reuse arg flag parse logic in rustdoc handling

Author: RalfJung

cargo-miri/src/phases.rs

@@ -310,17 +310,17 @@ pub fn phase_rustc(mut args: impl Iterator<Item = String>, phase: RustcPhase) {
             let mut cmd = miri();
 
             // Ensure --emit argument for a check-only build is present.
-            // We cannot use the usual helpers since we need to check specifically in `env.args`.
-            if let Some(i) = env.args.iter().position(|arg| arg.starts_with("--emit=")) {
+            if let Some(val) = ArgFlagValueIter::new(env.args.clone().into_iter(), "--emit").next()
+            {
                 // For `no_run` tests, rustdoc passes a `--emit` flag; make sure it has the right shape.
-                assert_eq!(env.args[i], "--emit=metadata");
+                assert_eq!(val, "metadata");
             } else {
                 // For all other kinds of tests, we can just add our flag.
                 cmd.arg("--emit=metadata");
             }
 
             // Alter the `-o` parameter so that it does not overwrite the JSON file we stored above.
-            let mut args = env.args.clone();
+            let mut args = env.args;
             for i in 0..args.len() {
                 if args[i] == "-o" {
                     args[i + 1].push_str(".miri");
@@ -344,7 +344,7 @@ pub fn phase_rustc(mut args: impl Iterator<Item = String>, phase: RustcPhase) {
         return;
     }
 
-    if runnable_crate && ArgFlagValueIter::new("--extern").any(|krate| krate == "proc_macro") {
+    if runnable_crate && get_arg_flag_values("--extern").any(|krate| krate == "proc_macro") {
         // This is a "runnable" `proc-macro` crate (unit tests). We do not support
         // interpreting that under Miri now, so we write a JSON file to (display a
         // helpful message and) skip it in the runner phase.
@@ -568,7 +568,7 @@ pub fn phase_rustdoc(mut args: impl Iterator<Item = String>) {
 
     // Doctests of `proc-macro` crates (and their dependencies) are always built for the host,
     // so we are not able to run them in Miri.
-    if ArgFlagValueIter::new("--crate-type").any(|crate_type| crate_type == "proc-macro") {
+    if get_arg_flag_values("--crate-type").any(|crate_type| crate_type == "proc-macro") {
         eprintln!("Running doctests of `proc-macro` crates is not currently supported by Miri.");
         return;
     }

cargo-miri/src/util.rs

@@ -81,7 +81,7 @@ pub fn has_arg_flag(name: &str) -> bool {
 
 /// Determines how many times a `--flag` is present.
 pub fn num_arg_flag(name: &str) -> usize {
-    std::env::args().take_while(|val| val != "--").filter(|val| val == name).count()
+    env::args().take_while(|val| val != "--").filter(|val| val == name).count()
 }
 
 /// Yields all values of command line flag `name` as `Ok(arg)`, and all other arguments except
@@ -121,15 +121,15 @@ impl<I: Iterator<Item = String>> Iterator for ArgSplitFlagValue<'_, I> {
 }
 
 /// Yields all values of command line flag `name`.
-pub struct ArgFlagValueIter<'a>(ArgSplitFlagValue<'a, env::Args>);
+pub struct ArgFlagValueIter<'a, I>(ArgSplitFlagValue<'a, I>);
 
-impl<'a> ArgFlagValueIter<'a> {
-    pub fn new(name: &'a str) -> Self {
-        Self(ArgSplitFlagValue::new(env::args(), name))
+impl<'a, I: Iterator<Item = String>> ArgFlagValueIter<'a, I> {
+    pub fn new(args: I, name: &'a str) -> Self {
+        Self(ArgSplitFlagValue::new(args, name))
     }
 }
 
-impl Iterator for ArgFlagValueIter<'_> {
+impl<I: Iterator<Item = String>> Iterator for ArgFlagValueIter<'_, I> {
     type Item = String;
 
     fn next(&mut self) -> Option<Self::Item> {
@@ -141,9 +141,14 @@ impl Iterator for ArgFlagValueIter<'_> {
     }
 }
 
+/// Gets the values of a `--flag`.
+pub fn get_arg_flag_values<'a>(name: &'a str) -> impl Iterator<Item = String> + 'a {
+    ArgFlagValueIter::new(env::args(), name)
+}
+
 /// Gets the value of a `--flag`.
 pub fn get_arg_flag_value(name: &str) -> Option<String> {
-    ArgFlagValueIter::new(name).next()
+    get_arg_flag_values(name).next()
 }
 
 /// Escapes `s` in a way that is suitable for using it as a string literal in TOML syntax.
@@ -296,7 +301,7 @@ fn cargo_extra_flags() -> Vec<String> {
 
     // Forward `--config` flags.
     let config_flag = "--config";
-    for arg in ArgFlagValueIter::new(config_flag) {
+    for arg in get_arg_flag_values(config_flag) {
         flags.push(config_flag.to_string());
         flags.push(arg);
     }