre::Result<String> {
         cmd.arg(postmaster_path);
         cmd
     } else if let Some(runas) = get_runas() {
+        #[inline]
+        fn accept_envar(var: &str) -> bool {
+            // taken from https://doc.rust-lang.org/cargo/reference/environment-variables.html
+            var.starts_with("CARGO")
+                || var.starts_with("RUST")
+                || var.starts_with("DEP_")
+                || ["OUT_DIR", "TARGET", "HOST", "NUM_JOBS", "OPT_LEVEL", "DEBUG", "PROFILE"]
+                    .contains(&var)
+        }
+
         let mut cmd = sudo_command(runas);
+
+        // when running the `postmaster` process via `sudo`, we need to copy the cargo/rust-related
+        // environment variables and pass as arguments to sudo, ahead of the `postmaster` command itself
+        //
+        // This ensures that in-process #[pg_test]s will see the `CARGO_xxx` envars they expect
+        for (var, value) in std::env::vars() {
+            if accept_envar(&var) {
+                let env_as_arg = format!("{var}={}", shlex::try_quote(&value)?);
+                cmd.arg(env_as_arg);
+            }
+        }
+
+        // now we can add the `postmaster` as the command for `sudo` to execute
         cmd.arg(postmaster_path);
         cmd
     } else {