Auto merge of #9469 - PaulDance:fossil-local-settings, r=ehuss

Fix #4482 and #9449: set Fossil ignore and clean settings locally

This aims to close #4482 and close #9449.

Context: currently, the Fossil extension for `cargo new` would call `fossil settings [...]` in order to configure the created repository to ignore and allow cleaning the `target` build directory. However, as #9449 shows, it is ran from the CWD, which is probably outside of the repo, therefore it modifies global settings instead of local ones. This PR fixes that by writing the settings to local versioned files as the issue recommends.

Furthermore, as #9449 notes, configuring the repository's ignore settings only in `util::vcs::FossilRepo::init` means it is not done when the repository is not new and makes it harder to maintain equivalent support for VCS ignore system implementations. It also completely ignores the `--lib` CLI option which adds `Cargo.lock` to the ignore list for Git and Mercurial.

Therefore, the following modifications have been performed, using [the Fossil documentation](https://fossil-scm.org/home/doc/trunk/www/globs.md) as a reference for the ignore syntax:

 * All settings logic has been removed from `FossilRepo::init`.
 * `ops::cargo_new::IgnoreList::push` now requires a third argument for Fossil-specific glob syntax that is stored in a new `fossil_ignore` field.
 * `IgnoreList::format_new` uses the `fossil_ignore` field when needed just like any other VCS.
 * `IgnoreList::format_existing` handles Fossil separately for a few operations as its glob syntax does not support comments, so any lines starting with `#` cannot be included: the configurations can only be merged here.
 * `write_ignore_file` has been modified a bit as well to enable writing to two files for Fossil specifically in order to keep supporting its cleaning feature. The return type of the function is now `CargoResult<()>` instead `CargoResult<String>`: it makes the implementation easier and as the return value was actually not used, I figured it would be okay to do so, plus that return value would not make too much sense anymore for Fossil because of the two possibly different file contents.
 * `mk` has been updated to provide the correct ignore glob to `IgnoreList::push` for Fossil.

src/cargo/ops/cargo_new.rs

@@ -517,6 +517,8 @@ struct IgnoreList {
     ignore: Vec<String>,
     /// mercurial formatted entries
     hg_ignore: Vec<String>,
+    /// Fossil-formatted entries.
+    fossil_ignore: Vec<String>,
 }
 
 impl IgnoreList {
@@ -525,22 +527,25 @@ impl IgnoreList {
         IgnoreList {
             ignore: Vec::new(),
             hg_ignore: Vec::new(),
+            fossil_ignore: Vec::new(),
         }
     }
 
-    /// add a new entry to the ignore list. Requires two arguments with the
-    /// entry in two different formats. One for "git style" entries and one for
-    /// "mercurial like" entries.
-    fn push(&mut self, ignore: &str, hg_ignore: &str) {
+    /// Add a new entry to the ignore list. Requires three arguments with the
+    /// entry in possibly three different formats. One for "git style" entries,
+    /// one for "mercurial style" entries and one for "fossil style" entries.
+    fn push(&mut self, ignore: &str, hg_ignore: &str, fossil_ignore: &str) {
         self.ignore.push(ignore.to_string());
         self.hg_ignore.push(hg_ignore.to_string());
+        self.fossil_ignore.push(fossil_ignore.to_string());
     }
 
     /// Return the correctly formatted content of the ignore file for the given
     /// version control system as `String`.
     fn format_new(&self, vcs: VersionControl) -> String {
         let ignore_items = match vcs {
             VersionControl::Hg => &self.hg_ignore,
+            VersionControl::Fossil => &self.fossil_ignore,
             _ => &self.ignore,
         };
 
@@ -557,20 +562,30 @@ impl IgnoreList {
 
         let ignore_items = match vcs {
             VersionControl::Hg => &self.hg_ignore,
+            VersionControl::Fossil => &self.fossil_ignore,
             _ => &self.ignore,
         };
 
-        let mut out = "\n\n# Added by cargo\n".to_string();
-        if ignore_items
-            .iter()
-            .any(|item| existing_items.contains(item))
-        {
-            out.push_str("#\n# already existing elements were commented out\n");
+        let mut out = String::new();
+
+        // Fossil does not support `#` comments.
+        if vcs != VersionControl::Fossil {
+            out.push_str("\n\n# Added by cargo\n");
+            if ignore_items
+                .iter()
+                .any(|item| existing_items.contains(item))
+            {
+                out.push_str("#\n# already existing elements were commented out\n");
+            }
+            out.push('\n');
         }
-        out.push('\n');
 
         for item in ignore_items {
             if existing_items.contains(item) {
+                if vcs == VersionControl::Fossil {
+                    // Just merge for Fossil.
+                    continue;
+                }
                 out.push('#');
             }
             out.push_str(item);
@@ -584,30 +599,35 @@ impl IgnoreList {
 /// Writes the ignore file to the given directory. If the ignore file for the
 /// given vcs system already exists, its content is read and duplicate ignore
 /// file entries are filtered out.
-fn write_ignore_file(
-    base_path: &Path,
-    list: &IgnoreList,
-    vcs: VersionControl,
-) -> CargoResult<String> {
-    let fp_ignore = match vcs {
-        VersionControl::Git => base_path.join(".gitignore"),
-        VersionControl::Hg => base_path.join(".hgignore"),
-        VersionControl::Pijul => base_path.join(".ignore"),
-        VersionControl::Fossil => return Ok("".to_string()),
-        VersionControl::NoVcs => return Ok("".to_string()),
-    };
+fn write_ignore_file(base_path: &Path, list: &IgnoreList, vcs: VersionControl) -> CargoResult<()> {
+    // Fossil only supports project-level settings in a dedicated subdirectory.
+    if vcs == VersionControl::Fossil {
+        paths::create_dir_all(base_path.join(".fossil-settings"))?;
+    }
 
-    let ignore: String = match paths::open(&fp_ignore) {
-        Err(err) => match err.downcast_ref::<std::io::Error>() {
-            Some(io_err) if io_err.kind() == ErrorKind::NotFound => list.format_new(vcs),
-            _ => return Err(err),
-        },
-        Ok(file) => list.format_existing(BufReader::new(file), vcs),
-    };
+    for fp_ignore in match vcs {
+        VersionControl::Git => vec![base_path.join(".gitignore")],
+        VersionControl::Hg => vec![base_path.join(".hgignore")],
+        VersionControl::Pijul => vec![base_path.join(".ignore")],
+        // Fossil has a cleaning functionality configured in a separate file.
+        VersionControl::Fossil => vec![
+            base_path.join(".fossil-settings/ignore-glob"),
+            base_path.join(".fossil-settings/clean-glob"),
+        ],
+        VersionControl::NoVcs => return Ok(()),
+    } {
+        let ignore: String = match paths::open(&fp_ignore) {
+            Err(err) => match err.downcast_ref::<std::io::Error>() {
+                Some(io_err) if io_err.kind() == ErrorKind::NotFound => list.format_new(vcs),
+                _ => return Err(err),
+            },
+            Ok(file) => list.format_existing(BufReader::new(file), vcs),
+        };
 
-    paths::append(&fp_ignore, ignore.as_bytes())?;
+        paths::append(&fp_ignore, ignore.as_bytes())?;
+    }
 
-    Ok(ignore)
+    Ok(())
 }
 
 /// Initializes the correct VCS system based on the provided config.
@@ -650,12 +670,12 @@ fn mk(config: &Config, opts: &MkOptions<'_>) -> CargoResult<()> {
     let name = opts.name;
     let cfg = config.get::<CargoNewConfig>("cargo-new")?;
 
-    // Using the push method with two arguments ensures that the entries for
-    // both `ignore` and `hgignore` are in sync.
+    // Using the push method with multiple arguments ensures that the entries
+    // for all mutually-incompatible VCS in terms of syntax are in sync.
     let mut ignore = IgnoreList::new();
-    ignore.push("/target", "^target/");
+    ignore.push("/target", "^target/", "target");
     if !opts.bin {
-        ignore.push("Cargo.lock", "glob:Cargo.lock");
+        ignore.push("Cargo.lock", "glob:Cargo.lock", "Cargo.lock,*/Cargo.lock");
     }
 
     let vcs = opts.version_control.unwrap_or_else(|| {

src/cargo/util/vcs.rs

@@ -95,21 +95,6 @@ impl FossilRepo {
             .arg(db_fname)
             .exec()?;
 
-        // set `target` as ignoreable and cleanable
-        ProcessBuilder::new("fossil")
-            .cwd(cwd)
-            .arg("settings")
-            .arg("ignore-glob")
-            .arg("target")
-            .exec()?;
-
-        ProcessBuilder::new("fossil")
-            .cwd(cwd)
-            .arg("settings")
-            .arg("clean-glob")
-            .arg("target")
-            .exec()?;
-
         Ok(FossilRepo)
     }
 }