Warn if using hash in git URL, Fixes #8241

src/cargo/util/toml/mod.rs

@@ -1661,6 +1661,17 @@ impl DetailedTomlDependency {
                     .or_else(|| self.rev.clone().map(GitReference::Rev))
                     .unwrap_or_else(|| GitReference::Branch("master".to_string()));
                 let loc = git.into_url()?;
+
+                if let Some(fragment) = loc.fragment() {
+                    let msg = format!(
+                        "URL fragment `#{}` in git URL is ignored for dependency ({}). \
+                        If you were trying to specify a specific git revision, \
+                        use `rev = \"{}\"` in the dependency declaration.",
+                        fragment, name_in_toml, fragment
+                    );
+                    cx.warnings.push(msg)
+                }
+
                 SourceId::for_git(&loc, reference)?
             }
             (None, Some(path), _, _) => {

tests/testsuite/bad_config.rs

@@ -861,6 +861,36 @@ This will be considered an error in future versions
         .run();
 }
 
+#[cargo_test]
+fn fragment_in_git_url() {
+    let p = project()
+        .file(
+            "Cargo.toml",
+            r#"
+            [package]
+            name = "foo"
+            version = "0.0.0"
+            authors = []
+
+            [dependencies.bar]
+            git = "http://127.0.0.1#foo"
+        "#,
+        )
+        .file("src/lib.rs", "")
+        .build();
+
+    p.cargo("build -v")
+        .with_status(101)
+        .with_stderr_contains(
+            "\
+[WARNING] URL fragment `#foo` in git URL is ignored for dependency (bar). \
+If you were trying to specify a specific git revision, \
+use `rev = \"foo\"` in the dependency declaration.
+",
+        )
+        .run();
+}
+
 #[cargo_test]
 fn bad_source_config1() {
     let p = project()