fix!: Remove --upgrade <policy> support

In preparing `cargo-add` for upstreaming into cargo, this feature felt
far enough from being ready that it didn't seem worth putting behind a
feature flag.

The policy names don't map well to what Rust developers are used to
(operator characters) and the policy name for ^ isn't correct, calling
it `minor`.

Removing it seems acceptable because
- Most people use the default policy and we should generally be
  encouraging that because too often people try to out smart the default
  policy and things break.
- Redundant with `--vers <req>` and `<name>@<req>` except when no
  version is specified and cargo-add looks up the latest. If someone does
  want to specify it, they are most likely to specify = which means they
  probably have a reason and a specific version in mind rather than
  "latest".

src/bin/add/args.rs

@@ -108,21 +108,6 @@ pub struct Args {
     )]
     pub pkgid: Option<String>,
 
-    /// Choose method of semantic version upgrade.  Must be one of "none" (exact version, `=`
-    /// modifier), "patch" (`~` modifier), "minor" (`^` modifier), "all" (`>=`), or "default" (no
-    /// modifier).
-    #[clap(
-        long,
-        value_name = "METHOD",
-        possible_value = "none",
-        possible_value = "patch",
-        possible_value = "minor",
-        possible_value = "all",
-        possible_value = "default",
-        default_value = "default"
-    )]
-    pub upgrade: String,
-
     /// Include prerelease versions when fetching from crates.io (e.g.
     /// '0.6.0-alpha').
     #[clap(long)]
@@ -223,11 +208,8 @@ impl Args {
                         p.manifest_path.parent().map(|p| p.as_std_path())
                             == Some(dep_path.as_path())
                     }) {
-                        let v = format!(
-                            "{prefix}{version}",
-                            prefix = self.get_upgrade_prefix(),
-                            version = package.version
-                        );
+                        let op = "";
+                        let v = format!("{op}{version}", op = op, version = package.version);
 
                         dependency = dependency.set_version(&v);
                     }
@@ -283,11 +265,8 @@ impl Args {
                         );
                         // dev-dependencies do not need the version populated
                         if !self.dev {
-                            let v = format!(
-                                "{prefix}{version}",
-                                prefix = self.get_upgrade_prefix(),
-                                version = package.version
-                            );
+                            let op = "";
+                            let v = format!("{op}{version}", op = op, version = package.version);
                             dependency = dependency.set_version(&v);
                         }
                     } else {
@@ -297,9 +276,10 @@ impl Args {
                             &manifest_path,
                             Some(&registry_url),
                         )?;
+                        let op = "";
                         let v = format!(
-                            "{prefix}{version}",
-                            prefix = self.get_upgrade_prefix(),
+                            "{op}{version}",
+                            op = op,
                             // If version is unavailable `get_latest_dependency` must have
                             // returned `Err(FetchVersionError::GetVersion)`
                             version = dependency.version().unwrap_or_else(|| unreachable!())
@@ -357,17 +337,6 @@ impl Args {
             })
             .collect()
     }
-
-    fn get_upgrade_prefix(&self) -> &'static str {
-        match self.upgrade.as_ref() {
-            "default" => "",
-            "none" => "=",
-            "patch" => "~",
-            "minor" => "^",
-            "all" => ">=",
-            _ => unreachable!(),
-        }
-    }
 }
 
 #[cfg(test)]
@@ -388,7 +357,6 @@ impl Default for Args {
             optional: false,
             manifest_path: None,
             pkgid: None,
-            upgrade: "minor".to_string(),
             allow_prerelease: false,
             features: None,
             no_default_features: false,

tests/cmd/add/dev_build_conflict.toml

@@ -6,7 +6,7 @@ stderr = """
 error: The argument '--dev' cannot be used with '--build'
 
 USAGE:
-    cargo add --dev --upgrade <METHOD> <CRATE>...
+    cargo add --dev <CRATE>...
 
 For more information try --help
 """

tests/cmd/add/git_conflicts_path.toml

@@ -6,7 +6,7 @@ stderr = """
 error: The argument '--git <URI>' cannot be used with '--path <PATH>'
 
 USAGE:
-    cargo add --git <URI> --upgrade <METHOD> <CRATE>...
+    cargo add --git <URI> <CRATE>...
 
 For more information try --help
 """

tests/cmd/add/git_conflicts_registry.toml

@@ -6,7 +6,7 @@ stderr = """
 error: The argument '--git <URI>' cannot be used with '--registry <REGISTRY>'
 
 USAGE:
-    cargo add --git <URI> --upgrade <METHOD> <CRATE>...
+    cargo add --git <URI> <CRATE>...
 
 For more information try --help
 """

tests/cmd/add/git_conflicts_vers.toml

@@ -6,7 +6,7 @@ stderr = """
 error: The argument '--git <URI>' cannot be used with '--vers <URI>'
 
 USAGE:
-    cargo add --git <URI> --upgrade <METHOD> <CRATE>...
+    cargo add --git <URI> <CRATE>...
 
 For more information try --help
 """

tests/cmd/add/registry_conflicts_path.toml

@@ -6,7 +6,7 @@ stderr = """
 error: The argument '--registry <REGISTRY>' cannot be used with '--path <PATH>'
 
 USAGE:
-    cargo add --registry <REGISTRY> --upgrade <METHOD> <CRATE>...
+    cargo add --registry <REGISTRY> <CRATE>...
 
 For more information try --help
 """