Publish action wizard outputs without replacing existing files (#1805) (#1874)

crates/automation/src/a11y.rs

@@ -6,7 +6,7 @@ use serde_json::{Value, json};
 use sha2::{Digest, Sha256};
 use std::collections::BTreeSet;
 
-use crate::{Args, Automation, Result, ToolError, child, failed, unused, write_atomic};
+use crate::{Args, Automation, Result, ToolError, child, failed, write_atomic};
 
 mod documents;
 mod form_tools;

crates/automation/src/a11y/documents.rs

@@ -1,4 +1,4 @@
-use super::{Args, Automation, Result, ToolError, Value, child, failed, json, unused, write_atomic};
+use super::{Args, Automation, Result, ToolError, Value, child, failed, json, write_atomic};
 
 impl Automation {
     pub(crate) fn doc_export_office(&self, a: &Args) -> Result<Value> {
@@ -148,18 +148,7 @@ impl Automation {
                 .and_then(|bytes| run_on(&action, &name, std::sync::Arc::new(bytes), |_, _| {}));
             out.push(match result {
                 Ok(r) => {
-                    let target = child(&folder, &name);
-                    let target = if target.exists() {
-                        let stem =
-                            std::path::Path::new(&name).file_stem().map(|s| s.to_string_lossy().into_owned()).unwrap_or_else(|| "document".into());
-                        unused(&folder, &stem)
-                    } else {
-                        target
-                    };
-                    if target.exists() {
-                        return Err(failed(format!("{}: no unused output name available", target.display())));
-                    }
-                    write_atomic(&target, &r.bytes)?;
+                    let target = crate::batch::publish(&child(&folder, &name), &r.bytes)?;
                     json!({ "path": p, "output": target.to_string_lossy(), "log": r.log })
                 }
                 Err(e) => json!({ "path": p, "error": e }),

crates/automation/src/batch.rs

@@ -281,7 +281,7 @@ impl Automation {
 }
 
 /// Publish atomically without replacing any existing name, even if another writer wins a race.
-fn publish(target: &Path, bytes: &[u8]) -> Result<PathBuf> {
+pub(crate) fn publish(target: &Path, bytes: &[u8]) -> Result<PathBuf> {
     let dir = target.parent().ok_or_else(|| failed("output has no parent"))?;
     std::fs::create_dir_all(dir).map_err(failed)?;
     let mut temp = tempfile::NamedTempFile::new_in(dir).map_err(failed)?;

crates/automation/src/lib.rs

@@ -70,7 +70,7 @@ use pages::{DEFAULT_DPI, MAX_DPI, encode_png, rendered_content};
 use pages::{FIND_FIRST_BATCH, FIND_MAX_WARNING_BYTES, FIND_MAX_WARNINGS, extract_parallel};
 #[cfg(test)]
 pub(crate) use paths::MAX_INPUT;
-use paths::{child, lexical, unused, write_atomic};
+use paths::{child, lexical, write_atomic};
 pub(crate) use paths::{read_input, read_input_bytes};
 #[cfg(test)]
 use paths::{write_atomic_synced, write_atomic_with};

crates/automation/tests/it/automation.rs

@@ -8368,6 +8368,22 @@ fn action_run_keeps_outputs_with_duplicate_input_basenames() {
     assert_eq!(std::fs::read(first_path).unwrap(), first_bytes, "an earlier output must not be replaced");
 }
 
+#[cfg(unix)]
+#[test]
+fn action_run_never_replaces_an_entry_that_exists_check_misses() {
+    let dir = workdir("action-noclobber");
+    std::fs::create_dir_all(dir.join("results")).unwrap();
+    std::fs::write(dir.join("report.pdf"), fixture(1)).unwrap();
+    // A dangling link is invisible to `exists()` but is still an occupied name.
+    std::os::unix::fs::symlink(dir.join("nowhere.pdf"), dir.join("results/report.pdf")).unwrap();
+    let mut a = auto(&dir);
+    let args = json!({ "steps": [{ "step": "set_title", "arg": "Processed" }], "paths": ["report.pdf"], "folder": "results" });
+    let result = ok(&mut a, "action_run", args);
+    let output = result["files"][0]["output"].as_str().unwrap();
+    assert!(output.ends_with("report (2).pdf"), "{output}");
+    assert!(dir.join("results/report.pdf").symlink_metadata().unwrap().file_type().is_symlink(), "the existing entry must stay");
+}
+
 #[test]
 fn pdfa_through_tools() {
     let dir = workdir("pdfa");