separate function check_invalid_compression_with_non_archive_format

src/check.rs

@@ -3,13 +3,14 @@
 #![warn(missing_docs)]
 
 use std::{
+    ffi::OsString,
     ops::ControlFlow,
     path::{Path, PathBuf},
 };
 
 use crate::{
     error::FinalError,
-    extension::Extension,
+    extension::{build_archive_file_suggestion, Extension},
     info,
     utils::{pretty_format_list_of_paths, try_infer_extension, user_wants_to_continue, EscapedPathDisplay},
     warning, QuestionAction, QuestionPolicy, Result,
@@ -166,3 +167,59 @@ pub fn check_first_format_when_compressing<'a>(formats: &'a [Extension], output_
             .into()
     })
 }
+
+/// Check if compression is invalid because an archive format is necessary.
+pub fn check_invalid_compression_with_non_archive_format(
+    formats: &[Extension],
+    output_path: &Path,
+    files: &[PathBuf],
+    formats_from_flag: Option<&OsString>,
+) -> Result<()> {
+    let first_format = check_first_format_when_compressing(formats, output_path)?;
+
+    let is_some_input_a_folder = files.iter().any(|path| path.is_dir());
+    let is_multiple_inputs = files.len() > 1;
+
+    // If first format is not archive, can't compress folder, or multiple files
+    if !first_format.is_archive() && (is_some_input_a_folder || is_multiple_inputs) {
+        let first_detail_message = if is_multiple_inputs {
+            "You are trying to compress multiple files."
+        } else {
+            "You are trying to compress a folder."
+        };
+
+        let (from_hint, to_hint) = if let Some(formats) = formats_from_flag {
+            let formats = formats.to_string_lossy();
+            (
+                format!("From: --format {formats}"),
+                format!("To:   --format tar.{formats}"),
+            )
+        } else {
+            // This piece of code creates a suggestion for compressing multiple files
+            // It says:
+            // Change from file.bz.xz
+            // To          file.tar.bz.xz
+            let suggested_output_path = build_archive_file_suggestion(output_path, ".tar")
+                .expect("output path should contain a compression format");
+
+            (
+                format!("From: {}", EscapedPathDisplay::new(output_path)),
+                format!("To:   {suggested_output_path}"),
+            )
+        };
+        let output_path = EscapedPathDisplay::new(output_path);
+
+        let error = FinalError::with_title(format!("Cannot compress to '{output_path}'."))
+            .detail(first_detail_message)
+            .detail(format!(
+                "The compression format '{first_format}' does not accept multiple files.",
+            ))
+            .detail("Formats that bundle files into an archive are tar and zip.")
+            .hint(format!("Try inserting 'tar.' or 'zip.' before '{first_format}'."))
+            .hint(from_hint)
+            .hint(to_hint);
+
+        return Err(error.into());
+    }
+    Ok(())
+}

src/commands/mod.rs

@@ -14,7 +14,7 @@ use crate::{
     cli::Subcommand,
     commands::{compress::compress_files, decompress::decompress_file, list::list_archive_contents},
     error::{Error, FinalError},
-    extension::{self, build_archive_file_suggestion, parse_format},
+    extension::{self, parse_format},
     info,
     list::ListOptions,
     utils::{self, to_utf, EscapedPathDisplay, FileVisibilityPolicy},
@@ -59,54 +59,12 @@ pub fn run(
                 None => (None, extension::extensions_from_path(&output_path)),
             };
 
-            let first_format = check::check_first_format_when_compressing(&formats, &output_path)?;
+            check::check_invalid_compression_with_non_archive_format(
-
+                &formats,
-            let is_some_input_a_folder = files.iter().any(|path| path.is_dir());
+                &output_path,
-            let is_multiple_inputs = files.len() > 1;
+                &files,
-
+                formats_from_flag.as_ref(),
-            // If first format is not archive, can't compress folder, or multiple files
+            )?;
-            // Index safety: empty formats should be checked above.
-            if !first_format.is_archive() && (is_some_input_a_folder || is_multiple_inputs) {
-                let first_detail_message = if is_multiple_inputs {
-                    "You are trying to compress multiple files."
-                } else {
-                    "You are trying to compress a folder."
-                };
-
-                let (from_hint, to_hint) = if let Some(formats) = formats_from_flag {
-                    let formats = formats.to_string_lossy();
-                    (
-                        format!("From: --format {formats}"),
-                        format!("To:   --format tar.{formats}"),
-                    )
-                } else {
-                    // This piece of code creates a suggestion for compressing multiple files
-                    // It says:
-                    // Change from file.bz.xz
-                    // To          file.tar.bz.xz
-                    let suggested_output_path = build_archive_file_suggestion(&output_path, ".tar")
-                        .expect("output path should contain a compression format");
-
-                    (
-                        format!("From: {}", EscapedPathDisplay::new(&output_path)),
-                        format!("To:   {suggested_output_path}"),
-                    )
-                };
-                let output_path = EscapedPathDisplay::new(&output_path);
-
-                let error = FinalError::with_title(format!("Cannot compress to '{output_path}'."))
-                    .detail(first_detail_message)
-                    .detail(format!(
-                        "The compression format '{first_format}' does not accept multiple files.",
-                    ))
-                    .detail("Formats that bundle files into an archive are tar and zip.")
-                    .hint(format!("Try inserting 'tar.' or 'zip.' before '{first_format}'."))
-                    .hint(from_hint)
-                    .hint(to_hint);
-
-                return Err(error.into());
-            }
-
             check::check_archive_formats_position(&formats, &output_path)?;
 
             let output_file = match utils::ask_to_create_file(&output_path, question_policy)? {