fix: ignore comments and continuations in python lockfiles (#11035)

* fix: ignore comments and continuations in python lockfiles

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NVNKkWNGPuggLucMzFeoa1

* fix: warn when a lockfile's hash pins are not enforced

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NVNKkWNGPuggLucMzFeoa1

* fix: state only what the continuation warning can know

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01NVNKkWNGPuggLucMzFeoa1

---------

Co-authored-by: Claude Opus 5 (1M context) <noreply@anthropic.com>

backend/windmill-common/src/worker.rs

@@ -2512,6 +2512,42 @@ pub fn split_python_requirements<T: AsRef<str>>(requirements: T) -> Vec<String>
         .collect()
 }
 
+/// Byte offset of the comment marker, per pip's rule: a `#` at line start or preceded by
+/// whitespace. A `#` elsewhere belongs to the requirement (`pkg @ https://h/p.whl#sha256=…`).
+fn requirement_comment_start(line: &str) -> Option<usize> {
+    line.char_indices()
+        .find(|(i, c)| *c == '#' && (*i == 0 || line[..*i].ends_with(char::is_whitespace)))
+        .map(|(i, _)| i)
+}
+
+/// The installable requirement carried by one lockfile line, or `None` for a comment, a
+/// `-r`/`-e`/`--flag` directive, or a blank.
+///
+/// Windmill installs a lockfile one entry at a time as a `uv pip install` argument, so
+/// requirements-file syntax a file-level parser would absorb is an unparseable package name
+/// here and has to be stripped first.
+pub fn requirement_from_lockfile_line(line: &str) -> Option<&str> {
+    let requirement = match requirement_comment_start(line) {
+        Some(i) => &line[..i],
+        None => line,
+    }
+    .trim()
+    // Continuations are stripped, not joined: right for `--generate-hashes` locks, whose
+    // continued lines are `--hash=` flags this function drops, but a lock continuing onto a
+    // marker or extra would lose it.
+    .trim_end_matches('\\')
+    .trim_end();
+
+    (!requirement.is_empty() && !requirement.starts_with('-')).then_some(requirement)
+}
+
+/// Whether a lockfile line continues onto the next one. The continued lines reach the
+/// installer as entries of their own rather than being joined, so a caller that cares what
+/// they carried — `--hash=` pins, for a `--generate-hashes` lock — has to say so itself.
+pub fn lockfile_line_has_continuation(line: &str) -> bool {
+    line.trim_end().ends_with('\\')
+}
+
 #[derive(Eq, PartialEq, Clone, Copy, Default, Debug)]
 #[repr(u32)]
 pub enum PyVAlias {
@@ -2630,6 +2666,52 @@ mod tests {
         ids.iter().map(|s| s.to_string()).collect()
     }
 
+    /// Fixtures are verbatim `uv pip compile` output (uv 0.11.28): split and inline
+    /// annotation styles, and `--generate-hashes`.
+    #[test]
+    fn test_requirement_from_lockfile_line() {
+        assert_eq!(requirement_from_lockfile_line("    # via httpx"), None);
+        assert_eq!(requirement_from_lockfile_line("    # via"), None);
+        assert_eq!(requirement_from_lockfile_line("    #   anyio"), None);
+        assert_eq!(
+            requirement_from_lockfile_line("    # via -r .tmp/requirements.in"),
+            None
+        );
+        assert_eq!(
+            requirement_from_lockfile_line("anyio==4.15.1 \\"),
+            Some("anyio==4.15.1")
+        );
+        assert_eq!(
+            requirement_from_lockfile_line(
+                "    --hash=sha256:6152fdbbf9a77fdec97731721bebf7c4c44f7c29b424b0065826173efc7 \\"
+            ),
+            None
+        );
+        assert_eq!(requirement_from_lockfile_line("# py: 3.11"), None);
+        assert_eq!(requirement_from_lockfile_line("-r other.txt"), None);
+        assert_eq!(
+            requirement_from_lockfile_line("--index-url https://x"),
+            None
+        );
+        assert_eq!(requirement_from_lockfile_line("   "), None);
+        assert_eq!(
+            requirement_from_lockfile_line("httpx==0.27.0"),
+            Some("httpx==0.27.0")
+        );
+        assert_eq!(
+            requirement_from_lockfile_line("httpx==0.27.0  # via -r requirements.in"),
+            Some("httpx==0.27.0")
+        );
+        // A `#` not preceded by whitespace is part of the requirement, not a comment.
+        assert_eq!(
+            requirement_from_lockfile_line("wmill @ https://h/wmill.whl#sha256=abc"),
+            Some("wmill @ https://h/wmill.whl#sha256=abc")
+        );
+
+        assert!(lockfile_line_has_continuation("anyio==4.15.1 \\"));
+        assert!(!lockfile_line_has_continuation("anyio==4.15.1"));
+    }
+
     #[test]
     fn test_parse_job_oom_score_adj() {
         assert_eq!(parse_job_oom_score_adj(Some("300")), 300);

backend/windmill-worker/src/python_executor.rs

@@ -37,8 +37,9 @@ use windmill_common::{
     scripts::ScriptLang,
     utils::calculate_hash,
     worker::{
-        copy_dir_recursively, is_allowed_file_location, pad_string, split_python_requirements,
-        write_file, Connection, PyVAlias, PythonAnnotations, WORKER_CONFIG,
+        copy_dir_recursively, is_allowed_file_location, lockfile_line_has_continuation, pad_string,
+        requirement_from_lockfile_line, split_python_requirements, write_file, Connection,
+        PyVAlias, PythonAnnotations, WORKER_CONFIG,
     },
 };
 
@@ -227,9 +228,9 @@ fn filter_pip_local_dependencies(lines: Vec<String>) -> (Vec<String>, Vec<String
 /// `(kept, ignored)`. A line is ignored when it is not a `#` comment and matches any of
 /// `compiled_deps`. Kept separate from config/regex loading so it can be unit-tested.
 fn filter_lines_by_deps(lines: Vec<String>, compiled_deps: &[Regex]) -> (Vec<String>, Vec<String>) {
-    let (ignored, kept): (Vec<String>, Vec<String>) = lines
-        .into_iter()
-        .partition(|s| !s.starts_with('#') && compiled_deps.iter().any(|dep| dep.is_match(s)));
+    let (ignored, kept): (Vec<String>, Vec<String>) = lines.into_iter().partition(|s| {
+        !s.trim_start().starts_with('#') && compiled_deps.iter().any(|dep| dep.is_match(s))
+    });
 
     (kept, ignored)
 }
@@ -2520,11 +2521,23 @@ pub async fn handle_python_reqs(
     // Find out if there is already cached dependencies
     // If so, skip them
     let mut in_cache = vec![];
+    if requirements
+        .iter()
+        .any(|r| lockfile_line_has_continuation(r))
+    {
+        tracing::warn!(workspace_id = %w_id, job_id = %job_id, "lockfile continues entries across lines; the continued lines are dropped");
+        append_logs(
+            job_id,
+            w_id,
+            "\n[!] lockfile continues entries across lines and the continued lines are dropped: `--hash=` pins, extras and markers written that way do not apply\n".to_string(),
+            conn,
+        )
+        .await;
+    }
     for req in &requirements {
-        // Ignore python version annotation backed into lockfile
-        if req.starts_with('#') || req.starts_with('-') || req.trim().is_empty() {
+        let Some(req) = requirement_from_lockfile_line(req) else {
             continue;
-        }
+        };
         let py_prefix = &py_version.to_cache_dir(false);
 
         let venv_p = format!(